KR20100133636A - Apparatus for dirving motor of air conditioner - Google Patents

Abstract

The present invention relates to a reactor, a first rectifying unit for rectifying an input AC power source, a switching element connected to the first rectifying unit and performing a turn-on operation to store energy of an input AC power source in a reactor, and a first rectifying unit in parallel. And a second rectifying part for rectifying the input AC power using the energy stored in the reactor, and a grounding part in which the first rectifying part and the second rectifying part are grounded in common. This makes it possible to easily implement the insulation in the motor drive.

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 that can easily realize the insulation in the electric motor driving apparatus.

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, converts the DC voltage into a DC voltage, converts the DC voltage into a commercial AC power having a predetermined frequency, and supplies the same to the motor, thereby controlling the motor to drive a motor such as a compressor or a fan.

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

For example, if harmonic current inflow and input power factor characteristics to the input power supply side become poor, it may adversely affect the malfunction and lifetime of other electric devices connected to the power system. Accordingly, countries are implementing or promoting regulations to improve power quality. In particular, the EU has implemented regulations such as IEC6100-3-2, which is the harmonic current regulation. Accordingly, various efforts have been made to improve the harmonic noise as well as to develop a motor driving apparatus of an air conditioner for reducing the manufacturing cost accordingly.

SUMMARY OF THE INVENTION An object of the present invention is to provide an electric motor driving apparatus of an air conditioner that can easily realize insulation in the electric motor driving apparatus.

The motor drive apparatus of the air conditioner according to the embodiment of the present invention for solving the above-mentioned problems and other problems is connected to the reactor, the first rectifying unit for rectifying the input AC power source, the first rectifying unit, A switching element performing a turn-on operation to store energy of the power source in the reactor, a second rectifying unit connected in parallel with the first rectifying unit and rectifying the input AC power using energy stored in the reactor, and a first rectifying unit; The second rectifier includes a ground that is commonly grounded.

As described above, the motor driving apparatus of the air conditioner according to the embodiment of the present invention, by using a common grounding portion, it is possible to easily implement the insulation in the motor driving apparatus.

In addition, the control unit for outputting the converter switching control signal for driving the switching element can also be commonly used in the ground, it is possible to simply implement the ground in the motor drive device.

In addition, by disposing a resistor between the rectifier and the smoothing capacitor, it is possible to simply detect the input current.

In addition, the control unit simultaneously controls the switching element for controlling the operation of the rectifier and the inverter, thereby effectively controlling the circuit element in the driving device.

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 (9), and the indoor fan (9a) and the room disposed on one side of the indoor side heat exchanger (9) to promote heat dissipation of the refrigerant. And an indoor blower 9 made of an electric motor 9b for rotating the fan 9a.

At least one indoor side heat exchanger (9) 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.

Referring to the drawings, the motor driving device 200 of FIG. 2 according to an embodiment of the present invention, the first rectifier 210, the second rectifier 215, the inverter 220, the controller 230, switching An element SW, a resistance element R, and a zero crossing detection unit B are included. In addition, the motor driving apparatus 200 of FIG. 2 may further include an input current detector A, a reactor L, a smoothing capacitor C, a dc terminal voltage detector D, an output current detector E, and the like. It may be.

The reactor L is disposed between the commercial AC power supplies 205 and v _s , the first rectifier 210, and the second rectifier 215 to perform power factor correction or boost operation. In addition, the reactor L may perform a function of limiting harmonic currents due to the high speed switching of the switching element SW.

The zero crossing detection unit B may detect the zero crossing point z _c of the commercial AC power supply 205. For example, the zero crossing point z _c can be detected while detecting the phase of the commercial AC power supply 205. To this end, a resistance element or the like may be used as the zero crossing detection unit B. FIG. The detected zero crossing point z _c is a discrete signal in the form of a pulse and may be input to the controller 230 to generate the converter switching control signal Scc.

The first rectifier 210 and the second rectifier 215 rectify and output the commercial AC power supply 205.

The switching element SW is connected to the first rectifier 210 and performs a turn on operation to store energy of the commercial AC power source 205 in the reactor L. FIG. On the other hand, the switching device (SW) may be implemented in various devices such as an insulated gate bipolar transistor (IGBT).

In addition, the switching element SW performs a turn-off operation to rectify the commercial AC power supply 205 using energy stored in the reactor L. FIG.

The voltage rectified and output by the second rectifier 215 is output to the dc terminal which is both ends of the smoothing capacitor C. FIG.

That is, the first rectifying unit 210 and the second rectifying unit 215 perform the step-up operation, the power factor improvement, and the DC power conversion by the switching operation of the switching element SW based on the zero crossing point z _c .

Meanwhile, according to the exemplary embodiment of the present invention, the first rectifying part 210 and the second rectifying part 215 may be connected to the common ground part 270. As shown in the figure, a common ground portion 270 is connected to one end of the smoothing capacitor C, and directly connected to the first rectifying portion 210 and the second rectifying portion 215 or electrically connected to one end of the smoothing capacitor C. It is possible to be connected with. As a result, the ground portions 270 of the plurality of rectifiers 210 and 215 may be easily disposed.

In addition, the control unit 230 which outputs the converter switching control signal Scc for driving the switching element SW may also use the grounding unit 270 in common. This makes it possible to simply implement the ground in the motor drive device.

On the other hand, although the commercial AC power supply 205 is shown as a single phase AC power in the figure, it may be a three phase AC power supply. The internal structures of the first rectifying unit 210 and the second rectifying unit 215 also vary according to the type of the commercial AC power supply 205. For example, in the case of a single phase AC power supply, four bridge diode elements may be connected, and in the case of a three phase AC power supply, six diode elements may be used.

The smoothing capacitor C is connected to the output terminal of the first rectifying unit 210 and the second rectifying unit 215, in particular the output terminal of the second rectifying unit 215. In particular, the smoothing capacitor C smoothes the converted DC power output from the second rectifier 215. Hereinafter, both ends of the smoothing capacitor are referred to as a dc end or a dc link end. The DC voltage smoothed at the dc stage is applied to the inverter 220.

The dc end voltage detector D may detect the dc end voltage Vc, which is both ends of the smoothing capacitor C. To this end, the dc terminal voltage detection unit D may include a resistor, an amplifier, or the like. The detected dc terminal voltage Vc is a discrete signal in the form of a pulse and may be input to the controller 230 to generate the converter switching control signal Scc.

On the other hand, the resistance element R may be disposed between the second rectifier 215 and the smoothing capacitor C for the detection of the input current i _s . Such a resistance element R may include a shunt resistor.

On the other hand, the input current detector A is supplied by the commercial AC power supply 205 and can detect the input current i _s flowing through the resistance element R. The detected input current i _s is a discrete signal in the form of a pulse and may be input to the controller 230 to generate a converter switching control signal Scc for driving the switching element SW. .

The inverter 220 includes a plurality of inverter switching elements, converts a smoothed DC power source into a three-phase AC power source having a predetermined frequency by on / off operation of the switching element, and outputs the same to the three-phase electric motor 250.

Inverter 220 is a pair of upper arm switching elements (Sa, Sb, Sc) and lower arm switching elements (S'a, S'b, S'c) connected in series with each other, a total of three pairs of upper and lower arms The switching elements are connected in parallel with each other (Sa & S'a, Sb & S'b, Sc & S'c). Diodes are connected in anti-parallel to each of the switching elements Sa, S'a, Sb, S'b, Sc, and S'c.

The switching elements in the inverter 220 perform on / off operations of the respective switching elements based on the inverter switching control signal Sic from the controller 230. As a result, the three-phase AC power supply having the predetermined frequency is output to the three-phase electric motor 250.

The controller 230 controls the switching operation of the switching element SW. To this end, the controller 230 receives the input current i _s detected by the input current detector A and the zero crossing point z _c detected by the zero crossing detector B. Accordingly, the controller 230 outputs a converter switching control signal Scc for controlling the switching operation of the switching element SW. The detailed operation of the output of the converter switching control signal Scc will be described later with reference to FIG. 4.

In addition, the controller 230 may control the switching operation of the inverter 220. To this end, the controller 230 may receive an output current io detected by the output current detector E. FIG.

The controller 230 outputs an inverter switching control signal Sic to the inverter 220 in order to control the switching operation of the inverter 220. The inverter switching control signal Sic is a PWM switching control signal and is generated and output based on the output current value io detected by the output current detector E. FIG. A detailed operation of the output of the inverter switching control signal Sic in the controller 230 will be described later with reference to FIG. 7.

The output current detector E detects the output current io flowing between the inverter 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 inverter 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. In addition, one end of the shunt resistor may be connected to three lower arm switching elements S'a, S'b, and S'c of the inverter 220, respectively.

The detected output current io may be applied to the controller 230 as a discrete signal in the form of a pulse, and an inverter switching control signal Sic is generated based on the detected output current io. .

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 brushless DC (BLDC) motor, a synchronous reluctance motor (synRM).

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.

On the other hand, when the driving device 200 of the air conditioner described above, for example, for driving a fan motor or a compressor motor used in the outdoor unit, the control unit 230 as an outdoor unit control unit, can be disposed separately in the indoor unit. It is also possible to perform further communication with the indoor unit controller. The outdoor unit control unit receives a driving command by communication with the indoor unit control unit, and can determine a speed command value to be described later based on the received driving command.

In addition, the controller 230 of the driving apparatus 200 of the air conditioner described above may control the fan motor and the compressor motor used in the outdoor unit at the same time.

3 is a circuit diagram illustrating an example of a first rectifying unit and a second rectifying unit of FIG. 2.

Referring to the drawings, the first rectifier 210 may include four bridge diodes D11 to D14 for rectifying single-phase commercial AC power. That is, the first and second diode elements D11 to D12 are connected in series to each other, the third and fourth diode elements D13 to D14 are connected to each other in series, and the first and second diode elements D11 are connected in series. To D12) in parallel.

The first rectifier 210 may be disposed between the reactor L and the switching element SW, and stores energy of a commercial AC power source in the reactor L by a turn-on operation of the switching element SW. .

In addition, the second rectifying unit 215 may include four bridge diodes D21 to D24 for rectifying single-phase commercial AC power supplies. That is, the first and second diode elements D21 to D22 are connected in series with each other, the third and fourth diode elements D23 to D24 are connected to each other in series, and the first and second diode elements D21 are also connected. To D22) in parallel.

The second rectifier 215 may be disposed between the reactor L and the smoothing capacitor C, and rectifies energy stored in the commercial AC power supply and the reactor L by the turn-off operation of the switching element SW. To print.

The power rectified through the first rectifying unit 210 and the second rectifying unit 215 is stored in the smoothing capacitor C, and the stored dc terminal voltage v _c is a load (corresponding to the inverter or less of FIG. 2). According to the condition, a predetermined load current i _L is caused to flow.

Meanwhile, in the first rectifying unit 210, the second rectifying unit 215, and the switching device SW of FIG. 3, the switching device SW is partially turned on, as described above. Converter (PSC).

Briefly describing the operation, the switching element SW is turned on after a predetermined delay period from the time of zero crossing of the input power supply v _s , and a current component is stored in the reactor L during the turned on period. After that, the switching element SW is turned off, and the current component stored in the reactor L is stored in the smoothing capacitor C. Thereby, the boosting function is performed, and the power factor correction is performed by the on / off switching period. Operation of the first rectifying unit 210 and the second rectifying unit 215 of FIG. 3 will be described in detail below.

4 is a diagram illustrating an input voltage and an input current waveform according to the switching operation of the switching device of FIG. 3, and FIG. 5 is a schematic circuit diagram of an operating state of the switching device of FIG. 3.

Referring to the drawings, the zero crossing detection unit A outputs a zero crossing point signal z _c as shown in FIG. 4. The zero crossing point signal z _c is in the form of a pulse and one zero crossing point is detected during an electrical angle of 180 degrees of the input power supply v _s .

On the other hand, the converter switching control signal Scc for driving the switching element SW has a delay period Td which is a period from the time of zero crossing to the turn-on time of the actual switching element SW, and the actual switching element SW is turned on. And a turn-off period Toff at which the switching element SW is turned off.

Meanwhile, in the drawing, although the delay period Td, the turn on period Ton, and the turn off period Toff are repeated every 180 degrees of electric angle, the converter switching control signal Scc for the switching element SW is shown. ) Is shown at the same time, the actual switching element (SW) repeats the delay period (Td), turn-on period (Ton), and turn-off period (Toff) with a period of 360 degrees of electrical angle.

Hereinafter, the electric equation of the motor driving device 200 centering on the first rectifying unit 210, the second rectifying unit 215, and the switching element SW according to each of the above-described periods will be described.

(1) delay period

During the delay period Td, the switching element SW is in the off state. During this period, since the input voltage v _s is lower than the dc terminal voltage v _c , all the diode elements D11 to D14 and D21 to D24 of the first rectifying unit 210 and the second rectifying unit 215 may also be used. It turns off without conducting. However, the load current I _L caused by the dc terminal voltage v _c charged in the capacitor C flows along the load.

The modeling circuit diagram according to this is as shown in FIG. The electrical equation at this time is as follows.

Since the input voltage v _s is an alternating current, it is defined as in Equation 1.

Meanwhile, since all diode elements D11 to D14 and D21 to D24 of the first rectifying unit 210 and the second rectifying unit 215 are in an off state, the input current i _s according to this is represented by Equation 2 below. .

On the other hand, since the load current (I _L ) flows by the charged dc terminal voltage (v _c ), the electrical equation for this is as shown in Equation 3 below.

If Equation 3 is arranged in an integral form, it is as Equation 4 below.

Here, Vdc is an initial dc terminal voltage value stored in the smoothing capacitor C before the delay period Td.

(2) turn-on period

During the turn-on period Ton, the switching element SW is in an on state.

For example, when the switching element SW is turned on in a state in which the input voltage v _s is positive, the input current i _s is the first diode of the reactor L and the first rectifier 210. D11), the switching element SW, the resistance element R, and the fourth diode D14 of the first rectifying unit 210 are sequentially flowed.

As another example, when the switching element SW is turned on in a state in which the input voltage v _s is negative, the input current i _s is a second diode (L) of the reactor L and the first rectifier 210. D12), the resistance element R, the switching element SW, and the third diode D13 of the first rectifying unit 210 are sequentially flowed.

Hereinafter, a description will be given of the case where the switching element SW is turned on while the input voltage v _s is positive in the turn-on period. The modeling circuit diagram according to this is as shown in FIG.

During this period, since the inside of the first rectifier 210 is short-circuited as described above, the electric equation for this is as follows.

In this way, the input current i _s component is accumulated in the reactor L.

Integrating the above Equation 5 and summarizing it is shown in Equation 6 below.

On the other hand, since the load current (I _L ) is flowed by the charged dc terminal voltage (v _c ), the electrical equation for this is shown in Equation 7 below.

(3) turn off period

During the turn off period Toff, the switching element SW remains in an on state. However, unlike the delay period Td, the input voltage v _s is higher than the dc terminal voltage v _c , so that the diode element in the second rectifier 215 is in a conductive state. The modeling circuit diagram according to this is as shown in FIG.

The electrical equation according to this is shown in Equation 8 below.

Equation (8) is summarized as Equation (9) below.

At this time, using Equation 10 below Equation 9,

If you put it in,

It is summarized by the following state equation.

If this is re-arranged using the Laplace transform, it is arranged as in Equation 12 below.

When the Laplace inverse transform is performed again, the following equation (13) is arranged.

here,

,

to be.

In summary, the input current i _s and the dc short voltage v _c are based on the inductance of the reactor L, the magnitude of the input voltage Vs, the turn on period Ton, and the capacitance of the smoothing capacitor C. Is determined.

6 is a simplified block diagram of the inside of the control unit of FIG. 2.

Referring to the drawings, the controller 230 may include a turn-on period setting unit 610, a delay period setting unit 620, and a switching control signal output unit 630 to generate the converter switching control signal Scc. ).

The turn on period setting unit 610 sets the turn on period Ton based on the detected dc terminal voltage v _c and the dc voltage command value v ^* _c . For example, the turn-on period setting unit 610 may perform the PI control based on the detected difference between the dc terminal voltage v _c and the dc voltage command value v ^* _{c to} determine the turn-on period Ton. Can be set. To this end, the turn on period setting unit 610 may include a PI controller 615. In addition, a limiter (not shown) may be further provided to limit the level so that the result of the PI control does not exceed the allowable range.

For example, the turn-on period setting unit 610 may detect the detected dc terminal voltage v _c and the dc voltage command value v ^* _c as the motor load increases, that is, as the dc terminal voltage v _c is smaller. Since the difference of) increases, to compensate for this, the turn-on period Ton may be set to increase. As a result, as the load increases, the phenomenon in which the dc terminal voltage v _c becomes small can be prevented, and the dc terminal voltage v _c can be maintained at a constant range level.

On the other hand, the delay period setting unit 620 sets the delay period Td based on the detected input current i _s and the input current command value i ^* _s . For example, the delay period setting unit 620 may set the delay period Td by performing PI control based on the difference between the detected input current i _s and the input current command value i ^* _s . . To this end, the delay period setting unit 620 may include a PI controller 625. In addition, a limiter (not shown) may be further provided to limit the level so that the result of the PI control does not exceed the allowable range.

For example, the delay period setting unit 620 may set the delay period Td to be larger for increasing the power factor as the motor load increases, that is, as the detected input current i _s increases.

The switching control signal output unit 630 receives the zero crossing time point z _c , the turn on period Ton, and the delay period Td, and the switching control signal Scc for the converter as shown in FIG. 4. Is generated and output to the switching element (SW). Accordingly, the switching device SW performs an on / off switching operation.

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

Referring to the drawings, the controller 230 of FIG. 2 may not only output the converter switching control signal Scc but also output the inverter switching control signal Sic.

To this end, the controller 230 may further include an estimator 905, a current command generator 910, a voltage command generator 920, and a switching control signal output unit 930.

On the other hand, although not shown in the drawings, the three-phase output current (io) to convert the d-axis, q-axis current or may further include an axis conversion unit for converting the d-axis, q-axis current to the three-phase current.

The estimator 905 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 910 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 910 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 910 may include 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 920 generates a voltage command value v ^* _d , v ^* _q based on the detected output current io and the calculated current command value i ^* _d , i ^* _q . For example, the voltage command generation unit 920 performs PI control based on the difference between the detected output current io and the calculated current command value i ^* _d , i ^* _q , so that the voltage command value v ^* _d , v ^* _q ) To this end, the voltage command generation unit 920 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 switching control signal output unit 930 generates an inverter switching control signal Sic, which is a PWM signal, based on the voltage command values v ^* _d and v ^* _q and outputs the same to the inverter 220. Accordingly, the switching elements Sa, S'a, Sb, S'b, Sc, and S'c in the inverter 220 perform an on / off switching operation.

On the other hand, although not shown in the drawings, when the current detected from the input current detector (A) exceeds the allowable range, or when the dc terminal voltage detected from the dc terminal voltage detector (D) exceeds the allowable range, The controller 230 may stop not only the output of the switching control signal Scc for the converter but also the output of the switching control signal Sic for the inverter. Accordingly, it is possible to prevent burnout of circuit elements including the first rectifying unit 210, the second rectifying unit 215, and the inverter 220 in the driving device 200.

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 according to an embodiment of the present invention.

3 is a circuit diagram illustrating an example of a first rectifying unit and a second rectifying unit of FIG. 2.

4 is a diagram illustrating input voltage and input current waveforms according to the switching operation of the switching device of FIG. 3.

5 is a schematic circuit diagram according to an operating state of the switching device of FIG. 3.

6 is a simplified block diagram of the inside of the control unit of FIG. 2.

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

<Explanation of symbols on main parts of the drawings>

210: first rectifier 215: second rectifier

220: inverter 230: control unit

610: turn-on period setting unit 620: delay period setting unit

630: switching control signal output unit A: input current detection unit

B: Zero crossing detector C: Smoothing capacitor

D: dc stage voltage detector E: output current detector

Claims (11)

Reactor; A first rectifying unit rectifying the input AC power; A switching element connected to the first rectifier and configured to turn on to store energy of the input AC power in the reactor; A second rectifier connected in parallel with the first rectifier and configured to rectify the input AC power using energy stored in the reactor; And And a grounding part in which the first rectifying part and the second rectifying part are grounded in common. The method of claim 1, And a smoothing capacitor that smoothes the rectified voltage rectified by the second rectifier. And the grounding part is connected to one end of the smoothing capacitor. The method of claim 2, And a resistor for detecting an input current between the second rectifier and the smoothing capacitor. The method of claim 1, And a second rectifying unit performs a rectifying operation by a turn-off operation of the switching element. The method of claim 1, A zero crossing detector for detecting zero crossing of the commercial AC power supply; And And a control unit for outputting a converter switching control signal for driving the switching element based on the detected zero crossings. The method of claim 5, The control unit, the electric motor drive device of the air conditioner, characterized in that the ground in common. The method of claim 5, The control unit, A turn-on period setting unit configured to set the turn-on period based on a detection value of the dc terminal voltage which is the output terminal of the second rectifier and a command value of the dc terminal voltage; A delay period setting unit that sets the delay period based on the detected value of the input current and the command value of the input current; And And a switching control signal output unit configured to generate and output a converter switching control signal for driving the switching element based on the zero crossing point of the commercial AC power, the set delay period, and the turn on period. Electric motor drive of air conditioner. The method of claim 1, And a dc stage voltage detector configured to detect a dc stage voltage as an output terminal of the second rectifier. The method of claim 1, The first rectifier and the second rectifier, An electric motor driving device of an air conditioner, comprising a plurality of bridge diode elements. The method of claim 5, An inverter having a plurality of switching elements and converting the voltage rectified by the first rectifying unit and the second rectifying unit into an AC power source having a predetermined frequency by a switching operation to drive an electric motor; And And an output current detector for detecting an output current flowing between the inverter and the motor. The control unit, the motor driving apparatus of the air conditioner, characterized in that for outputting an inverter switching control signal for driving the switching elements of the inverter. The method of claim 10, The control unit, An estimator estimating a speed of the electric motor based on the detected output current; 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 switching control signal output unit configured to generate and output the inverter switching control signal based on the voltage command value.

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