KR102313302B1 - Motor driving device and air conditioner including the same - Google Patents

Abstract

The present invention relates to a motor driving device and an air conditioner having the same. A motor driving device according to an embodiment of the present invention includes a rectifying unit for rectifying an input AC power, a boost converter for boosting and outputting the power rectified from the rectifying unit, and a capacitor for storing the pulsating dc terminal voltage from the boost converter; An output current detector for detecting an output current flowing through the motor, a dc voltage detector for detecting a pulsating dc end voltage across the capacitor, and a plurality of switching elements, using the pulsating dc end voltage, converts AC power It includes an inverter that outputs to the motor, and a control unit that controls the inverter based on the detected instantaneous value of the detected pulsating dc terminal voltage and the output current. Accordingly, in the motor driving apparatus using the boost converter and the low-capacitance capacitor, it is possible to improve the driving efficiency at the time of driving the motor.

Description

A motor driving device and an air conditioner having the same

The present invention relates to a motor driving device and an air conditioner having the same, and more particularly, to a motor driving device capable of improving driving efficiency when driving a motor in a motor driving device using a boost converter and a low-capacitance capacitor, and the same. It relates to an air conditioner provided.

The air conditioner is installed to provide a more comfortable indoor environment to humans by discharging hot and cold air into the room to create a comfortable indoor environment, controlling the indoor temperature, and purifying the indoor air. In general, an air conditioner includes an indoor unit configured as a heat exchanger and installed indoors, and an outdoor unit configured as a compressor and a heat exchanger and supplying a refrigerant to the indoor unit.

SUMMARY OF THE INVENTION An object of the present invention is to provide a motor driving device capable of improving operating efficiency when driving a motor in a motor driving device using a boost converter and a low-capacitance capacitor, and an air conditioner having the same.

A motor driving apparatus according to an embodiment of the present invention for achieving the above object includes a rectifying unit for rectifying an input AC power, a boost converter for boosting and outputting the power rectified from the rectifying unit, and a pulsating dc stage from the boost converter A capacitor for storing a voltage, an output current detector for detecting an output current flowing through the motor, a dc end voltage detector for detecting a pulsating dc end voltage across the capacitor, and a plurality of switching elements, using the pulsating dc end voltage Accordingly, the inverter includes an inverter for outputting the converted AC power to the motor, and a controller for controlling the inverter based on the detected instantaneous value of the detected pulsating dc terminal voltage and the output current.

On the other hand, a motor driving apparatus according to another embodiment of the present invention for achieving the above object includes: a boost converter for boosting and outputting power rectified from a rectifier; and a capacitor for storing the pulsating dc voltage from the boost converter; An inverter including a dc terminal voltage detection unit detecting a pulsating dc terminal voltage across the capacitor, a plurality of switching elements, and outputting the converted AC power to the motor using the pulsating dc terminal voltage; and a control unit for generating a current command value proportional to an instantaneous value of , and generating an inverter switching control signal for inverter control based on the current command value.

Meanwhile, an air conditioner according to an embodiment of the present invention for achieving the above object includes the motor driving device according to the various embodiments described above.

According to an embodiment of the present invention, a motor driving device and an air conditioner having the same include a rectifier for rectifying input AC power, a boost converter for boosting and outputting the power rectified from the rectifier, and pulsating dc from the boost converter. A capacitor for storing the short voltage, an output current detecting unit for detecting an output current flowing through the motor, a dc short voltage detecting unit detecting a pulsating dc end voltage across the capacitor, and a plurality of switching elements, wherein the pulsating dc end voltage is provided By using an inverter that outputs the converted AC power to the motor, and a control unit that controls the inverter based on the detected instantaneous value of the detected pulsating dc terminal voltage, and the output current, a boost converter and a low-capacitance capacitor are included. In a motor drive device, in spite of the voltage across the pulsating capacitor, the operable range for the load is extended. Accordingly, the operating efficiency of the motor driving device is improved.

In particular, by generating a current command value proportional to the instantaneous value of the detected pulsating dc terminal voltage, and generating an inverter switching control signal for inverter control based on the current command value, it is possible to improve the voltage utilization rate of the inverter.

On the other hand, when the magnitude of the pulsating dc voltage is smaller than the target voltage of the motor, by controlling the over-modulation operation or the field-weakening operation not to be performed, it is possible to prevent the inability to control or stop the motor, thereby enabling the stable driving of the motor. do.

On the other hand, by varying the dc terminal voltage shaping waveform according to the back electromotive force induced by the motor, it is possible to improve the driving efficiency at the time of driving the motor.

Meanwhile, according to another embodiment of the present invention, a motor driving device and an air conditioner having the same include a boost converter that boosts and outputs power rectified from a rectifier, and a capacitor that stores a pulsating dc terminal voltage from the boost converter; , A dc terminal voltage detection unit for detecting the pulsating dc terminal voltage across the capacitor, an inverter having a plurality of switching elements, and outputting the converted AC power to the motor by using the pulsating dc terminal voltage, and the detected pulsating dc terminal In a motor driving apparatus using a boost converter and a low-capacitance capacitor, the pulsation circuit includes a control unit that generates a current command value proportional to the instantaneous value of the voltage and generates an inverter switching control signal for inverter control based on the current command value. Despite the voltage across the capacitor, the operable range for the load is expanded. Accordingly, the operating efficiency of the motor driving device is improved.

In addition, by using the voltage boosted by the boost converter by the inverter, the torque ripple at the time of driving the motor is reduced.

In addition, by using the boost converter, a power factor improvement effect occurs.

1 is a diagram illustrating the configuration of an air conditioner according to an embodiment of the present invention.
FIG. 2 is a schematic diagram of an outdoor unit and an indoor unit of FIG. 1 .
FIG. 3 is a block diagram of a compressor motor driving device in the outdoor unit of FIG. 1 .
FIG. 4 is an example of a circuit diagram of the motor driving apparatus of FIG. 3 .
5A to 6B are diagrams referenced in the description of the motor driving apparatus of FIG. 4 .
FIG. 7 is an example of an internal block diagram of the converter control unit of FIG. 4 .
FIG. 8 is an example of an internal block diagram of the inverter control unit of FIG. 4 .
9 to 11C are diagrams with reference to the operation of the inverter control unit of FIG. 8 .

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

The suffixes "module" and "part" for the components used in the following description are given simply in consideration of the ease of writing the present specification, and do not give a particularly important meaning or role by themselves. Accordingly, the terms “module” and “unit” may be used interchangeably.

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

As shown in FIG. 1 , 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 .

The indoor unit 31 of the air conditioner may be any of a stand-type air conditioner, a wall-mounted air conditioner, and a ceiling-type air conditioner, but in the drawings, the stand-type indoor unit 31 is exemplified.

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 and compresses a refrigerant, an outdoor heat exchanger (not shown) that exchanges heat between the refrigerant and outdoor air, and an accumulator (not shown) that extracts a gaseous refrigerant from the supplied refrigerant and supplies it to the compressor. time) and a four-way valve (not shown) for selecting a flow path of the refrigerant according to the heating operation. In addition, it further includes a plurality of sensors, valves, and an oil recovery device, but a description of its configuration will be omitted below.

The outdoor unit 21 operates a provided compressor and an outdoor heat exchanger to compress or heat exchange a refrigerant according to a setting to supply the refrigerant to the indoor unit 31 . The outdoor unit 21 may be driven by a remote controller (not shown) or a demand of the indoor unit 31 . In this case, as the cooling/heating capacity is changed corresponding to the driven indoor unit, it is also possible that the operating number of the outdoor unit and the operating number of the compressor installed in the outdoor unit are varied.

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

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

At this time, the outdoor unit 21 and the indoor unit 31 are connected through a communication line to transmit and receive data, and the outdoor unit and the indoor unit are connected to a remote controller (not shown) by wire or wirelessly and operate according to the control of the remote controller (not shown). can do.

A remote controller (not shown) may be connected to the indoor unit 31 to input a user's control command to the indoor unit, and may receive and display status information of the indoor unit. In this case, the remote control can communicate with the indoor unit by wire or wirelessly depending on the connection type.

FIG. 2 is a schematic diagram of an outdoor unit and an indoor unit of FIG. 1 .

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

The outdoor unit 21 includes a compressor 102 serving to compress the refrigerant, a compressor electric motor 102b for driving the compressor, an outdoor heat exchanger 104 serving to radiate heat from the compressed refrigerant, and an outdoor unit. An outdoor blower 105 comprising an outdoor fan 105a disposed on one side of the heat exchanger 104 to promote heat dissipation of the refrigerant and an electric motor 105b rotating the outdoor fan 105a, and expansion to expand the condensed refrigerant The mechanism 106, the cooling/heating switching valve 110 for changing the flow path of the compressed refrigerant, and the accumulator 103 for temporarily storing the vaporized refrigerant to remove moisture and foreign substances and then supplying the refrigerant at a constant pressure to the compressor etc.

The indoor unit 31 includes an indoor heat exchanger 109 disposed indoors to perform a cooling/heating function, an indoor fan 109a disposed at one side of the indoor heat exchanger 109 to promote heat dissipation of the refrigerant, and an indoor unit. and an indoor blower 109 including an electric motor 109b that rotates 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 .

In addition, the air conditioner 100 may be configured as an air conditioner for cooling the room, or may be configured as a heat pump for cooling or heating the room.

The compressor 102 in the outdoor unit 21 of FIG. 1 may be driven by a compressor motor driving device ( 200 of FIG. 3 ) that drives the compressor motor 250 .

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

Referring to the drawings, the compressor motor driving device 200 includes an inverter 220 for outputting a three-phase alternating current to the compressor motor 250 , an inverter controller 230 for controlling the inverter 220 , and an inverter 220 . It may include a converter 210 for supplying DC power to the converter 210 , a converter controller 215 for controlling the converter 210 , and a dc terminal capacitor C between the converter 210 and the inverter 220 . Meanwhile, the compressor motor driving apparatus 200 may further include a dc stage 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 driving device 200 receives AC power from the system, converts power, and supplies the converted power to the motor 250 . Accordingly, the motor driving device 200 may also be referred to as a power conversion device.

On the other hand, in the motor driving apparatus according to the embodiment of the present invention, it is assumed that a low-capacity dc terminal capacitor C of several tens of μF or less is used. For example, the low-capacity dc terminal capacitor C may include a film capacitor, not an electrolytic capacitor.

When a low-capacity capacitor is used, the change in the dc terminal voltage becomes large, pulsating, and the smoothing operation is hardly performed.

A motor driving device having such a low-capacity dc terminal capacitor C of several tens of μF or less may be referred to as a capacitorless-based motor driving device.

In this specification, the motor driving device 200 having a low-capacity dc stage capacitor (C) will be mainly described.

The converter 210 converts the input AC power to DC power. The converter 210 may be a concept including a rectifier 410 and a boost converter 420 . On the other hand, the input power based on the input AC power can be named Pgrid.

The rectifying unit 410 receives and rectifies the single-phase AC power 201 and outputs the rectified power.

To this end, in the rectifying unit 410, the upper-arm diode elements Da, Db and the lower-arm diode elements D'a, D'b each connected in series become a pair, and a total of two pairs of upper and lower arm diode elements are formed. It is exemplified that they are connected to each other in parallel (Da&D'a, Db&D'b). That is, they may 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 with each other, and a switching element S1 connected between the inductor L1 and the diode D1 between the rectifying unit 410 and the inverter 220 . ) is provided. When the switching element S1 is turned on, energy is stored in the inductor L1, and when the switching element S1 is turned off, the energy stored in the inductor L1 is output through the diode D1. .

In particular, in the motor driving device 200 using the low-capacity dc stage capacitor C, a voltage in which a constant voltage is boosted, that is, an offset voltage, may be output from the boost converter 420 .

The converter controller 215 may control the turn-on timing of the switching element S1 in the boost converter 420 . Accordingly, the converter switching control signal Scc for the turn-on timing of the switching element S1 may be output.

To this end, the converter control unit 215 may 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 detection unit A can detect the input voltage Vs from the input AC power supply 201 . For example, it may be located in front of the rectifying unit 410 .

The input voltage detection unit A may include a resistance element, an OP AMP, and the like for voltage detection. The detected input voltage Vs is a discrete signal in the form of a pulse, and may be applied to the converter controller 215 to generate the converter switching control signal Scc.

On the other hand, the zero crossing point of the input voltage can also be detected by the input voltage detection unit A.

Next, the input current detection unit D may detect the input current Is from the input AC power supply 201 . Specifically, it may be located in front of the rectifying unit 410 .

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

The dc voltage detection unit B detects the pulsating voltage Vdc of the dc terminal capacitor C. For power detection, a resistive element, an OP AMP, or the like may be used. The detected voltage Vdc of the dc stage capacitor C is a discrete signal in the form of a pulse, and may be applied to the inverter control unit 230 and is applied to the DC voltage Vdc of the dc stage capacitor C. Based on the inverter switching control signal Sic may be generated.

Meanwhile, unlike the drawing, the detected dc voltage may be applied to the converter control unit 215 to generate the converter switching control signal Scc.

The inverter 220 includes a plurality of inverter switching elements, converts the smoothed DC power (Vdc) by the on/off operation of the switching elements into three-phase AC power of a predetermined frequency, and outputs to the three-phase motor 250 . can

Accordingly, the inverter 220 may supply the inverter power Pinv to the motor 250 serving as a load. In this case, the inverter power Pinv is power required by the motor 250 serving as a load, and can follow the required target power. Accordingly, in this specification, the inverter power Pinv may be described as the same concept as the target power required by the load.

Specifically, the inverter 220 may include a plurality of switching elements. For example, a pair of upper-arm switching elements (Sa, Sb, Sc) and lower-arm switching elements (S'a, S'b, S'c) connected in series with each other are a pair, and a total of three pairs of upper and lower arm switching elements are provided. may be connected to each other in parallel (Sa&S'a, Sb&S'b, Sc&S'c). In addition, a diode may be connected in anti-parallel to each of the switching elements Sa, S'a, Sb, S'b, Sc, and S'c.

The inverter controller 230 may 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 a switching control signal of the pulse width modulation method (PWM), based on the output current (i _o ) flowing through the motor 250 and the dc terminal voltage (Vdc) across the dc terminal capacitor, generated can be printed out. At this time, the output current i _o may be detected from the output current detection unit E, and the dc terminal voltage Vdc may be detected from the dc terminal voltage detection unit B.

The output current detection unit E may detect the _{output current i o} flowing between the inverter 420 and the motor 250 . That is, the current flowing through the motor 250 is detected. The output current detection unit E may detect all of the output currents ia, ib, and ic of each phase, or may detect the output currents of two phases using three-phase balance.

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

Meanwhile, the inverter control unit 230 includes a torque command generator (510 in FIG. 8 ), a current command generator ( 530 in FIG. 8 ), a voltage command generator ( 540 in FIG. 8 ), and a switching control signal output unit ( FIG. 8 ). 560 of 8). In addition, it may further include a power command generation unit (520 in FIG. 8), a power controller (525 in FIG. 8), and a Vdc voltage waveform detection unit (535 in FIG. 8). This will be described in more detail with reference to FIG. 8 or less.

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

On the other hand, in relation to the embodiment of the present invention, based on the pulsating Vdc voltage, in order to more stably drive the motor 250 as a load, in particular, in order to expand the range of the operation area, the motor driving device 200 The inverter control unit 230 of the , controls the inverter 220 based on the instantaneous power command value of the inverter power Pinv.

In particular, when the inverter power (Pinv) for driving the motor 250 is less than the reference power, the inverter control unit 230 controls the inverter 220 based on the average power command value of the inverter power (Pinv) as the first mode. When the inverter power Pinv for driving the motor 250 is equal to or greater than the reference power, the inverter 220 may be controlled based on the instantaneous power command value of the inverter power Pinv. Accordingly, the boost converter 420 and the motor driving device 200 using the low-capacity capacitor C can be driven stably with respect to the load. This will be described in more detail in the description of FIG. 8 .

5A to 6B are diagrams referenced in the description of the motor driving apparatus of FIG. 4 .

First, FIG. 5A exemplifies the dc stage voltage Vdc when the low-capacity dc stage capacitor C is connected to the rectifier 410 without the boost converter 420 of FIG. 4 .

When a low-capacity dc terminal capacitor (C) is used, as shown in the figure, the low-capacity dc terminal capacitor (C) does not smooth the dc terminal voltage (Vdc), and thus the pulsating dc terminal voltage (Vdc) is It is supplied to the inverter 220 as it is.

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

The inverter 220 may generate a three-phase AC power supply using a voltage of approximately 0.7VL1, but it is difficult to smoothly drive the motor in a section below the voltage of approximately 0.7VL1. Accordingly, the voltage utilization rate is lowered.

Also, referring to the drawings, when the frequency of the input voltage is about 60 Hz, a voltage ripple of about 120 Hz, which is twice the frequency, is generated.

Meanwhile, when the motor 250 is driven through the inverter 220 using the pulsating voltage as shown in FIG. 5A , a torque ripple corresponding to ΔT1 is generated as shown in FIG. 5B . Due to this torque ripple, vibration and noise are generated.

On the other hand, as the capacitance of the low-capacity dc terminal capacitor C decreases, current control is not performed, so that a low input power factor characteristic occurs.

In order to solve this point, in the present invention, as shown in FIG. 4 , the boost converter 420 is disposed after the rectifier 410 .

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

When the boost converter 420 is used to boost the voltage by VL2, the minimum voltage is VL2, and the pulsating voltage whose peak value is VL2+VL1 is output to the dc terminal. According to this, roughly, an average voltage can be formed at the VL1 voltage.

The inverter 220 may generate a three-phase AC power supply using approximately VL1 voltage, but in most voltage sections, it is possible to smoothly drive the motor. Accordingly, the voltage utilization rate is increased, and the operation area is increased.

On the other hand, when driving the motor 250 through the inverter 220 by the dc stage voltage (Vdc) in the case of using the boost converter 420 and the low-capacity dc stage capacitor (C) as shown in FIG. 6a , a torque ripple corresponding to ΔT2 occurs as shown in FIG. 6B . That is, a torque ripple corresponding to ΔT2 smaller than ΔT1 of FIG. 5A may occur. That is, the torque ripple is significantly reduced.

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

FIG. 7 is an example of an internal block diagram of the converter control unit of FIG. 4 .

Referring to the drawing, the converter control unit 215 may include an input current command generation unit 720 , a current flow control unit 730 , and a forward compensating unit 740 .

The input current command generation unit 720 may receive the input voltage Vs detected by the input voltage detection unit A, and generate an ^{input current command value I * s based on the input voltage Vs.} .

On the other hand, the subtractor 725 ^{calculates a difference between the input current command value I *} s and the input current Is detected by the input current detection unit D, and applies the difference to the current control unit 730 .

The current control unit 730, based on the input current command value (I ^* s) and the input current (Is) detected by the input current detection unit (D), the first switching control signal corresponding to the first duty (duty) ( Sp1) is created.

Specifically, the current controller 730 generates a first switching control signal corresponding to a first duty based on a 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 in order to remove the disturbance composed of the input voltage Vs and the dc terminal voltage Vdc of the boost converter 420 . Accordingly, the forward compensator 740 may generate the second switching control signal Sp2 corresponding to the second duty in consideration of the disturbance removal.

The adder 735 may add the first switching control signal Sp1 and the second switching control signal Sp2 to output the converter switching control signal Scc. That is, the adder 735 may output the converter switching control signal Scc in consideration of the first duty and the second duty.

8 is an example of an internal block diagram of the inverter control unit of FIG. 4 , and FIGS. 9 to 11C are diagrams referenced for the operation of the inverter control unit of FIG. 8 .

First, referring to FIG. 8 , the inverter control unit 230 includes an axis converting unit 510 , a speed calculating unit 520 , a current command generating unit 530 , a voltage command generating unit 540 , and an axis converting unit 550 . , and a switching control signal output unit 560 .

The axis conversion unit 510 receives the three-phase output current (ia, ib, ic) detected by the output current detection unit (E) and converts it into a two-phase current (iα, iβ) of a stationary coordinate system.

Meanwhile, the axis conversion unit 510 may convert the two-phase currents (iα, iβ) of the stationary coordinate system into the two-phase currents (id, iq) of the rotational coordinate system.

)와 연산된 속도(

)를 출력할 수 있다.The speed calculating unit 520, the calculated position (

) and the calculated speed (

) can be printed.

)와 속도 지령치(ω^* _r)에 기초하여, 전류 지령치(i^* _q)를 생성한다. 예를 들어, 전류 지령 생성부(530)는, 연산 속도(

)와 속도 지령치(ω^* _r)의 차이에 기초하여, PI 제어기(535)에서 PI 제어를 수행하며, 전류 지령치(i^* _q)를 생성할 수 있다. On the other hand, the current command generation unit 530, the calculation speed (

) and the speed command value (ω ^* _r ), a current command value (i ^* _q ) is generated. For example, the current command generation unit 530 may set the calculation speed (

) and the speed command value (ω ^* _r ) based on the difference, the PI controller 535 performs PI control, it is possible to generate a ^{current command value (i *} _{q ).}

In the figure, the q-axis current command value (i ^* _q ) and the d-axis current command value (i ^* _d ) are exemplified as the current command value. On the other hand, the value of the d-axis current command value (i ^* _d ) may be set to 0.

On the other hand, the current command generation unit 530, the current command value (i ^* _q ) may further include a limiter (not shown) for limiting the level so as not to exceed the allowable range.

Next, the voltage command generation unit 540 includes the d-axis and q-axis currents (i _d ,i _q ) that are axis-transformed into the two-phase rotational coordinate system by the axis transformation unit, and the current command value ( Based on i ^* _d ,i ^* _q ), d-axis and q-axis voltage command values (v ^* _d ,v ^* _q ) are generated. For example, the voltage command generation unit 540 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 ), q} A shaft voltage setpoint (v ^* _q ) can be generated. In addition, the voltage command generator 540 performs PI control in the PI controller 548 based on the difference between the _{d-axis current (i d} ) and the d-axis current command value (i ^* _{d), and the d-axis voltage} A setpoint (v ^* _d ) can be generated. On the other hand, the voltage command generation unit 540, the d-axis, q-axis voltage command values (v ^* _d , v ^* _q ) may further include a limiter (not shown) for limiting the level so as not to exceed the allowable range. .

On the other hand, the generated d-axis and q-axis voltage command values (v ^* _d , v ^* _q ) are input to the axis conversion unit 550 .

)와, d축, q축 전압 지령치(v^* _d,v^* _q)를 입력받아, 축변환을 수행한다.The axis conversion unit 550, the position calculated by the speed calculating unit 520 (

) and d-axis and q-axis voltage command values (v ^* _d ,v ^* _q ) are received and axis transformation is performed.

)가 사용될 수 있다.First, the axis transformation unit 550 performs transformation from a two-phase rotational coordinate system to a two-phase stationary coordinate system. At this time, the position calculated by the speed calculating unit 520 (

) can be used.

Then, the axis transformation unit 550 performs transformation from the two-phase stationary coordinate system to the three-phase stationary coordinate system. Through this conversion, the shaft conversion unit 1050 outputs a three-phase output voltage command value (v ^* a, v ^* b, v ^* c).

The switching control signal output unit 560 generates a switching control signal (Sic) for an inverter according to a pulse width modulation (PWM) method based on the three-phase output voltage command value (v ^* a, v ^* b, v ^{* c)} to output

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

Meanwhile, the inverter controller 230 may control the inverter 220 based on the detected instantaneous value of the pulsating dc terminal voltage Vdc and the output current. Accordingly, in spite of the pulsating voltage Vdc across the capacitor, the operable range for the load is expanded. Accordingly, the operating efficiency of the motor driving apparatus 200 is improved.

In particular, the inverter control unit 230 generates a current command value proportional to the instantaneous value of the detected pulsating dc terminal voltage (Vdc), and based on the current command value, the inverter switching control signal (Sic) for controlling the inverter 220 can create Accordingly, it is possible to improve the voltage utilization rate of the inverter 220 .

Meanwhile, when the magnitude of the pulsating dc terminal voltage Vdc is smaller than the motor target voltage Vmot, the inverter controller 230 may control the over-modulation operation or the field-weakening operation not to be performed. Accordingly, it is possible to prevent inability to control or stop the motor, thereby enabling stable driving of the motor.

)에 기초하여, 전류 지령치의 크기(Imag)를 연산하며, 검출된 맥동 dc단 전압의 순시치(Vdc_real)에 기초하여 dc단 전압 쉐이핑 파형(Vdcsh)을 연산하고, 전류 지령치의 크기(Imag), 및 dc단 전압 쉐이핑 파형(Vdcsh)에 기초하여, 생성된 인버터 스위칭 제어 신호(Sic)를 인버터(220)로 출력할 수 있다.On the other hand, the inverter control unit 230, the speed of the motor calculated based on the output current (io) (

), calculates the magnitude (Imag) of the current command value, calculates the dc stage voltage shaping waveform (Vdcsh) based on the detected instantaneous value (Vdc_real) of the detected pulsating dc stage voltage, and calculates the magnitude (Imag) of the current command value , and the generated inverter switching control signal Sic based on the dc terminal voltage shaping waveform Vdcsh may be output to the inverter 220 .

)에 기초하여, 전류 지령치의 크기(Imag)를 연산하며, 검출된 맥동 dc단 전압의 순시치(Vdc_real)에 기초하여 dc단 전압 쉐이핑 파형(Vdcsh)을 연산하고, 전류 지령치의 크기(Imag), 및 dc단 전압 쉐이핑 파형(Vdcsh)에 기초하여, 토크분 전류 지령치(i_q)와 자속분 전류 지령치(i_d)를 생성할 수 있다.Alternatively, in the inverter control unit 230, the current command generation unit 530, the speed of the motor calculated based on the output current (io) (

), calculates the magnitude (Imag) of the current command value, calculates the dc stage voltage shaping waveform (Vdcsh) based on the detected instantaneous value (Vdc_real) of the detected pulsating dc stage voltage, and calculates the magnitude (Imag) of the current command value Based on the , and the dc terminal voltage shaping waveform Vdcsh, the torque equivalent current command value i _q and the magnetic flux current command value i _d can be generated.

On the other hand, the inverter control unit 230, based on the detected instantaneous value (Vdc_real) of the detected pulsating dc terminal voltage, the detected peak value (Vdc_peak) of the pulsating dc terminal voltage, and the offset voltage (Voffset), the dc terminal voltage shaping waveform ( Vdcsh) and the offset voltage Voffset may be controlled to vary according to the instantaneous value (Vdc_real) of the pulsating dc terminal voltage.

Meanwhile, the inverter controller 230 may vary the dc terminal voltage shaping waveform Vdcsh according to a Back Electro-Motive Force (BEMF) induced by the motor 250 . Accordingly, by varying the dc stage voltage shaping waveform (Vdcsh), it is possible to improve the driving efficiency at the time of driving the motor.

On the other hand, the control of the inverter 220 based on the above-described instantaneous value (Vdc_real) of the detected pulsating dc terminal voltage and the output current (io) is described in more detail with reference to FIGS. 9 to 11 below. describe

9 is a diagram illustrating a pulsating dc terminal voltage (Vdc) and a voltage (Vmot) required by the motor 250 .

Referring to the drawing, the dc terminal voltage Vdc boosted by the boost converter 420 pulsates due to the small-capacity film capacitor C, as described above.

Meanwhile, it is assumed that the voltage required by the motor 250, that is, the motor target voltage Vmot, has an approximately constant level.

When the small-capacity film capacitor C is used, a section in which the magnitude of the pulsating dc terminal voltage Vdc is smaller than the motor target voltage Vmot occurs, such as the Ta and Tb sections in the drawing.

In these sections (Ta, Tb), since the actual dc voltage (Vdc) is smaller than the motor target voltage (Vmot), due to the lack of the dc terminal voltage (Vdc), when the inverter 220 is driven, overmodulation As a result, motor control is disabled or stopped.

That is, in a section (Ta, Tb) in which the magnitude of the dc terminal voltage (Vdc) is smaller than the motor target voltage (Vmot), the PWM switching control signal, that is, the inverter switching control signal, is overmodulated by the space vector technique. driving occurs. Accordingly, desired motor control cannot be achieved.

On the other hand, in order to make up for the shortfall in the dc stage voltage, that is, to prevent an increase in the overmodulation region, a field-weakening control operation may be generally performed.

However, when the field-weakening control operation is performed due to the dc terminal voltage (Vdc), there is a problem in that the operation efficiency is lowered due to the too early field-weakening control operation.

In the present invention, in order to solve this problem, as described above, the inverter 220 is controlled based on the detected instantaneous value (Vdc_real) of the detected pulsating dc terminal voltage and the output current (io).

In particular, the inverter control unit 230 generates a current command value proportional to the instantaneous value (Vdc_real) of the detected pulsating dc terminal voltage, and based on the current command value, the inverter switching control signal (Sic) for controlling the inverter 220 to create

)에 기초하여, 전류 지령치의 크기(Imag)를 연산하며, 검출된 맥동 dc단 전압의 순시치(Vdc_real)에 기초하여 dc단 전압 쉐이핑 파형(Vdcsh)을 연산하고, 전류 지령치의 크기(Imag), 및 dc단 전압 쉐이핑 파형(Vdcsh)에 기초하여, 토크분 전류 지령치(i_q)와 자속분 전류 지령치(i_d)를 생성하는 전류 지령 생성부(530)와, 토크분 전류 지령치(i_q)와 자속분 전류 지령치(i_d)에 기초하여, 토크분 전압 지령치(v^* _q)와 자속분 전압 지령치(v^* _d)를 생성하는 전압 지령 생성부(540)와, 토크분 전압 지령치(v^* _q)와 자속분 전압 지령치(v^* _d)에 기초하여, 인버터 스위칭 제어 신호(Sic)를 생성하는 스위칭 제어 신호 출력부(560)를 포함할 수 있다.To this end, the inverter control unit 230, the speed of the motor calculated based on the output current (io) (

), calculates the magnitude (Imag) of the current command value, calculates the dc stage voltage shaping waveform (Vdcsh) based on the detected instantaneous value (Vdc_real) of the detected pulsating dc stage voltage, and calculates the magnitude (Imag) of the current command value , and a current command generation unit 530 that generates a current command _{value for torque (i q} ) and a current command value for magnetic flux (i _d ) based on the dc stage voltage shaping waveform (Vdcsh), _{and a current command value for torque (i q )} ) and the magnetic flux current command value (i _d ) based on the torque equivalent voltage command value (v ^* _q ) and the magnetic flux voltage command value (v ^* _d ), the voltage command generation unit 540 for generating, and the torque equivalent voltage command value ( Based on v ^* _q ) and the magnetic flux component voltage command value (v ^* _d ), a switching control signal output unit 560 that generates an inverter switching control signal Sic may be included.

10 illustrates an example of an internal block diagram of the current command generation unit 530 of FIG. 8 .

Referring to the drawings, the current command generation unit 530 may include a speed controller 536 , a dc stage voltage shaping unit 537 , and a torque controller 539 . Meanwhile, a multiplier 538 may be further provided.

)와 속도 지령치(ω^* _r)에 기초하여, 전류 지령치의 크기(Imag)를 연산할 수 있다. 속도 제어기(536)는, 도 8의 PI 제어기(535)에 대응할 수도 있다.The speed controller 536 calculates the motor speed (

) and the speed command value (ω ^* _r ), it is possible to calculate the magnitude (Imag) of the current command value. The speed controller 536 may correspond to the PI controller 535 of FIG. 8 .

Meanwhile, FIG. 11A illustrates an example of the magnitude Imag of the current command value calculated and output by the speed controller 536 . During the control period, the magnitude Imag of the current command value may have a constant value.

Meanwhile, the magnitude of the current command value during the first control period and the magnitude of the current command value during the second control period may be different.

On the other hand, the dc stage voltage shaping unit 537 receives the dc stage voltage (Vdc) from the dc stage voltage detection unit (B), and shapes the dc stage voltage based on the detected instantaneous value (Vdc_real) of the detected pulsating dc stage voltage. The waveform (Vdcsh) can be calculated and output.

Specifically, the dc stage voltage shaping unit 537 is a dc stage voltage (Vdc) from the dc stage voltage detection unit (B), the instantaneous value (Vdc_real) of the pulsating dc stage voltage, and the detected pulsating dc stage voltage. A peak value (Vdc_peak) may be extracted.

On the other hand, the inverter control unit 230, particularly the dc stage voltage shaping unit 537, the instantaneous value (Vdc_real) of the pulsating dc stage voltage, and the detected peak value of the pulsating dc stage voltage (Vdc_peak), and the offset voltage (Voffset) Based on the dc terminal voltage shaping waveform (Vdcsh) may be output.

In this case, the dc stage voltage shaping unit 537 may control the offset voltage Voffset to vary according to the instantaneous value Vdc_real of the pulsating dc stage voltage.

For example, the inverter control unit 230 , in particular the dc stage voltage shaping unit 537 , is a voltage command value v _d ,v _{generated based on the torque current command value i q} and the magnetic flux current command value i _{d . When q} ) corresponds to the overmodulation region, the offset voltage Voffset may be controlled to decrease according to the instantaneous value Vdc_real of the pulsating dc terminal voltage.

On the other hand, the inverter control unit 230, particularly the dc stage voltage shaping unit 537, controls the offset voltage Voffset to be varied according to the instantaneous value (Vdc_real) of the pulsating dc stage voltage, but during the same control period, constant voltage can be controlled. That is, it is possible to control the offset voltage Voffset to be different for each control period.

Meanwhile, the multiplier 538 may multiply (multiply operation) the magnitude Imag of the current command value and the dc terminal voltage shaping waveform Vdcsh.

_{Next, the torque controller 539 is configured to generate a torque current command value i q} and a magnetic flux current command value i _d based on the magnitude of the current command value Imag and the dc stage voltage shaping waveform Vdcsh. can

In particular, the torque controller 539, based on the product of the magnitude of the current command value (Imag) and the dc stage voltage shaping waveform (Vdcsh), the torque equivalent current command value (i _q ) and the magnetic flux current command value (i _d ) can create

As a result, the current command generation unit 530 generates and outputs the torque equivalent current command value (i _q ) and the magnetic flux current command value (i _d ) based on the detected instantaneous value (Vdc_real) of the detected pulsating dc terminal voltage. do. Accordingly, in spite of the pulsating voltage Vdc across the capacitor, the operable range for the load is expanded. Accordingly, the operating efficiency of the motor driving device is improved.

On the other hand, the inverter control unit 230 , particularly the dc stage voltage shaping unit 537 , may vary the dc stage voltage shaping waveform Vdcsh according to a Back Electro-Motive Force (BEMF) induced by the motor 250 . can

For example, when the back electromotive force BEMF induced by the motor 250 is less than or equal to the first predetermined value, the first dc terminal voltage shaping waveform Vdcsh1 is output, and the back electromotive force BEMF induced by the motor 250 is the second When it is greater than or equal to the second predetermined value greater than 1 predetermined value, the dc terminal voltage shaping waveform Vdcsh2 may be output.

Specifically, the inverter control unit 230 , in particular the dc stage voltage shaping unit 537 , when the back electromotive force BEMF induced by the motor 250 is less than or equal to the first predetermined value, the detected pulsation as shown in Equation 1 below. Based on the instantaneous value of the dc voltage Vdc_real, the detected peak value of the pulsating dc voltage Vdc_peak, and the offset voltage Voffset, the calculated first dc voltage shaping waveform Vdcsh1 may be output.

11B illustrates the first dc terminal voltage shaping waveform Vdcsh1 calculated by Equation 1;

On the other hand, the inverter control unit 230, in particular, the dc stage voltage shaping unit 537 may control the offset voltage Voffset in Equation 1 to vary according to the instantaneous value (Vdc_real) of the pulsating dc stage voltage. .

For example, when the voltage command value (v _d ,v _q ) generated based on the torque current command value (i _q ) and the magnetic flux current command value (i _d ) corresponds to the overmodulation region, the offset in Equation 1 The voltage Voffset may be controlled to decrease according to the instantaneous value Vdc_real of the pulsating dc terminal voltage.

On the other hand, the inverter control unit 230, particularly the dc stage voltage shaping unit 537, controls the offset voltage (Voffset) in Equation 1 to vary according to the instantaneous value (Vdc_real) of the pulsating dc stage voltage, but the same During the control period, it is possible to control to have a constant voltage.

Next, the inverter control unit 230 , particularly the dc stage voltage shaping unit 537 , when the back electromotive force BEMF induced by the motor 250 is greater than or equal to a second predetermined value greater than the first predetermined value, the following Equation 2 and Similarly, the second dc terminal voltage shaping waveform calculated based on the square of the detected instantaneous value (Vdc_real) of the detected pulsating dc terminal voltage, the square of the detected peak value (Vdc_peak) of the detected pulsating dc terminal voltage, and the offset voltage (Voffset) (Vdcsh2) can be output.

FIG. 1C illustrates a first dc terminal voltage shaping waveform Vdcsh1 calculated by Equation 1;

On the other hand, the inverter control unit 230, in particular, the dc stage voltage shaping unit 537 may control the offset voltage Voffset in Equation 1 to vary according to the instantaneous value (Vdc_real) of the pulsating dc stage voltage. .

For example, when the voltage command value (v _d ,v _q ) generated based on the torque current command value (i _q ) and the magnetic flux current command value (i _d ) corresponds to the overmodulation region, the offset in Equation 1 The voltage Voffset may be controlled to decrease according to the instantaneous value Vdc_real of the pulsating dc terminal voltage.

On the other hand, the inverter control unit 230, particularly the dc stage voltage shaping unit 537, controls the offset voltage (Voffset) in Equation 2 to vary according to the instantaneous value (Vdc_real) of the pulsating dc stage voltage, but the same During the control period, it is possible to control to have a constant voltage.

As described above, by varying the dc terminal voltage shaping waveform Vdcsh according to the back electromotive force BEMF induced by the motor 250 , it is possible to improve the driving efficiency at the time of driving the motor.

In addition, by varying the offset voltage Voffset according to the instantaneous value (Vdc_real) of the pulsating dc terminal voltage, it is possible to further expand the operating range at the time of driving the motor.

The motor driving device and the air conditioner having the same according to the present invention are not limited to the configuration and method of the described embodiments as described above, but the embodiments are all of each embodiment so that various modifications can be made. Alternatively, some may be selectively combined and configured.

Meanwhile, the operating method of the motor driving device or the air conditioner of the present invention can be implemented as a processor readable code on a processor readable recording medium provided in the motor driving device or the air conditioner. The processor-readable recording medium includes all types of recording devices in which data readable by the processor is stored. Examples of the processor-readable recording medium include ROM, RAM, CD-ROM, magnetic tape, floppy disk, optical data storage device, etc., and also includes those implemented in the form of carrier waves such as transmission over the Internet . In addition, the processor-readable recording medium is distributed in a computer system connected through a network, so that the processor-readable code can be stored and executed in a distributed manner.

In addition, although preferred embodiments of the present invention have been illustrated and described above, the present invention is not limited to the specific embodiments described above, and the technical field to which the present invention belongs without departing from the gist of the present invention as claimed in the claims Various modifications are possible by those of ordinary skill in the art, and these modifications should not be individually understood from the technical spirit or prospect of the present invention.

Claims (14)

a rectifier for rectifying the input AC power;
a boost converter for boosting and outputting the rectified power from the rectifying unit;
a capacitor to store the pulsating dc stage voltage from the boost converter;
an output current detection unit detecting an output current flowing through the motor;
a dc terminal voltage detection unit detecting a pulsating dc terminal voltage across the capacitor;
an inverter having a plurality of switching elements and outputting the converted AC power to the motor by using the pulsating dc voltage; and
and a control unit controlling the inverter based on the detected instantaneous value of the pulsating dc terminal voltage and the output current. According to claim 1,
The control unit is
and generating a current command value proportional to the instantaneous value of the detected pulsating dc terminal voltage, and generating an inverter switching control signal for controlling the inverter based on the current command value. According to claim 1,
The control unit is
The motor driving apparatus, characterized in that when the magnitude of the pulsating dc terminal voltage is smaller than the motor target voltage, the over-modulation operation or the field-weakening operation is controlled not to be performed. According to claim 1,
The control unit is
Based on the speed of the motor calculated on the basis of the output current, the magnitude of the current command value is calculated,
calculating a dc stage voltage shaping waveform based on the instantaneous value of the detected pulsating dc stage voltage;
The motor driving apparatus according to claim 1, wherein the generated inverter switching control signal is output to the inverter based on the magnitude of the current command value and the dc terminal voltage shaping waveform. According to claim 1,
The control unit is
Based on the speed of the motor calculated on the basis of the output current, the magnitude of the current command value is calculated,
calculating a dc stage voltage shaping waveform based on the instantaneous value of the detected pulsating dc stage voltage;
Based on the magnitude of the current command value and the dc stage voltage shaping waveform, the motor driving apparatus according to claim 1, wherein the torque equivalent current command value and the magnetic flux current command value are generated. According to claim 1,
The control unit is
Based on the speed of the motor calculated on the basis of the output current, the magnitude of the current command value is calculated, the dc stage voltage shaping waveform is calculated based on the instantaneous value of the detected pulsating dc stage voltage, and the magnitude of the current command value and a current command generation unit for generating a torque current command value and a magnetic flux current command value based on the dc terminal voltage shaping waveform;
a voltage command generation unit that generates a voltage command value for torque and a voltage command value for magnetic flux based on the torque current command value and the magnetic flux current command value;
and a switching control signal output unit configured to generate an inverter switching control signal based on the voltage command value for torque and the voltage command value for magnetic flux. 7. The method of claim 6,
The current command generation unit,
a speed controller configured to calculate a magnitude of the current command value based on the calculated motor speed and a speed command value;
a dc stage voltage shaping unit for calculating and outputting a dc stage voltage shaping waveform based on the instantaneous value of the detected pulsating dc stage voltage;
and a torque controller configured to generate the torque current command value and the magnetic flux current command value based on the magnitude of the current command value and the dc terminal voltage shaping waveform. 6. The method of claim 5,
The control unit is
The motor driving apparatus, characterized in that the dc terminal voltage shaping waveform is varied according to the back electromotive force induced by the motor. 9. The method of claim 8,
The control unit is
When the counter electromotive force induced in the motor is equal to or less than a first predetermined value, the calculated first dc end voltage shaping waveform is output based on the detected instantaneous value of the detected pulsating dc end voltage and the detected peak value of the pulsating dc end voltage. do,
The control unit is
When the counter electromotive force induced in the motor is greater than or equal to a second predetermined value greater than the first predetermined value, calculation is based on the square of the instantaneous value of the detected pulsating dc terminal voltage and the square of the peak value of the detected pulsating dc terminal voltage. Motor driving device, characterized in that for outputting the second dc stage voltage shaping waveform. 6. The method of claim 5,
The control unit is
outputting the dc stage voltage shaping waveform based on the detected instantaneous value of the pulsating dc stage voltage, the detected peak value of the detected pulsating dc stage voltage, and the offset voltage;
The motor driving apparatus, characterized in that the control so that the offset voltage is changed according to the instantaneous value of the pulsating dc terminal voltage. 11. The method of claim 10,
The control unit is
When a voltage command value generated based on the torque current command value and the magnetic flux current command value corresponds to an overmodulation region, the offset voltage is controlled to decrease according to the instantaneous value of the pulsating dc voltage. motor drive device. 11. The method of claim 10,
The control unit is
The offset voltage is controlled to vary according to the instantaneous value of the pulsating dc terminal voltage, and is controlled to have a constant voltage during the same control period. a rectifier for rectifying the input AC power;
a boost converter for boosting and outputting the rectified power from the rectifying unit;
a capacitor to store the pulsating dc stage voltage from the boost converter;
a dc terminal voltage detection unit detecting a pulsating dc terminal voltage across the capacitor;
an inverter having a plurality of switching elements and outputting the converted AC power to the motor by using the pulsating dc voltage; and
and a control unit generating a current command value proportional to the instantaneous value of the detected pulsating dc voltage, and generating an inverter switching control signal for controlling the inverter based on the current command value. . An air conditioner comprising the motor driving device according to any one of claims 1 to 13.

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