JP2003153574A - Motor control device - Google Patents

Abstract

(57) [Object] To provide a motor control device capable of controlling a motor over a wide range with a small switching loss as compared with a DC voltage control system using a step-up chopper. A rectifying circuit for rectifying an alternating current, a smoothing capacitor having a capacitor connected in series, an inverter, an electric motor, and a bidirectional switch provided between a series connection point of the smoothing capacitor and the AC side of the rectifying circuit. In the first operation mode, the speed of the motor is controlled by controlling the pulse width of the inverter, and in the second operation mode, the motor is controlled by controlling the ON phase of the bidirectional switch with respect to the AC voltage. The DC stage voltage is controlled without using a boost chopper. Thereby, the switching loss of the boost chopper can be eliminated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a motor control device having a converter for rectifying AC and outputting a desired DC voltage, and an inverter for applying a rotating magnetic field to a brushless motor.

[0002]

2. Description of the Related Art Conventionally, a rectifier circuit for rectifying alternating current to convert it into direct current, which combines a power source circuit for suppressing harmonics of a power source current and controlling a direct current voltage with a drive circuit for a compressor electric motor. As a control device for controlling the rotation speed of a compressor electric motor, a technique described in Japanese Patent Laid-Open No. 2000-146392 (Prior Art 1) is known.

The control device for the electric motor for driving the compressor for the refrigerator described in the prior art 1 includes a rectifying circuit and a smoothing circuit for converting alternating current into direct current, a switching operation and a reactor.
(Inductance) converter circuit having a chopper circuit that performs boost control of DC voltage by utilizing the energy storage effect, an electric motor drive device having an inverter circuit and a DC brushless motor connected to the DC side of the converter circuit, and A converter control circuit that controls the switching operation of the chopper circuit and an inverter control circuit that applies a rotating magnetic field to the electric motor by controlling the switching operation of the inverter circuit are provided.

Further, a position detector for detecting the position of the rotor of the electric motor, a speed calculator for calculating the rotational speed of the electric motor from the output of the position detector, and a calculated speed value and a speed command value are inputted to the position detector. A speed control circuit for controlling the rotation speed of the electric motor via the inverter control circuit, and a converter operation determiner for controlling the DC voltage via a selection circuit for inputting a speed command value and selecting the operation mode of the converter. There is.

Further, the output of the DC voltage detecting circuit for detecting the DC voltage value of the output of the converter circuit, the output of the speed calculator and the output of the selecting circuit are input to generate an output voltage command value of the converter. The converter PAM voltage command generator, the output of the converter operation determiner and the output of the converter PAM voltage command generator,
The converter control circuit adjusts the DC voltage output from the converter to a predetermined voltage.

The inverter control circuit of the prior art 1 is
Based on the position signal from the position detector and the duty ratio signal from the speed calculator, the switching elements of the inverter circuit are sequentially driven to drive the compressor electric motor. The induced voltage of the electric motor is input to the position detector, the magnet position is calculated from this induced voltage, and the rotational speed of the electric motor is output by the speed calculator based on this position signal. The detected speed is compared with an externally calculated speed command by a comparator, and the speed deviation is input to the inverter PWM duty command generator, and proportional-integral calculation is performed based on the speed deviation to make the speed deviation zero. The pulse width is determined and the pulse train is output.

The output signal of the position detector is also input to the commutation output device, and a pulse train, which is the commutation timing of 120 ° commutation of each phase switching element, is output for each switching element. The switching element constituting the lower arm of each phase is turned on during this commutation timing, and the switching element constituting the upper arm is ANDed with the pulse train representing the commutation timing and the pulse train representing the previous PWM signal. And is controlled on and off via a driver.

The converter control circuit includes a converter PAM.
The switching element of the chopper circuit is driven according to the signals from the voltage command generator and the DC voltage detection circuit. The DC stage voltage of this conventional example is controlled in three stages of high voltage, medium voltage, and low voltage, and at high voltage and medium voltage, the voltage is realized by turning on / off the boost chopper. At low voltage, the boost chopper is turned off to widen the output pulse width of the inverter to save energy.

The actual rotation speed of the compressor electric motor calculated by the speed calculator and the speed command calculated by the speed command generator are input to the converter PAM voltage command generator and the converter operation determiner. The converter PAM voltage command generator generates a high voltage or medium voltage command based on the input actual rotation speed and speed command.

This voltage command value is compared with the DC voltage which is the voltage across the capacitor detected by the DC voltage detection circuit, and the voltage across the capacitor is changed to the selected high voltage or medium voltage through the proportional-plus-integration circuit. A command for the current peak value is output. Further, the converter operation determiner outputs a chopper off signal which is a signal for turning off the boost chopper when it is determined that the DC stage voltage should be set to a low voltage based on the input actual rotation speed and the speed command.

The current peak value command from the converter PAM voltage commander is multiplied by the voltage (pulsating current) which is full-wave rectified by the diode detected by the voltage detector and multiplied by the multiplier to be an instantaneous current command. The instantaneous current command and the actual instantaneous current detected by the current detection resistor are compared by the comparator 1, the deviation thereof is input to the comparator 2, and is compared with the sawtooth wave (triangular wave) generated by the oscillator. Obtain a pulse width modulated signal. This signal is input to the drive circuit and amplified to become the gate signal of the boost chopper.

In this way, the instantaneous current command and the instantaneous current are compared and controlled so as to eliminate the deviation, so that the phases of the input voltage and the input current are substantially equal and the power factor is close to 1. By making the current sinusoidal in this way, harmonic current can be suppressed. When a low voltage is required, the chopper off signal, which is the output of the converter operation determiner described above, is input to the drive circuit to block the gate signal and stop the switching operation of the boost chopper.

[0013]

The electric motor control device described in the prior art 1 uses the boost chopper control utilizing the energy storage effect of the reactor as a means for controlling the DC voltage of the converter circuit output. For this reason,
Although the motor can be driven efficiently, the converter circuit causes switching loss in the boost chopper circuit. Further, in the control device described in this prior art, the DC stage voltage has three stages of high voltage, medium voltage and low voltage.

When the high voltage and the medium voltage are selected in this configuration, the step-up chopper control of the converter for performing the DC voltage control requiring high frequency switching and the PWM control of the inverter for controlling the rotation speed of the electric motor are simultaneously performed. In addition, high-frequency noise is likely to occur, and there is a risk of affecting surrounding electrical products. Furthermore, in order to suppress this high frequency noise, it is necessary to add additional parts, which increases the cost of the control device and thus the refrigerator.

Further, the reactor used in the converter circuit of the prior art 1 requires a large inductance because the power factor is improved only by the inductance component without performing the boost chopper control when a low voltage is selected. become.
In addition, when selecting high voltage or medium voltage, the energy storage effect of high frequency switching is also used, so a material with excellent frequency characteristics and saturation characteristics is required, and in order to achieve both of these, the control device or refrigerator becomes expensive. Will end up.

An object of the present invention is to provide an electric motor control device capable of expanding the operation region of the electric motor while reducing the switching loss, as compared with the electric motor control using only the inverter (without changing the DC voltage).

[0017]

The above object is to provide a rectifier circuit in which a plurality of diodes are bridge-connected to rectify an alternating current.
In a motor control device including a smoothing capacitor connected in parallel to the DC side of the rectifier circuit, in which capacitors are connected in series, an inverter connected in parallel to the smoothing capacitor, and a motor to which drive power is supplied from the inverter. A full-wave rectification mode in which an output DC voltage of the rectifier circuit is applied across the smoothing capacitor, and a voltage doubler mode in which an output DC voltage of the rectifier circuit is alternately applied to a capacitor that is a constituent element of the smoothing capacitor, And a function of generating a voltage between the voltage across the smoothing capacitor in the full-wave rectification mode and the voltage across the smoothing capacitor in the voltage doubler mode based on the deviation between the speed command of the electric motor and the actual speed. It is achieved by

The above-mentioned object is to connect a plurality of diodes in a bridge to rectify an alternating current, a smoothing capacitor connected in parallel to the direct current side of the rectifier circuit, and a capacitor connected in series, and a smoothing capacitor connected in parallel to the smoothing capacitor. In an electric motor control device including an inverter and an electric motor to which driving power is supplied from the inverter, a bidirectionality provided between one line on the AC side of the rectifier circuit and a series connection point of a smoothing capacitor. It is achieved by including a switch and a function of controlling a phase in an alternating voltage that turns on a bidirectional switch based on a deviation between a speed command of an electric motor and an actual speed.

A further object of the present invention is to provide a rectifier circuit in which a plurality of diodes are bridge-connected to rectify an alternating current, a smoothing capacitor connected in parallel to the direct current side of the rectifier circuit, and a capacitor connected in series, and a smoothing capacitor connected in parallel to the smoothing capacitor. In a motor control device including a connected inverter and a motor supplied with drive power from the inverter, both of which are provided between one line on the AC side of the rectifier circuit and a series connection point of smoothing capacitors. A directional switch, a first operation mode for controlling the pulse width of the inverter based on the deviation between the speed command and the actual speed of the electric motor, and a bidirectional switch based on the deviation between the speed command and the actual speed of the electric motor. And a second operating mode for controlling the phase in the alternating voltage.

Further, the above object is to provide a rectifier circuit in which a plurality of diodes are bridge-connected to rectify an alternating current, a smoothing capacitor connected in parallel to the direct current side of the rectifier circuit, and a capacitor connected in series, and a smoothing capacitor connected in parallel with the smoothing capacitor. In a motor control device including a connected inverter and a motor supplied with drive power from the inverter, both of which are provided between one line on the AC side of the rectifier circuit and a series connection point of smoothing capacitors. A directional switch, a first operation mode for controlling the pulse width of the inverter based on the deviation between the speed command and the actual speed of the electric motor, and a bidirectional switch based on the deviation between the speed command and the actual speed of the electric motor. A second operation mode for controlling the phase in the AC voltage, and switching from the first operation mode to the second operation mode Performed based on the scan width is achieved by switching from the second operation mode to the first mode of operation comprises a function of performing, based on the phase.

More preferably, the above-mentioned bidirectional switch is an element which is turned on when a voltage is applied to the gate electrode so that the terminals are brought into conduction and no current flows between the terminals.

[0022]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

First, the outline of the configuration of the refrigerator according to the first embodiment of the present invention will be described with reference to FIGS. Figure 1
FIG. 1 is a vertical cross-sectional view showing the outline of the configuration of a refrigerator according to a first embodiment of the present invention. FIG. 2 is a schematic diagram showing connections between the compressor electric motor of the refrigerator shown in FIG. 1, the control device for driving the electric motor, the converter, and the inverter.

In FIG. 1, a refrigerator main body 100 has a refrigerator compartment 104 from the inside, which is formed inside a box body having an outer box 101, an inner box 102, and a heat insulating material 103 filled between them. A vegetable compartment 105, an ice making compartment 106 equipped with an automatic ice making device inside, and a freezing compartment 107 are arranged. In addition,
A partitioning body provided with a heat insulating material inside is arranged between the ice making chamber 106 and the vegetable chamber 105, and between the storage chambers having such a large temperature difference on the inside to be regulated, both of them are arranged. A partition having a heat insulating material is provided to suppress heat transfer between the two.

That is, in this embodiment, the refrigerator compartment 104, the vegetable compartment 105, and the ice making compartment 1 whose adjusted set temperatures are close to each other.
A heat insulating partition is arranged between the storage unit 06 and the freezer compartment 107. Further, although not shown, another storage chamber may be arranged adjacent to the ice making chamber 106, for example, a switching chamber capable of adjusting the internal temperature to a plurality of temperature zones.

Doors for opening and closing these storage chambers are arranged in front of these storage chambers, and a revolving door 108 for the refrigerator compartment 104, a vegetable compartment 105, an ice making compartment 106, and a freezing compartment 107 are provided.
Drawout doors 109, 110, and 111 that can be pulled out are attached to the box.

Furthermore, inside the refrigerator, the vegetable compartment 105
A freezing cycle is provided which is operated to cool the upper and lower storage chambers which are partitioned by a heat insulating partition for partitioning between the ice making chamber 106 and the freezing chamber 107. This refrigerating cycle includes a cooler 112 for cooling the air in the refrigerator compartment 104, the vegetable compartment 105, a cooler 113 for cooling the ice making compartment 105, the freezing compartment 107 or the switching compartment, and a compression mechanism part for the closed container 114. , A condenser (not shown), and a refrigerant pipe that connects these to allow a refrigerant to flow inside. In this refrigeration cycle, the refrigerant compressed by driving the compressor with the electric power supplied from the commercial power source 1 is sent to the coolers 112 and 113 which are evaporators, and the refrigerating room, the vegetable room cooling fan 115 and the ice making room, The air in the refrigerator is cooled by exchanging heat between the air in the refrigerator and the refrigerant flowing through the cooler by the rotation of the freezer compartment fan 116.

In this embodiment, the cooled air is supplied to each storage chamber by the fan to cool the storage chamber. For example, by rotating the fan 115, the cooler 112
The air cooled in the cold air passage 119 passes through the cold air passage 119 and passes through the cold storage room 10.
Inflow to 4. The air that has flowed into the refrigerator compartment 104 flows into the vegetable compartment 105 from the flow passage provided in the partition plate arranged between the refrigerator compartment 104 and the vegetable compartment 105, and the vegetable compartment container 1
A circulation path of the air in the refrigerator is formed, which flows around 20 and flows out from the vegetable chamber rear outlet provided behind the vegetable chamber container 120 and is supplied to the cooler 112 again. Further, the refrigerating compartment 104 and the vegetable compartment 105, and the ice making compartment 106 and the freezing compartment 107 (and the switching compartment) independently form a circulation path having a storage compartment and a cold air passage so that the air inside the compartment circulates. .

The compressor and fans 115 and 116 are
A board 41 having a control device for a refrigerator and a control device 117 having an electric component.

The connection between the controller 117 and the compressor will be described with reference to FIG. In the present embodiment, the electric power supplied from the commercial power source 1 is rectified using the converter circuit 61 and the like in the refrigerator control device of the control device 117 and supplied to the inverter circuit 25. The inverter circuit 25 receives a command from the arithmetic unit 118 having an arithmetic function, adjusts the value and frequency of the voltage supplied from the converter circuit, and causes the motor 27 for driving the compressor in the closed container 114. Adjust the rotation of a DC brushless motor. The rotation of the motor 27 drives the compression mechanism portion 28 of the compressor.

The rotor position associated with the rotation of the motor 27 is detected by the detection sensor, and the detected result is calculated by the calculator 11
8 is output. The computing unit 118 feeds back the output position information to the rotation signal for instructing the inverter circuit 25 to adjust the rotation of the motor 27.

FIG. 3 is a circuit block diagram showing the configuration of the refrigerator controller shown in FIG. 1, and is a circuit block diagram showing an embodiment of the refrigerator controller of the present invention.

In the figure, reference numeral 6 denotes the entire control device of the refrigerator, and 1 denotes a general AC commercial power source. As shown in the figure, power can be supplied by inserting a plug into an outlet. Reference numeral 2 is a common mode filter circuit connected to the commercial power supply 1. Reference numeral 3 is a normal mode filter circuit reactor (power factor improving reactor), and 4 is a normal mode filter circuit capacitor.

Reference numeral 5 is a well-known rectifying circuit for rectifying an alternating current, and four diodes are bridge-connected. Reference numeral 7 is a bidirectional switch such as a relay, and 8 and 9 are smoothing capacitors. The bidirectional switch 7 will be described in detail later. These bridge diodes (rectifier circuits) 5, bidirectional switches 7, smoothing capacitors 8, 9
Form a part of the converter circuit 61. Further, 10 and 11 are DC voltage detection resistors, and 12 is a DC current detection resistor.

The smoothing capacitors 8 and 9 are constructed by connecting two capacitors 8 and 9 in series. This is for doubling the DC output voltage of the rectifier circuit 5, and the number of capacitors used and the connection form are not limited as long as it is not necessary to use two capacitors and an intermediate voltage can be produced. . The bidirectional switch 7 is connected to an intermediate voltage section which is a connection section of the smoothing capacitors 8 and 9 connected in parallel to the DC stage of the rectifier circuit. When the switch 7 is turned on / off, the voltage output from the converter 61 is increased / decreased by a plurality of different magnitude values to be output. In the present embodiment, when the switch 7 is off (off), the converter circuit 61 becomes a so-called full-wave rectifier circuit, and when it is on (on), it forms a voltage doubler rectifier circuit and the full-wave rectifier circuit outputs. Outputs a voltage that is about twice the voltage.

Further, 13, 14, 15, 16, 17,
Reference numeral 18 is a semiconductor switching element forming an inverter bridge, and 19, 20, 21, 22, 23, 24 are freewheeling diodes forming an inverter bridge, and 25
Shows an entire inverter circuit including semiconductor switching elements 13 to 18 and free wheeling diodes 19 to 24 for driving these electric motors. Reference numeral 26 denotes semiconductor switching elements 13 to 18 which form an inverter bridge.
Is a driver for driving.

Reference numeral 28 denotes a compression mechanism portion of the compressor driven by the electric motor 27. The compression mechanism portion 28 and the electric motor 27 are housed in a hermetically sealed container, and the electric motor portion 2 is provided via a main shaft.
The rotational power of 7 is transmitted to the compression mechanism portion 28, and if the compression mechanism portion 28 is a reciprocating compressor, it is used as the power for reciprocating the piston, and if it is a rotary compressor, it is the power for eccentrically moving the rollers, If it is a scroll compressor, it will be the power to orbit the orbiting scroll. Hereinafter, the compression mechanism unit 28 will be described as the same as the compressor unless otherwise specified. Further, 29, 30, 31, 32, 33, 34 are detection resistors for detecting the motor terminal voltage of the DC motor 28, and 35 is for generating a signal indicating the detected rotor magnetic pole position of the DC brushless motor 27. Shows a comparator of.

Reference numeral 36 is a first microcomputer for controlling the converter and the inverter. The microcomputer 36 includes a phase detector 37 for detecting the phase of a commercial power source, a semiconductor memory element provided outside the microcomputer, an insulating element 39 for insulating between the second microcomputer and a refrigerator. The forced operation signal for driving is connected to the input terminal 40 and the DC power supply circuit, and signals are transmitted to and received from these terminals. Further, the microcomputer 36 is also connected to the bidirectional switch 7, and also controls the driving of this switch.

Reference numeral 59 is a second microcomputer, which controls the operation of the equipment arranged in the refrigerator. Reference numerals 42, 43 and 44 denote fan motors arranged inside the refrigerator and in the machine room to circulate air, and a driver 45 for giving a command signal to the fan motors to drive the fan motors is connected to the second microcomputer 59. Has been done. Reference numerals 46, 47, 48 and 49 are sensors for detecting the temperature of each part of the refrigerator, and the detection outputs from these sensors are transmitted to the second microcomputer 59, and by the command from this microcomputer 59,
A driver 50 that drives a damper 51 installed in a ventilation passage (not shown) for adjusting the opening of the ventilation passage in the refrigerator.
Is driven to activate the damper 51.

Similarly, 52 is a driver for driving a motor for rotating an ice tray of an automatic ice making machine and a motor for a pump for supplying water to the ice tray, 53 is an automatic ice maker, and 54 is installed in each part of a refrigerator (not shown). A driver that energizes the heater,
Reference numerals 55, 56, 57 and 58 denote heaters installed in various parts of the refrigerator (not shown), and 60 denotes a DC power supply circuit for controlling the devices arranged in the refrigerator.

Next, the operation of the control circuit and the refrigerator will be described.

The second microcomputer 59 operates under the conditions for operating each of the fan motors 42-44 (for example, the number of revolutions) based on the temperature information obtained by receiving the detection results detected by the sensors 46-49. And operating time), the opening of the damper 51, the condition for operating the automatic ice maker 53, and the rotation speed (including ON and OFF) for rotating the DC brushless motor built into the compressor 28.

In addition to the detection results from the sensors 46 to 49, based on the integrated time from a storage means (not shown) which stores the integrated operating time of the timed compressor electric motor 27 or compressor 28. Each heater 55-
Conditions for driving 58 (current, voltage, energization time, etc.),
And the rotation speed (including ON and OFF) for rotating the DC brushless motor 27 for the compressor 28 is calculated.

Based on the calculation result, the second microcomputer 59 outputs a command signal for driving the fan motors 42 to 44 to the fan motor driver 45 to drive the fan motors 42 to 44. It Similarly, a command signal for driving the damper 51 to a predetermined opening is output to the damper opening adjustment driver 50 to adjust the opening of the damper 51, and the automatic ice making machine 53 is also provided.
A command signal is output to the driver 52 that drives the ice tray and a water pump for supplying water to the ice tray, and the automatic ice machine is operated based on predetermined operating conditions. Furthermore, a command signal for operating the heaters 55 to 58 under a predetermined operating condition is output to the heater driver 54 to operate the heaters 55 to 58.

In addition, the second microcomputer 59
Converts the rotation speed (rotation speed per unit time) of the compressor DC brushless motor 27 determined by the previous calculation into a rotation speed command signal and outputs the rotation speed command signal to the first microcomputer 36 via the insulating element 39.

The comparator 35 includes the DC brushless motor 2
A signal is input through the motor terminal voltage detection resistors 29 to 34 of No. 7, and a rotor position detection signal of the DC brushless motor 27 is created. This generated signal is input to the first microcomputer 36, and this computer 3
At 6, the actual rotation speed of the DC brushless motor 27 is calculated based on this rotor position information. The first microcomputer 36 receives the actual rotation speed of the DC brushless motor 27 and the input DC brushless motor 27 for the compressor.
A signal for driving the inverter semiconductor switching element corresponding to the rotor position information is supplied to the driver 2 for the inverter circuit 25 so that the deviation from the rotation speed command signal for drive becomes zero.
Output to 6.

As a result, the semiconductor switching element 13
18 to 18 are sequentially driven by the driver 26 so that the DC brushless motor 27 becomes the speed of the rotation speed command (so that the deviation between the actual rotation speed and the rotation speed command approaches zero) or the DC corresponding to the rotation speed command. So that the converter circuit 61 outputs the voltage to the inverter circuit 25,
An operation command signal is output to the bidirectional switch 7 so as to adjust the DC voltage of the converter circuit 61.

In the present embodiment, when the rotation speed command of the DC brushless motor 27 calculated by the second microcomputer 59 is equal to or lower than the predetermined rotation speed,
Alternatively, when the detected rotation speed of the compressor 28 is lower than a predetermined rotation speed, the first operation mode is set. The operation at a speed higher than this is the second operation mode. In the first operation mode, the first microcomputer 36 sets the DC voltage output from the converter circuit 61 to the inverter circuit 25 to the minimum value, that is, the DC voltage output as a result of the full-wave rectification by the rectifier circuit 5. Then, a command signal is output to the bidirectional switch 7 to turn off the bidirectional switch 7 of the converter circuit 61, or the control signal of the bidirectional switch 7 is stopped.

The first microcomputer 36
Is the insulating element 39 from the second microcomputer 59.
The actual rotational speed of the electric motor 27 for the compressor calculated from the command information of the rotational speed of the DC brushless motor 27 input via the computer and the rotor position information of the DC brushless motor 27 input to the first microcomputer 36. The pulse width of the PWM control for operating the semiconductor switching elements 13 to 18 of the inverter circuit 25 is calculated so that the deviation between and becomes zero.

Next, the PW calculated previously based on the commutation information for driving the DC brushless motor 27 according to the rotor position information.
The M control pulse width information is superimposed to generate a motor drive signal, and this motor drive signal is output and transmitted to the inverter circuit driver 26. The inverter circuit driver 26 sequentially outputs semiconductor switch drive signals to each of the inverter semiconductor switches 13 to 18 based on the input motor drive signal, whereby the DC brushless motor 27 has a predetermined rotation speed. Driven.

Here, the first microcomputer 36
In superposing the PWM pulse information on the commutation information of the motor when the motor commutation information and the PWM pulse width information are superimposed to generate the motor drive signal, the semiconductor switch for the upper arm of the inverter circuit 25 is 13 to 15 only, or the lower arm semiconductor switch 16 to
The same result can be obtained with only 18 or both.

As described above, in the first operation mode in which the rotation speed of the compressor 28 or the electric motor 27 for the compressor is equal to or lower than a predetermined value, the DC voltage input to the inverter circuit 25 is minimized to the DC brushless. By driving the motor 27, the pulse width of the PWM control signal can be kept relatively large even in the region where the rotation speed of the motor is small, and thus the difference between the maximum current and the minimum current in one cycle of the inverter switching element can be reduced. Therefore, the pulsating magnetic flux density can be reduced, and as a result, the iron loss of the motor can be reduced and an efficient motor drive can be obtained.

In the first operation mode, the deviation between the speed (rotation speed) command of the compressor and the actual speed (rotation speed) generated based on the deviation between the temperature command of the freezer compartment of the refrigerator and the actual temperature is proportional. The pulse width of the inverter 25 is calculated by integration, and the voltage applied to the electric motor 27 is variably controlled to control the rotation speed of the electric motor.

Next, when the rotation speed command of the DC brushless motor 27 calculated by the second microcomputer 59 is higher than the predetermined rotation speed, or the detected rotation speed of the compressor 28 is predetermined. The second operation mode is set when the rotation speed is higher than the rotation speed.

In practice, the pulse width of the inverter 25 is 1
It detects that it has become 00% and shifts from the first operation mode to the second operation mode.

In the second operation mode, the first microcomputer 36 determines that the rotation speed command of the DC brushless motor 27 calculated by the second microcomputer 59 which is larger than that in the first operation mode is the insulating element 39. Input through the, a commutation signal of the DC brushless motor is calculated based on the rotor position information obtained from the rotor position detection signal generation comparator 35, and the commutation signal is output to the inverter circuit driver 26. .

At this time, the first microcomputer 36
The signal that the driver outputs to the driver 26 has a PWM conduction ratio of 1
It is set to 00% and only the commutation signal is output. On the other hand, the first microcomputer 36 uses the DC brushless motor 27.
In order to adjust the rotational speed, the actual rotational speed of the DC brushless motor 27 is calculated using the signal input from the rotor position detection signal generation comparator 35, and this actual rotational speed and the input rotational speed are calculated. Compare with the speed command signal. Then, the bidirectional switch 7 of the converter circuit 61 is set so that the deviation between the actual rotation speed and the rotation speed command becomes zero.
The output voltage of the converter circuit 61 is adjusted so that the desired rotation speed of the compressor 28 or the compressor driving electric motor 27 can be obtained by adjusting the flow time of the current that is applied to the.

That is, in the second operation mode, P
The value of the voltage applied to the DC brushless motor 27 is adjusted so that the conduction ratio by the WM control is 100%, and the voltage input to the inverter circuit 25 is adjusted by adjusting the conduction time of the bidirectional switch 7. By adjusting, a predetermined rotation speed of the DC brushless motor can be obtained. Accordingly, each semiconductor switching element 1 of the inverter circuit 25
3 to 18 is suppressed from switching at high speed,
Switching loss can be reduced. Further, since the current flowing through the motor does not include the pulsating flow component, the iron loss of the motor can be reduced and the driving efficiency of the motor can be improved.

The bidirectional switch 7 is connected to the intermediate voltage point of the smoothing capacitors 8 and 9 connected in series and either one of the AC stages of the rectifier circuit 5. When the bidirectional switch 7 is off, the DC voltage output from the rectifier circuit 5 is applied to both ends of the series body of the smoothing capacitors 8 and 9 (full-wave rectification), and when on, the DC voltage output from the rectifier circuit 5 is smoothed. It is applied to one of the capacitors 8 and 9 (doubled voltage). That is, when the line on the AC stage in the drawing is positive, the current returns to the line below the AC stage via the upper arm of the diode forming the rectifying circuit 5, the smoothing capacitor 8, and the bidirectional switch 9. On the contrary, when the lower line of the AC stage is positive, the current returns to the upper line of the AC stage through the bidirectional switch 7, the smoothing capacitor 9, and the diode forming the lower arm of the rectifying circuit 5. Therefore, the voltage of the series body of the smoothing capacitors 8 and 9 is twice the full-wave rectified value.

Here, adjustment of the rotation speed of the DC brushless motor in the second operation mode will be described with reference to FIG.
This will be described in detail with reference to Nos. 4 and 5.

In FIG. 3, in the comparator 35, the motor terminal voltage of each phase of the DC brushless motor 27 is detected by the motor terminal voltage detecting resistors 29 to 34, and the motor terminal voltage signal is input to the inverter circuit 25. The DC voltage signal obtained by dividing the DC voltage by, for example, 1/2 by the DC voltage detection resistors 10 and 11 is input. These input signals are compared with each other to generate a rotor magnetic pole position signal of the DC brushless motor 27, which is output to the first microcomputer 36.

The first microcomputer 36 receives the magnetic pole position detection signal from the comparator 35, generates a commutation signal of the motor according to the magnetic pole position of the rotor, and outputs the period of the input magnetic pole position detection signal. From this, the actual rotation speed of the DC brushless motor 27 is calculated. Further, since the signal of the motor rotation speed command output from the second microcomputer 59 is also input to the first microcomputer 36, the target rotation speed and the actual rotation speed are supplied and received. is doing. In the first microcomputer 36, these values are compared to determine the magnitude.

With this first microcomputer 36,
When it is determined that the value of the target rotation speed is larger than the value of the actual rotation speed, the PWM conduction ratio is 100% in the second operation mode, and thus the PWM conduction width is increased. The rotation speed cannot be increased. Therefore, in order to increase the rotation speed of the DC brushless motor 27, the first microcomputer 36 increases the DC voltage input by the inverter circuit 25 by adjusting the operation of the bidirectional switch 7 of the converter circuit 61. , A desired rotation speed, here, a rotation speed based on a rotation speed command is obtained.

That is, in the second operation mode, the speed (rotation speed) command and the actual speed (rotation speed) of the compressor are generated based on the deviation between the temperature command of the freezer compartment of the refrigerator and the actual temperature.
The on-timing of the bidirectional switch 7 is calculated by proportionally integrating the deviation between and, and the rotation speed of the electric motor is controlled by variably controlling the voltage applied to the electric motor 27.

On the other hand, during the first operation mode, the bidirectional switch 7 is normally switched off because the output voltage of the converter circuit 61 is set to the minimum. As a result, the converter circuit 61 forms a full-wave rectifier circuit, and the input commercial power source is 100V.
Then, in a normal operating state, the output voltage of the converter circuit 61 is about 120 to 140V. When increasing the rotation speed of the motor from this state, the output voltage of the converter circuit may be set to a voltage value corresponding to the predetermined rotation speed, and the first microcomputer 36 causes the bidirectional switch 7 in the converter circuit 36 to operate. By controlling the timing and time of turning on, it is possible to obtain a DC voltage value that matches the predetermined rotation speed.

Bidirectional switch 7 in the present embodiment
Will be described. As the bidirectional switch 7, a triac known as an element for controlling AC power is used. This triac is also called a bidirectional three-terminal thyristor, and is an element that cannot be turned off by the gate electrode like the thyristor, because the electrodes are electrically connected by applying an on-voltage to the gate electrode. To turn it off,
It is turned off by lowering the current below the holding current or by applying a reverse voltage for more than the turn-off time. Therefore, when an ON voltage is applied to the gate electrode at a certain phase of a half wave of the AC voltage, the terminals are electrically connected, and the positive / negative of the AC voltage is reversed at 180 °, and the current direction is also reversed, so that the current is turned OFF. As described above, since it has a property of being turned off without giving any control signal depending on the property of the AC voltage, only the ON signal needs to be controlled, and thus the controllability is good.

In addition to this, as the bidirectional switch 7, a high-speed relay and a circuit in which transistors are connected in anti-parallel are conceivable, but it is necessary to control OFF in both cases.

Bidirectional switch 7 in the present embodiment
The adjustment of the operation will be described with reference to FIGS. FIG. 4 shows the timing of turning on / off the bidirectional switch 7 together with the waveform of the input AC voltage.

In this figure, the phase of the voltage supplied to the horizontal axis,
The magnitude of the voltage is plotted on the vertical axis, and the change in the magnitude of the voltage supplied from the power source 1 with respect to the phase (time) is shown as a graph. Solid lines are written above and below the horizontal axis, and the change in voltage for one cycle is shown. In this graph, the shaded area indicates the phase (time) in which the bidirectional switch 7 is turned on and the converter 61 is energized to supply current. The switch 7 is turned on at the left end phase of each shaded portion and turned off at the right end portion.

In this figure, the phase when the voltage value becomes 0V is 0 degree, and the phase when it becomes 0V again is 180 degrees. In the present embodiment, the phase (time) at which the switch 7 is switched from the ON state to the OFF state is the phase at which the voltage becomes 0V again,
That is, it is set to 0 degrees or 180 degrees, and the first microcomputer 36 adjusts the phase (time) for switching to the on state, thereby adjusting the length of time for which the current is conducted while the switch is in the on state. .

That is, there is a time during which the switch 7 is turned on and current is supplied during each half cycle.
Then, in the present embodiment, the energization time for each half cycle is adjusted to be the same. In this way, when the voltage of the power supply to be supplied has a predetermined frequency, the time during which the switch 7 is turned on is adjusted so that the converter circuit 61 causes the inverter circuit 25 to drive the motor 27. The magnitude of the voltage supplied to the motor is adjusted so that the rotation speed thereof is driven to a prescribed value that is commanded.

FIG. 5 shows a case where the phase of a general commercial power source input to a capacitor input type circuit at 0V is 0 degree and the phase at the next 0V is 180 degrees (half cycle of supplied current). ), The phase is 1 as shown in FIG.
An example of the relationship between the value of the phase at which the switch 7 is turned on so as to maintain the on state until it reaches 80 degrees and the output voltage of the converter circuit 61 at that time is shown. In this figure, with the change of the phase that turns on the bidirectional switch 7,
The magnitude of the voltage output from the converter circuit 61 varies, and the output voltage of the converter 61 increases as the phase at which the switch 7 is turned on decreases. From this figure, it is understood that a predetermined output voltage can be obtained by arbitrarily adjusting the phase in which the bidirectional switch 7 is turned on.

In this embodiment, based on this knowledge, when the rotation speed of the DC brushless motor 27 is to be increased to the target rotation speed in the second operation mode, the phase detector 37 is used to switch the commercial power source. Phase (for example, 0V point) is detected,
After inputting this phase detection signal to the first microcomputer 36 to recognize the reference point of the phase of the commercial power source, the value of the actual rotation speed of the motor and the value of the target rotation speed (command rotation speed) Bidirectional switch 7 so that the deviation becomes zero
Is adjusted to adjust the time for which the converter circuit 61 is energized.

For example, the switch 7 is turned on within one cycle (each half cycle) by advancing the phase timing for turning on the switch 7 (the phase is brought close to 0 degree or 180 degrees). Prolong the energization time by. As a result, the value of the DC voltage output from the converter circuit 61 can be adjusted (increased), whereby the predetermined value of the motor 27 for the compressor 28 can be determined based on the command signal output from the inverter circuit 25. The rotation speed of can be obtained.

Further, the length of the energization time adjusted by the on / off operation of the bidirectional switch 7 is changed continuously or in a plurality of steps according to the magnitude of the rotation speed. That is, the energization time may be continuously lengthened (the voltage is continuously applied to the gate of the triac) as the rotation speed commanded by the microcomputer increases, or a predetermined rotation speed may be set according to the specifications of the device. The energization time may be increased stepwise for each speed region. Thereby, as the commanded rotation speed increases, the voltage supplied from converter 61 increases continuously or in a plurality of steps.

As for the decrease of the rotation speed of the DC brushless motor 27 in the second operation mode, as in the case of the above increase, the phase for turning on the bidirectional switch 7 is adjusted and the DC voltage is decreased to a predetermined rotation speed. Get speed. For example, delay the timing of the phase (time) (set the phase to 0
Away from 180 degrees or 180 degrees)
By shortening the length of time that the switch 7 is turned on in one cycle (each half cycle), the DC voltage output by the converter 61 can be lowered.

A phase control of the bidirectional switch 7 according to the present embodiment, as compared with the prior art 1 which controls the DC voltage by providing a boost chopper on the DC stage to store electromagnetic energy in the reactor. Controls the voltage between the full-wave rectified voltage and the doubled voltage. That is, the maximum voltage is the double voltage and the minimum voltage is the full-wave rectified voltage. Controlling the ON phase of the bidirectional switch 7 (controlling the energization time) is performed by the smoothing capacitor 8,
This is equivalent to controlling the ratio of the full-wave rectified voltage applied to 9 and the doubled voltage, whereby the voltage of the smoothing capacitors 8 and 9 which are the DC voltage source of the inverter 25 in the subsequent stage can be controlled.

Next, the control at the time of transition between the first operation mode and the second operation mode in the refrigerator of this embodiment will be described.

First, in the DC brushless motor 27 in this embodiment, when the bidirectional switch 7 of the converter circuit 61 is continuously turned on, the output voltage ( The maximum voltage), that is, the DC voltage when the converter circuit 61 performs the voltage doubler rectification, and the desired maximum rotation speed is obtained at the maximum load of the compressor 28.

When the rotation of such a DC brushless motor 27 is adjusted in the first operation mode, the first microcomputer 36 turns on the bidirectional switch 7 for one cycle of the voltage from the power supply. It is continuously turned off to cause the converter circuit 61 to perform full-wave rectification. Further, a PWM signal to be superimposed on the drive signal for switching the semiconductor switches 13 to 18 of the inverter circuit 25 so that the actual rotation speed of the motor 27 follows the command rotation speed calculated by the second microcomputer 59. The rotation speed of the motor 27 is increased by increasing the flow rate.

However, in the first operation mode, since the input voltage of the inverter circuit 25 is low, the cooling capacity obtained at the rotation speed of the motor 27 when the PWM signal conduction ratio is 100% is limited. . In other words, the rotation speed lower than the upper limit of the rotation speed that the compressor 28 can drive is obtained, and the cooling capacity smaller than the maximum cooling capacity that the refrigerator can achieve is obtained. That is, there is an upper limit to the rotation speed of the DC brushless motor 27 in this first operation mode, and this rotation speed at the upper limit may be smaller than the maximum value of the rotation speed that can be realized by the compressor 28 or the motor 27. In the state of this first operation mode, the rotation speed of the motor 27 is rotated at a rotation speed lower than the rotation speed commanded to the motor 27.

In such a case, that is, the first microcomputer 36 does not reach the target rotation speed based on the commanded rotation speed even though the actual rotation speed is 100% in the PWM signal conduction ratio. In this case, the control of the rotation speed of the motor is switched from the PWM control of the inverter circuit to the DC voltage control of the converter circuit. That is, when the PWM control duty ratio is 100% and the rotation speed of the motor needs to be further accelerated, the first microcomputer 3
6 switches the operation of the DC brushless motor 27 from the first operation mode to the second operation mode.

Thus, in the second operation mode, the operation of the bidirectional switch 7 is adjusted, and the operation of the motor 27 is adjusted so that the rotation speed of the motor 27 becomes the target rotation speed. In this second operating mode, the bidirectional switch 7
The phase that can be switched on is 0 degrees and 180 degrees,
The rotation speed is increased until the converter circuit 61 is continuously turned on and the converter circuit 61 is in a state of performing double voltage rectification.

FIG. 6 shows the magnitude of the effective value of the voltage output from the converter circuit 61 and the command rotational speed output from the inverter when switching from the first operation mode to the second operation mode. Show the relationship. In this figure, a constant voltage is output from the converter circuit 61 until a predetermined rotation speed N2 at which the first operation mode is switched to the second operation mode starting from the lowest rotation speed N1 at which the refrigerator can be driven, and the full wave is generated. It is shown that rectification is being performed.

At a rotation speed higher than the predetermined rotation speed N2, the voltage output according to the rotation speed of the converter 61 rises to the voltage obtained by the voltage doubler rectification. As described above, this voltage is stepwise in a plurality of steps for a predetermined rotation speed width as the rotation speed increases between the voltage value by full-wave rectification and the voltage value by double voltage rectification. It is increasing. The reason for doing this stepwise is simply because the resolution of the microcomputer is low, and the stairs become linear as the resolution is increased. If the width and step of the rotation speed are made finer, both of them are effectively changed continuously, and the refrigerator operation can be adjusted more linearly and the power consumption is further reduced. be able to.
In the present embodiment, the number of rotations that reaches the voltage value obtained by this voltage doubler rectification is the maximum rotation speed N3 that can drive the motor 27 for the compressor 28 as a refrigerator.

The control at the time of transition from the second operation mode to the first operation mode will be described.

When the rotation speed of the DC brushless motor 27 is controlled in the second operation mode to decrease the rotation speed of the motor, as described above, the first microcomputer 36 first causes the second microcomputer 36 to move to the second operation mode. Microcomputer 59
The phase timing for turning on the bidirectional switch 7 of the converter circuit 61 is adjusted to lower the DC voltage input to the inverter circuit 25 so that the actual rotation speed of the motor follows the command rotation speed calculated by Reduce the rotation speed.

However, the DC voltage that the converter circuit 61 can output is minimum, that is, the rotation speed of the motor may not reach the target rotation speed obtained from the command rotation speed even if the bidirectional switch 7 is turned off. In this case, the first microcomputer 36 reduces the PWM signal having a conduction ratio of 100% at this time with the bidirectional switch 7 turned off, and performs PWM control to obtain a predetermined rotation speed. That is, when the bidirectional switch 7 is off (the phase of the on command is larger than the predetermined phase) and the rotation speed needs to be reduced, the first microcomputer 36 switches from the second operation mode to the first operation mode. Switch to the first operation mode.

In the above embodiment, the first microcomputer 36 and the second microcomputer 59 are provided as shown in FIG. 1, but only one microcomputer 62 is used as shown in FIG. Even in this case, the same effect as above can be obtained. In this case, in the microcomputer 62, the target rotation speed of the compressor 28 is calculated based on the temperature detection values of the respective sensors 46 to 49, and the inverter circuit 25 or the direct current brushless motor 27 obtains this target rotation speed. The converter circuit 61 or both may be controlled as described above.

Further, in the above-described embodiment, the switch 7 is turned off by designating the switch-off timing as 0 degree or 180 degree in consideration of the easiness of adjusting the switch switching operation and the energization time and the cost. The energization time to the converter 61 is adjusted by the timing of turning on the
If the voltage output from the converter can be adjusted by adjusting the energization time, another phase for turning off may be set, or the timing for turning on / off may be set arbitrarily.

Further, in the refrigerator controller of the present invention,
In particular, the control method of the converter circuit and the control method of the inverter circuit for controlling the DC brushless motor are not limited to the use in the refrigerator, and can be widely applied to small general-purpose inverters and other electric motor control devices.

As described above, according to the controller for a refrigerator in the above-described embodiment, when the DC brushless motor is driven at a low speed, the DC voltage input to the inverter circuit can be reduced, so that the iron loss of the motor can be reduced. It is possible to improve the motor efficiency by reducing. Further, when driving the DC brushless motor at high speed, the DC voltage control is performed by the converter circuit without performing high-speed switching control of PWM control on each semiconductor switching element of the inverter circuit.
It is possible to improve the circuit efficiency (inverter efficiency) by reducing the switching loss of the semiconductor switching element.

Further, since the above effects can be obtained with a simple circuit structure having a small number of parts, it is possible to obtain a low-cost and highly efficient DC brushless motor drive device.

[0094]

As described above, according to the present invention, since the step-up chopper is not adopted, the switching loss can be reduced, and by controlling the on-phase of the bidirectional switch, only the inverter (changing the DC voltage is changed). It is possible to provide an electric motor control device capable of expanding the operation region of the electric motor as compared with the electric motor control of (not performed).

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view showing the outline of the configuration of a refrigerator according to a first embodiment of the present invention.

FIG. 2 is a schematic diagram showing a connection between a compressor electric motor of the refrigerator shown in FIG. 1, a control device for driving the electric motor, and an inverter.

FIG. 3 is a circuit block diagram showing a configuration of a control device of the refrigerator shown in FIG.

FIG. 4 is a diagram showing a timing at which the control device of the refrigerator according to the present embodiment turns on / off the bidirectional switch 7 with respect to the supplied power.

5 is an example diagram showing a relationship between a commercial power supply phase and an output DC voltage of the refrigerator shown in FIG. 1. FIG.

6 is a diagram showing the relationship between the magnitude of the effective value of the voltage output from the converter circuit of the control device for the refrigerator shown in FIG. 1 and the command rotational speed output from the inverter.

FIG. 7 is a circuit block diagram showing a configuration of a modified example of the control device for the refrigerator shown in FIG.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Commercial power supply, 2 ... Common mode filter circuit, 3 ... Normal mode filter circuit rearqua (power factor improving reactor), 4 ... Normal mode filter circuit capacitor, 5 ... Rectifying bridge diode, 7 ... Bidirectional switch , 8, 9 ... Smoothing capacitors, 10, 11 ... DC voltage detection resistors, 12 ... DC current detection resistors, 13-18 ... Semiconductor switching elements forming inverter bridge, 1
9 to 24 ... Reflux diode forming inverter bridge, 25 ... Inverter circuit, 26 ... Driver, 27 ... DC electric motor (DC brushless motor), 28 ... Compressor, 29
... 34 ... Resistance for detecting motor terminal voltage of DC motor, 35
... Comparator for creating rotor magnetic pole position detection signal, 36 ... First microcomputer, 37 ... Phase detector, 38 ... External semiconductor memory element, 39 ... Insulation element, 40 ... Forced operation signal input terminal, 41 ... Board, 42 ~ 44 ... Fan motor, 4
5 ... Driver, 46-49 ... Sensor for detecting temperature, 5
0 ... driver, 51 ... damper, 52 ... driver, 53 ...
Automatic ice maker, 54 ... Driver, 55-58 ... Heater, 5
9 ... Second microcomputer, 60 ... Control DC power supply circuit, 61 ... Converter circuit, 62 ... Microcomputer, 63-72 ... Insulation element,

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Yuutaka Takakura             800 Tomita, Ohira-cho, Shimotsuga-gun, Tochigi             Hitachi Co., Ltd., Cooling & Heat Division (72) Inventor Koji Murayama             800 Tomita, Ohira-cho, Shimotsuga-gun, Tochigi             Hitachi Co., Ltd., Cooling & Heat Division F term (reference) 3L045 AA02 BA01 CA02 DA02 EA01                       LA06 MA20 NA19 PA01 PA02                       PA04 PA06                 5H006 BB05 CA07 CB01 CB04 DA04                       DC05                 5H007 BB06 CA01 CB05 CC01 DA06                       DB01 DB12 DC05 EA02                 5H560 AA02 BB04 DA13 DB13 EB01                       GG04 JJ06 RR10 SS06 TT08                       TT15 UA02 XA03 XA12

Claims (7)

[Claims] 1. A rectifier circuit in which a plurality of diodes are bridge-connected to rectify an alternating current, a smoothing capacitor connected in parallel to the direct current side of the rectifier circuit, and a capacitor connected in series, and an inverter connected in parallel to the smoothing capacitor. And a motor controller including a motor to which drive power is supplied from the inverter, in a full-wave rectification mode in which the output DC voltage of the rectifier circuit is applied to both ends of the smoothing capacitor, and the output DC voltage of the rectifier circuit. A voltage doubler mode for alternately applying to the capacitor which is a component of the smoothing capacitor, and a voltage across the smoothing capacitor and the voltage doubler mode in the full-wave rectification mode based on the deviation between the speed command and the actual speed of the electric motor. And a function for generating a voltage between the voltage across the smoothing capacitor. 2. A rectifier circuit in which a plurality of diodes are bridge-connected to rectify an alternating current, a smoothing capacitor connected in parallel to the direct current side of the rectifier circuit, and a capacitor connected in series, and an inverter connected in parallel to the smoothing capacitor. And a motor control device including a motor to which driving power is supplied from the inverter, a bidirectional switch provided between one line on the AC side of the rectifying circuit and a series connection point of the smoothing capacitors. A motor control device having a function of controlling a phase in an AC voltage for turning on a bidirectional switch based on a deviation between a speed command of the motor and an actual speed. 3. A rectifier circuit in which a plurality of diodes are bridge-connected to rectify an alternating current, a smoothing capacitor connected in parallel to the direct current side of the rectifier circuit, and a capacitor connected in series, and an inverter connected in parallel to the smoothing capacitor. And a motor control device including a motor to which driving power is supplied from the inverter, a bidirectional switch provided between one line on the AC side of the rectifying circuit and a series connection point of the smoothing capacitors. A first operation mode for controlling the pulse width of the inverter based on the deviation between the speed command of the electric motor and the actual speed, and a phase in the AC voltage for turning on the bidirectional switch based on the deviation between the speed command of the electric motor and the actual speed And a second operation mode for controlling the motor. 4. A rectifier circuit in which a plurality of diodes are bridge-connected to rectify an alternating current, a smoothing capacitor connected in parallel to the direct current side of the rectifier circuit, and a capacitor connected in series, and an inverter connected in parallel to the smoothing capacitor. And a motor control device including a motor to which driving power is supplied from the inverter, a bidirectional switch provided between one line on the AC side of the rectifying circuit and a series connection point of the smoothing capacitors. A first operation mode for controlling the pulse width of the inverter based on the deviation between the speed command of the electric motor and the actual speed, and a phase in the AC voltage for turning on the bidirectional switch based on the deviation between the speed command of the electric motor and the actual speed And a second operation mode for controlling the pulse width, and switching from the first operation mode to the second operation mode is performed based on the pulse width. , Motor control device of the switching with the function of performing, based on the phase from the second operation mode to the first mode of operation. 5. A rectifier circuit in which a plurality of diodes are bridge-connected to rectify an alternating current, a smoothing capacitor connected in parallel to the direct current side of the rectifier circuit, and a capacitor connected in series, and an inverter connected in parallel to the smoothing capacitor. And a motor supplied with drive power from the inverter, in a motor control device, which is provided between one line on the AC side of the rectifier circuit and a series connection point of the smoothing capacitors, and has an ON voltage applied to the gate electrode. An element that is turned off when the terminals are electrically connected and current stops flowing between the terminals, and a function that controls the phase in the AC voltage that turns on the bidirectional switch based on the deviation between the speed command of the motor and the actual speed. An electric motor control device. 6. A rectifier circuit in which a plurality of diodes are bridge-connected to rectify an alternating current, a smoothing capacitor connected in parallel to the direct current side of the rectifier circuit, and a capacitor connected in series, and an inverter connected in parallel to the smoothing capacitor. And a motor supplied with drive power from the inverter, in a motor control device, which is provided between one line on the AC side of the rectifier circuit and a series connection point of the smoothing capacitors, and has an ON voltage applied to the gate electrode. The element that turns off when the terminals are electrically connected to each other and current stops flowing between the terminals, and the first operation mode that controls the pulse width of the inverter based on the deviation between the speed command and the actual speed of the motor and the motor. A second operation mode for controlling the phase in the alternating voltage that turns on the bidirectional switch based on the deviation between the speed command and the actual speed is provided. Motivation control device. 7. A rectifier circuit in which a plurality of diodes are bridge-connected to rectify an alternating current, a smoothing capacitor connected in parallel to the direct current side of the rectifier circuit, and a capacitor connected in series, and an inverter connected in parallel to the smoothing capacitor. And a motor supplied with drive power from the inverter, in a motor control device, which is provided between one line on the AC side of the rectifier circuit and a series connection point of the smoothing capacitors, and has an ON voltage applied to the gate electrode. The element that turns off when the terminals are electrically connected to each other and current stops flowing between the terminals, and the first operation mode that controls the pulse width of the inverter based on the deviation between the speed command and the actual speed of the motor and the motor. It has a second operation mode for controlling the phase in the AC voltage that turns on the bidirectional switch based on the deviation between the speed command and the actual speed, A motor control device having a function of switching from one operating mode to a second operating mode based on the pulse width, and switching from a second operating mode to a first operating mode based on the phase .