KR101449513B1 - Motor Driving Apparatus Having Power Return Function and Driving Method thereof - Google Patents

Abstract

The present invention relates to a motor-driving apparatus having a power return function, and a motor-driving method. The motor-driving apparatus can improve the efficiency and reduce the power consumption of a motor by converting back-electromotive force into AC, wherein the back-electromotive force is generated at the motor by the rotational energy of a rotator load with strong inertia when deceleration is made in order to change the rotational speed or rotational direction of the motor connected to the rotator load, and returning the AC to an AC power source; and can minimize a heat-releasing structure by minimizing the energy consumed by the motor, thus minimizing heat generation at the motor. According to the present invention, the motor-driving method comprises: an AC-DC conversion step of converting AC power supplied from an AC power source into DC and immediately boosting the DC and charging a first capacitor with the boosted DC; a DC-DC conversion step of down-converting the voltage of the first capacitor into an operating voltage (Vcc) of an inverter which drives the motor, and outputting the operating voltage; and a step of generating three-phase AC power required to drive the motor by the inverter using the operating voltage (Vcc), and applying the three-phase AC power to a three-phase stator coil of the motor. The motor-driving method converts back-electromotive force (BEMF) generated at the motor when the motor decelerates into DC, and returns power using DC-AC conversion.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a motor driving apparatus having a power return function,

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a motor driving apparatus having a power return function and a driving method thereof, and more particularly, to a motor driving apparatus having a power return function, (AC) generated by the motor due to the rotational energy of the motor is converted to alternating current (AC) and returned to the AC power source side. As a result, the efficiency of the motor can be increased and the power consumption can be reduced. To a motor driving apparatus having a power returning function capable of minimizing a heat dissipation structure and minimizing a heat dissipation structure, and a driving method thereof.

With growing interest in green energy, interest in renewable energy is increasing day by day. Methods for utilizing regenerative energy in various fields have been studied.

A motor, also called an electric motor or a prime mover, is a device that converts electrical energy into mechanical energy, which is estimated to account for about 60% of the total electric power consumption in Korea and about 70% of the electric power consumption in the industrial sector.

Motors dig deep into electrical appliances in almost every corner of our life, from the most common appliances of refrigerators, washing machines, dishwashers, to life appliances such as vending machines, water purifiers, food processors, medical and exercise devices , Copiers, printers, and other office equipment, as well as industrial appliances.

The high efficiency of the motor, which accounts for more than 60% of the total power consumption, is an indispensable factor in promoting energy efficiency. Therefore, there is a need for a study on a method for generating a regenerative energy in such a motor, thereby achieving high efficiency of the motor and saving energy.

The efficiency improvement of the motor is mainly performed in a motor applied to a vehicle such as a fuel cell vehicle or a fuel cell / battery hybrid vehicle, a train car, and a tower crane.

For example, if a permanent magnet synchronous motor used in a fuel cell vehicle or a fuel cell / battery hybrid vehicle drive system rotates at high speed and does not send an IGBT (Insulated Gate Bipolar Transistor) gate signal to the inverter due to a control board abnormality, Is operated as a generator. However, since the voltage generated from the generator at this time is not regulated at all, this is referred to as a UCG (uncontrolled generator) mode. In this case, since weak field control to apply the d-phase current in the reverse direction is not performed, not only a high counter-electromotive voltage appears at the terminal on the motor side but also the current is regenerated in the capacitor and the DC link voltage is rapidly increased.

Particularly, such a sudden change in the counter-electromotive force can be an important consideration in designing an electric automobile motor design and drive system having a wide variable range of speed. In order to solve this problem, in an industrial motor drive inverter system, dynamic braking ) Circuit is installed at the DC link voltage terminal and the regenerative energy generated in the UCG situation is consumed to the negative voltage terminal through the discharging resistor and the IGBT switch when the voltage exceeds the certain voltage, have.

In addition, in the variable speed drive of the large-capacity electric motor, when the electric motor rotates with a load having a large inertia, the amount of electric energy to be re-generated from the AC electric motor to the DC electric power by the inertia is very large . Accordingly, in order to prevent insulation breakdown in the capacitor due to excessive energy returning to the capacitor charging the DC voltage by reverse power generation, a chopper and a resistor are connected in series at both ends of the DC link voltage to return to the DC link And the overvoltage is consumed as electric energy from the resistance as heat energy.

However, the above-mentioned conventional regenerative energy control apparatus and method use a method of protecting the motor and the inverter by consuming the regenerative energy generated in the UCG situation as a negative voltage terminal through the discharging resistor and the IGBT switch when the voltage exceeds a predetermined voltage Therefore, the regenerative energy generated in the UCG situation is consumed through the discharge resistor, and unnecessary energy is consumed, resulting in a low energy efficiency as a whole.

In consideration of the problems of the prior art, Korean Patent Laid-Open No. 10-2005-56585 discloses a technique of using the basic dynamic braking structure as it is, not consuming the energy generated during regeneration and burning through discharge resistance, The present invention also provides a regenerative energy control apparatus and method for a motor drive system that can improve energy efficiency by recharging energy of a secondary battery by lowering a voltage level regenerated at a DC link voltage terminal, have.

Generally, DBU (Dynamic Braking Unit) type system which consumes the counter electromotive force generated when the motor is braked or excited by the braking resistor by using the inverter is used for the speed control of the crane and the suppression of the motor starting current .

In the DBU system, the voltage of the DC link rises due to the regenerative energy generated during the acceleration and deceleration of the motor, thereby giving a great stress to the inverter due to stress on the IGBT and the capacitor. , A braking unit is used to dissipate energy using resistors to prevent these symptoms.

In addition, the DBU system must always be accompanied by a large-volume resistance box, and there is a thermal problem, and the purchase cost is low, but the space cost and installation cost must be considered.

Furthermore, in the DBU system, there is a problem that energy is generated in terms of energy recycling by thermally consuming energy generated through a motor using a resistor.

In consideration of the above-mentioned problem of the DBU system, Korean Patent Laid-Open No. 10-2011-129098 discloses that the regenerative energy generated when the motor for driving the crane is braked is not consumed by the braking resistor, A power regenerative energy system is proposed to be used as a power source of an electric apparatus.

To this end, the power regenerative energy system includes a power unit for receiving AC AC power and converting it into DC power and supplying driving power to each component; An inverter including a series reactor that suppresses a fault current generated in the motor and outputs a DC voltage; A power regeneration unit rectifying the DC voltage input through the series reactor of the inverter to have a preset constant level and outputting the rectified voltage to the power unit with regenerative power; And an AC reactor that adjusts the voltage difference between the rectified output voltage of the power regeneration unit and the three-phase bus line to have a predetermined voltage difference and outputs the rectified output voltage to the motor.

In addition, when the tower crane is tilted or when the driving operation is decelerated, the electric energy generated by the inverse driving of the driving motor is converted into thermal energy through the resistor to be discarded into the atmosphere, resulting in waste of energy, Thereby contributing to environmental destruction. Especially, in the case of construction equipment having a height as high as a tower crane, the waste of energy and the environmental destruction due to the principle can be severe.

Korean Patent Laid-Open No. 10-2012-0017659 discloses a technique for recovering electric energy generated by reverse rotation of a drive motor when the tower crane is tilted or when the vehicle is decelerated in a turning operation. A first converting unit for converting electric energy generated by the driving motor; A second converting unit that supplies electric energy converted by the first converting unit to a power source and regenerates the electric energy; An electric energy regenerating device of a tower crane including a crane is proposed.

In Korean Patent Laid-Open Publication No. 10-2012-0017659, the three-phase AC input from the power source is rectified by the diode of the IGBT element of the second conversion section when the tower crane is hoisted or the hoisting operation is accelerated, When the three-phase AC input is unstable when the constant-voltage current charged in the capacitor is applied to the IGBT element of the first converter, the output of the first converter operating as an inverter also becomes unstable.

In addition, alternating current generated by a driving motor that operates as a generator when the tower crane is tilted or when the vehicle is decelerating is converted into a direct current by the first converting unit to be charged into the capacitor with a constant voltage current, and the constant- 2 conversion unit is converted into an alternating current and regenerated as a power source, it is impossible to ensure that the constant voltage charged in the capacitor is set higher than the power source, so that there is a problem that effective power can not be returned.

On the other hand, in a conventional motor driving apparatus for a washing machine using a BLDC motor as a motor for a washing machine, a DC voltage obtained by full-wave rectification from an AC power source is subjected to a smoothing process using a capacitor to remove ripples, And is supplied to the power source (Vcc) to drive the BLDC motor to rotate the washing tub.

The above-described conventional motor driving apparatus for a washing machine drives a BLDC motor by a power source applied to an AC power line. That is, power is applied only to the motor in the AC power line.

That is, in such a conventional motor drive apparatus, the energy applied to the motor side from the AC power supply line is eventually supplied to the driver circuit to which the motor is attached. This energy can be delivered as rotational energy to the washing machine, with motor losses, motor losses, and mechanical losses in the power transmission to transfer power between the motor and the washing machine. The energy configuration can be expressed as shown in FIG.

The recirculation type washing machine has a washing mode by an operation of rotating an inertial object. In such a washing mode, it is required to continuously repeat acceleration and deceleration of the washing tub. These acceleration and deceleration are realized by using a motor. That is, as the rotation speed of the motor is accelerated, the rotation speed of the washing tub is accelerated. In the deceleration, the rotation torque of the washing tub is consumed by the motor to achieve a desired deceleration. As described above, the electric energy in the acceleration and deceleration processes is consumed as heat in the motor, the driver, and the mechanical part (i.e., the power transmitting part) as shown in Fig.

In Fig. 2, the energy transmitted to the washing tub by the motor accelerates the washing tub, and the rotating force of the accelerated washing tub must decelerate the washing tub when decelerating. However, such a deceleration is mainly consumed by the motor as shown in FIG. 2, so that the washing tub is rapidly decelerated, and the water in the inner inertia is rubbed against the laundry to be washed.

The energy thus consumed eventually leads to the temperature rise of the motor. That is, even if the efficiency is high, most of the energy finally supplied to the motor is consumed by the washing mode characteristic of the washing machine, thereby raising the temperature of the motor.

Therefore, in order to solve this problem, as described above, energy consumed by the motor is consumed thermally in a resistor by employing a dynamic braking circuit and a discharging resistor (or a braking resistor) in the driver.

Such a configuration is a method widely used in a large-sized motor. The overall system efficiency is low, and a large resistance box must be provided. In addition, in a washing machine having frequent acceleration and deceleration, power consumption of the entire system is increased.

On the other hand, the washing mode in the washing machine can be realized by repeatedly rotating the washing tub in the forward / reverse direction at a predetermined low speed rpm. Even in this case, since the acceleration, deceleration, stop and direction switching operation of the motor for driving the washing tub is required, a large amount of energy is consumed in the motor similarly to the above.

In this prior art, it is preferable to provide an air-cooling vent hole in the rotor and the stator support to eliminate the heat of the stator and the rotor of the motor, and a heat sink for cooling the switching element constituting the inverter of the driver is adopted .

Therefore, there is a problem that the noise level is increased by employing the structure for cooling the motor, and the size of the heat sink increases with the increase of the capacity of the motor, which increases the size of the driver.

Patent Document 1: Korean Patent Publication No. 10-2005-56585 Patent Document 2: Korean Patent Laid-Open No. 10-2011-129098 Patent Document 3: Korean Patent Publication No. 10-2012-0017659

SUMMARY OF THE INVENTION The present invention has been conceived to solve the problems of the conventional art described above, and it is a first object of the present invention to provide a rotation control apparatus and a control method thereof, By converting the back electromotive force generated from the motor by the energy into AC (AC) and returning it to the AC power side, it is possible to increase the efficiency of the motor and to reduce the power consumption and to minimize the heat generation of the motor by minimizing the energy consumed by the motor A motor driving apparatus having a power return function capable of minimizing a heat dissipation structure, and a driving method thereof.

The second object of the present invention is to return the regenerative energy generated at the time of deceleration of the BLDC motor to the AC power source side, thereby minimizing the energy consumed by the motor, thereby minimizing the heat generation of the motor, And a method of driving the same.

A third object of the present invention is to provide a rectifying function for converting AC power into DC when operating in one direction, a boost-up function for boosting the voltage of DC to a desired voltage and outputting the DC voltage, And a bidirectional AC / DC converter for converting the AC power to AC and returning it to the AC side, and a driving method thereof.

A fourth object of the present invention is to provide a bidirectional AC / DC converter having a power factor correcting function for increasing a power factor of a system by synchronizing an AC current with an input voltage when performing a rectifying function of converting AC power into DC And a method of driving the motor drive apparatus.

A fifth object of the present invention is to provide a DC / DC converter between a bidirectional AC / DC converter and an inverter to step down a high voltage DC voltage generated from a bidirectional AC / DC converter to a low- Voltage DC voltage generated at the time of deceleration of the BLDC motor to a sufficiently high high-voltage DC voltage so that the regenerative energy can be efficiently returned to the AC power source through the bidirectional AC / DC converter, And to provide a motor driving apparatus having a power return function capable of raising the driving efficiency of the motor in a section and a driving method thereof.

A sixth object of the present invention is to provide a DC / DC converter and a DC / DC converter which includes a charging capacitor between a bidirectional AC / DC converter and a DC / DC converter to suppress ripple of a DC voltage generated from a bidirectional AC / And to provide a motor driving apparatus capable of stably supplying a stable voltage even in an unstable input voltage region and a driving method thereof.

A seventh object of the present invention is to provide a DC / DC converter that controls a modulation ratio in a PWM manner between a bidirectional AC / DC converter and an inverter, and adjusts a DC voltage applied to the inverter at a constant speed of the BLDC motor, And the DC voltage generated at the time of deceleration of the BLDC motor is prevented from being unnecessarily applied to the charging capacitor at a high voltage, and a driving method thereof.

The eighth object of the present invention is to provide a motor control apparatus and a motor control method thereof, which can control a speed of a motor by controlling a DC voltage applied to an inverter by a PWM controlled DC / DC converter, thereby lowering a PWM voltage (frequency) The present invention provides a motor driving apparatus capable of suppressing copying and a driving method thereof.

A ninth object of the present invention is to provide a motor drive device capable of easily starting a motor by controlling a duty ratio of a PWM-controlled DC / DC converter to lower a voltage and increasing a current required for starting a stopped motor, And to provide a driving method thereof.

According to a tenth aspect of the present invention, there is provided a washing machine, comprising: an AC power source for converting rotation energy of a washing tub into alternating current (AC) according to deceleration when accelerating and decelerating the washing tub to periodically rotate forward and backward, To thereby improve the efficiency of the washing machine motor, and a driving method thereof.

In order to achieve the above object, the present invention provides a motor drive apparatus for driving a motor connected to a load and for returning a counter electromotive force (BEMF) generated from a motor to the AC power source when deceleration of the motor occurs, DC-converted AC power is output to the rear end, and when a DC voltage higher than the peak voltage of the AC power source is applied at the rear end to return the back electromotive force (BEMF) generated at the time of deceleration of the motor to the AC power source side, A bidirectional AC / DC converter for performing AC conversion; A first capacitor charged with an AC-DC converted DC voltage through the bidirectional AC / DC converter; The high voltage charged in the first capacitor is lowered to the operating voltage Vcc of the inverter driving the motor and the DC voltage applied at the subsequent stage is boosted to a voltage higher than the peak voltage of the AC power source side to charge the first capacitor A bidirectional DC / DC converter; And a DC voltage supplied from the bidirectional DC / DC converter as an operation power source (Vcc) to generate AC power required to drive the motor and apply the generated AC power to the stator coil of the motor. And an inverter for converting the generated counter electromotive force (BEMF) to DC and delivering it to the bidirectional DC / DC converter.

According to another aspect of the present invention, there is provided an AC-DC conversion step of charging an AC power supplied from an AC power source side to a first capacitor by simultaneously boosting AC-DC conversion; A DC-DC conversion step of dropping the voltage charged in the first capacitor to a voltage Vcc of the inverter driving the motor and outputting the voltage; And generating three-phase AC power necessary for driving the motor in the inverter using the operation power source (Vcc) and applying the generated three-phase AC power to the three-phase stator coil of the motor, wherein when the motor decelerates, And converting the generated back electromotive force (BEMF) into DC, and then returning power by DC-AC conversion.

According to another aspect of the present invention, there is provided an AC-DC conversion step of charging an AC power supplied from an AC power source side to a first capacitor by simultaneously boosting AC-DC conversion in a bidirectional AC / DC converter; A DC-DC conversion step of outputting the voltage charged in the first capacitor by reducing the voltage of the bidirectional DC / DC converter to the operating power supply (Vcc) of the inverter driving the motor; And generating three-phase AC power necessary for driving the motor in the inverter using the operation power source (Vcc) and applying the generated three-phase AC power to the three-phase stator coil of the motor, wherein when the motor decelerates, The bidirectional DC / DC converter converts the generated back electromotive force (BEMF) from the inverter to DC, boosts the DC voltage applied from the inverter to a voltage higher than the peak voltage of the AC power source and charges the first capacitor, DC converter converts power from the AC power source to the AC power source by DC-AC conversion.

According to another aspect of the present invention, there is provided an AC-DC conversion step of charging an AC power supplied from an AC power source side to a first capacitor by simultaneously boosting AC-DC conversion in a bidirectional AC / DC converter; A DC-DC conversion step of outputting the voltage charged in the first capacitor by reducing the voltage of the bidirectional DC / DC converter to the operating power supply (Vcc) of the inverter driving the motor; And generating three-phase AC power necessary for driving the motor in the inverter using the operating power source (Vcc) and applying the three-phase AC power to the three-phase stator coil of the motor, wherein when the motor decelerates, The bidirectional DC / DC converter converts the generated back electromotive force (BEMF) from the inverter to DC, boosts the DC voltage applied from the inverter to a voltage higher than the peak voltage of the AC power source and charges the first capacitor, DC converter converts power from the AC power source to the AC power source by DC-AC conversion.

As described above, in the present invention, when the rotation speed of the motor connected to a large rotational load such as a washing machine is changed and a deceleration is generated for changing the rotational direction, the counter electromotive force generated from the motor by the rotational energy of the rotational load is converted into alternating current AC) and returning it to the AC power source side, the efficiency of the motor can be increased and the power consumption can be reduced.

In addition, in the present invention, by returning the counter electromotive force (i.e., regenerative energy) generated at the time of deceleration of the BLDC motor to the AC power source side, the energy consumed by the motor is minimized to minimize the heat generation of the motor, thereby minimizing the heat dissipation structure.

Further, the present invention has a rectifying function for converting AC power to DC when operating in one direction, a boost-up function for boosting the voltage of DC to a desired voltage and outputting the DC power to AC And a bidirectional AC / DC converter which converts the AC voltage to AC voltage.

In this case, the bidirectional AC / DC converter has a power factor correcting function for increasing the power factor of the power consumption of the system by outputting the AC current synchronized with the input voltage when performing the rectifying function for converting the AC power to DC .

In the present invention, since the DC / DC converter is provided between the bidirectional AC / DC converter and the inverter, the high-voltage DC voltage generated from the bidirectional AC / DC converter is lowered to the low- By increasing the low voltage DC voltage generated during the deceleration of the motor to a sufficiently high high voltage DC voltage, the regenerative energy can be efficiently returned to the AC side via the bidirectional AC / DC converter. In the low speed motor rotation section, The driving efficiency can be increased.

Also, in the present invention, a charging and smoothing capacitor is provided at the rear end of the bidirectional AC / DC conversion unit to suppress ripple of the DC voltage generated from the bidirectional AC / DC conversion unit and to supply a stable voltage to the DC / Therefore, it is possible to drive the motor stably even in an unstable input voltage range.

Further, in the present invention, a DC / DC converter is provided between the bidirectional AC / DC converter and the inverter to control the modulation ratio in PWM manner. By controlling the DC voltage applied to the inverter at the constant speed of the BLDC motor, The control can be made simple and the DC voltage generated at the time of deceleration of the BLDC motor can be prevented from being unnecessarily applied at high voltage to the charging capacitor.

The present invention can control the speed of the motor by controlling the DC voltage applied to the inverter by the PWM controlled DC / DC converter, thereby reducing the PWM voltage (frequency) applied to the motor through the inverter to suppress spurious radiation . Further, in the present invention, the duty ratio of the PWM controlled DC / DC converter is controlled to lower the voltage, and the current required for starting the stopped motor is increased and applied to the inverter, so that the motor can be easily started.

In the present invention, when the speed of the motor is sufficiently small, the terminals of each phase are short-circuited by using a switching element of the inverter to generate a dynamic break to stop the motor.

According to the present invention, when the motor driving device is applied to a washing machine motor, when the washing machine is accelerated and decelerated to periodically rotate the washing machine in a forward and reverse direction according to the washing mode, the rotation energy of the washing machine ) And returning it to the AC power source side, the efficiency of the motor can be increased.

1 is an explanatory diagram showing energy consumption in an acceleration section for accelerating a washing tub of a washing machine,
FIG. 2 is an explanatory diagram showing energy consumption in a deceleration section for decelerating a washing tub in a conventional washing machine,
3 is an explanatory view showing energy consumption in a deceleration section for decelerating the washing tub in the washing machine according to the present invention,
4A and 4B are a schematic block diagram and a detailed circuit diagram showing a motor drive apparatus having a power return function according to the present invention,
5 is a circuit diagram that is separately shown for explaining the operation of the bidirectional AC / DC converter shown in Fig. 4B. Fig.
6 is a reconfigured circuit diagram for explaining an operation in which AC-DC conversion is performed in the bidirectional AC / DC converter shown in FIG. 5,
FIG. 7 is an explanatory diagram showing a setting mode of a switching device for each polarity of an input voltage when AC-DC conversion is performed in the bidirectional AC / DC converter shown in FIG. 5;
8 is a reconfigured circuit diagram for explaining an operation in which DC-AC conversion is performed in the bidirectional AC / DC converter shown in FIG. 5,
FIG. 9 is an explanatory view showing a setting mode of a switching device for each polarity of an input voltage when DC-AC conversion is performed in the bidirectional AC / DC converter shown in FIG. 5;
FIG. 10 is a circuit diagram that is separately shown for explaining an operation in which DC-DC conversion is performed in the bidirectional DC / DC converter shown in FIG. 4B;
11 is a reconfigured circuit diagram for explaining an operation in which the DC-DC step-down conversion is performed in the bidirectional DC / DC converter shown in FIG. 10,
12 is a reconfigured circuit diagram for explaining the operation in which the DC-DC boost conversion is performed in the bidirectional DC / DC converter shown in FIG. 10,
13 is a flowchart illustrating a method of driving a motor for a washing machine using a motor driving apparatus having a power return function according to the present invention.
FIGS. 14A and 14B are operational flowcharts for explaining a method of driving the washing machine in forward and reverse directions at the time of driving the motor using the motor driving device having the power return function according to the present invention.

While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and will herein be described in detail. It should be understood, however, that the invention is not intended to be limited to the particular embodiments, but includes all modifications, equivalents, and alternatives falling within the spirit and scope of the invention. Like reference numerals are used for like elements in describing each drawing.

The terms first, second, etc. may be used to describe various components, but the components should not be limited by the terms. The terms are used only for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, the first component may be referred to as a second component, and similarly, the second component may also be referred to as a first component. And / or < / RTI > includes any combination of a plurality of related listed items or any of a plurality of related listed items.

It is to be understood that when an element is referred to as being "connected" or "connected" to another element, it may be directly connected or connected to the other element, . On the other hand, when an element is referred to as being "directly connected" or "directly connected" to another element, it should be understood that there are no other elements in between.

The terminology used in this application is used only to describe a specific embodiment and is not intended to limit the invention. The singular expressions include plural expressions unless the context clearly dictates otherwise. In the present application, the terms "comprises" or "having" and the like are used to specify that there is a feature, a number, a step, an operation, an element, a component or a combination thereof described in the specification, But do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, or combinations thereof.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. Hereinafter, the same reference numerals will be used for the same constituent elements in the drawings, and redundant explanations for the same constituent elements will be omitted.

Hereinafter, a BLDC (brushless DC) motor will be described as an example of a load driven by a motor driving device in the present invention. However, the present invention can be applied not only to a BLDC motor but also to other types of motors in the case of a motor driven by an inverter and having frequent acceleration and deceleration.

In the following description of the present invention, a motor driving apparatus according to the present invention drives a washing machine motor for rotating and driving a washing tub of a fully automatic washer. However, the present invention is not limited to this, The present invention can be applied to a drum driving motor or an automobile motor of a drum washing machine.

FIG. 3 is an explanatory view showing energy consumption in a deceleration section for decelerating the washing tub in the washing machine according to the present invention. FIG. 4A is a block diagram showing a motor driving apparatus having a power return function according to the present invention.

3 and 4A, a motor drive apparatus having a power return function according to the present invention mainly includes a bidirectional AC / DC converter 120, a charging and smoothing capacitor C1, a bidirectional DC / DC converter 140, And an inverter (160).

A 220 V AC power source 100 is connected to an input terminal of the bidirectional AC / DC converter 120 through an integrating power meter (not shown), and a power transmission unit, for example, a rotary shaft 190 A brushless DC (BLDC) motor 180 for rotating the washing tub 200 of the washing machine is connected to the washing tub 200.

The BLDC motor 180 includes a stator for generating a rotating magnetic field under the control of the inverter 160 and a plurality of N and S pole magnets alternately arranged and rotatably disposed on the outer circumferential surface of the stator with a predetermined gap And a rotor coupled to the rotating shaft 190 at a central portion thereof.

For example, the stator is composed of three coils L11-L13 of U, V, W three-phase structure so that the stator coils can be driven by a three-phase driving system.

Further, the motor driving apparatus having a power return function according to the present invention includes a controller 150 for PWM-controlling the bidirectional AC / DC converter 120, the bidirectional DC / DC converter 140, and the inverter 160 And generates a PWM control signal. The control unit 150 receives an external control signal applied from the system body such as a washing machine according to the type of washing mode selected by the user and controls the motor 180 to rotate the motor 180 through the inverter 160 A rotor position signal necessary for generating an electromagnetic field is supplied through three Hall elements (H1-H3).

The control unit 150 includes a processor, a RAM temporarily storing data during signal processing in the processor or the like, a microcomputer or a controller having a ROM, a PROM, or an EEPROM in which a system control program is stored, Purpose signal processing apparatus.

Since the rotor used in the BLDC motor 180 includes a permanent magnet having N poles and S poles, the controller 150 uses a magnetic detection sensor such as a Hall element H1-H3 at the time of rotor rotation Sensing the magnetic flux change and signaling it, you get the rotor position signal.

The gate driver may further include a gate driver for amplifying a switching signal required for driving the inverter 160 by PWM method and transmitting the amplified switching signal to the inverter between the controller 150 and the inverter 160. The gate driver may include a controller 150, And may be integrated together.

The bidirectional AC / DC converter 120 converts the AC power supplied from the 220V AC power supply 100 supplied to each home or business site through an integrated power meter (not shown) to AC-DC conversion, DC-AC conversion is performed when a DC voltage is applied to the AC power source 100 so that the back electromotive force generated when the motor 180 connected to the load of the motor driving apparatus is decelerated is returned to the AC power source 100.

Power must be supplied from the AC power supply 100 to the motor 180 in order for the motor speed to be accelerated. The bidirectional AC / DC converter 120 has a function of converting the AC power into DC, boosting the converted DC voltage to a desired voltage, and outputting the DC voltage. The basic configuration of the bidirectional AC / DC converter 120 is a circuit having a rectification function and an output voltage rise, that is, a boost function. The current in the AC power supply 100 side during the AC- And a 'power factor correcting function' that increases the power factor of the power consumption of the system by synchronizing with the input voltage.

The bidirectional AC / DC converter 120 is a bidirectional AC / DC converter based on the counter electromotive force (BEMF) generated by the motor 180 to send the rotational energy of the washing tub 200 to the AC power source 100 side when the motor 180 decelerates. DC converter 120 to the AC power source 100 side and also maintains the power factor of the power source.

The bidirectional AC / DC converter 120 according to the present invention does not require a power factor adjusting inductor that is separately provided when the function of the power factor corrector is performed. The bidirectional AC / DC converter 120 includes a charging and smoothing capacitor C1, So that the inverter 160 driving the motor 180 can perform a stable operation function in an area where the voltage is insufficient.

The capacitor C1 serves to minimize the ripple of the DC-converted voltage when the bidirectional AC / DC converter 120 converts the power on the AC power source 100 side to DC. The control unit 150 controls the charging voltage of the capacitor C1 to be higher than the input voltage of the AC power supply 100. When the charging voltage of the capacitor C1 is set higher than the input voltage of the AC power supply 100, Which is capable of supplying a stable voltage to the washing machine in an unstable region of the input voltage of the washing machine. That is, the motor driving apparatus of the present invention, in which the bidirectional AC / DC converter 120 and the capacitor C1 are combined, provides a function to stably drive the washing machine even in a region where the applied voltage of the commercial power source is unstable.

The voltage at the side of the AC power supply 100 is sufficiently charged to the capacitor C1. As a result, a stable voltage is supplied to the bidirectional DC / DC converter 140 and the inverter 160 that drive the motor 180 from the capacitor C1.

The capacitor C1 is charged with electric energy supplied by the motor at the time of deceleration of the BLDC motor 180. [ The stored voltage is set higher than the peak voltage on the AC power supply 100 side, so that it can be sent to the AC power supply 100 side with a sufficiently high efficiency. The adjustment of the voltage level charged in the capacitor C1 is performed by the bidirectional DC / DC converter 140 as described later.

The bidirectional DC / DC converter 140 serves as a buck converter and a boost converter depending on the direction of travel. When the bidirectional DC / DC converter 140 serves as a buck converter, the bidirectional AC / DC converter 120 converts the high voltage to a high voltage and supplies the high voltage charged in the capacitor C1 to the BLDC motor 180 A function of boosting the voltage generated by the BLDC motor 180 to the capacitor C1 when the inverter 160 serves as a boost converter and has a function of decreasing the voltage to the operating power supply Vcc of the driving inverter 160 Bidirectional converter with a current flowing in both directions.

The bidirectional DC / DC converter 140 has a function of appropriately controlling the voltage of both sides according to the control of the controller 150, and appropriately controls the operation power source Vcc of the inverter 160, The efficiency of the overall system such as the function of increasing the efficiency of the inverter 160 driven by the BLDC motor 180 in the washing period where the rotation of the brushless motor 160 is slow.

That is, the bidirectional DC / DC converter 140 level-converts the high-voltage DC voltage charged in the capacitor C1 during the acceleration and the constant speed operation of the motor to supply the minimum DC operation power supply Vcc necessary for the inverter 160 And a regenerative power generated by the BLDC motor 180 and converted from the inverter 160 to DC at the time of deceleration and stop of the motor, to the capacitor C1.

In the bidirectional DC / DC converter 140, the controller 150 appropriately controls the PWM modulation ratio to control the DC voltage and the current stored in the capacitor C1. The control unit 150 controls the voltage stored in the capacitor C1 to prevent the voltage applied to the capacitor C1 from being higher than necessary, thereby preventing a shortening of the life of the capacitor C1.

The inverter 160 is a motor driving circuit for controlling the rotation of the BLDC motor 180. The inverter 160 controls the PWM modulating ratio appropriately by the control unit 150 and is applied to the stator coils L11 to L13 of the motor 180 And controls the output of the motor 180 by controlling the voltage and the current. In other words, the inverter 160 is a circuit for controlling the driving force and the rotational speed of the motor 180, and controls the current and the terminal voltage flowing through the stator coils L11 to L13 of the motor.

In the present invention, the inverter 160 drives the motor 180 using a PWM driving signal to control the conversion of electrical energy into mechanical energy by rotating the washing tub 200, and conversely, When decelerating, a back electromotive force is generated from the motor 180 according to the rotational energy of the washing tub 200, thereby controlling the conversion of mechanical energy into electric energy, and controlling the amount of conversion.

The drive signal is not applied from the inverter 160 to the stator coils L11 to L13 of the motor 180 when the BLDC motor 180 is decelerated or the deceleration is performed for switching the rotation direction, 200 are rotated by inertia.

In this case, the rotational energy of the washing tub 200 is so large that it can not be ignored, and the motor 180 serves as a generator in accordance with the rotation of the washing tub 200.

As a result, as the rotational energy of the washing tub 200 rotates the permanent magnet of the rotor of the BLDC motor 180, AC power is generated in the stator coils L11-L13, and this AC power is transmitted through the inverter 160 DC converter 140, and is returned to the DC power source as the capacitor C1 is charged through the bidirectional DC / DC converter 140. The inverter 160 applies an appropriate driving current and voltage to the motor 180 when the motor 160 is decelerated as in the case of acceleration, And the brake force are applied to the washing tub 200.

In the present invention, the inverter 160 can suppress the unwanted radio wave by lowering the PWM voltage applied to the motor at the time of accelerating the motor and at the constant speed or decelerating the motor.

As described above, in the motor driving apparatus having the power return function according to the present invention, when the BLDC motor 180 accelerates the rotation of the washing tub 200, the electric energy of the AC power source 100 is supplied to the washing tub 200 do. At this time, the energy flow is not significantly different from the energy flow of the conventional motor drive apparatus shown in Fig.

However, at the time when the washing tub 200 is decelerated, the rotational energy of the washing tub is transmitted to the AC power source 100, which is different from the conventional washing machine operation. 3, most of the rotational energy of the washing tub 200 is transmitted to the AC power source 100, thereby minimizing the energy consumed by the motor 180. In this case, as shown in FIG. In this case, the energy consumed as heat in the mechanical part (i.e., the power transmitting part) is the same as the conventional one, but the energy consumed by the heat in the motor 180 and the inverter 160 is remarkably reduced as compared with the conventional one.

Such a power return operation is conspicuous in that the higher the efficiency of the motor 180 is, the more suppressed the heat rise of the motor 180 is. Therefore, in a conventional motor drive system in which both the acceleration and deceleration of the washing machine must be handled by the motor, the size, surface area, or heat dissipation system of the driving device and the casing must be provided in order to release heat generated. The higher the efficiency, the more free the problem of such heat dissipation.

Hereinafter, a motor driving apparatus having a power return function will be described in more detail with reference to embodiments according to the present invention.

FIG. 4B is a detailed circuit diagram showing the entire motor driving apparatus having a power return function according to the present invention. First, the circuit configuration and operation of the bidirectional AC / DC converter 120 will be described with reference to Figs. 5 to 9. Fig.

FIG. 5 is a circuit diagram for explaining the operation of the bidirectional AC / DC converter shown in FIG. 4B. FIG. 6 is a diagram for explaining the operation of AC-DC conversion in the bidirectional AC / DC converter shown in FIG. FIG. 7 is an explanatory view showing a setting mode of a switching device for each polarity of an input voltage when AC-DC conversion is performed in the bidirectional AC / DC converter shown in FIG. 5. FIG. FIG. 9 is a circuit diagram illustrating a DC-AC conversion operation in the DC-to-DC converter according to the first embodiment of the present invention. FIG. Fig.

The bidirectional AC / DC converter 120 includes two pairs of first to fourth switching elements Q1 and Q2 (Q3 and Q4) connected to each other through a totem pole connection structure. Each pair of first to fourth switching elements Q1 Q2 and Q3 and Q4 are supplied from the AC power source 100 through the first and second inductors L1 and L2, for example, The first to fourth diodes D1 to D4 for rectification are connected in parallel to the four switching elements Q1 to Q4 so as to constitute a full bridge rectifier circuit.

Each of the first to fourth switching devices Q1 to Q4 may be configured as a power switching semiconductor device such as a transistor, an FET, an IGBT, or the like, and the first to fourth switching devices Q1 to Q4, The control signal S1-S4 is applied from the control unit 150 to the gate of the transistor Q1.

The drain terminal of the upper first and third switching devices Q1 and Q3 and the lower second and fourth switching devices Q2 and Q3 in the two pairs of first to fourth switching devices Q1 and Q2 and Q3 and Q4 connected to the totem- And a common source terminal and a common source terminal of the bidirectional AC / DC converter 120 are connected to a charging and smoothing capacitor C1 so that a bidirectional AC / DC converter And serves to minimize the ripple of the DC converted voltage when the converter 120 converts the power on the AC power source 100 side to DC.

5 to 7, when the AC-DC conversion is performed, the bidirectional AC / DC converter 120 according to the present invention includes first to fourth switching elements Q1 to Q4, A full bridge rectification circuit is formed by the first to fourth diodes D1 to D4.

In the bidirectional AC / DC converter 120 of FIG. 5, when the first terminal V1 connected to the first inductor L1 of the AC power source 100 is positive, the first diode D1 is connected in parallel to the first The switching element Q1 has a diode, the second switching element Q2 connected in parallel with the second diode D2 is turned on, the third switching element Q3 connected in parallel with the third diode D3 is turned off, When the fourth switching device Q4, in which the fourth diode D4 is connected in parallel, is set to have a function as a diode, it can be expressed as shown in FIG.

The bidirectional AC / DC converter 120 shown in FIG. 6 forms a boost converter including a first inductor L1, a second switching device Q2, and a first diode D1. The boost converter boosts the AC voltage with the AC-DC rectification when the AC input voltage V ₁₂ is applied from the AC power source 100 to the first inductor Ll so as to be supplied to the output terminal of the bidirectional AC / DC converter 120 And charges the connected first capacitor C1 with a DC voltage.

Hereinafter, a method of operating the bidirectional AC / DC converter 120 will be described in detail. In the boost converter of FIG. 6, when one terminal V1 of the AC power supply 100 is positive, the first terminal V1 of the first to fourth switching devices Q1 to Q4 is connected to the first And the second switching elements Q1 and Q2 operate as a boost circuit and the third switching element Q3 is turned off to be in a cutoff state and the fourth switching element Q4 operates in a conduction state.

In the actual circuit, since the first diode D1 is connected to the first switching element Q1 in parallel, the switching element PWM controlled by the controller 150 is the second switching element Q2. The ratio of the total time to the on time in the pulse width modulation (PWM) signal applied to the second switching device Q2 is called a duty ratio D. That is, when that the total time for the On time ratio D of the second switching element (Q2), DC voltage (V ₃₄₎ that is accumulated in the first capacitor (C1) connected to the output terminal of the AC / DC converter 120 to the (1) < / RTI >

[Equation 1]

V ₃₄ = V ₁₂ / D

Here, ₃₄ V is the 1 DC voltage accumulated in the capacitor (C1), V ₁₂ is the AC input voltage. In this case, because D is a value between 0 and 1, the DC voltage to be always stored in the first capacitor (C1) it can be seen that higher than the AC input voltage (V _12).

In the boost converter of FIG. 6, when the second switching device Q2 is turned on, the current flows along the dotted line passing through the first inductor L1 and the second switching device Q2, Is accumulated. In this case, the DC voltage is supplied to the rear end of the first capacitor C1, that is, the bidirectional DC / DC converter 140 while the charges accumulated in the first capacitor C1 are discharged. When the second switching device Q2 is turned on, the first diode D1 serves to prevent the charge stored in the first capacitor C1 from flowing to the second switching device Q2.

When the second switching device Q2 is turned off, current flows from the AC power supply 100 to the first terminal V1 while flowing through the solid-line path passing through the first inductor L1 and the first diode D1. to include (AC input voltage (V ₁₂₎ + the voltage across the first inductor (L1) a first inductor (L1) of haejyeoseo energy is further first capacitor (C1) stored in the AC input voltage (V ₁₂₎ applied to ( VL). That is, the first capacitor C1 is charged with the voltage boosted by the energy voltage accumulated in the first inductor L1.

Generally, in the power factor correction circuit, the AC input voltage (V ₁₂ ) of the AC power supply 100 is controlled to be 1.2 times the maximum value in order to adjust the power factor to 0.9 or 0.95 desired. In addition, when the input current is made in the form of a pulse in accordance with the PWM control, harmonics are generated and the power factor is lowered.

In the AC / DC converter 120 of the present invention, the output voltage can be adjusted by adjusting the duty ratio D, and the input current can also be controlled. That is, the AC input voltage V ₁₂ and the current of the AC power source 100 input to the AC / DC converter 120 are sensed, and the PWM control signal applied to the second and fourth switching devices Q 2 and Q 4 It is possible to implement the waveform of the input current passing through the first and second inductors L1 and L2 in the form of a sinusoidal wave almost equal to the sinusoidal waveform of the input voltage, The power factor correcting function that increases the power factor of the power consumption of the system by removing the phase difference by synchronizing the input current on the side of the input power source 100 with the input voltage.

Accordingly, in the present invention, by controlling the duty value of the PWM control signal, if the input voltage and the current have appropriate phase difference and harmonic, the desired power factor can be controlled.

Further, the bidirectional AC / DC converter 120 has a symmetrical circuit configuration. As a result, as shown in Figure 7, when the voltage of the AC input voltage (V ₁₂₎ changes, that is, operate in the same manner, if the other terminal (V2) of the AC power source 100 (+), the external switching element and the AC-to-DC conversion is performed.

That is, the third and fourth switching elements Q3 and Q4 connected to the other terminal V2 of the first to fourth switching elements Q1 to Q4 act as a boost circuit, The switching element Q1 is turned off to be in the cutoff state, and the second switching element Q2 operates in the conduction state.

The description of the operation in the case where the other terminal V2 of the AC power supply 100 is positive is the same as described above, and a description thereof will be omitted.

Hereinafter, a case where the bidirectional AC / DC converter 120 according to the present invention operates as a DC / AC converter will be described with reference to FIGS. 8 and 9. FIG.

Referring to FIGS. 8 and 9, the bidirectional AC / DC converter 120 according to the present invention converts a back electromotive force (BEMF) generated by the deceleration of the motor 180 from the inverter 160 to DC, DC conversion is performed in a state where the voltage is boosted by the DC / DC converter 140 and the voltage is accumulated in the first capacitor C1 at a voltage sufficiently higher than the peak voltage of the AC power source 100 side.

When the DC-AC conversion is performed in the bidirectional AC / DC converter 120, the first to fourth switching elements Q1 to Q4 are connected to the first inductor L1 of the AC power supply 100 at one terminal V1 The first switching device Q1 in which the first diode D1 is connected in parallel in the bidirectional AC / DC converter 120 of FIG. 5 has a switch and a second diode D2 are connected in parallel The third switching element Q3 connected in parallel to the third diode D3 is turned off and the fourth switching element Q4 connected in parallel to the fourth diode D4, If it is set to maintain the turn-on state, it can be expressed as shown in FIG.

The AC / DC converter 120 shown in FIG. 8 has a function of flowing a current from the DC side to the AC power source 100 side in a reversible operation of AC-DC conversion when operating as a DC-AC converter. In this case, the first switching device Q1 operates as a switch, and sends a DC current to the AC power supply 100 side along the solid-line path in Fig. That is, when the first switching element Q1 is turned on and the one terminal V1 of the AC power supply 100 is positive, a DC voltage higher than the one terminal V1 is applied to the first capacitor C1 The current flows to the AC power source 100 side.

That is, when the first switching device Q1 is turned on, a current flows from the first capacitor C1 to the first inductor L1 and energy is accumulated in the first inductor L1 and returned to the AC power source 100 side . At this time, the DC voltage is higher than the peak value of the input voltage of the AC power supply 100.

In addition, when the first switching device Q1 is turned off, the second diode D2 forms a path through which the inductor current, which is the energy stored in the first inductor L1, flows to the AC power supply 100, Decreases until the first switching element Q1 is turned on again.

When the first switching device Q1 is turned on and off periodically as described above, a sinusoidal AC current is obtained as a return current that is returned to the AC power source 100 through the first inductor L1 .

At this time, the intensity of the current may be adjusted by adjusting the duty value of the PWM control signal applied to the first switching device Q1 in the controller 150, and the amount of current may be appropriately adjusted By adjusting the input current, phase and magnitude, it is possible to increase the power factor even during the power return period.

9, the bidirectional AC / DC converter 120 has a symmetrical circuit configuration. When the voltage of the AC input voltage V ₁₂ is changed after the above half period, that is, V2) is (+), the relative switching element operates in the same manner as above to perform the DC-AC conversion.

That is, in the first to fourth switching devices Q1 to Q4, the first switching device Q1 is turned off to be in a cutoff state, the second switching device Q2 is turned on to be in a conductive state, Q3 are the switches, and the fourth switching element Q4 is the diode.

The description of the operation in the case where the other terminal V2 of the AC power supply 100 is positive is the same as described above, and a description thereof will be omitted.

The capacitor C1 is charged to a voltage higher than the input voltage of the AC power source 100 and supplies a stable DC voltage to the bidirectional DC / DC converter 140 and the inverter 160 connected to the rear end of the capacitor C1 .

Hereinafter, the circuit configuration and operation of the bidirectional DC / DC converter will be described with reference to FIGS. 10 to 12. FIG.

FIG. 10 is a circuit diagram for explaining the operation in which the DC-DC conversion is performed in the bidirectional DC / DC converter shown in FIG. 4B, and FIG. 11 is a circuit diagram showing the DC-DC down conversion in the bidirectional DC / DC converter shown in FIG. 12 is a circuit diagram reconstructed to explain the operation in which the DC-DC boost conversion is performed in the bidirectional DC / DC converter shown in FIG. 10.

Referring to FIGS. 10 to 12, the bidirectional DC / DC converter 140 is configured to function as a buck converter and a boost converter according to the direction of travel. To this end, the bidirectional DC / DC converter 140 is connected in parallel with the charging and balancing capacitor C1 provided at the previous stage, so that a pair of fifth and sixth switching elements Q5 and Q6 are connected to the totem pole connection structure And the fifth and sixth diodes D5 and D6 are connected in parallel to form a bidirectional current flow path in each of the fifth and sixth switching elements Q5 and Q6 and the fifth and sixth switching elements Q5 and Q6 are connected in parallel. Converted DC voltage is applied from the connection point of the elements Q5 and Q6 through the third inductor L3 to the operation power supply Vcc of the inverter 160. [

Each of the fifth and sixth switching elements Q5 and Q6 may be constituted by a power switching semiconductor element such as a transistor, an FET, an IGBT, and the like, and the fifth and sixth switching elements Q5 and Q6 Control signals S5 and S6 are applied to the gate of the controller 150 to adjust the output voltage level of the bidirectional DC / DC converter 140.

A charging and smoothing capacitor C2 may be further provided between the bidirectional DC / DC converter 140 and the inverter 160 to suppress abrupt voltage fluctuation and to remove a high frequency signal.

The bidirectional DC / DC converter 140 according to the present invention shown in FIG. 10 converts the DC voltage input from the AC power supply 100 side to a DC voltage converted to the motor 180 side, Together form a buck converter.

The fifth and sixth switching elements Q5 and Q6 perform a complementary operation, and when one of them is turned on, the other is turned off. The fifth and sixth diodes D5 and D6 connected in parallel to the fifth and sixth switching elements Q5 and Q6 enable current to flow in both directions of the bidirectional DC / DC converter 140. [

10, when the bidirectional DC / DC converter 140 operates as a buck converter, the PWM control signal S6 is applied to the fifth switching device Q5, and the sixth switching device Q6 is turned off .

11, a pulse-like PWM control signal S5 is applied to the gate of the fifth switching device Q5, so that when the fifth switching device Q5 is in the turn-on state, the third inductor L3 Energy is stored in the inductor as a current flows through the third inductor L3 and is supplied to the inverter 160 connected to the rear stage as a load and is stored in the third inductor L3 when the fifth switching device Q5 is in the turn- And the inductor current based on the energy is supplied to the inverter 160 connected to the subsequent stage.

The bidirectional DC / DC converter 140 operating as the buck converter controls the duty ratio of the PWM control signal S5 applied to the gate of the fifth switching device Q5 to supply the inverter 160 with the operating power Vcc ) To regulate the level of the output voltage.

In this case, the bidirectional DC / DC converter 140 obtains the output voltage V ₅₆ smaller than the input voltage V ₃₄ .

Generally, a motor needs a high current instead of a low voltage when the motor starts. In this case, the bidirectional DC / DC converter 140 operates as a buck converter to lower the current on the AC side and increase the current on the output side, that is, the motor 180 side driven by the inverter 160. Therefore, the bi-directional DC / DC converter 140 has a driving function of a strong starting current.

Generally, a circuit using a buck converter is more likely to be used in EMI noise or the like than in a case where the sixteenth to sixteenth switching elements Q11 to Q16 forming the inverter 160 are driven by the PWM method to start the motor And has excellent characteristics.

Moreover, when controlling the operating power supply Vcc applied to the inverter 160 using the bidirectional DC / DC converter 140 operating as a buck converter, the speed control of the motor 180 is simplified. That is, the speed of a direct current (DC) motor can be controlled by controlling only the voltage. Therefore, the motor driving apparatus of the present invention for controlling the operating power supply Vcc applied to the inverter 160 by the bidirectional DC / DC converter 140 can easily apply the control algorithm of such a direct current (DC) motor.

On the other hand, when the bidirectional DC / DC converter 140 according to the present invention shown in FIG. 10 converts the DC voltage input from the motor 180 side to output the converted DC voltage to the AC power source 100 side, 12 to form a boost converter.

That is, in FIG. 10, the fifth switching device Q5 is set in the turn-off state and the PWM control signal S6 is set in the sixth switching device Q6.

When the bidirectional DC / DC converter 140 operates as a boost converter as shown in FIG. 12, the pulse-like PWM control signal S6 is applied to the gate of the sixth switching device Q6, Energy is accumulated in the first inductor L1 while current flows along the dotted line passing through the third inductor L3 and the sixth switching element Q6 when the switches Q6 and Q6 are turned on. In this case, the DC voltage is supplied to the rear end of the first capacitor C1, that is, the bidirectional AC / DC converter 120, while the charges accumulated in the first capacitor C1 are discharged. When the sixth switching element Q6 is turned on, the fifth diode D5 functions to block the electric charge accumulated in the first capacitor C1 from flowing to the sixth switching element Q6.

When the sixth switching element Q6 is turned off, current flows from the motor 180 through the inverter 160 while flowing through the solid-line path passing through the third inductor L3 and the fifth diode D5 third, the (DC input voltage (V ₅₆₎ + the third inductor are summed energy stored in the inductor (L3) the first capacitor (C1) to the DC input voltage (V ₅₆₎ applied to the terminal (V5) that is returned ( L3) voltage (V _L3 )). That is, the first capacitor C1 is charged with the voltage boosted by the energy voltage accumulated in the third inductor L3.

Accordingly, the bidirectional DC / DC converter 140 operating as the boost converter charges the first capacitor C1 by controlling the duty ratio of the PWM control signal S6 applied to the gate of the sixth switching device Q6 Adjust the level of charge voltage.

In this case, the bidirectional DC / DC converter 140 obtains the output voltage V ₃₄ larger than the input voltage V ₅₆ .

As described above, when the regenerative power is supplied from the motor side to the AC power source 100, the bidirectional DC / DC converter 140 operates as a boost converter, so that the energy of the motor can be efficiently transferred to the AC power source 100 side. In this case, since the controller 150 performs effective PWM control, EMI is minimized and unnecessary radiation of high frequency and speed control are simplified in the inverter.

Furthermore, when the first capacitor C1 is charged by raising the voltage to a sufficiently high high voltage required to be sent from the bidirectional DC / DC converter 140 to the AC power source 100, the AC power is supplied through the bidirectional AC / DC converter 120 100). When the regenerative power generated by the deceleration of the motor is efficiently returned to the AC power source 100, the motor can be effectively decelerated or stopped.

Hereinafter, an embodiment in which a motor driving apparatus having a power return function according to the present invention is applied to driving a motor for a washing machine will be described with reference to FIGS. 13 to 14B. FIG.

13 is a flowchart illustrating a method of driving a motor for a washing machine using a motor driving apparatus having a power return function according to the present invention.

Referring to FIG. 13, the power of the washing machine is turned on in step S300.

In this state, the controller 150 determines whether the current washing or rinsing mode is performed through the washing control signal input from the outside, that is, the washing machine main body according to the user's selection (S302).

As a result of the determination, when the washing or rinsing mode is performed, the controller 150 drives the inverter 160 according to the washing or rinsing mode (S304).

Then, the inverter 160 generates three-phase AC power, and the generated three-phase AC power is applied to the three-phase stator coils L1-L3 of the motor 180 for the washing machine so that the rotor and the washing machine (or pulsator) (200) is rotated to perform a washing operation or a rinsing operation.

At this time, the controller 150 controls one of three pairs of upper switching elements Q11, Q13 and Q15 provided in the inverter 160 and three pairs of lower switching elements Q12 and Q14 Phase alternating-current power applied to the three-phase stator coils L1-L3 while changing the alternating-current power of the generated U-phase, V-phase and W-phases by selectively turning on one of the three- (Or pulsator) 200 is changed to the forward direction or the backward direction by changing the phase of the washing water or washing water to perform the washing operation or the rinsing operation.

Thereafter, it is determined whether the washing operation or the rinsing operation has been performed a predetermined number of times while changing the motor 180 and the washing tub (or pulsator) 200 in the forward or reverse direction (S308) In step S302, the control unit 150 determines whether the dehydration mode is to be performed or not in step S302. If the dehydration mode is not performed in step S302, (S308).

If it is determined that the dehydration mode should be performed, the control unit 150 determines the direction of rotation of the rotor and controls the rotor to rotate in one direction according to the determined direction of rotation (S310).

Thereafter, the controller 150 controls the inverter 160 to generate three-phase AC power, and the generated three-phase AC power is applied to the three-phase stator coils L1-L3 of the motor 180 for washing machine When the rotor is rotated, the washing tank (or pulsator) 200 and the dewatering tank are rotated in the same direction to perform the dewatering mode operation.

Thereafter, the control unit 150 determines whether the execution time of the dehydration mode has elapsed by using the wash control signal (S312). When the dehydration mode time has elapsed, the controller 150 ends the laundry operation.

FIGS. 14A and 14B are operational flowcharts for explaining a method of driving the washing machine in forward and reverse directions at the time of driving the motor using the motor driving device having the power return function according to the present invention.

AC power is applied from the AC power source 100 to the bidirectional AC / DC converter 120 at the input terminal of the motor driving apparatus according to the present invention (S400), and AC-DC conversion is performed as shown in FIG. (S402). Then, the boosted DC voltage is charged into the first capacitor (C1) to smooth the ripple (S404).

In this case, the bidirectional AC / DC converter 120 appropriately controls the duty ratios of the PWM control signals S2 and S4 for the second and fourth switching devices Q2 and Q4 applied from the controller 150 It shows power factor correction function and output voltage regulation function.

According to the output voltage regulation function, even when the voltage of the commercial power source is used in an unstable region, the first capacitor C1 is charged with a DC voltage higher than the input voltage of the AC power source 100, The inverter 160 and the washing machine motor 180 using the DC voltage charged in the AC power source as the operating power supply Vcc can also perform a stable circuit operation.

Thereafter, the bidirectional DC / DC converter 140 operates as a buck converter so that the controller 150 appropriately controls the duty ratio of the PWM control signal S5 for the fifth switching element Q5 The high-voltage DC voltage charged in the first capacitor C1 is level-converted to a low-voltage DC voltage (S406), and is supplied to the operating power supply Vcc of the inverter 160. [

In this case, the bidirectional DC / DC converter 140 drives the BLDC motor when the motor 180 performs the washing operation or the rinsing operation in which the motor 180 rotates at a low speed by controlling the operation power source Vcc of the inverter 160 Thereby enhancing the efficiency of the inverter 160.

When the operation power source Vcc for the inverter 160 is applied from the bidirectional DC / DC converter 140 to the controller 150, the controller 150 receives the external control signal of the washing mode from the washing machine main body, 180). ≪ / RTI >

In this case, for example, the control unit 150 controls the three pairs of upper switching devices Q11, Q11, Q12, Q13 and Q15 and the PWM control signals S11 to S16 to selectively turn on one of the three pairs of the lower switching elements Q12, Q14 and Q16, the bidirectional AC / DC AC power is applied to two-phase stator coils of the three-phase stator coils L1-L3 as in the DC-AC conversion operation of the converter 120 (S408).

When the rotor position detected from the Hall elements H1 to H3 is, for example, 0 degrees, the inverter 160 switches the upper switching elements Q11, Q13, and Q15 on the U of the upper switching elements Q11, Q11) and the W-phase lower switching element Q16 are turned on to form a current flow path.

That is, as the current flows along the path passing through the upper switching element Q11 of the U phase, the U phase stator coil L1, the neutral point NP, the W phase stator coil L3, and the W phase lower switching element Q16, A magnetic flux is generated in the stator core in which the upper stator coil L1 and the W phase stator coil L3 are wound, and the magnet of the rotor disposed opposite thereto is rotated.

In this way, whenever the rotor position detected from the Hall elements H1 to H3 is changed, the control unit 150 sets one of the three pairs of upper switching elements Q11, Q13, and Q15 to three pairs When one of the lower switching elements Q12, Q14 and Q16 of the three-phase stator coils L1 to L3 is turned on / turned on, a rotating magnetic field is generated from the three-phase stator coils L1 to L3 to rotate the rotor in one direction.

In this case, the control unit 150 controls the voltage and current applied to the motor 180 by applying the PWM control signals S11-S16 to the switching elements Q11-Q16 of the inverter 160, ), And accelerates the speed of the motor until a predetermined speed is reached.

As described above, when the rotor of the motor 180 rotates in one direction (forward direction), the washing tub 200 of the washing machine in which the rotating force is transmitted through the rotating shaft 190 is also rotated in one direction (S410).

When the motor 180 is operated at a constant speed, it mainly performs a control function for operating at a constant speed. A change in the torque due to the disturbance may be given, and the control speed may fluctuate. In this case, the controller 150 finely adjusts the duty ratio of the DC / DC converter 140 to maintain the constant speed, and precisely measures the DC / DC converted current of the DC / DC converter 140, Can be prevented.

The control unit 150 controls the switching devices Q11 to Q16 to rapidly decrease the rotational speed of the washing tub 200 when the rotational speed of the washing tub 200 is rapidly reduced or the rotational direction is switched according to the washing mode The duty ratio of the applied PWM control signals S11-S16 is controlled and applied.

As a result, when the motor 180 decelerates, the washing tub 200 is rotated by inertia, and a back electromotive force (BEMF) is generated in the stator coils L11-L13. The back electromotive force (BEMF) generated in the sinusoidal form is converted into DC by passing through the inverter 160 in the same manner as the AC-DC conversion of the AC / DC converter 120 shown in FIG. 6 (S412).

Thereafter, the counter electromotive force converted to DC is boosted through the bidirectional DC / DC converter 140 serving as a boost converter to charge the first capacitor C1 (S414, S416).

The DC voltage charged in the first capacitor C1 is controlled to be higher than the peak voltage of the input voltage of the AC power supply 100 so that the DC voltage charged in the first capacitor C1 is supplied to the AC / (S418), and the meter of the integrated meter connected to the AC power source 100 is driven to rotate in the reverse direction (S420).

As a result, when the motor driving apparatus having the power return function according to the present invention is used, the power consumption can be reduced by returning the power.

In addition, the current and voltage returned to the AC power source 100 serve to apply an electromagnetic brake to the rotation of the washing tub 200. When the inverter 160 decelerates as in the case of acceleration, Thereby allowing the speed and the brake force of the motor 180 to be applied to the washing tub 200. [

Thereafter, when the speed of the motor 180 is sufficiently small, the output terminals of the phases U, V and W are short-circuited by using the switching elements Q12, Q14 and Q16 of the inverter 160, If applied, the motor 180 can be quickly stopped.

After the motor is stopped, the control unit 150 applies the control signals S11-S16 to the inverter 160 to rotate the motor in the reverse direction so as to drive the rotation direction of the washing tub 200 in the reverse direction. And is rotated in the reverse direction (S422).

The present invention can exert an excellent drive voltage control function in an environment where the input voltage fluctuates. That is, the AC / DC converter 120 can charge a predetermined voltage to the first capacitor C1. However, when the input voltage is too low, the control unit 150 can cut off the DC voltage to prevent the inverter 160 and the motor 180 from operating insufficiently at too low a voltage.

In the present invention, the duty ratio of the DC / DC converter 140, which is PWM-controlled at the start of the motor, is controlled so that the voltage is lowered and the current required for starting the stopped motor is increased and applied to the inverter 160, Can be easily started.

In this case, by controlling the six switching elements Q11 to Q16 constituting the inverter 160 with a minimum number of pulses, unnecessary high frequency can be suppressed and the switching loss of the inverter circuit can be minimized.

Although the motor driven by the motor driving apparatus having the electric power returning function according to the present invention is applied to rotational driving of the washing tub of the so-called coarse type washing machine in the above description of the embodiment, It can be applied to drive the tub or drum of the drum washing machine in which the reversal is required.

The structure of the motor is not limited to a general motor having a single rotor or a double rotor and a single stator for driving only a washing machine or a drum, but also two driven members such as a washing tub and a dehydrating tub, a pulsator and a washing tub, The present invention can also be applied to a dual motor having a double rotor and a double stator for separately driving the drum and the auxiliary drum.

Furthermore, although the present invention is applied to a motor for a washing machine in the above embodiment, the present invention can be applied to a motor applied to a train, a tower crane or the like operated by an AC power source.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, I will understand.

Therefore, the scope of the present invention should not be limited to the above-described embodiments, but should be determined by equivalents to the appended claims, as well as the appended claims.

The present invention can improve the efficiency of the motor and reduce the power consumption by converting the regenerative energy generated when the motor is decelerated to AC and returning it to the AC power source side, The heat dissipation structure can be minimized by minimizing the generation of the electric power, and it is applied to a motor driving device of a motor applied to a washing machine, an electric vehicle, a tower crane, etc. driven by an AC power source.

100: AC power source 120: bidirectional AC / DC converter
140: bi-directional DC / DC converter 150:
160: inverter 180: BLDC motor
190: rotating shaft 200: washing tub
C1, C2: Capacitors D1-D6, D11-D16: Diodes
H1-H3: Hall element L1-L3: Inductor
L11-L13: Coils Q1-Q6, Q11-Q16: Switching elements

Claims (22)

A motor drive apparatus for driving a motor connected to a load and returning a counter electromotive force (BEMF) generated from the motor to the AC power source when deceleration of the motor occurs,
A DC voltage higher than the peak voltage of the AC power source is applied to the AC power source side so that the BEMF generated at the time of deceleration of the motor is returned to the AC power source side by AC-DC conversion of the AC power source supplied from the AC power source side A bidirectional AC / DC converter where DC-to-AC conversion is performed;
A first capacitor charged with an AC-DC converted DC voltage through the bidirectional AC / DC converter;
The high voltage charged in the first capacitor is lowered to the operating voltage Vcc of the inverter driving the motor and the DC voltage applied at the subsequent stage is boosted to a voltage higher than the peak voltage of the AC power source side to charge the first capacitor A bidirectional DC / DC converter; And
DC voltage supplied from the bidirectional DC / DC converter is used as an operation power source (Vcc) to generate AC power required to drive the motor and apply the generated AC power to the stator coil of the motor. (BEMF) to a DC to a bi-directional DC / DC converter,
Wherein the bidirectional AC / DC converter has a power return function for performing a power factor correcting function of increasing a power factor by synchronizing a current of an AC power source with an input voltage during an AC-DC conversion operation. The method according to claim 1,
Wherein the washing machine of the washing machine is connected to the motor and a counter electromotive force (BEMF) is generated from the motor by the rotation energy of the washing machine when the motor decelerates. The method of claim 1, wherein the bi-directional AC / DC converter
First and second inductors to which commercial AC power is applied;
First and second switching elements connected to the totem pole connection structure and to which AC power is applied to the connection point through the first inductor;
First and second diodes connected in parallel to the first and second switching elements, respectively;
Third and fourth switching devices connected to the totem pole connection structure and to which AC power is applied to the connection point through the second inductor; And
And third and fourth diodes connected in parallel to the third and fourth switching elements, respectively,
Wherein the first to fourth diodes form a full bridge rectifier circuit. The method of claim 3,
Wherein the duty ratio of the PWM control signal for the bidirectional AC / DC converter is set such that when the bidirectional AC / DC converter performs the AC-DC conversion, the charge voltage of the first capacitor is charged to a voltage higher than the input voltage of the AC power supply. Further comprising: a control unit for controlling,
Wherein the first capacitor serves as a constant voltage circuit in an area where the input voltage of the commercial power supply is unstable. delete The method according to claim 1,
The bidirectional AC / DC converter is configured to convert the power on the DC side applied from the rear end of the bidirectional AC / DC converter based on the counter electromotive force generated in the motor to send the rotational energy of the washing tub connected to the motor to the AC power source side at the time of deceleration of the motor, Return to power source side,
And the meter of the integrated meter is driven in a reverse direction by the AC power returned to the AC power source side. The method of claim 3,
Wherein, when AC-DC conversion is performed in the bidirectional AC / DC converter, the first switching element is a diode, the second switching element is a switch, and the third switching element is a switch when the one terminal connected to the first inductor is (+ The element is turned off, the fourth switching element is set to have a function as a diode,
When the DC-AC conversion is performed in the bidirectional AC / DC converter, the first switching element is a switch, the second switching element is a diode, the third switching element is turned off, the fourth switching element is turned on State of the motor drive apparatus. The method of claim 1, wherein the bi-directional DC / DC converter
Fifth and sixth switching elements connected in a totem pole connection structure;
Fifth and sixth diodes connected in parallel to the fifth and sixth switching elements, respectively, to form a bi-directional current flow path, respectively; And
And a third inductor connected to a connection point of the fifth and sixth switching elements to generate an operating power supply voltage Vcc of the inverter. 9. The method of claim 8,
And the fifth switching element and the sixth switching element operate in a complementary relationship. The method according to claim 1,
Wherein the bidirectional DC / DC converter operates as a buck converter when operating in a load direction and operates as a boost converter in a reverse direction. 11. The method of claim 10,
Wherein the bidirectional DC / DC converter controls a speed of the motor by controlling an operation power source (Vcc) applied to the inverter when the bidirectional DC / DC converter operates as a buck converter. 11. The method as claimed in claim 10, further comprising the steps of: applying to the sixth switching device of the bidirectional DC / DC converter an output voltage of the power source (Vcc) applied to the inverter at the time of starting the motor And the duty ratio of the PWM control signal is controlled. 2. The inverter according to claim 1, wherein the inverter
Three pairs of first to sixth switching elements connected to each pair through a totem pole connection structure;
And first to sixth diodes connected in parallel to the first to sixth switching elements,
And an AC drive signal is applied to the three-phase stator coils of the three-phase drive type motor from the U, V, W connection points of the three pairs of first to sixth switching elements connected to the totem pole. Device. 14. The method of claim 13,
Wherein when the rotation speed of the motor is small, the first to sixth switching elements constituting the inverter are controlled to short-circuit the U, V, and W connection points to generate a dynamic break to stop the motor And a power returning function. 14. The method of claim 13,
Wherein the first to sixth diodes have a rectifying function when the counter electromotive force (BEMF) generated from the motor is converted into DC according to the deceleration of the motor. The method according to claim 1,
And a second capacitor connected in parallel between the bidirectional DC / DC converter and the inverter. An AC-DC conversion step of increasing the AC power supplied from the AC power source side simultaneously with the AC-DC conversion and charging the first capacitor;
A DC-DC conversion step of dropping the voltage charged in the first capacitor to a voltage Vcc of the inverter driving the motor and outputting the voltage; And
Generating three-phase AC power necessary for driving the motor in the inverter using the operating power supply (Vcc) and applying the three-phase AC power to the three-phase stator coil of the motor,
(BEMF) generated by the motor when the motor decelerates, converts the DC power into DC, and then DC-AC conversion is performed to return the power.
Wherein the AC-DC conversion step performs a power factor correcting function that increases the power factor by sending the current of the AC power source in synchronization with the input voltage. 18. The method of claim 17,
Converting the counter electromotive force (BEMF) generated from the motor at the time of deceleration of the motor into DC by the inverter;
A DC-DC conversion step of boosting a DC voltage applied from the inverter to a voltage higher than a peak voltage of an AC power source side to charge the first capacitor; And
And a DC-AC converting step of returning power to the AC power source side by DC-AC conversion when the DC voltage charged in the first capacitor is higher than the peak voltage of the AC power source side Way. The motor drive method according to claim 18, wherein the motor is connected to a washing machine of a washing machine, and a counter electromotive force (BEMF) is generated from the motor by the rotation energy of the washing machine when the motor is decelerated. The motor drive method according to claim 17, wherein the speed of the motor is controlled by controlling an operation power source (Vcc) applied to the inverter. 18. The method of claim 17,
And the meter of the integrated meter is driven in the reverse direction by the AC power returned to the AC power source side. An AC-DC conversion step of simultaneously boosting the AC power supplied from the AC power source side and the AC-DC conversion in the bidirectional AC / DC converter to charge the first capacitor;
A DC-DC conversion step of outputting the voltage charged in the first capacitor by reducing the voltage of the bidirectional DC / DC converter to the operating power supply (Vcc) of the inverter driving the motor; And
Generating three-phase AC power necessary for driving the motor in the inverter using the operating power supply (Vcc) and applying the three-phase AC power to the three-phase stator coil of the motor,
(BEMF) generated from the motor when the motor decelerates, converts the DC voltage applied from the inverter to a voltage higher than the peak voltage of the AC power source side in the bidirectional DC / DC converter after converting the BEMF generated from the motor to inverter DC-to-AC conversion in the bidirectional AC / DC converter by charging the capacitor to the AC power side,
Wherein the AC-DC conversion step performs a power factor correcting function that increases the power factor by sending the current of the AC power source in synchronization with the input voltage.

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