KR20170099245A - Motor driving apparatus and air conditioner including the same - Google Patents

Abstract

The present invention relates to a motor driving apparatus and an air conditioner having the same. A motor driving apparatus according to an embodiment of the present invention includes a plurality of switching elements and includes a matrix for driving the first motor by converting an input AC power of three phases into an output AC power of a predetermined frequency by a switching operation of the switching elements, A converter for converting the three-phase input AC power, and a plurality of switching elements, and the power from the converter is converted into an output AC power of a predetermined frequency by the switching operation of the switching element to drive the second motor An inverter, a matrix converter, and a control unit for controlling the inverter. As a result, a plurality of motors can be stably driven.

Description

[0001] The present invention relates to a motor driving apparatus and an air conditioner including the same,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a motor driving apparatus and an air conditioner having the same, and more particularly, to a motor driving apparatus capable of stably driving a plurality of motors and an air conditioner having the same.

The motor driving apparatus is an apparatus for driving a motor having a rotor for rotating and a stator for winding a coil.

On the other hand, the motor drive apparatus can be classified into a sensor-driven motor drive apparatus using sensors and a sensorless motor drive apparatus without sensor.

2. Description of the Related Art In recent years, sensorless motor drive devices have been used extensively for reasons such as reducing manufacturing costs, and various studies have been conducted for efficient motor drive.

An object of the present invention is to provide a motor driving apparatus capable of stably driving a plurality of motors and an air conditioner having the motor driving apparatus.

According to an aspect of the present invention, there is provided a motor drive apparatus including a plurality of switching elements, the three-phase input AC power source being converted into an output AC power source of a predetermined frequency by a switching operation of a switching element, 1 converter, a converter for converting three-phase input AC power, and a plurality of switching elements, and converts the power from the converter to an output AC power of a predetermined frequency by a switching operation of the switching elements An inverter for driving the second motor, a matrix converter, and a control unit for controlling the inverter.

According to another aspect of the present invention, there is provided an air conditioner including a plurality of switching elements, the switching operation of a switching element converting an input AC power of three phases into an output AC power of a predetermined frequency A converter for converting a three-phase input AC power; and a plurality of switching elements. The switching power supply for converting the power from the converter to an output AC power of a predetermined frequency An inverter for driving the second motor, a matrix converter, and a control unit for controlling the inverter.

According to an embodiment of the present invention, a motor drive apparatus and an air conditioner having the motor drive apparatus include a plurality of switching elements, and the switching operation of the switching elements converts the three-phase input AC power into an output AC power of a predetermined frequency A converter for converting an input AC power of three phases, and a plurality of switching elements, and the power from the converter is converted to an output AC power of a predetermined frequency by a switching operation of the switching elements And a controller for controlling the inverter, the matrix converter, and the inverter to drive the plurality of motors in a stable manner.

On the other hand, the matrix converter has three pairs of switching elements, each group having three pairs of switching elements, and each pair of switching elements is composed of two switching elements connected in series to each other And the switching elements corresponding to any one of the three switching element pairs in each group are connected in a collector common manner and the switching elements corresponding to the remaining switching elements in the three switching element pairs in each group The devices are connected in an emitter common mode. This allows the collector common to generate a dc stage.

On the other hand, since it can be connected to a part of the plurality of diode elements in the converter through the dc stage generated by the collector common, it is possible to stably convert the power source at the time of driving the second motor.

On the other hand, the matrix converter further includes a capacitor element connected between each emitter terminal of a pair of switching elements connected in a common-collector manner in the matrix converter, so that the electric power induced in the first motor is supplied to the capacitor So that the clamp function can be performed. Therefore, the second motor can be stably driven.

1 is a schematic view of an air conditioner according to an embodiment of the present invention.
Fig. 2 is an example of an internal block diagram of a motor driving apparatus for driving a motor in the air conditioner of Fig. 1. Fig.
3 is an example of a circuit diagram of a motor driving apparatus according to an embodiment of the present invention.
Figs. 4 to 6 are views referred to the description of the motor driving apparatus of Fig.
Fig. 7 illustrates an example of an internal block diagram of the control unit of Fig.

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

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

The motor driving apparatus described in this specification can estimate the rotor position of the motor by a sensorless method in which a position sensing unit such as a hall sensor for sensing the rotor position of the motor is not provided Which may be a motor drive device.

Meanwhile, the motor driving apparatus 200 according to the embodiment of the present invention may be referred to as a motor driving unit.

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

1 is a schematic view of an air conditioner according to an embodiment of 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 refrigerant, a compressor motor (2b) for driving the compressor, an outdoor heat exchanger (4) serving to dissipate the compressed refrigerant, An outdoor fan 5 disposed at one side of the heat exchanger 4 and composed of an outdoor fan 5a for accelerating the heat radiation of the refrigerant and a fan motor 5b for rotating the outdoor fan 5a, An accumulator (3) for temporarily storing the gasified refrigerant to remove moisture and foreign substances, and supplying a refrigerant of a predetermined pressure to the compressor ) And the like.

The indoor unit I includes an indoor heat exchanger 8 disposed inside the room and performing a cooling / heating function, an indoor fan 9a disposed at one side of the indoor heat exchanger 8 for promoting heat radiation of the refrigerant, And an indoor fan 9 composed of a fan motor 9b for rotating the fan 9a.

At least one indoor heat exchanger 8 may be installed. At least one of an inverter compressor and a constant speed compressor can be used as the compressor (2).

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.

On the other hand, the compressor 2 in the outdoor unit O of Fig. 1 can be driven by the motor driving apparatus 200, as shown in Fig. 2, which drives the compressor motor.

Fig. 2 is an example of an internal block diagram of a motor driving apparatus for driving a motor in the air conditioner of Fig. 1, Fig. 3 is an example of a circuit diagram of a motor driving apparatus according to an embodiment of the present invention, 3 is a view referred to in the description of the motor driving apparatus of Fig. 3;

2 and 3 according to an embodiment of the present invention includes a plurality of switching elements, and by switching operation of the switching elements, three-phase input AC power is supplied A matrix converter 220 for converting the input AC power into an output AC power of a predetermined frequency to drive the first motor 250, a converter 410 for converting the three-phase input AC power, and a plurality of switching elements, An inverter 420 that converts the power from the converter 410 to an output AC power of a predetermined frequency and drives the second motor 255 by the switching operation and the inverter 420 that controls the matrix converter 220 and the inverter 420 And may include a controller 230. Thus, the plurality of motors 250 and 255 can be stably driven.

On the other hand, the matrix converter 220 includes three pairs of switching elements 220a, 220b and 220c as shown in FIG. 4, and each group may have three pairs of switching elements.

Each pair of switching elements in each group may include two switching elements connected in series so as to enable bi-directional switching. That is, the three switching element pairs in the three groups may include two switching elements connected in series to each other so that bi-directional switching is possible.

On the other hand, the switching elements corresponding to any one of the three switching element pairs 220a, 220b and 220c in each group are connected in a collector common manner, and three switching element pairs The switching elements corresponding to the remaining pairs of switching elements are connected in an emitter common manner. As a result, it is possible to generate the dc stage at the collector terminal by the collector common.

On the other hand, at the time of driving the second motor 255, since a part of the plurality of diode elements in the converter 410 (in particular, it can be connected to the upper arm diode element) through the dc stage generated by the collector common, Can be stably converted.

On the other hand, the matrix converter 220 includes capacitor elements Caa, Cbb, and Ccc connected between respective emitter terminals of a pair of switching elements connected in a collector common manner in the matrix converter 220 . Such a capacitor element may be called a snubber capacitor element.

On the other hand, since the power generated in the first motor 250 can be stored in the capacitors in the matrix converter 220 in the elements Caa, Cbb, and Ccc, the clamping function can be performed.

3, the converter 410 includes a plurality of diode elements connected in a full bridge, and the upper-arm diode elements of the plurality of diode elements are connected in series between the switching elements connected in a collector common mode And the lower-arm diode elements among the plurality of diode elements can be connected between the switching elements connected in the emitter common mode.

On the other hand, the three-phase input AC power source can be input to the converter 410 via the diode element connected to the switching element connected in the collector common mode in the matrix converter 220.

On the other hand, the matrix converter 220 may further include capacitor elements Caa, Cbb, and Ccc connected between the respective emitter terminals of the pair of switching elements connected in the collector common mode in the matrix converter 220 have. At this time, the capacitor elements Caa, Cbb, and Ccc can store the electric power generated in the first motor 250.

7) for generating and outputting the switching control signal Smc based on the first output current io detected by the first current detecting unit E. The control unit 230 includes a switching control signal output unit 1030 ).

On the other hand, the control unit 230 generates a current command value based on an estimation unit (1005 in Fig. 7) that estimates the speed of the motor 250 based on the first output current io and an estimated speed and speed command value 7) for generating a voltage command value based on the current command value, and a voltage command generation section (1020 in Fig. 7) for generating a voltage command value based on the switching timing information T1 (T4 in Fig. 7).

On the other hand, the control unit 230 outputs a first switching control signal for controlling the matrix converter 220 based on the first output current flowing through the first motor, and outputs a second switching control signal for controlling the second output current The second switching control signal for controlling the inverter 420 can be output.

On the other hand, when the level of the first output current detected by the first current detector E is equal to or higher than the allowable level, all the switching elements in the matrix converter 220 can be controlled to be off.

2 may further include a filter unit 210 disposed between the three-phase input AC power source and the matrix converter 220.

2 may further include a filter unit 210, an input voltage detection unit A, an input current detection unit B, and the like.

Is arranged between the filter unit 210, the commercial AC power source (205, v _s) and the matrix converter (220), it serves to remove a noise component from the commercial AC power source 205. To this end, the filter unit 210 may include an inductor, a capacitor, and the like.

3, the filter unit 210 includes a plurality of inductors, resistors, and capacitors connected in series and in parallel to three phases (r, s, and t phases) of the commercial AC power source 205 can do.

With this configuration, the commercial AC power supply 205, that is, the harmonic current flowing in the system is stored in each capacitor and is hardly transmitted to the matrix converter 220.

In addition, the harmonic current components that may be generated by the high-speed switching of the matrix converter 220 are also stored in the capacitors C1, C2, and C3, and are hardly transmitted to the system.

On the other hand, the alternating current of the low frequency component is smoothly transmitted to the matrix converter 220 through the inductor. Also, the commercial AC power can be boosted by the switching operation of the matrix converter 220 and the inductor.

The matrix converter 220 includes a plurality of switching elements, and drives the motor 250 by converting the commercial AC power into an output AC power of a predetermined magnitude and a predetermined frequency by the switching operation of the switching element.

3, the matrix converter 220 converts an input AC power source 205 of three phases (r, s, and t phases) to output an output AC power of three phases (u, v, and w phases) have.

To this end, the matrix converter 220 may include each pair of switching elements SRU, SSU, STU, SRV, SSV, STV, SRW, SSW, and STW.

Each of the switching element pairs SRU, SSU, STU, SRV, SSV, STV, SRW, SSW and STW in the matrix converter 220 can be divided into three groups 220a, 220b and 220c have.

3, each switching element pair SRU, SSU, STU, SRV, SSV, STV, SRW, SSW and STW in the matrix converter 220 are connected in series to each other to enable bidirectional switching. Each of the switching elements can be provided. At this time, some of the two switching elements may be connected in a collector common mode, and the other may be connected in an emitter common mode.

(SRU) 220aa, the fifth switching device pair SSV (SSV), and the fourth switching device pair SSV (SSV) among the respective switching device pairs SRU, SSU, STU, SRV, SSV, STV, 220bb and the ninth switching element pair STW 220cc are connected in a collector common mode and the others are connected in an emitter common manner.

In this way, the first switching element pair (SRU) 220aa, the fifth switching element pair (SSV) 220bb, and the ninth switching element pair (STW) 220cc, which are connected in a collector common manner, A dc stage can be generated at the collector terminal of the transistor.

4, the first switching device pair (SRU) 220aa, the sixth switching device (SRU) 220aa, and the third switching device 220aa among the switching device pairs SRU, SSU, STU, SRV, SSV, STV, SRW, SSW, (STV) 220bc and the eighth switching element pair SSW 220cb are connected in a collector common mode and the remaining are connected in an emitter common manner do.

In this way, the first switching device pair (SRU) 220aa, the sixth switching device pair (STV) 220bc, and the eighth switching device pair (SSW) 220cb, which are connected in a collector common manner, A dc stage can be generated at the collector terminal of the transistor.

Each of the switching device pairs SRU, SSU, STU, SRV, SSV, STV, SRW, SSW, and STW in the matrix converter 220 can operate in the 27 switching patterns shown in FIG.

On the other hand, the first current detector E may include three-phase (u, v, w phase) output currents as shown in FIG.

For example, a shunt resistive element for output current detection may be provided.

The detected three-phase output current io can be applied to the control unit 230 as a discrete signal in the form of a pulse and the control unit 230 can control the output current io based on the detected three- , And generate a switching control signal Smc for driving the matrix converter.

7, the control unit 230 generates the switching control signal Smc based on the three-phase output current io detected by the first current detecting unit E, (1030). ≪ / RTI >

On the other hand, the control unit 230 includes an estimating unit 1005 that estimates the speed of the motor 250 based on the detected three-phase output current io, A voltage command generation section 1020 for generating a voltage command value based on the current command value and a duty command generation section 1020 for generating switching timing information T1 to T4 of the switching element on the basis of the generated voltage command value, And may further include a generation unit 1025.

The switching control signal output unit 1030 at this time can generate and output the switching control signal Smc based on the switching timing information T1 to T4 of the switching element.

On the other hand, when the level of the three-phase output current detected by the first current detector E is equal to or higher than the allowable level, the controller 230 can control all the switching elements in the matrix converter 220 to be off. In this way, it becomes possible to protect the circuit elements in the motor driving apparatus 200.

On the other hand, the first motor 250 may be a compressor motor 2b of an outdoor unit, and the second motor 255 may be a fan motor 5b of an outdoor unit.

The controller 230 may output the inverter output control signal Sic for driving the second motor 255 to the second output current io2 detected by the second output current detector E1.

On the other hand, when the switching timing information T0, T1, T2, T3, and T4 and the sector information Sector of the switching elements Ssu, Stu, Srv, Ssv, Stv, Srw, Ssw, It is possible to generate the switching information including the switching information.

When the switching control signal smc for driving the switching elements in the matrix converter 220 is generated by the space vector pulse width modulation (SVPWM), the switching information is the switching timing information T0, T1, T2, T3, T4). The switching timing information T0, T1, T2, T3 and T4 is constituted by dividing the switching period or the sampling period Ts. Here, T0 represents the application time information of the zero vector.

On the other hand, the switching timing information T0, T1, T2, T3 and T4 can be calculated in accordance with the voltage command calculated based on the speed command for driving the motor 250. [

According to the space vector technique, six switching voltage vectors {V1 (1,0,0), V2 (1,1,0), V3 (0,1,0), V4 V5 (0, 0, 1), V6 (1, 0, 1)}.

The plurality of sector intervals S1 to S6 are divided into six switching voltage vectors {V1 (1,0,0), V2 (1,1,0), V3 (0,1,0) , V4 (0, 1, 1), V5 (0, 0, 1), and V6 (1, 0, 1).

Although not shown in the drawing, six sector sections are also divided for three-phase output AC power (Vu, Vv, Vw).

Accordingly, the sector information Sector is matched with 36 sector sections which are the products of the sector sections S1 to S6 of the input AC power source and the sector sections S11 to S16 of the output AC power source.

Meanwhile, the controller 230 can calculate the sector interval of the input AC power using the detected first output current io and calculate the sector interval of the output AC power using the detected first output current io. Can be calculated. In addition, the sector information (Secotr) can be calculated by combining these sector intervals.

On the other hand, the control unit 230 determines the connection state of each of the switching elements SRU, SSU, STU, SRV, SSV, STV, SRW, SSW, and STW based on the switching information T0 to T4 can do. For example, the connection state of each switching element SRU, SSU, STU, SRV, SSV, STV, SRW, SSW, and STW may be performed using a stored connection state 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-on switching elements among nine switching elements can be selected.

The connection state switching table includes six input power sectors S1 to S6 and six output power sectors S11 to S16 corresponding thereto and the switching timing information T0, T1, T2, T3 and T4 described above, On states of the respective switching elements SRU, SSU, STU, SRV, SSV, STV, SRW, SSW, and STW. As a result, the switching table includes switching elements SRU, SSU, STU, SRV, SSV, and STV according to the sector information and switching timing information T0, T1, T2, T3, and T4 of 36 , SRW, SSW, STW).

Next, the control unit 230 uses the switching state change information according to the change in the switching connection state and the polarity information Po of the output AC power flowing to the motor 250 to generate the switching control signal smc Can be generated and 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.

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

Meanwhile, the controller 230 may be a DSP (Digital Signal Processor), but it is not limited thereto and various examples are possible.

The three-phase motor 250 has a stator and a rotor, and alternating current power of a predetermined frequency is applied to the coils of the stator of each phase, so that the rotor rotates. As the type of the motor 250, various types such as a BLDC (blushless DC) motor and synRM (Synchronous Reluctance Motor) can be used.

The three-phase motor 250 may be a motor for a compressor in an outdoor unit of the air conditioner. On the other hand, the three-phase motor 255 may be a fan motor in an outdoor unit.

5 is a diagram illustrating that the power generated in the first motor 250 is partly stored in the matrix converter 220. FIG.

Referring to the drawing, power may be regenerated in the first motor 250 and transmitted to the matrix converter 220 by stopping the first motor 250 or the like.

At this time, the Iu current may flow from the first motor 250 to the matrix converter 220 as shown in the figure.

3, when the switching elements corresponding to any one of the three switching element pairs SRU, SSV and STW in the respective groups are connected in a collector common mode, the switching element pair SRU, At least part of the power by the Iu current is stored in the capacitor elements Caa, Cbb, and Ccc, which are respectively connected to the power supply lines SSV, SSV, and STW.

That is, at least a part of power by the Iu current is stored in the capacitor elements Caa, Cbb, and Ccc connected to the dc stages formed in the pair of switching elements SRU, SSV, and STW by the collector common method . That is, the clamping function is performed.

That is, the capacitor elements Caa, Cbb, and Ccc can store the electric power generated in the first motor 250. [

Therefore, the matrix converter 220 can perform the clamping function despite the stop of the first motor 250 and the like, so that the circuit elements inside the matrix converter 220 can be protected, So that it can be stably driven.

On the other hand, currents Iaa, Ibb, and Icc due to power sources stored in the capacitor elements Caa, Cbb, and Ccc can flow to the converter 410, and based on this, ifm current can flow through the inverter 420 do.

6 illustrates that the commercial AC power is converted by the converter 410 via the matrix converter 220. [

3, a three-phase commercial AC power source 205 is input to drive the second motor 255. Thus, the input current Iim is supplied to the matrix converter 220 through the filter unit 210 and the like, Lt; / RTI >

3, when the switching elements corresponding to any one of the three switching element pairs SRU, SSV and STW in the respective groups are connected in a collector common mode, the switching element pair SRU, At least a part of the power by the Iim current is stored in the capacitor elements Caa, Cbb, and Ccc, which are respectively connected to the power supply lines SSV, SSV, and STW.

That is, at least a part of the power by the Iim current is stored in the capacitor elements Caa, Cbb and Ccc connected to the dc stages formed in the pair of switching elements SRU, SSV and STW by the collector common method .

On the other hand, currents Iaa, Ibb, and Icc due to power sources stored in the capacitor elements Caa, Cbb, and Ccc can flow to the converter 410, and based on this, ifm current can flow through the inverter 420 do. Thus, the second motor 255 can be stably driven.

Fig. 7 illustrates an example of an internal block diagram of the control unit of Fig.

The control unit 230 includes an estimation unit 1005, a current command generation unit 1010, a voltage command generation unit 1020, a duty generation unit 1025, and a switching control signal output unit 1030 ).

The estimating unit 1005 estimates the speed v of the motor based on the output current io in the first current detecting unit E. [ It is also possible to estimate the position of the rotor. This can compare the mechanical and electrical equations of the motor 250 with one another and estimate the speed v of the motor accordingly.

The current command generation section 1010 generates the current command value i ^* _d , i ^* _q based on the estimated speed v and the speed command value v ^* . For example, the current command generation section 1010 performs PI control based on the difference between the estimated speed v and the speed command value v ^* to generate the current command value i ^* _d , i ^* _q . To this end, the current command generator 1010 may include a PI controller (not shown). It is also possible to further include a limiter (not shown) for limiting the current command value (i ^* _d , i ^* _q ) so that it does not exceed the allowable range.

The voltage command generation unit 1020 generates voltage command values v ^* _d and v ^* _q based on the calculated output currents iu, iv and iw and the calculated current command values i ^* _d and i ^* _q . For example, the voltage command generation unit 1020 performs PI control based on the difference between the calculated output currents iu, iv, iw and the calculated current command values i ^* _d , i ^* _q , (V ^* _d , v ^* _q ). To this end, the voltage command generation unit 1020 may include a PI controller (not shown). It is also possible to further include a limiter (not shown) for limiting the level so that the voltage command values v ^* _d and v ^* _q do not exceed the permissible range.

Duty-generator 1025 includes a voltage command value (v ^* _d, v ^* _q) to the basis, the switching element switching timing information (Ssu, Stu, Srv, Ssv, Stv, Srw, Ssw, Stw) (T0, T1 , T2, T3, T4).

The switching control signal output unit 1030 outputs the switching timing information T0, T1, T2, T3 and T4, the sector information or the output current polarity Po, And can output the matrix converter switching control signal smc.

Accordingly, each of the switching elements SRU, SSU, STU, SRV, SSV, STV, SRW, SSW, and STW in the matrix converter 220 stably performs ON / OFF switching operation.

The motor driving apparatus and the air conditioner having the same according to the embodiment of the present invention are not limited to the configuration and method of the embodiments described above, All or some of the embodiments may be selectively combined.

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 (11)

A matrix converter having a plurality of switching elements and converting the three-phase input AC power into an output AC power having a predetermined frequency by a switching operation of the switching element to drive the first motor;
A converter for converting the three-phase input AC power;
An inverter that has a plurality of switching elements and converts a power from the converter to an output AC power of a predetermined frequency by a switching operation of the switching element to drive a second motor; And
And a controller for controlling the inverter, the matrix converter, and the inverter. The method according to claim 1,
The matrix converter includes:
Each group including three pairs of switching elements, each group including three pairs of switching elements,
Wherein each of the switching element pairs includes two switching elements connected in series so as to enable bidirectional switching,
The switching elements corresponding to any one of the three switching element pairs in each group are connected in a collector common mode,
Wherein switching elements corresponding to the remaining switching element pairs of the three switching element pairs in each group are connected in an emitter common mode. 3. The method of claim 2,
The converter includes:
And a plurality of diode elements connected by a full bridge,
The uppermost one of the plurality of diode elements is connected between the switching elements connected in the collector common mode,
And the lower-stage diode elements of the plurality of diode elements are connected between the switching elements connected in the emitter common mode. The method of claim 3,
The three-phase input AC power source
And a diode element connected to a switching element connected in the collector common mode in the matrix converter, and is input to the converter. The method of claim 3,
The matrix converter includes:
Further comprising a capacitor element connected between each emitter terminal of a pair of switching elements connected in the collector common mode in the matrix converter. 6. The method of claim 5,
Wherein the capacitor element comprises:
And stores the electric power generated in the first motor. The method according to claim 1,
Wherein,
And outputs a first switching control signal for controlling the matrix converter based on a first output current flowing in the first motor,
And outputs a second switching control signal for controlling the inverter based on a second output current flowing to the second motor. 8. The method of claim 7,
And a current detector disposed between the first motor and the matrix converter,
Wherein,
An estimating unit that estimates a speed of the motor based on the first output current detected by the current detecting unit;
A current command generator for generating 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
And a duty generating unit for generating switching timing information of the switching element based on the generated voltage command value,
Wherein the switching control signal output unit comprises:
And generates and outputs the first switching control signal based on the switching timing information of the switching element. 9. The method of claim 8,
Wherein,
And controls all the switching elements in the matrix converter to be turned off when the level of the first output current detected by the current detection unit is equal to or higher than an allowable level. The method according to claim 1,
And a filter unit disposed between the three-phase input AC power supply and the matrix converter. An air conditioner comprising the motor driving device according to any one of claims 1 to 10.

Images