KR101936631B1 - Motor driving device and air conditioner including the same - Google Patents

Abstract

The present invention relates to a motor driving apparatus and an air conditioner having the same. A converter unit for converting an input AC power according to an embodiment of the present invention to output a DC power source for pulsating, a first capacitor for storing a DC power source pulsating from the converter unit, and a plurality of switching elements, A first inverter for outputting the converted AC power to the first motor using a voltage across the capacitor, a one-way conduction element having one end connected to one end of the first capacitor, a second conduction element connected to the other end of the one- And a second inverter having a plurality of switching elements and outputting the converted AC power to the second motor using the voltage across the second capacitor. This makes it possible to reduce the voltage increase across the first capacitor due to the counter electromotive force caused when the first motor stops.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a motor driving apparatus and an air conditioner having the same,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a motor driving apparatus and an air conditioner having the motor driving apparatus and more particularly to a motor driving apparatus capable of reducing a voltage rise across a first capacitor due to a back electromotive force The present invention relates to an air conditioner.

The air conditioner is installed to provide a comfortable indoor environment for humans by discharging cold air to the room to adjust the room temperature and purify the room air to create a pleasant indoor environment. Generally, the air conditioner includes an indoor unit which is constituted by a heat exchanger and installed in a room, and an outdoor unit which is constituted by a compressor, a heat exchanger and the like and supplies the refrigerant to the indoor unit.

An object of the present invention is to provide a motor driving apparatus capable of reducing a voltage rise across a first capacitor due to a back electromotive force generated when a first motor stops, and an air conditioner having the same.

It is another object of the present invention to provide a motor driving apparatus capable of reducing a voltage rise across a first capacitor due to a counter electromotive force generated when a first motor is stopped in a motor driving apparatus using a capacitor of a low capacity, .

According to an aspect of the present invention, there is provided a motor driving apparatus including a converter unit for converting an input AC power and outputting a pulsating DC power, a first capacitor for storing pulsating DC power from the converter unit, A first inverter having a plurality of switching elements and outputting the converted AC power to the first motor by using a voltage across the first capacitor, a one-way conduction element having one end connected to one end of the first capacitor, , A second capacitor connected between the other terminal of the one-way conduction element and the other terminal of the first capacitor, and a plurality of switching elements, and outputting the converted AC power to the second motor using the voltage across the second capacitor And a second inverter for driving the second inverter.

According to another aspect of the present invention, there is provided an air conditioner including a compressor for compressing refrigerant, a heat exchanger for performing heat exchange using compressed refrigerant, and a motor driving device for driving a motor in the compressor Wherein the motor driving apparatus includes a converter section for converting an input AC power to output a DC power source for pulsating, a first capacitor for storing a DC power source pulsating from the converter section, and a plurality of switching elements, A first inverter for outputting the converted AC power to the first motor using a voltage across the first capacitor, a one-way conduction element having one end connected to one end of the first capacitor, a second conduction element connected to the other end of the first conduction element, A second capacitor connected between the other ends of the capacitors, and a plurality of switching elements, and using the voltage across the second capacitor, And a second inverter for outputting to the motor.

According to an embodiment of the present invention, a motor driving apparatus and an air conditioner having the same include a rectifying unit for rectifying an input AC power source, a boost converter for boosting and outputting a rectified power from the rectifying unit, A first inverter that has a plurality of switching elements and outputs a converted AC power to the compressor motor using a voltage across the first capacitor; and a second inverter that uses a voltage across the first capacitor to store the rectified power A second inverter that has a second capacitor and a plurality of switching elements and outputs the converted AC power to the first fan motor using the voltage across the second capacitor; and a second inverter that reduces the voltage across the second capacitor And a voltage step-down unit for outputting the voltage that is generated when the first motor is stopped. Therefore, the voltage rise across the first capacitor due to the back electromotive force It is able to.

Specifically, at least a part of the current due to the counter electromotive force caused at the time of stopping the first motor flows through the first inverter, the one-way conduction element, and the second capacitor, and the current due to the counter electromotive force The voltage across the first capacitor due to the counter electromotive force caused when the first motor is stopped can be reduced by flowing a part of the first capacitor through the first inverter and the first capacitor.

Particularly, in a motor drive apparatus using a capacitor of a low capacity, it is possible to reduce a voltage increase across the first capacitor due to a counter electromotive force generated when the first motor stops. As a result, it is possible to prevent burnout of the first capacitor.

On the other hand, in a motor drive apparatus using a low-capacity capacitor, it is possible to drive the compressor motor and the fan motor based on the same input AC power source.

Further, by using the same second capacitor, it becomes possible to generate the fan motor drive and the operation power source.

Further, by using the voltage boosted by the boost converter by the inverter for the compressor, the torque ripple at the time of driving the motor is reduced.

Further, by using the boost converter, the power factor improving effect is generated.

1 is a diagram illustrating a configuration of an air conditioner according to an embodiment of the present invention.
2 is a schematic view of the outdoor unit and the indoor unit of FIG.
3 is a block diagram of a motor driving device in the outdoor unit of Fig.
4 is an example of a circuit diagram of the motor driving apparatus of Fig.
Figs. 5A and 6B are views referred to the description of the motor driving apparatus of Fig.
7 is an example of a circuit diagram of a motor driving apparatus according to an embodiment of the present invention.
8A to 8B are views referred to in the description of the operation of FIG.
9 is an example of a circuit diagram of a motor driving apparatus according to another embodiment of the present invention.
10 is an example of a circuit diagram of a motor driving apparatus according to another embodiment of the present invention.
11 is an example of a circuit diagram of a motor driving apparatus according to another embodiment of the present invention.
12 is an example of an internal block diagram of the converter control unit of FIG.

Hereinafter, the present invention will be described in detail with reference to the drawings.

The suffix " module " and " part " for components used in the following description are given merely for convenience of description, and do not give special significance or role in themselves. Accordingly, the terms " module " and " part " may be used interchangeably.

1 is a diagram illustrating a configuration of an air conditioner according to an embodiment of the present invention.

The air conditioner 100 according to the present invention may include an indoor unit 31 and an outdoor unit 21 connected to the indoor unit 31 as shown in FIG.

The indoor unit 31 of the air conditioner is applicable to any of the stand-type air conditioner, the wall-mounted air conditioner, and the ceiling type air conditioner, but the stand type indoor unit 31 is exemplified in the figure.

Meanwhile, the air conditioner 100 may further include at least one of a ventilator, an air purifier, a humidifier, and a heater, and may operate in conjunction with the operation of the indoor unit and the outdoor unit.

The outdoor unit 21 includes a compressor (not shown) that receives refrigerant and compresses the refrigerant, an outdoor heat exchanger (not shown) that exchanges heat between the refrigerant and outdoor air, an accumulator that extracts the gas refrigerant from the supplied refrigerant, And a four-way valve (not shown) for selecting the flow path of the refrigerant according to the heating operation. In addition, a number of sensors, valves, oil recovery devices, and the like are further included, but a description thereof will be omitted below.

The outdoor unit (21) operates the compressor and the outdoor heat exchanger to compress or heat-exchange the refrigerant according to the setting to supply the refrigerant to the indoor unit (31). The outdoor unit 21 can be driven by a demand of a remote controller (not shown) or the indoor unit 31. At this time, as the cooling / heating capacity is changed corresponding to the indoor unit to be driven, the number of operation of the outdoor unit and the number of operation of the compressor installed in the outdoor unit can be varied.

At this time, the outdoor unit 21 supplies the compressed refrigerant to the indoor unit 310 connected thereto.

The indoor unit (31) receives the refrigerant from the outdoor unit (21) and discharges the cold air to the room. The indoor unit 31 includes an indoor heat exchanger (not shown), an indoor unit fan (not shown), an expansion valve (not shown) to which refrigerant supplied is expanded, and a plurality of sensors (not shown).

At this time, the outdoor unit 21 and the indoor unit 31 are connected to each other via a communication line to transmit and receive data. The outdoor unit and the indoor unit are connected to a remote controller (not shown) by wire or wireless, can do.

The remote controller (not shown) is connected to the indoor unit 31, and inputs a control command of the user to the indoor unit, and receives and displays the status information of the indoor unit. At this time, the remote controller can communicate by wire or wireless according to the connection form with the indoor unit.

2 is a schematic view of the outdoor unit and the indoor unit of FIG.

Referring to the drawings, an air conditioner 100 is roughly divided into an indoor unit 31 and an outdoor unit 21.

The outdoor unit 21 includes a compressor 102 for compressing the refrigerant, a compressor 102b for driving the compressor, an outdoor heat exchanger 104 serving to dissipate the compressed refrigerant, An outdoor fan 105 which is disposed at one side of the heat exchanger 104 and includes an outdoor fan 105a for accelerating the heat radiation of the refrigerant and an electric motor 105b for rotating the outdoor fan 105a and an outdoor fan 105 for expanding the condensed refrigerant An accumulator 103 for temporarily storing the gasified refrigerant to remove moisture and foreign substances, and then supplying a refrigerant with a predetermined pressure to the compressor, a compressor 106 for compressing the refrigerant, a cooling / heating switching valve 110 for changing the flow path of the compressed refrigerant, And the like.

The indoor unit 31 includes an indoor heat exchanger 109 disposed inside the room and performing a cooling / heating function, an indoor fan 109a disposed at one side of the indoor heat exchanger 109 for promoting heat radiation of the refrigerant, And an indoor air blower 109 composed of an electric motor 109b for rotating the fan 109a.

At least one indoor heat exchanger 109 may be installed. At least one of an inverter compressor and a constant speed compressor may be used as the compressor 102. [

Further, the air conditioner 100 may be constituted by a cooling unit that cools the room, or a heat pump that cools or heats the room.

The compressor 102 in the outdoor unit 21 of Fig. 1 can be driven by a motor drive device (200 in Fig. 3) that drives the compressor motor 250. [

Fig. 3 is a block diagram of a motor driving apparatus in the outdoor unit of Fig. 1, and Fig. 4 is an example of a circuit diagram of the motor driving apparatus of Fig.

The motor driving apparatus 200 includes an inverter 220 for outputting a three-phase AC current to the compressor motor 250, an inverter control unit 230 for controlling the inverter 220, A converter control unit 215 for controlling the converter unit 210 and a dc-side capacitor C between the converter unit 210 and the inverter 220. [ The motor driving apparatus 200 may further include a dc voltage detection unit B, an input voltage detection unit A, an input current detection unit D, and an output current detection unit E.

The motor drive apparatus 200 receives the AC power from the system, converts the power, and supplies the converted power to the motor 250. Accordingly, the motor drive apparatus 200 may be referred to as a power conversion apparatus.

On the other hand, the motor driving apparatus according to the embodiment of the present invention uses a low-capacity dc single capacitor C of several tens of microfarads or less. For example, the low capacity dc single capacitor C may comprise a film capacitor, rather than an electrolytic capacitor.

When a capacitor of a low capacity is used, the change of the dc step voltage becomes large and pulsates, and the smoothing operation is hardly performed.

Such a motor driving apparatus having a dc short-circuit capacitor C of a low capacity of several tens of microfarads or less can be referred to as a capacitorless-based motor driving apparatus.

In the present specification, the motor driving apparatus 200 having the low-capacity dc short-circuit capacitor C will mainly be described.

The converter section 210 converts the input AC power source into the DC power source. The converter section 210 may be a concept including the rectifying section 410 and the boost converter 420.

The rectifying unit 410 receives the single-phase AC power source 201 and rectifies it to output rectified power.

To this end, the rectifying part 410 is formed by pairing the upper and lower laminated diode elements Da and Db and the lower arm diode elements D'a and D'b, which are connected in series to each other, and two pairs of upper and lower arm diode elements Are connected to each other in parallel (Da & D & a, Db & D'b). That is, they can be connected to each other in the form of a bridge.

The boost converter 420 includes an inductor L1 and a diode D1 connected in series to each other and a switching element S1 connected between the inductor L1 and the diode D1 between the rectifying part 410 and the inverter 220. [ . The energy stored in the inductor L1 can be output by turning off the switching element S1 and the energy stored in the inductor L1 can be output via the diode D1 by turning off the switching element S1 .

Particularly, in the motor driving apparatus 200 using the dc short capacitor C of a low capacity, a boosted voltage, that is, an offset voltage, can be output from the boost converter 420.

The converter control unit 215 can control the turn-on timing of the switching element S1 in the boost converter 420. [ Thus, the converter switching control signal Scc for turning-on timing of the switching element S1 can be output.

To this end, the converter control unit 215 can receive the input voltage Vs and the input current Is from the input voltage detection unit A and the input current detection unit B, respectively.

The input voltage detecting section A can detect the input voltage Vs from the input AC power supply 201. [ For example, at the front end of the rectifying part 410. [

The input voltage detecting unit A may include a resistance element, an OP AMP, or the like for voltage detection. The detected input voltage Vs can be applied to the converter control unit 215 for generation of the converter switching control signal Scc as a discrete signal in the form of a pulse.

On the other hand, the input voltage detecting section A can also detect the zero crossing point of the input voltage.

Next, the input current detection section D can detect the input current Is from the input AC power source 201. [ Specifically, it can be positioned at the front end of the rectifying part 410. [

The input current detection unit D may include a current sensor, a current transformer (CT), a shunt resistor, or the like, for current detection. The detected input voltage Is may be applied to the converter control unit 215 to generate a converter switching control signal Scc as a discrete signal in the form of a pulse.

The dc voltage detection unit B detects the voltage Vdc which is pulsated by the dc short-circuit capacitor C. For power detection, a resistance element, OP AMP, or the like can be used. The detected voltage Vdc of the dc short-circuit capacitor C may be applied to the inverter control unit 230 as a discrete signal in the form of a pulse and may be supplied to the DC voltage Vdc of the dc- The inverter switching control signal Sic can be generated.

On the other hand, unlike the drawing, the detected dc voltage is applied to the converter control unit 215 so that the converter switching control signal Scc may be used to generate it.

The inverter 220 includes a plurality of inverter switching elements and converts the smoothed direct current power supply Vdc into a three-phase alternating current power having a predetermined frequency by the on / off operation of the switching element, .

More specifically, the inverter 220 may include a plurality of switching elements. For example, the upper arm switching elements Sa, Sb, Sc and the lower arm switching elements S'a, S'b, S'c are connected in series to each other and a total of three pairs of upper and lower arm switching elements Can be connected to each other in parallel (Sa & S'a, Sb & S'b, Sc & S'c). Diodes may be connected in anti-parallel to each switching element Sa, S'a, Sb, S'b, Sc, S'c.

The inverter control unit 230 can output the inverter switching control signal Sic to the inverter 220 in order to control the switching operation of the inverter 220. [ The inverter switching control signal (Sic) is based on a switching control signal of a pulse width modulation (PWM), the motor output current flowing through the (250) (i _o) and a dc terminal capacitor ends the dc terminal voltage (Vdc), generated And output. The output current i _{o at} this time can be detected from the output current detection section E and the dc short voltage Vdc can be detected from the dc short voltage detection section B. [

The output current detection section E can detect the output current i _o flowing between the inverter 420 and the motor 250. [ That is, the current flowing in the motor 250 is detected. The output current detection unit E can detect all of the output currents ia, ib, ic of each phase or can detect the output currents of two phases using the three-phase balance.

The output current detector E may be located between the inverter 220 and the motor 250. For current detection, a current transformer (CT), a shunt resistor, or the like may be used.

The inverter control unit 230 includes an inverter control unit (not shown), a speed calculation unit (not shown), a current command generation unit (not shown), a voltage command generation unit (not shown), an axis conversion unit And a control signal output unit (not shown).

(Not shown) receives the three-phase output currents (ia, ib, ic) detected by the output current detecting unit E and converts the three-phase output currents ia, ib and ic into two phase currents iα and iβ in the stationary coordinate system.

On the other hand, the axial conversion unit (not shown) can convert the two-phase current i ?, i? Of the still coordinate system into the two-phase current id, iq of the rotational coordinate system.

)를 연산할 수 있다. 즉, 위치 신호에 기반하여, 시간에 대해, 나누면, 속도를 연산할 수 있게 된다.Based on the position signal H of the rotor input from the position sensing unit (not shown), the speed calculating unit (not shown)

) Can be calculated. That is, based on the position signal, it is possible to calculate the speed by dividing it with respect to time.

Meanwhile, the position sensing unit (not shown) may sense the rotor position of the motor 250. To this end, the position sensing unit (not shown) may include a Hall sensor.

)와 연산된 속도(

)를 출력할 수 있다.On the other hand, the speed calculating section (not shown) calculates the position (H) calculated based on the position signal H of the input rotor

) And the calculated speed (

Can be output.

)와 목표 속도(ω)에 기초하여, 속도 지령치(ω^* _r)를 연산하며, 속도 지령치(ω^* _r)에 기초하여, 전류 지령치(i^* _q)를 생성한다. 예를 들어, 전류 지령 생성부(미도시)는, 연산 속도(

)와 목표 속도(ω)의 차이인 속도 지령치(ω^* _r)에 기초하여, PI 제어기(535)에서 PI 제어를 수행하며, 전류 지령치(i^* _q)를 생성할 수 있다. 도면에서는, 전류 지령치로, q축 전류 지령치(i^* _q)를 예시하나, 도면과 달리, d축 전류 지령치(i^* _d)를 함께 생성하는 것도 가능하다. 한편, d축 전류 지령치(i^* _d)의 값은 0으로 설정될 수도 있다. On the other hand, the current command generator (not shown)

) Based on the speed command value ω ^* _r and the target speed ω and generates the current command value i ^* _q based on the speed command value ω ^* _r . For example, the current command generator (not shown)

The PI controller 535 performs the PI control based on the speed command value? ^* _{R that} is the difference between the target speed? And the target speed?, And generates the current command value i ^* _q . In the figure, the q-axis current command value (i ^* _q ) is exemplified by the current command value, but it is also possible to generate the d-axis current command value (i ^* _d ) unlike the figure. On the other hand, the value of the d-axis current command value i ^* _d may be set to zero.

On the other hand, the current command generator (not shown) may further include a limiter (not shown) for limiting the current command value i ^* _q so that the current command value i ^* _q does not exceed the allowable range.

Next, the voltage command generator (not shown) generates a voltage command generator (not shown) based on the d-axis and q-axis currents (i _d , i _q ) The d-axis and q-axis voltage instruction values (v ^* _d , v ^* _q ) are generated based on the instruction values (i ^* _d and i ^* _q ). For example, the voltage command generator (not shown) performs PI control in the PI controller 544 based on the difference between the q-axis current i _q and the q-axis current command value i ^* _q , the q-axis voltage command value (v ^* _q ) can be generated. The PI controller 548 performs PI control based on the difference between the d-axis current i _d and the d-axis current command value i ^* _d , It is possible to generate the voltage command value v ^* _d . On the other hand, the value of the d-axis voltage command value v ^* _d may be set to zero corresponding to the case where the value of the d-axis current command value i ^* _d is set to zero.

On the other hand, the voltage command generating unit (not shown), d-axis, q-axis voltage command value (v ^* _d, v ^* _q) might further include a limiter (not shown) to limit the level does not exceed the permissible range have.

On the other hand, the generated d-axis and q-axis voltage command values (v ^* _d , v ^* _q ) are input to an axial conversion unit (not shown).

)와, d축, q축 전압 지령치(v^* _d,v^* _q)를 입력받아, 축변환을 수행한다.The axis converting unit (not shown) is connected to a position calculating unit (not shown)

) And the d-axis and q-axis voltage command values (v ^* _d , v ^* _q ).

)가 사용될 수 있다.First, the axis converting unit (not shown) performs conversion from the two-phase rotating coordinate system to the two-phase stationary coordinate system. At this time, the position calculated in the speed calculation unit (not shown)

) Can be used.

Then, the axial conversion unit (not shown) performs conversion from the two-phase stationary coordinate system to the three-phase stationary coordinate system. Through this conversion, the axial conversion unit 1050 outputs the three-phase output voltage instruction values v ^* a, v ^* b, v ^* c.

The switching control signal output unit (not shown) outputs the inverter switching control signal Sic according to the pulse width modulation (PWM) method based on the three-phase output voltage instruction values v ^* a, v ^* b and v ^* And outputs it.

The output inverter switching control signal Sic may be converted into a gate driving signal in a gate driver (not shown) and input to the gate of each switching element in the inverter 220. [ As a result, the switching elements Sa, S'a, Sb, S'b, Sc, and S'c in the inverter 220 perform the switching operation.

Figs. 5A and 6B are views referred to the description of the motor driving apparatus of Fig.

First, FIG. 5A illustrates a dc short-circuit voltage Vdc when the low-capacity dc short-circuit capacitor C is connected to the rectification unit 410 without the boost converter 420 of FIG.

When the dc short capacitor C having a small capacity is used, the dc short capacitor C having a small capacity does not smooth the dc voltage source Vdc as shown in the drawing, and therefore the dc voltage source Vdc And is supplied to the inverter 220 as it is.

In this case, an average voltage is formed at a voltage of about 0.7 VL1, which is lower than the peak value VL1 of the pulsating dc short voltage Vdc.

The inverter 220 can generate three-phase AC power using the voltage of approximately 0.7 VL1, but it is difficult to smoothly drive the motor in a section of approximately 0.7 VL1 or less. Therefore, the voltage utilization rate becomes low.

Also, in the drawing, when the frequency of the input voltage is approximately 60 Hz, a voltage ripple of approximately 120 Hz corresponding to twice the frequency of the input voltage occurs.

On the other hand, when the motor 250 is driven through the inverter 220 using the pulsating voltage as shown in FIG. 5A, a torque ripple corresponding to? T1 is generated as shown in FIG. 5B. This torque ripple causes vibration and noise.

On the other hand, as the capacitance of the low-capacity dc short-circuit capacitor C becomes smaller, the current control or the like is not performed, resulting in a low input power factor characteristic.

To solve this problem, in the present invention, the boost converter 420 is disposed after the rectifying part 410 as shown in Fig.

6A illustrates the dc short voltage Vdc when the boost converter 420 of FIG. 4 and the low-capacity dc short-circuit capacitor C are used.

When the boost converter 420 is used to boost the voltage by the voltage VL2, the ripple voltage having the minimum voltage VL2 and the peak value VL2 + VL1 is output at the dc stage. According to this, approximately, an average voltage can be formed at the voltage VL1.

The inverter 220 can generate three-phase AC power using the voltage VL1 substantially, but can drive the motor smoothly in most voltage periods. Therefore, the voltage utilization ratio increases and the operation region increases.

6A, when the motor 250 is driven through the inverter 220 by the dc short voltage Vdc when the boost converter 420 and the low-capacity dc short-circuit capacitor C are used , Torque ripple corresponding to? T2 is generated as shown in Fig. 6B. That is, a torque ripple corresponding to? T2, which is smaller than? T1 in Fig. 5A, may occur. That is, the torque ripple is considerably reduced.

On the other hand, if the boost converter 420 is used, the input current Is is controlled, and as a result, the input power factor is improved.

7 is an example of a circuit diagram of a motor driving apparatus according to an embodiment of the present invention.

7, the motor driving apparatus 700 includes a rectifying unit 410, a boost converter 420, a first capacitor C, a first inverter 220, a second capacitor Cm, An inverter 720, and a voltage down converter 910. [

Among them, the boost converter 420, the first capacitor C, and the first inverter 220 may be referred to as a compressor driver 705 for driving the first motor 250, particularly, the compressor motor 250 .

The second capacitor Cm and the second inverter 720 may be referred to as a first fan drive unit 710 for driving the second motor 750, particularly, the first fan motor 750.

The compressor motor 250 requires a high voltage and the first fan motor 750 requires a lower voltage than the compressor motor 250. [

When the circuit elements for driving the compressor motor 250 and the first fan motor 750 are implemented on one board for compacting the motor driving apparatus, the required voltage is applied to the compressor motor 250, It is preferable that the required voltage of one fan motor 750 is different and reflects this.

On the other hand, when the low-capacity capacitor C is used for the dc stage, since the dc stage is pulsating, it is preferable to use the boost converter 420 as described above.

Therefore, when the compressor motor 250 and the first fan motor 750 are driven by the booster converter 420 using the boosted common dc stage, a significant amount of step-down performance must be performed for the fan motor drive There is a burden.

In order to solve this problem, in the present invention, the rectifier unit 410 is commonly used in the compressor motor 250 and the first fan motor 750.

Accordingly, a small capacity capacitor C can be used to drive the compressor motor 250, and the first fan motor 750 can be stably driven at a voltage lower than that of the compressor motor 250.

One end of the unidirectional conduction element Dp is connected to one end (a terminal) of both terminals (ab terminals) of the capacitor C of a low capacity and the other end of the one- And a second capacitor Cm connected between the other ends of the capacitors C are connected.

That is, the second capacitor Cm is connected in parallel to both the terminals (ab terminals) of the capacitor C of the low capacity, but the terminal a of both terminals ab of the capacitor C of the low capacity and the second capacitor The one-way conduction element Dp is connected between the terminals c of both terminals cd of the transistors Cm and Cm.

The one-way conduction element Dp may be a diode element as shown in the figure, but is not limited thereto, and a switching element is also possible.

The inverter controller 230 controls the switching element as a one-way conductive element at the time when the dc terminal voltage, which is the voltage across the capacitor C, suddenly rises despite the stop of the motor 250 Can be turned on.

Thereby, at least part of the current due to the induced electromotive force caused by the stop of the motor 250 can flow to the first inverter 250, the one-way conduction element Dp, and the second capacitor Cm.

On the other hand, by stopping the motor 250, another part of the current due to the induced electromotive force can flow to the first inverter 250 and the capacitor C. [

On the other hand, the boost converter 420, the first capacitor C, and the inverter for the compressor 220 are arranged in order on both terminals (a-b terminals) of the rectifying section 410.

A unidirectional conduction element Dp, a second capacitor Cm and a fan inverter 720 are arranged in order on both terminals (a-b terminals) of the capacitor C.

The rectifying part 410 is a pair of the upper and lower dam diode elements Da and Db and the lower arm diode elements D'a and D'b connected in series to each other and the two pairs of upper and lower arm diode elements are connected in parallel Da & D'a, Db & D'b). That is, they can be connected to each other in the form of a bridge.

The boost converter 420 includes an inductor L1 and a diode D1 connected in series to each other between the rectification part 410 and the first capacitor C and a switching element Q2 connected between the inductor L1 and the diode D1. (S1). The energy stored in the inductor L1 can be output by turning off the switching element S1 and the energy stored in the inductor L1 can be output via the diode D1 by turning off the switching element S1 .

 Particularly, in the motor driving apparatus 700 using a low capacity film capacitor as the dc single capacitor C, the boosted voltage may be output from the boost converter 420 at a constant voltage, that is, offset.

On the other hand, it is preferable that the capacitance of the first capacitor C is smaller than the capacitance of the second capacitor Cm. That is, it is preferable that the capacitance of the second capacitor Cm is larger than the capacitance of the first capacitor C.

It is also preferable that the level of the voltage Vc stored in the first capacitor C is larger than the level of the voltage Vcm stored in the second capacitor Cm. The voltage Vc level stored in the first capacitor C may be approximately 450 V and the voltage Vcm level stored in the second capacitor Cm may be approximately 300 V. [

As a result, the first fan motor 750 is driven stably based on the DC power source Vcm that pulsates less.

On the other hand, the voltage step-down unit 910 is connected between both terminals (cd terminals) of the second capacitor Cm and outputs a stepped down voltage by stepping down the voltage Vcm across the second capacitor Cm .

To this end, the voltage down converter 910 may include a switch mode power supply (SMPS). The output voltage may be an operating power (Vcc) of approximately 15V, 7.5V, or 5V. The operating power source may be used as an operating power source for the inverter 220 and the inverter controller 230.

In this manner, the same second capacitor Cm can be used to drive the fan motor and generate operating power, so that the design of the voltage step-down unit 910 can be facilitated.

8A to 8B are views referred to in the description of the operation of FIG.

First, FIG. 8A is a diagram showing current flow during operation of the first motor 250 and the second motor 750. FIG.

The control unit 230 may output the switching control signals for operating the first motor 250 and the second motor 750 to the first inverter 220 and the second inverter 730, respectively.

As a result, the current based on the voltage stored in the capacitor C of the low capacity flows to the first motor 250 via the first inverter 220 as shown in Path 1 in the drawing.

On the other hand, a voltage is stored in the second capacitor Cm through the low-capacitance capacitor C and the one-way conduction element Dp.

Then, the current based on the voltage stored in the second capacitor C flows to the second motor 705 through the second inverter 720 as shown in Path 2 in the figure.

Next, FIG. 8B is a diagram showing current flow when the first motor 250 is stopped.

When the first motor 250 in operation is stopped, a counter electromotive force is caused by the stop of the first motor 250. Then, the current based on the induced counter electromotive force flows through the diode element or the like in the first inverter 220 to the capacitor C of the low capacity.

In this case, a part of the current based on the counter electromotive force induced in the first motor 250 due to the second capacitor Cm and the one-way conduction element Dp, which are connected in parallel to both ends of the capacitor C of the low capacity, And flows in the direction of the second capacitor Cm.

8B, a part of the current based on the counter electromotive force induced in the first motor 250 flows through the first inverter 220, the one-way conduction element Dp, the second capacitor Cm, Lt; / RTI >

On the other hand, another part of the current based on the counter electromotive force induced in the first motor 250 flows to the first inverter 220 and the first capacitor C of a small capacity, like Pathb shown in FIG. 8B.

Accordingly, it is possible to reduce the voltage rise of the first capacitor C due to the counter electromotive force generated when the first motor 250 is stopped. Particularly, it is possible to prevent a small amount of the first capacitor C from being burned out.

On the other hand, when the second motor 750 in operation is stopped, a counter electromotive force is caused by the stop of the second motor 750. Then, a current based on the induced counter-electromotive force flows through the diode element or the like in the second inverter 720 to the second capacitor Cm.

On the other hand, since the capacitance of the second capacitor Cm is larger than that of the first capacitor C, the possibility of burnout is low.

On the other hand, the current due to the counter electromotive force caused by the stop of the second motor 750 can not flow to the first capacitor C due to the one-way conduction element Dp, . ≪ / RTI >

9 is an example of a circuit diagram of a motor driving apparatus according to another embodiment of the present invention.

9, the motor driving apparatus 800 of FIG. 9 is similar to the motor driving apparatus 700 of FIG. 7, except that a switching element for a fan, which is disposed between the single-phase input AC power source 201 and the rectifying section 410, (Saf) can be further provided.

Then, the third motor 805, particularly, the AC type second fan motor 805 operates immediately by the ON operation of the switching element Saf for the fan. Therefore, the motor drive apparatus 800 of FIG. 9 can stably drive the compressor motor 250, the first fan motor 750, and the second fan motor 805.

10 is an example of a circuit diagram of a motor driving apparatus according to another embodiment of the present invention.

10, the motor driving apparatus 900 of FIG. 10 is similar to the motor driving apparatus 700 of FIG. 7 except that three-phase input AC power sources 201a, 201b and 201c are used .

Accordingly, the rectifying section 510 receives the three-phase input AC power sources 201a, 201b, and 201c, and rectifies and outputs the rectified power.

To this end, the rectifying part 510 may include a three-phase bridge diode. The rectifying part 510 is a pair of the upper-arm diode elements Da, Db and Dc and the lower-arm diode elements D'a, D'b and D'c connected in series to each other, And that the diode elements are connected in parallel to each other (Da & D & a, Db & D'b, Dc & D'c). That is, they can be connected to each other in the form of a bridge.

11 is an example of a circuit diagram of a motor driving apparatus according to another embodiment of the present invention.

11 is similar to the motor driving apparatus 900 of FIG. 10 except that the two phases 201a and 201b of the three-phase input AC power sources 201a, 201b and 201c, And a switching element (Saf) for the fan which is disposed between the switching element (Saf).

Then, the third motor, particularly, the AC type second fan motor 805 operates immediately by the ON operation of the switching element Saf for the fan. Therefore, the motor driving apparatus 1000 of Fig. 11 can stably drive the compressor motor 250, the first fan motor 750, and the second fan motor 805. [

12 is an example of an internal block diagram of the converter control unit of FIG.

Referring to the drawing, the converter controller 215 may include an input current command generator 720, a current controller 730, and a deflector 740.

The input current command generation section 720 receives the input voltage Vs detected by the input voltage detection section A and can generate the input current command value I ^* s based on the input voltage Vs .

The subtractor 725 calculates the difference between the input current command value I ^* s and the input current Is detected by the input current detector D and applies the difference to the current controller 730.

The current control section 730 outputs a first switching control signal (first duty control signal) corresponding to the first duty based on the input current instruction value I ^* s and the input current Is detected by the input current detection section D Sp1).

Specifically, the current controller 730 generates the first switching control signal corresponding to the first duty based on the difference between the input current command value I ^* s and the input current Is.

On the other hand, the forward compensation unit 740 performs feed-forward compensation to remove the disturbance caused by the input voltage Vs and the dc voltage Vdc of the boost converter 420. Accordingly, the deflection compensation unit 740 can generate the second switching control signal Sp2 corresponding to the second duty, taking into consideration disturbance cancellation.

The adder 735 can output the converter switching control signal Scc by adding the first switching control signal Sp1 and the second switching control signal Sp2. That is, the adder 735 can output the converter switching control signal Scc in consideration of the first duty and the second duty.

The motor driving apparatus and the air conditioner having the same according to the present invention are not limited to the configuration and the method of the embodiments described above but the embodiments can be applied to all of the embodiments Or some of them may be selectively combined.

Meanwhile, the motor driving apparatus or the air conditioner operating method of the present invention can be implemented as a processor-readable code on a recording medium readable by a processor included in a motor driving apparatus or an air conditioner. The processor-readable recording medium includes all kinds of recording apparatuses in which data that can be read by the processor is stored. Examples of the recording medium that can be read by the processor include a ROM, a RAM, a CD-ROM, a magnetic tape, a floppy disk, an optical data storage device, and the like, and may also be implemented in the form of a carrier wave such as transmission over the Internet . In addition, the processor-readable recording medium may be distributed over network-connected computer systems so that code readable by the processor in a distributed fashion can be stored and executed.

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 exemplary embodiments, but, on the contrary, It will be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the spirit and scope of the present invention.

Claims (15)

A converter unit for converting input AC power to output pulsating DC power;
A first capacitor for storing a DC power source pulsating from the converter unit;
A first inverter having a plurality of switching elements, using a voltage across the first capacitor, for outputting the converted AC power to the first motor;
A one-way conduction element having one end connected to one end of the first capacitor;
A second capacitor connected between the other end of the one-way conduction element and the other end of the first capacitor;
And a second inverter having a plurality of switching elements and using the voltage across the second capacitor to output the converted AC power to the second motor,
Wherein a capacitance of the first capacitor is smaller than a capacitance of the second capacitor,
Part of the current due to the counter electromotive force caused when the first motor is stopped flows through the first inverter, the one-way conduction element, and the second capacitor,
Another part of the current due to the counter electromotive force caused when the first motor is stopped flows through the first inverter and the first capacitor,
A current due to a counter electromotive force caused when the second motor is stopped flows through the second inverter and the second capacitor,
Wherein the unidirectional conduction element blocks the current due to the counter electromotive force caused when the second motor is stopped from flowing to the first capacitor. delete delete The method according to claim 1,
The converter unit includes:
A rectifying unit for rectifying the input AC power;
And a boost converter for boosting a power source rectified by the rectifying unit and outputting the boosted power,
Wherein the first capacitor comprises:
And stores the pulsating DC power from the boost converter. 5. The method of claim 4,
The boost converter includes:
An inductor and a diode connected in series between the rectifying unit and the first capacitor;
And a switching element connected between the inductor and the diode. The method according to claim 1,
And a voltage step-down unit for stepping down the voltage across the second capacitor and outputting the step-down voltage. 5. The method of claim 4,
Further comprising a switching element disposed between the input AC power supply and the rectifying part,
And the third motor is operated by the ON operation of the switching element. The method according to claim 1,
Wherein the first motor is a compressor motor,
And the second motor is a fan motor. The method according to claim 1,
Wherein a voltage level stored in the first capacitor is greater than a voltage level stored in the second capacitor. The method according to claim 1,
Wherein the first capacitor comprises a film capacitor. The method according to claim 1,
An input current detector for detecting an input current from the input AC power supply;
An input voltage detector for detecting an input voltage from the input AC power supply; And
Further comprising a converter control unit for outputting a converter switching control signal for controlling a switching element in the converter unit based on the input current and the input voltage. 12. The method of claim 11,
The converter control unit includes:
An input current command generator for generating an input current command value based on the detected input voltage;
And a current control unit for generating a first switching control signal based on the input current command value and the detected input current. 13. The method of claim 12,
The converter control unit includes:
And a directional compensation unit for generating a second switching control signal,
And outputs the converter switching control signal based on the first switching control signal and the second switching control signal. The method according to claim 1,
A dc voltage detection unit detecting a dc voltage between the converter unit and the first inverter;
An output current detector for detecting an output current flowing to the first motor; And
And an inverter control unit for controlling the first inverter based on the detected dc voltage and the detected output current. An air conditioner comprising: the motor driving apparatus according to any one of claims 1 to 4.

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