KR102396563B1 - Motor driver 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 apparatus according to an embodiment of the present invention operates based on a common input AC power, and includes a first inverter and a second inverter for driving a first motor and a second motor, respectively, and a first inverter for controlling the first inverter. a first inverter control unit and a second inverter control unit for controlling the second inverter, wherein at least one of the first inverter control unit and the second inverter control unit has a first order or less among harmonic components of an input current from a common input AC power supply When the level of the harmonic component of is equal to or greater than the first reference level, the phase difference between the first output current flowing through the first motor and the second output current flowing through the second motor is controlled to be sequentially reduced. Accordingly, when a plurality of motors are driven in parallel, low-order harmonics generated in the input current of the motor driving device can be reduced.

Description

Motor driver and air conditioner including 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 reducing low-order harmonics generated in an input current when a plurality of motors are driven in parallel, and to an air conditioner having the same it's about

The air conditioner is installed to provide a more comfortable indoor environment for 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 refrigerant to the indoor unit.

On the other hand, in order to drive the compressor of the air conditioner, a compressor motor driving device is used.

On the other hand, according to the international surge protection standard IEC 61000, standards for harmonic reduction are set, and accordingly, various efforts are being made to reduce harmonics due to the input AC current in the compressor motor driving device.

SUMMARY OF THE INVENTION An object of the present invention is to provide a motor driving device capable of reducing low-order harmonics generated in an input current when a plurality of motors are driven in parallel, and an air conditioner having the same.

Another object of the present invention is to provide a motor driving apparatus capable of improving a power factor due to a reduction in reactive current when a plurality of motors are driven in parallel, and an air conditioner having the same.

A motor driving apparatus and an air conditioner having the same according to an embodiment of the present invention for achieving the above object, operate based on a common input AC power source, and include a first inverter for driving a first motor and a second motor, respectively; a second inverter, a first inverter control unit for controlling the first inverter, and a second inverter control unit for controlling the second inverter, wherein at least one of the first inverter control unit and the second inverter control unit includes a common input AC power supply When the level of the harmonic component of the first order or less among the harmonic components of the input current from , control to decrease sequentially.

On the other hand, the motor driving device and the air conditioner having the same according to another embodiment of the present invention for achieving the above object operate based on a common input AC power source, respectively, the first motor and the second motor driving the second motor 1 inverter and a second inverter, a first inverter control unit for controlling the first inverter, and a second inverter control unit for controlling the second inverter, wherein at least one of the first inverter control unit and the second inverter control unit has a common When the level of the higher-order harmonic component among the harmonic components of the input current from the input AC power supply is equal to or higher than the reference level, the first PWM control period corresponding to the first inverter and the second PWM control period corresponding to the second inverter is controlled so that the phase difference of .

On the other hand, a motor driving apparatus and an air conditioner having the same according to another embodiment of the present invention for achieving the above object operate based on a common input AC power, respectively, to drive the first motor and the second motor A first inverter and a second inverter, and an inverter control unit for controlling the first inverter and the second inverter, wherein the inverter control unit includes a harmonic component of a first order or less among harmonic components of an input current from a common input AC power supply. When the level is equal to or greater than the first reference level, a phase difference between the first output current flowing through the first motor and the second output current flowing through the second motor is controlled to be sequentially reduced.

On the other hand, a motor driving apparatus and an air conditioner having the same according to another embodiment of the present invention for achieving the above object operate based on a common input AC power, respectively, to drive the first motor and the second motor a first inverter and a second inverter, and an inverter control unit for controlling the first inverter and the second inverter, wherein the inverter control unit includes: harmonic components of higher than the first order among harmonic components of an input current from a common input AC power supply When the level is equal to or greater than the reference level, the phase difference between the first PWM carrier signal corresponding to the first inverter and the second PWM carrier signal corresponding to the second inverter is sequentially controlled to decrease.

According to an embodiment of the present invention, a motor driving apparatus and an air conditioner having the same operate based on a common input AC power source, and include a first inverter and a second inverter for driving a first motor and a second motor, respectively. , a first inverter control unit for controlling the first inverter, and a second inverter control unit for controlling the second inverter, wherein at least one of the first inverter control unit and the second inverter control unit includes an input current from a common input AC power source When the level of the first-order or less harmonic components among the harmonic components of By controlling so as to decrease the voltage, it is possible to reduce the low-order harmonics generated in the input current of the motor driving device when a plurality of motors are driven in parallel.

In particular, when both the first inverter and the second inverter are operating, it is possible to reduce the low-order harmonics generated from the input current, so that the stability when driving the motor is improved.

On the other hand, the motor driving device and the air conditioner having the same according to another embodiment of the present invention for achieving the above object operate based on a common input AC power source, respectively, the first motor and the second motor driving the second motor 1 inverter and a second inverter, a first inverter control unit for controlling the first inverter, and a second inverter control unit for controlling the second inverter, wherein at least one of the first inverter control unit and the second inverter control unit has a common When the level of the higher-order harmonic component among the harmonic components of the input current from the input AC power supply is equal to or higher than the reference level, the first PWM control period corresponding to the first inverter and the second PWM control period corresponding to the second inverter By controlling the phase difference to be sequentially reduced, it is possible to improve the power factor due to a reduction in reactive current when a plurality of motors are driven in parallel.

On the other hand, a motor driving apparatus and an air conditioner having the same according to another embodiment of the present invention for achieving the above object operate based on a common input AC power, respectively, to drive the first motor and the second motor A first inverter and a second inverter, and an inverter control unit for controlling the first inverter and the second inverter, wherein the inverter control unit includes a harmonic component of a first order or less among harmonic components of an input current from a common input AC power supply. When the level is equal to or greater than the first reference level, by controlling the phase difference between the first output current flowing through the first motor and the second output current flowing through the second motor to be sequentially small, when driving a plurality of motors in parallel, the motor It becomes possible to reduce the low-order harmonics generated in the input current of the driving device.

On the other hand, a motor driving apparatus and an air conditioner having the same according to another embodiment of the present invention for achieving the above object operate based on a common input AC power, respectively, to drive the first motor and the second motor a first inverter and a second inverter, and an inverter control unit for controlling the first inverter and the second inverter, wherein the inverter control unit includes: harmonic components of higher than the first order among harmonic components of an input current from a common input AC power supply When the level is greater than or equal to the reference level, by controlling the phase difference between the first PWM carrier signal corresponding to the first inverter and the second PWM carrier signal corresponding to the second inverter to be small sequentially, when driving multiple motors in parallel, invalid It is possible to improve the power factor due to the decrease in current.

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 .
3A is an example of a block diagram of a motor driving apparatus according to an embodiment of the present invention.
3B is an example of a block diagram of a motor driving apparatus according to another embodiment of the present invention.
4 is an example of an internal block diagram of the inverter control unit of FIG. 3B.
5A to 5I are diagrams referenced to explain a phenomenon that occurs when a plurality of motors are driven in parallel.
6 is an example of a circuit diagram of a motor driving apparatus according to an embodiment of the present invention.
7A to 7C are diagrams referred to in the description of the operation of FIG. 6 .
8 is a flowchart illustrating a method of operating a motor driving apparatus according to an embodiment of the present invention.
9 to 12 are diagrams referenced in the operation description 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 impart 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 according to the present invention is a large-sized air conditioner 50, including a plurality of indoor units 31 to 35, a plurality of outdoor units 21 and 22 connected to the plurality of indoor units, and a plurality of air conditioners. It may include a remote controller 41 to 45 connected to each of the indoor units, and a remote controller 10 for controlling a plurality of indoor units and outdoor units.

The remote controller 10 is connected to the plurality of indoor units 31 to 36 and the plurality of outdoor units 21 and 22 to monitor and control operations thereof. In this case, the remote controller 10 may be connected to a plurality of indoor units to perform operation setting, lock setting, schedule control, group control, and the like for the indoor units.

The air conditioner may be any one of a stand-type air conditioner, a wall-mounted air conditioner, and a ceiling-type air conditioner. However, for convenience of description, the ceiling-type air conditioner will be described as an example below. In addition, the air conditioner 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 units 21 and 22 include 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 that extracts a gaseous refrigerant from the supplied refrigerant and supplies it to the compressor. (not shown) and a four-way valve (not shown) for selecting a refrigerant flow path according to the heating operation. In addition, a plurality of sensors, valves, and an oil recovery device are further included, but a description of the configuration will be omitted below.

The outdoor units 21 and 22 operate a provided compressor and an outdoor heat exchanger to compress or heat-exchange the refrigerant according to a setting to supply the refrigerant to the indoor units 31 to 35 . The outdoor units 21 and 22 are driven by the request of the remote controller 10 or the indoor units 31 to 35, and as the cooling/heating capacity is changed in response to the driven indoor unit, the number of outdoor units operated and the The number of operations is variable.

In this case, the outdoor units 21 and 22 are described on the basis of supplying refrigerant to the indoor units to which the plurality of outdoor units are respectively connected. can also be supplied.

The indoor units 31 to 35 are connected to any one of the plurality of outdoor units 21 and 22 , receive refrigerant, and discharge hot and cold air into the room. The indoor units 31 to 35 include 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 units 21 and 22 and the indoor units 31 to 35 are connected through a communication line to transmit and receive data, and the outdoor unit and the indoor unit are connected to the remote controller 10 through a separate communication line to control the remote controller 10 . operate according to

The remote controllers 41 to 45 may be respectively connected to the indoor unit, input a user's control command to the indoor unit, and receive and display status information of the indoor unit. In this case, the remote control communicates with the indoor unit by wire or wirelessly depending on the connection type to the indoor unit, and in some cases, one remote control is connected to a plurality of indoor units, and the settings of the plurality of indoor units may be changed through one remote control input.

In addition, the remote controllers 41 to 45 may include a temperature sensor therein.

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

Referring to the drawings, the air conditioner 50 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 50 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.

Meanwhile, although FIG. 2 shows one indoor unit 31 and one outdoor unit 21, the driving device of the air conditioner according to the embodiment of the present invention is not limited thereto. Of course, it is applicable to an air conditioner, an air conditioner including one indoor unit and a plurality of outdoor units.

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

3A is an example of a block diagram of a motor driving apparatus according to an embodiment of the present invention.

First, the motor driving device 200 of FIG. 3A is characterized in that a plurality of motors are driven in parallel.

To this end, the motor driving device 200 includes a first motor 250a, a second motor 250b, a first inverter 220a for outputting an AC current to the first motor 250a, and a second motor 250b. A second inverter 220b for outputting an alternating current may be provided.

Also, the motor driving device 200 may include a first converter and a second converter that operate to supply DC power to the first inverter 220a and the second inverter 220b.

In the drawings, as an example of the first converter and the second converter, the first rectifying unit 210a and the second rectifying unit 210b are illustrated.

Meanwhile, the first rectifying unit 210a and the second rectifying unit 210b may rectify the input AC power from the common input AC power source 201 to output the rectified DC power.

Meanwhile, a first capacitor Ca for storing DC power is disposed between the first rectifying unit 210a and the first inverter 220a, and DC power is stored between the second rectifying unit 210b and the second inverter 220b. A second capacitor Cb for

Meanwhile, the motor driving device 200 of FIG. 3A receives AC power from the system, converts power, and supplies the converted power to the first motor 250a and the second motor 250b, which are compressor motors. . Accordingly, the motor driving device 200 may be referred to as a power conversion device or a compressor driving device.

Meanwhile, the first capacitor Ca and the second capacitor Cb in the motor driving apparatus 200 according to the embodiment of the present invention may be low-capacitance capacitors of several tens of μF or less. For example, the first capacitor Ca and the second capacitor Cb may be low-capacity film capacitors, not electrolytic capacitors.

On the other hand, when the first capacitor Ca and the second capacitor Cb are low-capacitance capacitors, the change in the dc terminal voltage increases and pulsates, and the smoothing operation is hardly performed.

Such a motor driving device having a capacitor having a low capacity 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 capacitor will be mainly described.

On the other hand, when the capacitors of the first capacitor Ca and the second capacitor Cb have a low capacitance, the first motor 250a and the second motor 250b are driven in parallel using a common input AC power supply. In this case, the pulsations at both ends of the first capacitor Ca and the second capacitor Cb are affected, as well as the front ends of the first rectifying part 210a and the second rectifying part 210b.

That is, a harmonic component is generated in the input current flowing through the front ends of the first rectifying unit 210a and the second rectifying unit 210b.

In the present invention, a method for reducing a harmonic component generated in an input current when the first motor 250a and the second motor 250b are driven in parallel is proposed. This will be described in more detail with reference to FIG. 5A or less.

On the other hand, in order to reduce harmonic components generated in the input current, the motor driving device 200 includes an input voltage detection unit (A), an input current detection unit (D), a first dc voltage detection unit (Ba), and a second dc voltage detection unit ( Bb) and the like may be further provided.

On the other hand, unlike the drawing, in addition to the input current detection unit (D), it is also possible to further include a second input current detection unit for detecting the input current flowing through the front end of the second rectifying unit (210b).

The input voltage detection unit A can detect the input voltage Vs from the input AC power supply 201 .

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 may be applied to the first inverter controller 230a or the second inverter controller 230b as a discrete signal in the form of a pulse.

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 converter 210 .

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 first inverter controller 230a or the second inverter controller 230b as a discrete signal in the form of a pulse.

The first and second dc voltage detection units Ba and Bb detect pulsating voltages Vdca and Vdcb of the first and second dc terminal capacitors Ca and Cb, respectively. For power detection, a resistive element, an OP AMP, or the like may be used. The detected voltages (Vdca, Vdcb) of the dc terminal capacitors (Ca, Cb) may be applied to the first inverter control unit 230a or the second inverter control unit 230b as a discrete signal in the form of a pulse. , and the first and second inverter switching control signals Sica and Sicb may be generated based on the voltages Vdca and Vdcb of the capacitors Ca and Cb in the c stage.

Each of the first inverter 220a and the second inverter 220b includes a plurality of inverter switching elements, and converts DC power smoothed by on/off operation of the switching elements into AC power of a predetermined frequency, It can output to the motor 250a and the second motor 250b.

The first inverter controller 230a may output the first inverter switching control signal Sica to the first inverter 220a to control the switching operation of the first inverter 220a. The first inverter switching control signal Sica is a switching control signal of the pulse width modulation method (PWM), and the output current i _oa flowing through the first motor 250a or the first dc terminal voltage that is both ends of the first dc terminal capacitor Based on (Vdca), it may be generated and output. At this time, the output current i _oa may be detected by the first output current detecting unit Ea , and the first dc terminal voltage Vdca may be detected by the first dc terminal voltage detecting unit Ba.

The second inverter controller 230b may output the second inverter switching control signal Sicb to the second inverter 220b to control the switching operation of the second inverter 220b. The second inverter switching control signal Sicb is a switching control signal of the pulse width modulation method (PWM), and the output current i _ob flowing through the second motor 250b or the second dc terminal voltage that is both ends of the second dc terminal capacitor Based on (Vdcb), it may be generated and output. At this time, the output current i _ob may be detected by the second output current detection unit Eb, and the second dc terminal voltage Vdcb may be detected by the second dc terminal voltage detection unit Bb.

The first output current detection unit Ea may detect the output current i _oa flowing between the first inverter 220a and the first motor 250a. That is, the current flowing through the first motor 250a is detected. The detected output current i _oa may be applied to the first inverter control unit 230a.

The second output current detection unit Eb may detect the output current i _ob flowing between the second inverter 220b and the second motor 250b. That is, the current flowing through the second motor 250b is detected. The detected output current i _ob may be applied to the second inverter control unit 230b.

Meanwhile, according to an embodiment of the present invention, at least one of the first inverter control unit 230a and the second inverter control unit 230b may include a first order or less harmonic component among harmonic components of an input current from a common input AC power supply. When the level of is equal to or greater than the first reference level, the phase difference between the first output current flowing through the first motor and the second output current flowing through the second motor may be controlled to be sequentially reduced. Accordingly, it is possible to reduce the low frequency component among the harmonic components of the input current.

Meanwhile, in at least one of the first inverter control unit 230a and the second inverter control unit 230b, the level of the harmonic component exceeding the first order among harmonic components of the input current from the common input AC power supply is equal to or greater than the second reference level. In this case, the phase difference between the first PWM carrier signal corresponding to the first inverter 220a and the second PWM carrier signal corresponding to the second inverter 220b may be sequentially controlled to decrease. Accordingly, it is possible to reduce the high frequency component among the harmonic components of the input current.

Meanwhile, in at least one of the first inverter control unit 230a and the second inverter control unit 230b, the level of the harmonic component exceeding the first order among harmonic components of the input current from the common input AC power supply is equal to or greater than the second reference level. In this case, the phase difference between the first PWM control period corresponding to the first inverter 220a and the second PWM control period corresponding to the second inverter 220b may be controlled to be sequentially reduced. Accordingly, it is possible to reduce the high frequency component among the harmonic components of the input current.

On the other hand, the first inverter control unit 230a and the second inverter control unit 230b include a first PWM control cycle corresponding to the first inverter 220a and a second PWM control cycle corresponding to the second inverter 220b, Information about the phase of the first output current and the phase of the second output current may be shared.

Meanwhile, the first inverter control unit 230a calculates the current output frequency of the first inverter 220a, transmits the current output frequency of the first inverter 220a to the second inverter control unit 230b, and the second inverter The controller 230b may calculate the current output frequency of the second inverter 220b and control to compensate for a difference between the current output frequency of the first inverter 220a and the current output frequency of the second inverter 220b. . Accordingly, it is possible to reduce the low frequency component among the harmonic components of the input current.

Meanwhile, the first inverter control unit 230a transmits cycle information of the first inverter 220a to the second inverter control unit 230b, and the second inverter control unit 230b provides cycle information of the first inverter 220a. and an error of period information of the second inverter 220b may be calculated and controlled to compensate for the error. Accordingly, it is possible to reduce the high frequency component among the harmonic components of the input current.

Meanwhile, the first inverter controller 230a may be a master inverter controller, and the second inverter controller 230b may be a slave inverter controller. Accordingly, the second inverter control unit 230b may operate based on an operation command or information of the first inverter control unit 230a.

3B is an example of a block diagram of a motor driving apparatus according to another embodiment of the present invention.

Referring to the drawings, the motor driving device 200b of FIG. 3B drives a plurality of motors in parallel, similarly to the motor driving device 200 of FIG. 3A , but controls the first and second inverters 220a and 220b For this purpose, the common inverter control unit 230 is used.

Accordingly, the input current detection unit D, the input voltage detection unit A, the first and second dc voltage detection units Ba, Bb, the first output current detection unit Ea, and the second output current detection unit Eb respectively detect The current, voltage, etc. are input to the inverter control unit 230, and the inverter control unit 230, based on this, to the first and second inverters 220a and 220b, respectively, control the first and second inverter switching Signals (Sica, Sicb) can be output.

On the other hand, according to the embodiment of the present invention, the inverter control unit 230, when the level of the harmonic component of the first order or less among the harmonic components of the input current from the common input AC power source is equal to or greater than the first reference level, the first motor A phase difference between the first output current flowing through the motor and the second output current flowing through the second motor may be controlled to be sequentially reduced. Accordingly, it is possible to reduce the low frequency component among the harmonic components of the input current.

On the other hand, the inverter control unit 230, when the level of the harmonic component exceeding the first order among harmonic components of the input current from the common input AC power supply is equal to or greater than the second reference level, the first inverter corresponding to the first inverter 220a The phase difference between the PWM carrier signal and the second PWM carrier signal corresponding to the second inverter 220b may be controlled to decrease sequentially. Accordingly, it is possible to reduce the high frequency component among the harmonic components of the input current.

On the other hand, the inverter control unit 230, when the level of the harmonic component exceeding the first order among harmonic components of the input current from the common input AC power supply is equal to or greater than the second reference level, the first inverter corresponding to the first inverter 220a The phase difference between the PWM control period and the second PWM control period corresponding to the second inverter 220b may be controlled to be sequentially decreased. Accordingly, it is possible to reduce the high frequency component among the harmonic components of the input current.

On the other hand, the inverter control unit 230 calculates the current output frequency of the first inverter 220a, calculates the current output frequency of the second inverter 220b, the current output frequency of the first inverter 220a and the second It can be controlled to compensate for the difference in the current output frequency of the inverter 220b. Accordingly, it is possible to reduce the low frequency component among the harmonic components of the input current.

Meanwhile, the inverter controller 230 may calculate an error between the period information of the first inverter 220a and the period information of the second inverter 220b and control the error to be compensated. Accordingly, it is possible to reduce the high frequency component among the harmonic components of the input current.

4 is an example of an internal block diagram of the inverter control unit of FIG. 3B.

Referring to FIG. 4 , the inverter control unit 230 includes an axis conversion unit 310 , a speed calculation unit 320 , a current command generation unit 330 , a voltage command generation unit 340 , an axis conversion unit 350 , and A switching control signal output unit 360 may be included.

The axis conversion unit 310 receives the three-phase output current (iaa, iba, ica or iab, ibb, icb) detected by the first and second output current detection units Ea and Eb, and receives the two-phase current of the stationary coordinate system. Convert to (iα,iβ).

Meanwhile, the axis conversion unit 310 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.

)를 추정한다. 또한, 추정된 회전자 위치(

)에 기초하여, 연산된 속도(

)를 출력할 수 있다.The speed calculating unit 320, the rotor position (

) is estimated. Also, the estimated rotor position (

) based on the calculated speed (

) can be printed.

)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(330)는, 연산 속도(

)와 목표 속도(ω)의 차이인 속도 지령치(ω^* _r)에 기초하여, PI 제어기(435)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 generation unit 330, the calculation speed (

) and the target speed ω, a speed command value ω ^* _r is calculated, and a current command value i ^* _q is generated based on the speed command value ω ^* _r . For example, the current command generation unit 330 may set the calculation speed (

) and the target speed ω, based on the speed command value ω ^* _r , the PI controller 435 may perform PI control and generate the current command value i ^* _q . In the drawing, the q-axis current command value (i ^* _q ) is exemplified as the current command value, but unlike the drawing, it is also possible to generate the d-axis current command value (i ^* _d ) together. 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 330, 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 340 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 values ( 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 340 performs PI control in the PI controller 444 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 340 performs PI control in the PI controller 448 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. Meanwhile, the value of the d-axis voltage command value (v ^* _d ) may be set to 0, corresponding to the case where the value of the d-axis current command value (i ^* _d ) is set to 0.

On the other hand, the voltage command generation unit 340, the d-axis, q-axis voltage command value (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 350 .

)와, d축, q축 전압 지령치(v^* _d,v^* _q)를 입력받아, 축변환을 수행한다.The axis conversion unit 350, the position calculated by the speed calculating unit 320 (

) 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 350 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 320 (

) can be used.

Then, the axis transformation unit 350 performs transformation from the two-phase stationary coordinate system to the three-phase stationary coordinate system. Through this conversion, the axis conversion unit 1050 outputs a three-phase output voltage command value (v ^* a, v ^* b, v ^* c).

^{The switching} control signal output unit 360 includes first and second ^inverter switching control signals ( Sica, Sicb) can be created and output.

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

On the other hand, according to the embodiment of the present invention, the switching control signal output unit 360, when the level of the harmonic component of the first order or less among the harmonic components of the input current from the common input AC power source is equal to or greater than the first reference level, In order to sequentially decrease the phase difference between the first output current flowing through the first motor and the second output current flowing through the second motor, the corresponding first and second inverter switching control signals Sica and Sicb are can be printed out. Accordingly, it is possible to reduce the low frequency component among the harmonic components of the input current.

On the other hand, the switching control signal output unit 360 corresponds to the first inverter 220a when the level of the harmonic component exceeding the first order among the harmonic components of the input current from the common input AC power is equal to or higher than the second reference level. In order to sequentially decrease the phase difference between the first PWM carrier signal and the second PWM carrier signal corresponding to the second inverter 220b, the corresponding first and second inverter switching control signals Sica and Sicb are can be printed out. Accordingly, it is possible to reduce the high frequency component among the harmonic components of the input current.

On the other hand, the switching control signal output unit 360 corresponds to the first inverter 220a when the level of the harmonic component exceeding the first order among the harmonic components of the input current from the common input AC power is equal to or higher than the second reference level. In order to sequentially decrease the phase difference between the first PWM control period and the second PWM control period corresponding to the second inverter 220b, the corresponding first and second inverter switching control signals Sica and Sicb are can be printed out. Accordingly, it is possible to reduce the high frequency component among the harmonic components of the input current.

5A to 5I are diagrams referenced to explain a phenomenon that occurs when a plurality of motors are driven in parallel.

First, (a) of FIG. 5A shows that when only one of the first and second motors 250a and 250b of FIG. 3A or 3B operates, the power factor PF, effective in the motor driving device 200 or 200b Parameters such as power (P), reactive power (Q), apparent power (S), and current (I) are exemplified.

Next, FIG. 5A (b) shows, when both the first and second motors 250a and 250b of FIG. 3A or 3B operate, in the motor driving device 200 or 200b, the power factor (PF), active power Parameters such as (P), reactive power (Q), apparent power (S), and current (I) are exemplified.

Comparing (a) of FIG. 5A and (b) of FIG. 5A, as shown in (b) of FIG. 5A, when both the first and second motors 250a and 250b operate, the active power P is large. Although there is no change, it can be seen that the power factor (PF) is lowered, and the reactive power (Q), the apparent power (S), the current (I), etc. are greatly increased.

In particular, when the first capacitor Ca and the second capacitor Cb are low-capacitance capacitors, a decrease in power factor, an increase in reactive power, and the like are further aggravated.

Meanwhile, in FIG. 5B , the phase difference between the first PWM carrier signal PMWaa corresponding to the first inverter 220a and the second PWM carrier signal PWMba corresponding to the second inverter 20b is approximately 180 degrees. exemplify that

The first PWM carrier signal PMWaa corresponding to the first inverter 220a is generated by the first inverter control unit 230a or the inverter control unit 230, and the like, a pulse width variable-based first inverter switching control signal Sica. A signal used for generation of , approximately corresponding to the first PWM control period.

On the other hand, the second PWM carrier signal PMWba corresponding to the second inverter 220a is generated by the second inverter control unit 23ba or the inverter control unit 230, and the like, a second inverter switching control signal based on a variable pulse width ( A signal used for generation of Sicb), approximately corresponding to the second PWM control period.

As a result, FIG. 5B illustrates that the phase difference between the first PWM control period and the second PWM control period is approximately 108 degrees.

In this case, as shown in FIG. 5C , the power factor in the motor driving device 200 or 200b becomes the lowest.

On the other hand, in FIG. 5D , the phase difference between the first PWM carrier signal PMWab corresponding to the first inverter 220a and the second PWM carrier signal PWMbb corresponding to the second inverter 20b is approximately coincident. , which is approximately 0 degrees.

As a result, FIG. 5D illustrates that the phase difference between the first PWM control period and the second PWM control period is approximately equal to, approximately 0 degrees.

In this case, as shown in FIG. 5E , the power factor in the motor driving device 200 or 200b becomes the highest.

Next, FIG. 5F illustrates that there is a phase difference between the first output current Ioa1 and the second output current Iob1 flowing through the first and second motors 250a and 250b, respectively.

In this case, a harmonic component in the input current can be exemplified, as in FIG. 5G .

Next, FIG. 5H illustrates that there is a phase difference between the first output current Ioa2 and the second output current Iob2 flowing through the first and second motors 250a and 250b, respectively.

In this case, a harmonic component in the input current can be exemplified, as in FIG. 5I .

Comparing FIG. 5G and FIG. 5I, it can be seen that, in the case of FIG. 5I, the low frequency component of the 14th order or less among the harmonic components in the input current is significantly reduced.

5A to 5I, in the present invention, in order to reduce the 14th order or less low-frequency components among the harmonic components in the input current, the first output current Ioa2 flowing through the first and second motors 250a and 250b, respectively and the phase difference between the second output current Iob2 and the second output current Iob2 are sequentially decreased.

In addition, with reference to FIGS. 5A to 5I , in the present invention, the phase difference between the first PWM carrier signal and the second PWM carrier signal is sequentially in order to reduce the higher than 14th order among the harmonic components in the input current. make it smaller Alternatively, the phase difference between the first PWM control period and the second PWM control period is sequentially decreased.

This will be described in more detail with reference to FIG. 6 or less.

6 is an example of a circuit diagram of a motor driving apparatus according to an embodiment of the present invention, and FIGS. 7A to 7C are diagrams referenced in the operation description of FIG. 6 .

The motor driving device 700 of FIG. 6 corresponds to the motor driving device 200 of FIG. 3A or the motor driving device 200b of FIG. 3B , however, the first rectifying unit 210a includes three pairs of upper and lower arms. A diode element (Daa, D'aa, Dba, D'ba, Dca, D'ca) is provided, and the second rectifying unit 210b includes three pairs of upper-arm and lower-arm diode elements (Dab, D'ab, Dbb, D). 'bb, Dcb, D'cb) is exemplified.

7A illustrates the input current waveform Is1.

Next, FIG. 7B (a) exemplifies the fundamental wave waveform Isp of the input current waveform Is1 of FIG. 7A, and FIG. 7B (b) is a low-frequency waveform of the input current waveform Is1 of FIG. 7A (Isda) is illustrated, and FIG. 7B (c) illustrates the high-frequency waveform Isua of the input current waveform Is1 of FIG. 7A .

Referring to FIG. 7B , it can be seen that the level of the low frequency waveform Isda of the input current waveform Is1 of FIG. 7A is equal to or greater than the first reference level ref1.

7B, according to an embodiment of the present invention, at least one of the first inverter control unit 230a and the second inverter control unit 230b includes a first output current flowing through the first motor and a first output current flowing through the second motor. It is preferable to control so that the phase difference between the second output currents becomes small sequentially.

Next, FIG. 7C (a) exemplifies the fundamental wave waveform Isp of the input current waveform Is1 of FIG. 7A , and FIG. 7C (b) is a low-frequency waveform of the input current waveform Is1 of FIG. 7A . (Isdb) is illustrated, and FIG. 7C (c) illustrates the high-frequency waveform Isub of the input current waveform Is1 of FIG. 7A .

Referring to FIG. 7C , it can be seen that the level of the high frequency waveform Isub of the input current waveform Is1 of FIG. 7A is equal to or greater than the second reference level ref2.

7c, according to an embodiment of the present invention, the phase difference between the first PWM carrier signal corresponding to the first inverter 220a and the second PWM carrier signal corresponding to the second inverter 220b is sequentially It is desirable to control it so that it becomes small.

8 is a flowchart illustrating a method of operating a motor driving apparatus according to an embodiment of the present invention, and FIGS. 9 to 12 are diagrams referred to in the description of the operation of FIG. 8 .

Referring to the drawings, the motor driving apparatuses 200 , 200b , and 700 according to an embodiment of the present invention drive the first and second inverters 220a and 220b ( S8215 ). That is, the switching elements in the first and second inverters 220a and 220b perform a switching operation.

Accordingly, the first and second output currents flow to the first and second motors 815 in the motor driving devices 200, 200b, and 700, and the first and second motors 815 are operated ( S815).

Next, the motor driving devices 200 , 200b , and 700 detect an input current ( S820 ).

For example, as in FIG. 3 or FIG. 3A , when there is only one input current detection unit D, the input current detection unit D is detected, and the detected input current is the first inverter control unit 230a or the inverter control unit. 230 may be input.

Unlike other erotic, FIG. 3 or FIG. 3A, when the first and second input current detection units are provided, respectively, the first and second input current detection units flow in front of the first and second rectifying units, respectively, first and second Two input currents are detected, and the detected first and second input currents may be input to the first inverter controller 230a , the second inverter controller 230b , or the inverter controller 230 .

Next, the first inverter control unit 230a, the second inverter control unit 230b, or the inverter control unit 230 extracts a harmonic of the input current (S825).

Then, the first inverter control unit 230a, the second inverter control unit 230b, or the inverter control unit 230 determines whether the same frequency control is currently being performed on the output current of each inverter (S827). That is, it is currently determined whether the first and second motors 250a and 250b are in a mode in which they rotate at the same speed.

And, if applicable, the first inverter control unit 230a, the second inverter control unit 230b, or the inverter control unit 230 determines whether the low-order harmonic is rising (S830), and, if applicable, the low-order harmonic is rising. In order to reduce , the phase of the inverter output current is controlled (S835). The phase control of the inverter output current will be described in more detail with reference to FIG. 9 .

On the other hand, the first inverter control unit 230a, the second inverter control unit 230b, or the inverter control unit 230 determines whether the higher-order harmonic is rising (S840), and, if applicable, to reduce the higher-order harmonic rise. , to control the PWM phase of each inverter (S845). The PWM phase control of each inverter will be described in more detail with reference to FIG. 10 .

9 is a flowchart illustrating a method for controlling a phase of an inverter output current to reduce low-order harmonics.

First, the first inverter control unit 230a generates an interrupt signal for controlling the first inverter 220a (S910).

Then, the first inverter controller 230a drives the first inverter 220a and operates the first motor 250a based on the interrupt signal for controlling the first inverter 220a (S915).

Next, the first inverter control unit 230a calculates the current output frequency based on the first output current ioa flowing through the first motor 250a ( S920 ). That is, the rotation speed of the first motor 250a is calculated.

Next, the first inverter control unit 230a transmits the current output frequency information of the first inverter 220a to the second inverter control unit 230b (S925).

Next, when receiving the current output frequency information of the first inverter 220a is completed ( S930 ), the second inverter control unit 230b generates an interrupt signal for controlling the second inverter 220b, and the second inverter Based on the interrupt signal for control of 220b, the second inverter 220b is driven and the second motor 250b is operated (S935).

Next, the second inverter control unit 230b calculates the current output frequency based on the second output current iob flowing through the second motor 250b ( S940 ). That is, the rotation speed of the second motor 250b is calculated.

Next, the second inverter controller 230b controls to compensate the difference between the current output frequency information of the first inverter 220a and the current output frequency information of the second inverter 220b (S945).

Specifically, the second inverter control unit 230b is configured to, when the level of the harmonic components of the first order or less among the harmonic components of the input current from the common input AC power supply is equal to or higher than the first reference level, the first output flowing to the first motor The phase difference between the current and the second output current flowing through the second motor may be controlled to be sequentially decreased.

Fig. 11 (a) shows the fundamental wave waveform (Isp) of the input current, Fig. 11 (b) shows the low-order harmonic waveform (Isdaa) of the input current, and Fig. 11 (c) shows the high-order harmonic of the input current The waveform Isuaa is shown, and FIG. 11D shows the first output current Ioaa and the second output current Ioba.

Referring to FIG. 11 , before the time Ta, the first reference level refn of the low-order harmonic waveform Isdaa of the input current is greater than or equal to the first reference level refn, and accordingly, the second inverter control unit 230b, the first output current Ioaa The corresponding control is performed from the point of time Ta so that the phase difference between and the second output current Ioba becomes small.

For example, when the phase of the first output current Ioaa is faster, the second inverter controller 230b may control the phase of the second output current Ioba to sequentially increase.

As another example, when the phase of the first output current Ioaa is slower, the second inverter controller 230b may control the phase of the second output current Ioba to sequentially decrease.

By this control, the phase difference between the first output current Ioaa and the second output current Ioba is sequentially decreased from the time point Ta, and at the time point Tb, the first output current Ioaa and the second output current Ioba Ioba) may have approximately the same phase difference.

Accordingly, from the time point Tb onwards, it becomes less than the first reference level refn of the low-order harmonic waveform Isdaa of the input current. can be reduced, and furthermore, the stability at the time of driving the motor is improved.

10 is a flowchart illustrating a PWM phase control method of each inverter to reduce higher-order harmonics.

First, the first inverter control unit 230a generates an interrupt signal for controlling the first inverter 220a (S1010).

In addition, the first inverter control unit 230a drives the first inverter 220a and operates the first motor 250a based on the interrupt signal for controlling the first inverter 220a.

Next, the first inverter control unit 230a transmits the control period information of the first inverter (S1015).

Here, the control period information may include PWM control period information or phase information of a PWM carrier signal.

Next, the second inverter control unit 230b receives control period information of the first inverter from the first inverter control unit 230a ( S1020 ).

Next, the second inverter control unit 230b generates an interrupt signal for controlling the second inverter 220b, and based on the interrupt signal for controlling the second inverter 220b, operates the second inverter 220b. and operates the second motor 250b (S1025).

Next, the second inverter control unit 230b compares the control period information of the first inverter with the control period information of the second inverter and calculates an error ( S1030 ).

Then, the second inverter control unit 230b compensates for an error between the control period of the first inverter and the control period of the second inverter ( S1035 ).

For example, the second inverter control unit 230b may include a first PWM carrier signal corresponding to the first inverter 220a and a second inverter ( 220b) can be controlled so that the phase difference of the second PWM carrier signal corresponding to the sequentially decreases.

As another example, the second inverter control unit 230b, when the level of the harmonic component exceeding the first order is equal to or greater than the second reference level, the first PWM control period corresponding to the first inverter 220a, and the second inverter 220b ) can be controlled such that the phase difference of the second PWM control cycle corresponding to the sequentially decreases.

Fig. 12 (a) shows the fundamental wave waveform (Isp) of the input current, Fig. 12 (b) shows the low-order harmonic waveform (Isdbb) of the input current, and Fig. 12 (c) shows the high-order harmonic of the input current The waveform Isubb is shown, and FIG. 12( d ) shows the first PWM carrier signal and the second PWM carrier signal for each time point.

12, before the time Tm, the second reference level ref2 of the high-order harmonic waveform Isubb of the input current is greater than or equal to the second reference level ref2, and accordingly, the second inverter control unit 230b, the first inverter 220a The corresponding control is performed from the time Tm so that the phase difference between the corresponding first PWM carrier signal and the second PWM carrier signal corresponding to the second inverter 220b is sequentially decreased.

Before the time Tm, the phase difference between the first PWM carrier signal (PWMax) and the second PWM carrier signal (PWMbx) was approximately 180 degrees, and the second inverter control unit 230b, the first PWM carrier signal (PWMax) and , the second PWM carrier signal PWMbx may be controlled such that the phase difference becomes small.

For example, when the phase of the first PWM carrier signal is faster, the second inverter control unit 230b may control the phase of the second PWM carrier signal to sequentially increase.

As another example, when the phase of the first PWM carrier signal is slower, the second inverter control unit 230b may control the phase of the second PWM carrier signal to be sequentially slow.

By this control, the phase difference between the first PWM carrier signal (PWMax) and the second PWM carrier signal (PWMbx) is sequentially decreased from the time Tm, and at the time Tn, the first PWM carrier signal (PWMax) and The phase difference of the phase difference of the second PWM carrier signal PWMbx may be substantially the same.

Meanwhile, in the drawing, between the time Tm and the time Tn, the phase difference between the first PWM carrier signal PWMMay and the second PWM carrier signal PWMby is approximately 30 degrees, and after the time Tn, the first PWM It is exemplified that the phase difference between the carrier signal PWMaz and the second PWM carrier signal PWMbz is approximately 0 degrees.

According to this method, if the level of the high-order harmonic waveform of the input current is reduced, it is possible to improve the power factor due to the reduction of the reactive current when a plurality of motors are driven in parallel.

Meanwhile, the method for reducing the phase difference between the first PWM carrier signal and the second PWM carrier signal of FIG. 12 is the same as reducing the phase difference between the first PWM control period and the second PWM control period, as described above. .

That is, the second inverter control unit 230b, when the level of the harmonic component exceeding the first order among the harmonic components of the input current is equal to or higher than the second reference level, the first PWM control period corresponding to the first inverter 220a; It is possible to control so that the phase difference of the second PWM control period corresponding to the second inverter 220b is sequentially decreased. Accordingly, when a plurality of motors are driven in parallel, it is possible to improve the power factor due to a reduction in reactive current.

On the other hand, although the control method of FIGS. 8 to 12 has been mainly described with respect to the operations of the first inverter control unit 230a and the second inverter control unit 230b, when the common inverter control unit 230 of FIG. 3B is used, It is possible for the common inverter control unit 230 of FIG. 3B to perform the operations of the first inverter control unit 230a and the second inverter control unit 230b.

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 In addition, 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 perspective of the present invention.

Claims (15)

a first inverter and a second inverter that operate based on a common input AC power and drive the first motor and the second motor, respectively;
a first inverter control unit for controlling the first inverter;
Including; a second inverter control unit for controlling the second inverter;
At least one of the first inverter control unit and the second inverter control unit is configured to, when a level of a harmonic component of a first order or less among harmonic components of an input current from the common input AC power supply is equal to or greater than a first reference level, the first The motor driving apparatus according to claim 1, wherein the phase difference between the first output current flowing through the motor and the second output current flowing through the second motor is controlled so that the sequentially decreases. According to claim 1,
At least one of the first inverter control unit and the second inverter control unit is configured to, when a level of a harmonic component exceeding the first order among harmonic components of an input current from the common input AC power supply is equal to or greater than a second reference level, Motor driving apparatus, characterized in that the control so that the phase difference between the first PWM carrier signal corresponding to one inverter and the second PWM carrier signal corresponding to the second inverter is sequentially reduced. According to claim 1,
At least one of the first inverter control unit and the second inverter control unit is configured to, when a level of a harmonic component exceeding the first order among harmonic components of an input current from the common input AC power supply is equal to or greater than a second reference level, A motor driving apparatus, characterized in that the control is performed so that a phase difference between a first PWM control period corresponding to one inverter and a second PWM control period corresponding to the second inverter is sequentially decreased. According to claim 1,
a first rectifying unit rectifying the input AC power;
a first capacitor for storing the pulsating voltage from the first rectifying unit;
a first inverter control unit for controlling the first inverter;
a second rectifying unit rectifying the input AC power;
The motor driving device further comprising a; a second capacitor for storing the pulsating voltage from the second rectifying unit. 5. The method of claim 4,
It further comprises;
At least one of the first inverter control unit and the second inverter control unit,
When the level of a first-order or less harmonic component among harmonic components of the input current is equal to or greater than a first reference level, the phase between the first output current flowing through the first motor and the second output current flowing through the second motor A motor driving device, characterized in that the difference is controlled so that it becomes smaller in sequence. The method of claim 1,
The first inverter control unit and the second inverter control unit,
Sharing information about a first PWM control period corresponding to the first inverter, a second PWM control period corresponding to the second inverter, a phase of the first output current, and a phase of the second output current Characterized by the motor drive. According to claim 1,
The first inverter control unit,
calculating the current output frequency of the first inverter and transmitting the current output frequency of the first inverter to the second inverter control unit;
The second inverter control unit,
and calculating the current output frequency of the second inverter and controlling to compensate for a difference between the current output frequency of the first inverter and the current output frequency of the second inverter. 4. The method of claim 3,
The first inverter control unit,
Transmitting the period information of the first inverter to the second inverter control unit,
The second inverter control unit calculates an error between the period information of the first inverter and the period information of the second inverter, and controls to compensate the error. delete a first inverter and a second inverter that operate based on a common input AC power and drive the first motor and the second motor, respectively;
Including; an inverter control unit for controlling the first inverter and the second inverter;
The inverter control unit may include a first output current flowing through the first motor and a first output current flowing through the first motor when a level of a harmonic component of a first order or less among harmonic components of an input current from the common input AC power supply is equal to or higher than a first reference level; A motor driving device, characterized in that the phase difference between the second output currents flowing through the two motors is controlled to be sequentially decreased. 11. The method of claim 10,
The inverter control unit,
a first PWM carrier signal corresponding to the first inverter; Motor driving apparatus, characterized in that the control so that the phase difference of the second PWM carrier signal corresponding to the sequentially decreases. 11. The method of claim 10,
The inverter control unit includes a first PWM control period corresponding to the first inverter when a level of a harmonic component exceeding the first order among harmonic components of an input current from the common input AC power supply is equal to or greater than a second reference level; , The motor driving apparatus, characterized in that the control so that the phase difference of the second PWM control period corresponding to the second inverter is sequentially reduced. 11. The method of claim 10,
a first rectifying unit rectifying the input AC power;
a first capacitor for storing the pulsating voltage from the first rectifying unit;
a first inverter control unit for controlling the first inverter;
a second rectifying unit rectifying the input AC power;
The motor driving device further comprising a; a second capacitor for storing the pulsating voltage from the second rectifying unit. a first inverter and a second inverter that operate based on a common input AC power and drive the first motor and the second motor, respectively;
Including; an inverter control unit for controlling the first inverter and the second inverter;
The inverter control unit,
When the level of the higher-order harmonic component among the harmonic components of the input current from the common input AC power supply is equal to or higher than the reference level, the first PWM carrier signal corresponding to the first inverter and the corresponding to the second inverter A motor driving apparatus, characterized in that the second PWM carrier signal is controlled so that the phase difference is sequentially decreased. An air conditioner comprising a; the motor driving device according to any one of claims 1 to 8 and 10 to 14.

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