KR20110045357A - Apparatus for dirving motor of air conditioner - Google Patents

Abstract

PURPOSE: An apparatus for driving a motor of an air conditioner is provided to reduce distortion due to harmonic current by using a matrix converter, since there is no need to use a capacitor. CONSTITUTION: An apparatus for driving a motor of an air conditioner comprises a power conversion unit and a controller(230). The power conversion unit comprises a plurality of switching elements The switching elements convert an input power into an output AC power of a certain frequency to drive a motor. A controller generates switching information of the switching elements based on at least one of input current and voltage and output current and voltage.

Description

Apparatus for dirving motor of air conditioner

The present invention relates to an electric motor driving apparatus of an air conditioner, and more particularly, to an electric motor driving apparatus of an air conditioner capable of improving energy efficiency.

An air conditioner is a device that is disposed in a room, a living room, an office, or a business store to adjust a temperature, humidity, cleanliness, and airflow of an air to maintain a comfortable indoor environment.

Air conditioners are generally divided into one-piece and separate types. The integrated type and the separate type are functionally the same, but the integrated type integrates the functions of cooling and heat dissipation to install a hole in the wall of the house or hang the device on the window. On the side, an outdoor unit that performs heat dissipation and compression functions was installed, and two separate devices were connected by refrigerant pipes.

In the air conditioner, an electric motor is used for a compressor, a fan, and the like, and an electric motor driving device for driving the air conditioner is used.

The motor driving device receives a commercial AC power and converts it into a DC voltage, and converts a DC voltage into a commercial AC power having a predetermined frequency and supplies the motor to the motor, thereby controlling the motor such as a compressor and a fan.

On the other hand, as the requirements for high performance and high efficiency of air conditioners increase, problems such as improved power consumption efficiency, harmonic current, input power factor, EMC, and the like have been raised.

An object of the present invention is to provide an electric motor driving apparatus of an air conditioner capable of improving energy efficiency.

The motor driving apparatus of the air conditioner according to the embodiment of the present invention for solving the above-described problems and other problems is provided with a plurality of switching elements, by the switching operation of the switching elements, the input power to the output AC of a predetermined frequency Generating switching information of the switching element on the basis of at least one of a power conversion unit for converting a power source to drive the motor, an input current and an input voltage by the input power source, an output current flowing through the motor, and polarity information of the output current; And a controller configured to generate and output a switching control signal according to the switching information.

As described above, the motor driving apparatus of the air conditioner according to the embodiment of the present invention is a power converter for driving an electric motor, and by using a matrix converter, converting directly into alternating current without converting to direct current, thereby improving energy efficiency. do.

On the other hand, the control unit according to the embodiment of the present invention generates the switching information of the switching element, and generates and outputs a switching control signal according to the switching information, such a control unit is implemented by a single module (module) or a single chip (chip), The efficiency is improved.

Further, as a power converter for driving an electric motor, by using a matrix converter, it is not necessary to use a smoothing capacitor for smoothing a DC power supply, thereby reducing distortion due to harmonic currents.

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

1 is a schematic diagram of an air conditioner according to the present invention.

Referring to the drawings, the air conditioner 50 is largely divided into an indoor unit (I) and an outdoor unit (O).

The outdoor unit O includes a compressor 2 serving to compress the refrigerant, a compressor electric motor 2b for driving the compressor, an outdoor side heat exchanger 4 serving to radiate the compressed refrigerant, and an outdoor unit. An outdoor blower 5 disposed on one side of the heat exchanger 4 and including an outdoor fan 5a for promoting heat dissipation of the refrigerant and an electric motor 5b for rotating the outdoor fan 5a, and an expansion for expanding the condensed refrigerant; The mechanism 6, the cooling / heating switching valve 10 for changing the flow path of the compressed refrigerant, and the accumulator 3 for temporarily storing the gasified refrigerant to remove moisture and foreign matter and then supplying a refrigerant of a constant pressure to the compressor. And the like.

The indoor unit (I) is disposed in the room to perform a cooling / heating function of the indoor side heat exchanger (10), and the indoor fan (10a) and the room disposed on one side of the indoor side heat exchanger (10) to promote heat dissipation of the refrigerant. And an indoor blower 10 made of an electric motor 10b for rotating the fan 10a.

At least one indoor side heat exchanger 10 may be installed. The compressor 2 may be at least one of an inverter compressor and a constant speed compressor.

In addition, the air conditioner 50 may be configured as a cooler for cooling the room, or may be configured as a heat pump for cooling or heating the room.

On the other hand, the motor in the motor drive device of the air conditioner according to an embodiment of the present invention can be each of the motor (2b, 5b, 9b) to operate the outdoor fan, compressor or indoor fan of the air conditioner, shown in the figure have.

Meanwhile, although FIG. 1 illustrates one indoor unit (I) and one outdoor unit (O), the driving device of the air conditioner according to the embodiment of the present invention is not limited thereto, and includes a plurality of indoor units and outdoor units. Applicable to the air conditioner, an air conditioner having a single indoor unit and a plurality of outdoor units, of course.

2 is a circuit diagram illustrating a motor driving apparatus of an air conditioner according to an embodiment of the present invention, FIG. 3 is a diagram illustrating an example of the matrix converter of FIG. 2, and FIG. 4 is a switching element in the matrix converter of FIG. 3. 5 is a diagram illustrating an example of a filter unit, and FIG. 6 illustrates a plurality of sector sections according to a three-phase AC power supply.

Referring to the drawings, the motor driving apparatus 200 of FIG. 2 according to an embodiment of the present invention includes a matrix converter 220, a controller 230, and an output current polarity detector D.

In addition, the motor driving apparatus 200 of FIG. 2 may further include a filter unit 210, an input voltage detector A, an input current detector B, an output current detector E, and the like.

The filter unit 210 is disposed between the commercial AC power supplies 205 and v _s and the matrix converter 220 to remove noise components from the commercial AC power supply 205. To this end, the filter unit 210 may include a plurality of capacitors and a reactor.

Referring to FIG. 5, the filter unit 210 may include reactors L1, L2, and L3 connected in series to a commercial AC power supply, resistance elements R1, R2, and R3, and a capacitor connected in parallel to the commercial AC power supply. C1, C2, C3). Reactors L1, L2, and L3 and resistors R1, R2, and R3 may be connected in parallel with each other.

By such a configuration, the harmonic current flowing from the commercial AC power source, that is, the grid, is stored in the capacitors C1, C2, and C3, and is hardly transmitted to the matrix converter 220. In addition, harmonic current components that may be generated by the fast switching of the matrix converter 220 are also stored in the capacitors C1, C2, and C3, so that they are hardly transmitted to the system.

On the other hand, the alternating current of the low frequency component is smoothly transferred to the matrix converter 220 through the reactors L1, L2, and L3. In addition, a commercial AC power supply may be boosted by the switching operation of the matrix converter 220 and the reactors L1, L2, and L3.

The matrix converter 220 includes a plurality of switching elements, and drives the electric motor 250 by converting commercial AC power into output AC power having a predetermined size and a predetermined frequency by a switching operation of the switching device. That is, the matrix converter 220 directly converts an input AC power source into an AC power source having a variable size and variable frequency to drive an electric motor. Accordingly, by converting directly into alternating current without conversion into direct current, energy efficiency is improved. In addition, it is not necessary to use a separate smoothing capacitor for smoothing the DC power supply, and does not need to perform a separate DC power conversion, thereby reducing distortion due to harmonic currents.

As an example of the matrix converter 220, as shown in FIG. 3, when a commercial AC power source 205, for example, a three-phase AC power source is an input side, inputs three-phase input AC power sources Vr, Vs, and Vt. And convert it into a three-phase output AC power supply (Vu, Vv, Vw).

To this end, three switching elements are arranged to switch the three phase output AC power based on each phase of the input power. As a result, 3 * 3 = 9 switching elements Sru, Ssu, Stu, Srv, Ssv, Stv, Srw, Ssw, and Stw are arranged.

At this time, each switching element (Sru, Ssu, Stu, Srv, Ssv, Stv, Srw, Ssw, Stw) is not only switched from the commercial AC power source 205 to the motor 250 but also commercially available in the motor 250. A bidirectional switching element may be included to enable switching to the AC power source 205.

4 shows a switching element Sru corresponding to the r phase of the input power and the u phase of the output power. As shown in the drawing, the first diode D1 and the first switching device SW1 connected in parallel to each other may be connected in reverse parallel with the second diode D2 and the second switching device SW2. In addition to the switching element Sru, the other switching elements Ssu, Stu, Srv, Ssv, Stv, Srw, Ssw, and Stw may be bidirectional switching elements as shown in FIG. 4. In the following description, it is assumed that each switching element in the matrix converter 220 is a bidirectional switching element.

The controller 230 includes switching timing information T0, T1, T2, T3, and T4 and sector information Sector of each switching element Ssu, Stu, Srv, Ssv, Stv, Srw, Ssw, and Stw. The switching information may be generated.

The switching timing information T0, T1, T2, T3, and T4 may be information indicating a turn-on state of each switching element Sru, Ssu, Stu, Srv, Ssv, Stv, Srw, Ssw, Stw. The switching timing information T0, T1, T2, T3, T4 is configured by dividing the switching period or the sampling period Ts. Here, T0 represents application time information of the zero vector.

The switching timing information T0, T1, T2, T3, and T4 may be calculated according to a voltage command calculated based on a speed command for driving the motor 250.

Meanwhile, according to the space vector technique, six switching voltage vectors {V1 (1,0,0), V2 (1,1,0), V3 (0,1,0), V4 (0,1,1), Six sectors may be divided by V5 (0,0,1) and V6 (1,0,1)}.

FIG. 6 shows a plurality of sector sections S1 to S6 divided by time by three phase input AC power supplies Vr, Vs, and Vt. The plurality of sector sections S1 to S6 of FIG. 6 include six switching voltage vectors V1 (1,0,0), V2 (1,1,0), and V3 (0,1) according to the space vector scheme described above. , 0), V4 (0,1,1), V5 (0,0,1), and V6 (1,0,1)} correspond to six sector sections.

Although not shown in the figure, six sector sections are also divided for three-phase output AC power supplies Vu, Vv, and Vw.

Therefore, the sector information Sector may be 36 sector section information which is a product of sector sections S1 to S6 of the input AC power supply and sector sections S11 to S16 of the output AC power supply.

Meanwhile, the controller 230 may calculate a sector section of the input AC power using the input current i _i or the input voltage v _i , and use the output current i _o to sector the output AC power. The interval can be calculated. In addition, the sector information Secotr may be calculated by combining the sector sections.

On the other hand, the control unit 230 determines the connection state of each switching element (Sru, Ssu, Stu, Srv, Ssv, Stv, Srw, Ssw, Stw) based on the above-described switching information (T0 to T4, sector). can do.

In addition, the controller 230 uses the connection state change information according to the change in the switching connection state and the switching control signal smc for controlling the switching element by using the polarity information Po of the output AC power flowing through the motor 250. ) Can be generated and printed.

Here, the connection state change information may be determined according to the previous switching connection state information and the current switching connection state information.

The switching control signal pattern according to the polarity information Po of the output AC power, the previous switching connection state information, and the current switching connection state information may be previously stored in a table, and thus the switching control signal Smc may be output. .

Meanwhile, in the exemplary embodiment of the present invention, the single controller 230 receives the input current i _i , the input voltage v _i , the output current i _o , and the polarity information Po of the output current, The above-described switching information is generated, and finally, the switching control signal is output.

In order to control the matrix converter 220, since a significant amount of computation and a control signal are generated, a digital signal processor (DSP) generating the switching information (T0 to T4, sector) and the generated switching information (T0 to) A field programmable gate array (FPGA) for generating and outputting a switching control signal (Smc) for driving nine switching elements based on T4, sector) is separately provided.

However, the controller 230 according to an embodiment of the present invention implements the above functions as a single module or a single chip. As described above, by using the polarity information Po of the output current, the switching connection state information and the like may be hidden in advance so that it may be easily implemented in a single module or a single chip. By this configuration, various advantages such as cost reduction and reduction of the substrate on which the controller 230 is mounted are generated.

Meanwhile, the controller 230 according to the embodiment of the present invention may be a digital signal processor (DSP), but various examples are not limited thereto.

On the other hand, the input voltage detection unit A detects each phase voltage from the commercial AC power supply 205. To this end, the input voltage detector A may include a resistor, an amplifier, or the like. Detected input voltage (v _i) are, as discrete signals (discrete signal) of the pulse type, in order to generate the switching control signals (Smc), may be input to the controller 230.

On the other hand, the input current detector B detects each phase current from the commercial AC power supply 205. To this end, a current sensor, a current trnasformer (CT), a shunt resistor, or the like can be used. The detected input current i _i is a discrete signal in the form of a pulse and may be input to the controller 230 to generate the switching control signal Smc.

The output current polarity detector D detects the polarity p _o of the output current i _o flowing between the matrix converter 220 and the three-phase motor 250. To this end, diode elements can be connected in parallel in each phase. The polarity p _o may be sensed by inputting the voltage difference across the diode due to the voltage drop through the diode to the comparator. The detected polarity information p _o is a discrete signal in the form of a pulse and may be input to the controller 230 to generate the switching control signal Smc.

The output current detector E detects the output current i _o flowing between the matrix converter 220 and the three-phase motor 250. In other words, the current flowing through the motor 250 is detected. The output current detector E may detect the output current of each phase, or may detect the output current of one or two phases by using three-phase equilibrium.

The output current detector E may be located between the matrix converter 220 and the motor 250, and a current sensor, a current trnasformer (CT), a shunt resistor, or the like may be used for current detection. The detected output current i _o is a discrete signal in the form of a pulse and may be input to the controller 230 to generate the switching control signal Smc.

Three-phase electric motor 250 is provided with a stator and a rotor, each phase AC power of a predetermined frequency is applied to the coil of each stator, the rotor is rotated. The type of the motor 250 may be a variety of forms such as a BLDC (blushless DC) motor, synRM (Synchronous Reluctance MoT0r).

The three-phase electric motor 250 may be used as a fan motor or a compressor motor in an outdoor unit of an air conditioner, and may also be used as a fan motor in an indoor unit of an air conditioner.

FIG. 7 is a block diagram schematically illustrating the inside of the controller of FIG. 2.

Referring to the drawings, the controller 230 may include a switching information generation unit 510, a switching connection determination unit 520, and a switching control signal output unit 530.

The switching information generation unit 510 includes switching timing information T0, T1, T2, T3, and T4 and sector information Sector of each switching element Ssu, Stu, Srv, Ssv, Stv, Srw, Ssw, and Stw. It may generate switching information including a.

When the switching control signal smc for driving the switching element in the matrix converter 220 is generated by Space VecTor Pulse Width Modulation (SVPWM) based on space vector, the switching information may include switching timing information ( T0, T1, T2, T3, T4). The switching timing information T0, T1, T2, T3, T4 is configured by dividing the switching period or the sampling period Ts. Here, T0 represents application time information of the zero vector.

The switching timing information T0, T1, T2, T3, and T4 may be calculated according to a voltage command calculated based on a speed command for driving the motor 250.

Meanwhile, according to the space vector method, six switching voltage vectors V1 (1,0,0), V2 (1,1,0), V3 (0,1,0), V4 (0, 1, 1), V5 (0, 0, 1), V 6 (1, 0, 1)} can be divided into six sectors. It can also be divided into six different sectors based on the output AC power source.

Accordingly, the sector information Sector may be 36 sector sections that are a product of the sector sections S1 to S6 of the input AC power supply and the sector sections S11 to S16 of the output AC power supply.

Meanwhile, the switching information generator 510 may calculate a sector section of the input AC power by using the input current i _i or the input voltage v _i , and output AC by using the output current i _o . The sector section of the power supply can be calculated. In addition, the sector information Secotr may be calculated by combining the sector sections.

On the other hand, the switching connection determination unit 520 is connected to each switching element (Sru, Ssu, Stu, Srv, Ssv, Stv, Srw, Ssw, Stw) based on the above-described switching information (T0 to T4, sector). Status can be determined. For example, the connection state of each switching element Sru, Ssu, Stu, Srv, Ssv, Stv, Srw, Ssw, Stw may be performed using a stored connection state switching table.

For example, when the input power sector is S1, the output power sector is S16, and the switching timing information is T3, three switching elements turned on among nine switching elements may be selected.

The connection state switching table includes six input power sectors S1 to S6, six output power sectors S11 to S16 corresponding to them, and the above-described switching timing information T0, T1, T2, T3, and T4. ), It may represent the turn-on state of each switching element (Sru, Ssu, Stu, Srv, Ssv, Stv, Srw, Ssw, Stw). As a result, the switching table is based on 36 (6 * 6) sector information (sector) and switching timing information (T0, T1, T2, T3, T4), and each switching element Sru, Ssu, Stu, Srv, Ssv, Stv. , Srw, Ssw, Stw) may indicate a turn-on state.

Next, the switching control signal output unit 530 switches the switching element to control the switching element by using the connection state change information according to the change of the switching connection state and the polarity information Po of the output AC power flowing through the motor 250. The control signal smc may be generated and output. For example, the switching control signal pattern according to the polarity information Po of the output AC power, the previous switching connection state information, and the current switching connection state information may be stored in a table in advance, so that the switching control signal Smc may be stored. Can be output.

Here, the connection state change information may be determined according to the previous switching connection state information and the current switching connection state information.

Meanwhile, the previous switching connection state information may be stored in the switching connection determination unit 520 or the switching control signal output unit 530.

FIG. 8 is a block diagram schematically illustrating the inside of the switching information generator of FIG. 7.

Referring to the drawings, the switching information generator 510 may include an estimator 1005, a current command generator 1010, a voltage command generator 1020, and a duty generator 1025. .

The estimator 1005 estimates the speed v of the electric motor based on the detected output current io. It is also possible to estimate the position of the rotor. This compares the mechanical equations and the electric equations of the motor 250 with each other and thus estimates the speed v of the motor.

The current command generation unit 1010 generates the current command values i ^* _d and i ^* _q based on the estimated speed v and the speed command value v ^* . For example, the current command generation unit 1010 may generate a current command value i ^* _d , i ^* _q by performing PI control based on the difference between the estimated speed v and the speed command value v ^* . Can be. To this end, the current command generation unit 1010 may be provided with a PI controller (not shown). Further, a limiter (not shown) may be further provided to limit the level so that the current command value i ^* _d , i ^* _q does not exceed the allowable range.

The voltage command generation unit 1020 generates a voltage command value v ^* _d , v ^* _q based on the detected output current i _o and the calculated current command value i ^* _d , i ^* _q . For example, the voltage command generation unit 1020 performs PI control based on the difference between the detected output current i _o and the calculated current command value i ^* _d , i ^* _q to perform the voltage command value v. ^* _d , v ^* _q ) To this end, the voltage command generation unit 1020 may include a PI controller (not shown). Further, a limiter (not shown) may be further provided to limit the level so that the voltage command value v ^* _d , v ^* _q does not exceed the allowable range.

The duty generator 1025 is configured to switch switching timing information T0 and T1 of each switching element Ssu, Stu, Srv, Ssv, Stv, Srw, Ssw, and Stw based on the voltage command values v ^* _d and v ^* _q . , T2, T3, T4) can be generated.

The switching control signal output unit 530 described above uses the switching timing information T0, T1, T2, T3, and T4 as well as the sector information, the output current polarity Po, and the like. Finally, the matrix converter switching control signal smc can be output. Accordingly, each of the switching elements Ssu, Stu, Srv, Ssv, Stv, Srw, Ssw, and Stw in the matrix converter 220 performs an on / off switching operation.

While the present invention has been described in connection with what is presently considered to be practical exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, It will be understood that the invention may be practiced. Therefore, the embodiments described above are to be understood as illustrative and not restrictive in all aspects. In addition, the scope of the present invention is shown by the claims below, rather than the above detailed description. Also, it is to be construed that all changes or modifications derived from the meaning and scope of the claims and their equivalent concepts are included in the scope of the present invention.

1 is a schematic diagram of an air conditioner according to the present invention.

2 is a circuit diagram illustrating a motor driving apparatus of an air conditioner according to an embodiment of the present invention.

3 is a diagram illustrating an example of the matrix converter of FIG. 2.

4 is a diagram illustrating an example of a switching device in the matrix converter of FIG. 3.

5 is a diagram illustrating an example of the filter unit of FIG. 2.

6 is a diagram illustrating a plurality of sector sections according to a three-phase AC power source.

FIG. 7 is a block diagram schematically illustrating the inside of the controller of FIG. 2.

FIG. 8 is a block diagram schematically illustrating the inside of the switching information generator of FIG. 7.

<Explanation of symbols on main parts of the drawings>

210: filter unit 220: matrix converter

230: control unit 250: motor

Claims (10)

A power conversion unit including a plurality of switching elements, and converting an input power source into an output AC power source having a predetermined frequency by a switching operation of the switching element to drive an electric motor; And Based on at least one of an input current and an input voltage by the input power, an output current flowing to the motor, and polarity information of the output current, switching information of the switching element is generated, and a switching control signal is generated according to the switching information. And a controller for generating and outputting the electric motor driving apparatus of the air conditioner. The method of claim 1, The switching information is, And switching timing information which is turn-on information of each switching element, sector information of the input power source, and sector information of the output AC power source. The method of claim 2, The control unit, And the input voltage sector information is calculated based on the input voltage. The method of claim 1, The control unit, A switching information generator for generating the switching information; And And a switching control signal output unit for outputting the switching control signal based on the switching information. The method of claim 4, wherein The control unit, Further comprising: a switching connection determination unit for determining the connection state of each switching element, And the switching control signal is output using the connection state information of the switching element. The method of claim 5, The switching control signal output unit, And the switching control signal is output using the previous switching connection state information, the current switching connection state information, and the polarity information of the output current. The method of claim 1, The power converter, And a matrix converter for converting commercial AC power into AC power of the predetermined frequency to drive the motor. The method of claim 1, The control unit, An electric motor drive device of an air conditioner, characterized in that a single module or a single chip. The method of claim 1, And a filter unit including a reactor connected to each phase of the input power source and a capacitor connected to the reactor in parallel, respectively. The method of claim 4, wherein The switching information generation unit, An estimator for estimating a speed of the motor based on an output current flowing in the motor; A current command generation unit that generates a current command value based on the estimated speed and the speed command value; A voltage command generator for generating a voltage command value based on the current command value and the detected output current; And And a duty generator configured to generate switching timing information of the switching device based on the generated voltage command value.

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