KR20190052389A - 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. According to an embodiment of the present invention, the motor driving device comprises: a first inverter and a second inverter operated based on a common input alternating current power and individually driving a first motor and a second motor; and an inverter controlling unit controlling the first inverter and the second inverter. The inverter controlling unit controls polarity of a level of first noise generated from the first motor and polarity of a level of second noise generated from the second motor to be opposite to each other. Therefore, common-mode noise can be effectively reduced when the plurality of motors are driven in parallel.

Description

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

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a motor driving apparatus and an air conditioner having the same, and more particularly, to a motor driving apparatus and an air conditioner having the motor driving apparatus capable of effectively reducing common mode noise when a plurality of motors are driven in parallel .

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

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

On the other hand, according to IEC 61000, an international surge protection standard, a standard for reducing harmonics is set, and various attempts have been made to reduce harmonics due to the input alternating current in the compressor motor drive apparatus.

SUMMARY OF THE INVENTION An object of the present invention is to provide a motor drive apparatus capable of effectively reducing common mode noise when a plurality of motors are driven in parallel and an air conditioner having the same.

According to an aspect of the present invention, there is provided a motor driving apparatus and an air conditioner having the same, the motor driving apparatus including: a first inverter that operates based on a common input AC power source and drives a first motor and a second motor; And the inverter control section controls the polarity of the level of the first noise generated in the first motor and the polarity of the level of the second noise generated in the second motor, The polarity of the level is reversed.

According to another aspect of the present invention, there is provided a motor driving apparatus and an air conditioner including the motor driving apparatus. The motor driving apparatus and the air conditioner include a first motor and a second motor, Wherein the inverter control unit controls the polarity of the first offset voltage of the first motor and the polarity of the polarity of the second offset voltage of the second motor and the polarity of the first offset voltage of the second motor, and the inverter control unit controls the first inverter and the second inverter, Are opposite to each other.

A motor driving apparatus and an air conditioner having the same according to an embodiment of the present invention operate based on a common input AC power source and include a first inverter and a second inverter for driving the first motor and the second motor, And the inverter control unit controls the first inverter and the second inverter so that the polarity of the level of the first noise generated in the first motor and the level of the second noise generated in the second motor , So that the common mode noise can be effectively reduced when the plurality of motors are driven in parallel.

Particularly, by controlling the sum of the first leakage current leaking from the first motor and the second leakage current leaking from the second motor to be minimum, it is possible to effectively reduce the common mode noise in the parallel driving of a plurality of motors do.

On the other hand, by controlling the polarity of the first offset voltage of the first motor and the polarity of the second offset voltage of the second motor to be opposite to each other, the common mode noise can be effectively reduced do.

On the other hand, when the switching cycle of the first inverter is synchronized with the switching cycle of the second inverter, and the switching timing of the second inverter is varied so as to correspond to the switching timing of the first inverter, The mode noise can be effectively reduced.

According to another aspect of the present invention, there is provided a motor driving apparatus and an air conditioner including the motor driving apparatus. The motor driving apparatus and the air conditioner include a first motor and a second motor, Wherein the inverter control unit controls the polarity of the first offset voltage of the first motor and the polarity of the polarity of the second offset voltage of the second motor and the polarity of the first offset voltage of the second motor, and the inverter control unit controls the first inverter and the second inverter, So that the common mode noise can be effectively reduced when the plurality of motors are driven in parallel.

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

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

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

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

1, a large-sized air conditioner 50 includes a plurality of indoor units 31 to 35, a plurality of outdoor units 21 and 22 connected to a plurality of indoor units, Remote controllers 41 to 45 connected to the respective indoor units, and a remote controller 10 for controlling the plurality of indoor units and the outdoor units.

The remote controller 10 is connected to a plurality of indoor units 31 to 36 and a plurality of outdoor units 21 and 22 to monitor and control the operation thereof. At this time, 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 of a stand-type air conditioner, a wall-mounted air conditioner, and a ceiling-type air conditioner, but a ceiling-type air conditioner will be described as an example for convenience of explanation. 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 are provided with a compressor (not shown) for receiving and compressing the refrigerant, an outdoor heat exchanger (not shown) for exchanging heat between the refrigerant and the outdoor air, an accumulator for extracting the gas refrigerant from the supplied refrigerant, And a four-way valve (not shown) for selecting the flow path of the refrigerant according to the heating operation. In addition, a number of sensors, valves, oil recovery devices, and the like are further included, but a description thereof will be omitted below.

The outdoor units (21, 22) operate the compressor and the outdoor heat exchanger to compress or heat-exchange the refrigerant according to the setting, and 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. The number of operation of the outdoor units and the number of operation of the compressors installed in the outdoor units The number of operations is variable.

At this time, the outdoor units (21, 22) are explained on the basis that the plurality of outdoor units supply the refrigerant to the indoor units connected to the indoor units, respectively. However, according to the connection structure of the outdoor units and the indoor units, .

The indoor units 31 to 35 are connected to any one of the plurality of outdoor units 21 and 22 to receive the refrigerant and discharge the cold air to the room. The indoor units 31 to 35 include an indoor heat exchanger (not shown), an indoor fan (not shown), an expansion valve (not shown) in which the refrigerant to be supplied 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 to each other via a communication line to transmit and receive data, and the outdoor unit and the indoor unit are connected to the remote controller 10 by a separate communication line, .

The remote controllers 41 to 45 are connected to the indoor units, respectively, to input control commands of the user to the indoor units, and to receive and display status information of the indoor units. At this time, the remote controller communicates wired or wirelessly according to the connection form with the indoor unit, and in some cases, one remote controller is connected to the plurality of indoor units, and the settings of the plurality of indoor units can be changed through one remote control input.

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

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

Referring to the drawings, the air conditioner 50 is roughly divided into an indoor unit 31 and an outdoor unit 21.

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

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

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

Further, the air conditioner 50 may be constituted by a cooling unit that cools the room, or a heat pump that cools or heats the room.

2, the indoor unit 31 and the outdoor unit 21 are shown as one unit. However, the driving unit of the air conditioner according to the embodiment of the present invention is not limited to this, The present invention is also applicable to an air conditioner, an air conditioner having one indoor unit and a plurality of outdoor units.

The compressor 102 in the outdoor unit 21 of Fig. 1 can be driven by the motor drive unit 200 for the compressor shovel driving the compressor motor 250. Fig.

FIG. 3A is an example of a block diagram of a motor driving apparatus according to the present invention, and FIG. 3B is a diagram referred to in an operation description of FIG. 3A.

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

3A includes a first motor 250ax, a second motor 250bx, a first inverter 220ax for outputting an alternating current to the first motor 250ax, A first inverter control unit 230ax for controlling the first inverter 220ax and a second inverter control unit 230bx for controlling the second inverter 220bx are connected to the first inverter 220bx and the second inverter 220bx, .

The motor driving apparatus 200x may further include a converter 210x that operates to supply a common DC power to the first inverter 220ax and the second inverter 220bx.

According to the motor driving apparatus 200x of FIG. 3A, the first inverter control unit 230ax and the second inverter control unit 230bx control the first inverter 220ax and the second inverter 220bx, respectively.

3B illustrates a common mode noise Nsix at an input end of the converter 210x of the motor driving apparatus 200x of FIG. 3A, and FIG. 3A illustrates the common mode noise Nscx in the first motor 250ax in FIG. 3A, and FIG. 3C illustrates the common mode noise Nsfx in the second motor 250bx in FIG. For example.

3B, the common mode noise Nscx in the first motor 250ax and the common mode noise Nscx in the second motor 250bx due to the first inverter 220ax and the second inverter 220bx, The common mode noise (Nsfx) is summed and appears as the common mode noise (Nsix) at the input terminal.

On the other hand, the common mode noise Nscx in the first motor 250ax may be caused by the leakage current isax leaking from the first motor 250ax and may be the sum of the common mode noise in the second motor 250bx Nsfx may be caused by a leakage current Isbx leaking from the second motor 250bx.

Due to the common mode noise (Nsix), which is a harmonic component at the input terminal, the durability of the internal circuit element is weakened and the power conversion efficiency may be lowered.

Accordingly, the present invention proposes a method for reducing common mode noise when a motor is driven in parallel. This will be described with reference to FIG. 4 and subsequent figures.

4 is an example of a block diagram of a motor drive apparatus according to an embodiment of the present invention.

The motor driving apparatus 200 of FIG. 4 is characterized in that a plurality of motors are driven in parallel.

To this end, the motor driving apparatus 200 includes a first motor 250a, a second motor 250b, a first inverter 220a that outputs an alternating current to the first motor 250a, a second motor 250b, And a second inverter 220b for outputting an alternating current to the second inverter 220b.

The motor driving apparatus 200 may further include a converter 210 that operates to supply a common DC power to the first inverter 220a and the second inverter 220b.

The converter 210 converts the commercial AC power source 201 that has passed through the reactor L into DC power and outputs the DC power. Although the commercial AC power source 201 is shown as a single-phase AC power source in the figure, it may be a three-phase AC power source. The internal structure of the converter 210 also changes depending on the type of the commercial AC power source 201.

Meanwhile, the converter 210 may include a diode without a switching element, and may perform a rectifying operation without a separate switching operation.

For example, in the case of a single-phase AC power source, four diodes may be used in the form of a bridge, and in the case of a three-phase AC power source, six diodes may be used in the form of a bridge.

On the other hand, as the converter 210, for example, a half-bridge type converter in which two switching elements and four diodes are connected may be used, and in the case of a three-phase AC power source, six switching elements and six diodes may be used .

When the converter 210 includes a switching element, the boosting operation, the power factor correction, and the DC power conversion can be performed by the switching operation of the switching element.

The dc-capacitors (C1, C2) smooth the input power supply and store it. In the drawing, a node between the dc-stage capacitors C1 and C2 is shown as an n-node.

On the other hand, both ends of the dc-stage capacitors C1 and C2 store direct-current power, and may be referred to as a dc-stage or a dc-link stage.

The dc short-circuit voltage detector B can detect the dc short-circuit voltage Vdc at both ends of the dc short-circuit capacitors C1 and C2. For this purpose, the dc voltage detection unit B may include a resistance element, an amplifier, and the like. The detected dc voltage source Vdc may be input to the inverter control unit 230 as a discrete signal in the form of a pulse.

The input voltage detecting section A can detect the input voltage Vs from the input AC power supply 201. [

The input voltage detecting unit A may include a resistance element, an OP AMP, or the like for voltage detection. The detected input voltage Vs can be applied to the inverter control unit 230 as a discrete signal in the form of a pulse.

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

Next, the input current detection section D can detect the input current Is from the input AC power source 201. [ Specifically, it can be located at the front end of the converter 210. [

The input current detection unit D may include a current sensor, a current transformer (CT), a shunt resistor, or the like, for current detection. The detected input voltage Is may be applied to the inverter control unit 230 as a discrete signal in the form of a pulse.

Each of the first inverter 220a and the second inverter 220b includes a plurality of inverter switching elements and converts the smoothed direct current power to an alternating current power of a predetermined frequency by on / off operation of the switching element, And outputs it to the motor 250a and the second motor 250b.

The inverter control unit 230 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 is a switching control signal for switching the output current i _oa flowing through the first motor 250a or the first dc step voltage (Vdca), and can be generated and output. The output current i _{oa at} this time can be detected from the first output current detection unit Ea and the first dc step voltage Vdca can be detected from the first dc voltage detection unit Ba.

The inverter control unit 230 can 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 is used as a switching control signal for switching the output current i _ob flowing to the second motor 250b or the second dc terminal voltage across the second dc- (Vdcb), and can be generated and output. The output current i _{ob at} this time can be detected from the second output current detection unit Eb and the second dc voltage Vdcb can be detected from the second dc voltage detection unit Bb.

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

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

Each of the first motor 250a and the second motor 250b has a stator and a rotator and is provided with a coil of a stator of each phase (a, b, c) AC power is applied, and the rotor rotates.

The first and second motors 250a and 250b may be a permanent magnet synchronous motor such as a surface mounted permanent magnet synchronous motor (SMPMSM), a permanent permanent magnet synchronous motor (Interior Permanent Magnet) A synchronous motor (IPMSM), and a synchronous reluctance motor (Synrm). Among them, SMPMSM and IPMSM are permanent magnet applied Permanent Magnet Synchronous Motor (PMSM), and Synrm is characterized by having no permanent magnet.

Meanwhile, the motor driving apparatus 200 according to the embodiment of the present invention suggests a method for reducing harmonics, particularly, common mode noise generated by the input AC power supply when the motors 250a and 250b are driven in parallel.

On the other hand, the common mode noise can be generated by asynchronous driving of the first motor 250a and the second motor 250b. Accordingly, in the present invention, in order to reduce the common mode noise caused by the first motor 250a and the second motor 250b, the first motor 250a and the second motor 250b are synchronously driven Suggest a plan.

To this end, the inverter control unit 230 in the motor driving apparatus 200 according to an embodiment of the present invention controls the first inverter 220a and the second inverter 220b in common.

The inverter controller 230 controls the polarity of the level of the first noise generated in the first motor 250a and the level of the second noise generated in the second motor 250b in accordance with an embodiment of the present invention, The common mode noise can be effectively reduced when the plurality of motors are driven in parallel.

In particular, the inverter control unit 230 controls the inverter 250 so that the sum of the first leakage current isa leaked from the first motor 250a and the second leakage current isb leaked from the second motor 250b is minimized Thus, the common mode noise can be effectively reduced when the plurality of motors are driven in parallel.

4, the nodes a1, b1, and c1, which are the output terminals of the first inverter 220a, and the nodes n1 and n2, which are nodes between the dc short capacitors C1 and C2, the relationship between the polar voltages Va1n, Vb1n and Vc1n, the phase voltages Va1s1, Vb1s1 and Vc1s1 and the offset voltage Vs1n1 can be formed by the equation (1) as shown in the following equation (1).

[Equation 1]

Va1n = Va1s1 + Vs1n1

Vb1n = Vb1s1 + Vs1n1

Vc1n = Vc1s1 + Vs1n1

4, the nodes a2, b2, and c2, which are the output terminals of the second inverter 220b, and the internal nodes of the second motor 250b, which are the nodes between the dc short capacitors C1 and C2, the relationship between the polarities Va2n, Vb2n and Vc2n, the phase voltages Va2s2, Vb2s2 and Vc2s2 and the offset voltage Vs2n2 can be formed by the equation (2) as shown in the following equation (2).

&Quot; (2) "

Va2n = Va2s2 + Vs2n2

Vbn2 = Vb2s2 + Vs2n2

Vcn2 = Vc2s2 + Vs2n2

The common mode noise Nsix in the motor driving apparatus 200x of FIG. 3A is a difference between the polarity of the first offset voltage Vs1n1a of the first motor 250a and the polarity of the second offset voltage Vs1n1b of the second motor 250b Vs2n2a are the same, the common mode noise Nsix tends to be amplified as shown in Fig. 3B (a).

The inverter controller 230 according to the embodiment of the present invention controls the polarity of the first offset voltage Vs1n1a of the first motor 250a and the polarity of the polarity of the second offset voltage Vs2n2a of the second motor 250b Are opposite to each other. As a result, when the plurality of motors are driven in parallel, the common mode noise can be effectively reduced.

Meanwhile, the inverter controller 230 synchronizes the switching period of the first inverter 220a with the switching period of the second inverter 220b. In response to the switching timing of the first inverter 220a, 220b are varied so that the common mode noise can be effectively reduced when the plurality of motors are driven in parallel.

The driving operation of the inverter control unit 230 according to the embodiment of the present invention will be described in more detail with reference to FIG.

5 is an example of an internal block diagram of the inverter control unit of Fig.

5, 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.

The axial conversion unit 310 receives the three phase output currents iaa, iba, ic or iab, ibb, icb detected by the first and second output current detection units Ea and Eb, (i?, i?).

On the other hand, the axis converting unit 310 can convert the two-phase current i ?, i? Of the still coordinate system into the two-phase current id, iq of the rotating coordinate system.

)를 추정한다. 또한, 추정된 회전자 위치(

)에 기초하여, 연산된 속도(

)를 출력할 수 있다.The speed computing unit 320 computes the rotor position of the motor 250 based on the two-phase currents i? And i? Of the stationary coordinate system converted by the axis converting unit 310

). In addition, the estimated rotor position (

), The calculated speed (

Can be output.

)와 목표 속도(ω)에 기초하여, 속도 지령치(ω^* _r)를 연산하며, 속도 지령치(ω^* _r)에 기초하여, 전류 지령치(i^* _q)를 생성한다. 예를 들어, 전류 지령 생성부(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 generates the current command

) Based on the speed command value ω ^* _r and the target speed ω and generates the current command value i ^* _q based on the speed command value ω ^* _r . For example, the current command generation section 330 generates the current command

The PI controller 435 performs the PI control based on the speed command value? ^* _{R that} is the difference between the target speed? And the target speed?, And generates the current command value i ^* _q . In the figure, the q-axis current command value (i ^* _q ) is exemplified by the current command value, but it is also possible to generate the d-axis current command value (i ^* _d ) unlike the figure. On the other hand, the value of the d-axis current command value i ^* _d may be set to zero.

On the other hand, the current command generation section 330 may further include a limiter (not shown) for limiting the current command value (i ^* _q ) so that the current command value (i ^* _q ) does not exceed the allowable range.

Next, the voltage command generating unit 340 generates the voltage command generating unit 340 with the d-axis and q-axis currents (i _d , i _q ) axially transformed into the two-phase rotational coordinate system in the axial converting unit and the current command value based on ^{_{i * d, i * q)}} , and generates a d-axis, q-axis voltage command value ^{_{(v * d, v * q}} ). 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 ) It is possible to generate the axial voltage command value v ^* _q . Further, voltage command generation unit 340, on the basis of the difference between the d-axis current (i _d) and, the d-axis current command value (i ^* _d), and performs the PI control in the PI controller (448), d-axis voltage It is possible to generate the command value v ^* _d . On the other hand, the value of the d-axis voltage command value v ^* _d may be set to zero corresponding to the case where the value of the d-axis current command value i ^* _d is set to zero.

The voltage command generator 340 may further include a limiter (not shown) for limiting the level of the d-axis and q-axis voltage command values v ^* _d and v ^* _q so as not to exceed the permissible range .

On the other hand, the generated d-axis and q-axis voltage command values (v ^* _d and v ^* _q ) are input to the axial conversion unit 350.

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

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

)가 사용될 수 있다.First, the axis converting unit 350 performs conversion from a two-phase rotating coordinate system to a two-phase stationary coordinate system. At this time, the position calculated by the speed calculator 320 (

) Can be used.

Then, the axial conversion unit 350 performs conversion from the two-phase stationary coordinate system to the three-phase stationary coordinate system. Through this conversion, the axial conversion unit 1050 outputs the three-phase output voltage instruction values v ^* a, v ^* b, v ^* c.

Switching control signal output unit 360, three-phase output voltage command value (v ^* a, v ^* b, v ^* c) to the first and second inverter switching control signal according to a pulse width modulation (PWM) manner based on ( Sica, Sicb) can be generated and output.

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

6 to 10 are views referred to in the description of the operation of FIG.

6, the inverter controller 230 according to the embodiment of the present invention compares the polarity of the level of the first noise generated in the first motor 250a and the polarity of the level of the second noise generated in the second motor 250b The polarity of the level can be controlled to be opposite.

6A illustrates a common mode noise Nsi at an input end of the converter 210 of the motor driving apparatus 200 of FIG. 4, and FIG. 6 illustrates a common mode noise Nsc in the first motor 250a of FIG. 4, and FIG. 6C illustrates a common mode noise Nsf in the second motor 250b of FIG. 4 .

6, the common mode noise Nsc in the first motor 250a and the common mode noise Nsc in the second motor 250b are different from each other due to the first inverter 220a and the second inverter 220b, The common mode noise (Nsf) is summed and appears as a common mode noise (Nsi) at the input.

On the other hand, the common mode noise Nsc in the first motor 250a may be caused by the leakage current isa leaking from the first motor 250a and the common mode noise Nsc in the second motor 250b Nsf may be caused by a leakage current Isb leaking from the second motor 250b.

Meanwhile, the inverter controller 230 according to the embodiment of the present invention controls the polarity of the level of the first noise Nsc generated in the first motor 250a and the polarity of the level of the second noise Nsc generated in the second motor 250b, It is preferable to control the polarity of the level Nsf to be opposite.

For example, the inverter control unit 230 determines the level Nsf of the second noise generated in the second motor 250b based on the polarity of the level of the first noise Nsc generated in the first motor 250a Can be controlled to be opposite.

As another example, the inverter control unit 230 determines whether the level of the first noise Nsc generated in the first motor 250a is higher than the level of the second noise Nsc generated in the first motor 250a, based on the polarity of the level Nsf of the second noise generated in the two motors 250b. The polarity can be controlled to be opposite.

In FIG. 6, the polarity of the common mode noise Nsc in the first motor 250a in FIG. 6 (b) is opposite to the polarity of the common mode noise Nsc in the second motor 250b in FIG. Nsf) is displayed. Thus, as shown in Fig. 6A, the common mode noise (Nsi) at the input stage is exemplified.

Compared to the common mode noise Nsix at the input stage of FIG. 3b, it can be seen that the common mode noise Nsi at the input stage is significantly reduced, as shown in FIG. 6 (a).

6, the inverter control unit 230 determines whether or not the polarity of the level of the first noise generated in the first motor 250a and the polarity of the level of the first noise generated in the second motor 250b 2 can be controlled so that the polarity of the level of the noise is opposite.

On the other hand, the polarity of the common mode noise Nsc in the first motor 250a of FIG. 6 (b) can correspond to the polarity of the first leakage current isa leaked from the first motor 250a, The polarity of the common mode noise Nsf in the second motor 250b of Fig. 6 (c) can correspond to the polarity of the second leakage current isb leaking from the second motor 250b.

Accordingly, the inverter control unit 230 controls the polarity of the first leakage current isa leaked from the first motor 250a and the polarity of the second leakage current isb leaked from the second motor 250b, It is preferable to control to be opposite.

That is, the inverter control unit 230 controls the control so that the sum of the first leakage current isa leaked from the first motor 250a and the second leakage current isb leaked from the second motor 250b is minimized . As a result, when the plurality of motors are driven in parallel, the common mode noise can be effectively reduced.

Next, Fig. 7A can be the turn-on timing waveform PCSa of the first switching element among the plurality of switching elements in the first inverter 220a.

Next, FIG. 7C can be the turn-on timing waveform PFSa of the first switching element corresponding to the first inverter 220a among the plurality of switching elements in the second inverter 220b.

7B shows the turn-on timing waveform PCSa of the first switching element in the first inverter 220a and the turn-on timing waveform PFSa of the first switching element in the second inverter 220b. (PFSax) are exemplified.

The inverter control unit 230 according to the embodiment of the present invention synchronizes the switching period of the first inverter 220a with the switching period of the second inverter 220b and the first inverter 220a The switching timing of the second inverter 220b can be controlled to be variable.

In particular, as shown in FIG. 7, the inverter control unit 230 according to the embodiment of the present invention controls the inverter control unit 230 such that the first switching device of the first inverter 220a is turned on during the first period Ta1 to Ta2 The first switching element of the second inverter 220b is controlled to be turned off during the first section Ta1 to Ta2 and the first switching element of the first inverter 220a is controlled to be turned off during the second section Tb1 to Tb2, the first switching device of the second inverter 220b can be controlled to be turned on during the second period Tb1 to Tb2.

7 (b), the turn-on timing waveform PCSa of the first switching element in the first inverter 220a and the turn-on timing waveform PCSa of the first switching element in the second inverter 220b The level difference of the waveform PFSax, which is the sum of the PFSa and the PFSa, is reduced. As a result, the common mode noise can be effectively reduced.

8, when the turn-on duty (Taa to Tab) of the switching element of the second inverter 220b is increased during the first control period Ts1, the inverter control unit 230 controls the first control period The turn-on duty (Tbe to Tbd) of the switching element of the second inverter 220b may be controlled to decrease during the second control period Ts2 after the first control period Ts1.

8, during the first control period Ts1, the duty ratio of the turn-on timing waveform PCSaa of the first switching element of the first inverter 220a and the duty ratio of the first switching element of the second inverter 220b, The turn-on duty (Taa to Tab) of the switching element of the second inverter 220b can be increased so that the turn-on duty of the turn-on timing waveform PFSam of the element is the same.

However, in order to operate in accordance with the speed command of the second motor 250b, the switching of the second inverter 220b during the second control period Ts2 after the first control period Ts1, It is preferable to control so that the turn-on duty (Tbe to Tbd) of the device is reduced.

Thus, the common mode noise can be effectively reduced during the first control period Ts1, and the second motor 250b can be driven by the second control period Ts2 in accordance with the speed command of the second motor 250b Can be rotated.

9, the inverter control unit 230 shifts the switching timing of one of the switching elements of the second inverter 220b so as not to overlap the switch timing of the corresponding switching element of the first inverter 220a Can be controlled.

9A illustrates the turn-on timing periods Tsa, Tsb and Tsc of the three-phase switching elements Sa, Sb and Sc of the first inverter 220a, The turn-on timing periods Tsa, Tsba, Tsbb and Tsc of the three-phase switching elements Sa, Sb and Sc of the switching element 220b are illustrated.

The inverter control unit 230 sets the turn-on timing of the second switching element Sb among the three-phase switching elements Sa, Sb, Sc of the second inverter 220b to the control period Ts On the basis of the boundary of the first switching device Sb and the second switching device Sb, respectively, thereby turning off the turn-on timing of the second switching device Sb.

That is, the inverter controller 230 sets the turn-on timings Tsba and Tsbb of the second switching element Sb among the three-phase switching elements Sa, Sb and Sc of the second inverter 220b to the first inverter 220b, Off timing (Tsb) of the second switching device (Sb) among the three-phase switching devices (Sa, Sb, Sc) of the first switching device (Sb). As a result, the common mode noise can be effectively reduced.

10, the polarity of the first offset voltage Vs1n1a of the first motor 250a and the polarity of the second offset voltage Vs2n2a of the second motor 250b are opposite to each other, It is preferable to control them to be opposite to each other.

The common mode noise Nsix in the motor driving apparatus 200x of FIG. 3A is a difference between the polarity of the first offset voltage Vs1n1a of the first motor 250a and the polarity of the second offset voltage Vs1n1b of the second motor 250b The common mode noise Nsix tends to be amplified as shown in FIG. 3B (a) when the polarity of the first motor 250a (Vs2n2a) is the same. Therefore, in order to reduce common mode noise, The polarity of the first offset voltage Vs1n1a of the second motor 250b and the polarity of the second offset voltage Vs2n2a of the second motor 250b are opposite to each other. As a result, when the plurality of motors are driven in parallel, the common mode noise can be effectively reduced.

4 to 10 can be applied to various home appliances in addition to the air conditioner 100 of FIG. For example, it can be applied to various fields such as laundry processing apparatuses (washing machines, dryers, etc.), refrigerators, water purifiers, and robot cleaners.

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

Referring to the drawings, the air conditioner 100b of Fig. 11 differs from the system type air conditioner of Fig. 1 in that one outdoor unit 31b is provided.

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

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

Meanwhile, the air conditioner 100b 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 21b includes a compressor (not shown) for receiving and compressing refrigerant, an outdoor heat exchanger (not shown) for exchanging heat between the refrigerant and outdoor air, an accumulator for extracting the gas refrigerant from the supplied refrigerant and supplying it to the compressor And a four-way valve (not shown) for selecting the flow path of the refrigerant according to the heating operation. In addition, a number of sensors, valves, oil recovery devices, and the like are further included, but a description thereof will be omitted below.

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

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

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

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

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

12 is a schematic view of the outdoor unit and the indoor unit of Fig.

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

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

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

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

Further, the air conditioner 100b may be constituted by a cooler for cooling the room, or a heat pump for cooling or heating the room.

The compressor 102b in the outdoor unit 21b of Fig. 11 can be driven by the motor drive unit 220, such as Fig. 3, which drives the compressor motor 250b.

Alternatively, the indoor fan 109ab or the outdoor fan 105ab may be driven by the motor driving device 220 as shown in Fig. 3, which drives the indoor fan motor 109bb and the outdoor fan motor 150bb, respectively .

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

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, It will be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the spirit and scope of the present invention.

Claims (15)

A first inverter and a second inverter operating based on a common input AC power source and driving the first motor and the second motor, respectively;
And an inverter control unit for controlling the first inverter and the second inverter,
The inverter control unit includes:
And controls the polarity of the level of the first noise generated in the first motor and the polarity of the level of the second noise generated in the second motor to be opposite to each other. The method according to claim 1,
The inverter control unit includes:
Wherein the controller controls the polarity of the level of the first noise generated in the first motor and the polarity of the level of the second noise generated in the second motor to be opposite to each other at the first time. The method according to claim 1,
The inverter control unit includes:
Wherein the control unit controls the motor so that a sum of a first leakage current leaking from the first motor and a second leakage current leaking from the second motor is minimized. The method according to claim 1,
The inverter control unit includes:
Controls the polarity of the first offset voltage of the first motor and the polarity of the second offset voltage of the second motor to be opposite to each other. The method according to claim 1,
The inverter control unit includes:
Wherein the control unit synchronizes the switching cycle of the first inverter with the switching cycle of the second inverter and controls the switching timing of the second inverter to vary in accordance with the switching timing of the first inverter. . 6. The method of claim 5,
The inverter control unit includes:
Wherein when the switching element of the first inverter is turned on during the first period, the switching element of the second inverter is controlled to be turned off during the first period,
Wherein when the switching element of the first inverter is turned off during the second period, the switching element of the second inverter is controlled to be turned on during the second period. 6. The method of claim 5,
The inverter control unit includes:
In case that the turn on duty of the switching element of the second inverter is decreased during the first control period and during the second control period after the first control period when the turn on duty of the switching element of the second inverter is increased Wherein the motor control device controls the motor. 6. The method of claim 5,
The inverter control unit includes:
The switching timing of one of the switching elements of the second inverter is shifted so as not to overlap the switch timing of the corresponding switching element of the first inverter. The method according to claim 1,
Wherein the first inverter and the second inverter operate based on a common DC power supply. The method according to claim 1,
A converter for converting the common input AC power into DC power; And
And a dc capacitor that stores a DC power from the converter,
Wherein the first inverter and the second inverter operate based on a DC power supply across the dc short capacitor. A first inverter and a second inverter operating based on a common input AC power source and driving the first motor and the second motor, respectively;
And an inverter control unit for controlling the first inverter and the second inverter,
The inverter control unit includes:
Controls the polarity of the first offset voltage of the first motor and the polarity of the second offset voltage of the second motor to be opposite to each other. 12. The method of claim 11,
The inverter control unit includes:
Wherein the control unit synchronizes the switching cycle of the first inverter with the switching cycle of the second inverter and controls the switching timing of the second inverter to vary in accordance with the switching timing of the first inverter. . 13. The method of claim 12,
The inverter control unit includes:
Wherein when the switching element of the first inverter is turned on during the first period, the switching element of the second inverter is controlled to be turned off during the first period,
Wherein when the switching element of the first inverter is turned off during the second period, the switching element of the second inverter is controlled to be turned on during the second period. 13. The method of claim 12,
The inverter control unit includes:
In case that the turn on duty of the switching element of the second inverter is decreased during the first control period and during the second control period after the first control period when the turn on duty of the switching element of the second inverter is increased Wherein the motor control device controls the motor. An air conditioner comprising the motor driving apparatus according to any one of claims 1 to 14.

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