JP2001178177A - Motor drive apparatus and air conditioner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To operate an air conditioner with high efficiency by reducing the loss in the inverter circuit and the chopper circuit of a motor drive apparatus. SOLUTION: A rectifier circuit 1, which converts the alternating current of a commercial power supply into a direct current, is provided. A filter circuit 3 which filters the direct current is provided. An inverter circuit 4, which converts the filtered direct current into an alternating current with an arbitrary frequency and which comprises a frequency control means used to supply electric power to a motor is provided. A power storage means, which supplies secondary power to the filter circuit 3 and which comprises a voltage control means (a converter circuit 8), is provided. A DC power-supply voltage is stepped up to an arbitrary voltage by the electricity storage means, electric power is supplied to the inverter circuit 4, AC electric power with an arbitrary frequency is supplied to the motor by the inverter circuit 4, and the speed of the motor is controlled variably.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a motor drive device and an air conditioner, and more particularly to a motor drive device and an air conditioner that receive power from a secondary battery.

[0002]

2. Description of the Related Art As an air conditioner, a storage type air conditioner which receives power from a secondary battery (storage battery) charged with nighttime power for effective use of nighttime power is known. A power storage type air conditioner is disclosed, for example, in Japanese Patent Laid-Open No. 11-75328. The electric motor driving device of the power storage type air conditioner will be described with reference to FIG. The electric motor drive device of the power storage type air conditioner includes a power conversion unit 100, a converter drive circuit 110, an inverter drive circuit 120, and a secondary battery unit 200.
And a control unit 300 for supplying power to the induction motor 500 for driving the compressor. Induction motor 50
Reference numeral 0 denotes a load that drives the compressor by receiving control power output from an inverter circuit 105 described later, and controls the number of revolutions.

[0003] The power conversion unit 100 includes a reactor 101.
And a converter unit 104 including a rectifying circuit 102 and a smoothing circuit 103, and an inverter circuit 105 including a transistor module including a switching element. Power conversion section 100 supplies AC power from commercial power supply 400 to reactor 101 via breaker 401, current transformer 402 for detecting input current, and main electromagnetic relay 403.

The secondary battery unit 200 includes a storage battery 201.
, A charging electromagnetic relay 202, and a charging constant current source 20.
3 and a discharge circuit 206 including a voltage converter 204 and a DC switch 205. The control unit 300 includes a voltage detection unit 301, a voltage command unit 302, and a converter control unit 3
03 and a remote controller 310
And an air conditioning controller 305 to which a signal is given.

When the main electromagnetic relay 403 is closed,
The alternating current of the commercial power supply 400 is supplied to the rectifier circuit 102 via the reactor 101 and is converted into direct current.
The signal is smoothed at 3 and input to the inverter circuit 105.
Inverter drive circuit 120 is used for air conditioning controller 30
On / off control of the switching element of the inverter circuit 105 is performed so that the rotation speed of the electric motor 500 becomes the command rotation speed in response to the rotation speed command from the control unit 5. As a result, control power that is AC power of a predetermined frequency is output from inverter circuit 105. The air conditioning operation is performed by controlling the rotation speed of the electric motor 500 together with the operation of the actuator required for the air conditioner when an operation command from the remote controller 310 is input to the air conditioning controller 305.

[0006] The converter unit 104 has a PWM (Puls
The DC voltage of the smoothing circuit 103 is raised and lowered by an operation according to an e Width Modulation control method. The step-up and step-down of the DC voltage is performed by issuing a command from the voltage command unit 302 to the converter control unit 303, monitoring the smoothed voltage by the voltage detection unit 301, and driving the transistor of the converter unit 104 by the converter drive circuit 110. Controlled by value. Converter section 104 boosts the voltage to a DC voltage required for driving motor 500, converts the voltage to an arbitrary frequency and an AC voltage by inverter circuit 105, and drives motor 500.

To charge the storage battery 201, the charging electromagnetic relay 202 is closed, and the commercial power 400
Is reduced to a DC voltage required for charging the storage battery 201, and is performed by the operation of a constant current source. Discharge from the storage battery 201 is performed during air-conditioning operation. When an operation command from the remote controller 310 is input to the air conditioning controller 305, the DC switch 205 is closed, the secondary power of the storage battery 201 is boosted to a required voltage by the voltage converter 204, and input to the inverter circuit 105. Thereafter, the air-conditioning controller 305 performs a normal air-conditioning operation.

[0008]

In the above-described conventional motor driving device, when the air conditioner has a high output, for example, during rapid heating or rapid cooling, commercial power is supplied to the smoothing circuit 103 and the rectifying circuit 102. With the rectified and smoothed DC voltage, the power supplied to the compressor may be insufficient, and when the air conditioner is at high output, the power supply from the commercial power supply is large, and the reactor in the power supply system and the outdoor unit Is large, and the smoothing circuit 103
However, there is a problem that the DC voltage of the device becomes low.

[0009] In the air-conditioning operation when the commercial power supply is abnormally lowered or during a power failure, it is necessary to supply power from the storage battery 201 to the compressor 500.
The voltage of the storage battery 201 is once boosted by a voltage converter (boost circuit) 204 to supply power to the smoothing circuit 103, and the inverter circuit 105 controls the DC voltage of the smoothing circuit 103 by PWM control to drive the compressor 500. Since the voltage is reduced and supplied, the efficiency of the power conversion circuit including the voltage converter 204 and the inverter circuit 105 is low, and the inverter circuit 105 performs a large number of switching operations by PWM control, thereby increasing the switching loss. By doing so, the conversion efficiency has deteriorated. For this reason, the storage battery 20
There is a problem that the air-conditioning operation time using the method No. 1 is shortened.

[0010] In addition, in order to perform the air-conditioning operation by the storage battery 201 for a long time when the commercial power supply is abnormally lowered or the power failure occurs, it is necessary to connect the storage battery cells in parallel to increase the storage battery capacity, and the volume and cost are greatly reduced. There were issues such as an increase. Further, in order to improve the efficiency of the charging / discharging circuit connected between the storage battery 201 and the smoothing circuit 103, it is necessary to increase the storage battery output voltage to approach the voltage of the smoothing circuit 103,
For this purpose, it is necessary to connect many battery cells in series,
There were problems such as a large increase in volume and cost.

In the conventional motor driving device, the leakage current from the motor 500 is reduced by the increase in the output pulse voltage and the number of switching times of the inverter circuit 105, the winding structure of the motor 500, and the refrigerant used in the air conditioner. There were issues such as an increase. The electric motor 5
When an induction motor is used as 00, there is a problem that vibration due to current distortion increases and noise of the motor driving device, the compressor, and the air conditioner increases.

Further, in the conventional motor drive device, when the commercial power supply abnormally drops or the power failure occurs, the air conditioner needs to reduce the air conditioning capacity in order to operate the air conditioner for a long time. There is a problem that it cannot be made to recognize that it is an air-conditioning operation by supply.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and can increase the output of a motor by increasing the voltage of a storage battery to a DC bus voltage value or more, thereby increasing the output of a motor. By reducing the number of operations and the motor current, it is possible to reduce the loss in the circuit and the motor and the loss in the chopper circuit, to improve the efficiency of the device, and to reduce the storage battery without requiring many battery cells. It is an object of the present invention to obtain an electric motor drive device and an air conditioner that can extend the operation time using the motor and can operate with low noise.

[0014]

In order to achieve the above-mentioned object, a motor driving apparatus according to the present invention comprises a rectifier circuit for converting AC of a commercial power supply into DC, a smoothing circuit for smoothing DC, and a smoothing circuit for smoothing DC. An inverter circuit having frequency control means for converting a direct current into an alternating current of an arbitrary frequency and supplying electric power to the motor; and a power storage means having a voltage control means for supplying a secondary power supply to the smoothing circuit. The DC power supply voltage is boosted to an arbitrary voltage to supply power to an inverter circuit, and the inverter circuit supplies AC power of an arbitrary frequency and voltage to a motor to perform variable speed control.

A motor driving device according to the next invention provides a power supply to an inverter circuit by boosting a DC power supply voltage to a voltage value obtained by rectifying a commercial power supply by the power storage means, and supplying power to the inverter circuit. The variable speed control is performed by supplying AC power of an arbitrary frequency to the electric motor.

A motor drive device according to the next invention selectively stops a voltage control function of the power storage means to supply power to the inverter circuit, performs PWM control in the inverter circuit, and controls a desired frequency and voltage. Is supplied to the electric motor to perform variable speed control.

A motor drive device according to the next invention is one in which the operation / stop switching of the voltage control function by the power storage means is performed based on the output of the motor, and the switching is provided with hysteresis.

A motor driving apparatus according to the next invention has a power supply voltage detecting means for detecting a voltage value of a commercial power supply, and operates when a power supply voltage detected by the power supply voltage detecting means is equal to or lower than a predetermined value.

The motor drive device according to the next invention is to output a signal and display when the power supply voltage detected by the power supply voltage detecting means is equal to or lower than a predetermined value.

In the electric motor driving device according to the next invention, the electric motor is a DC brushless motor.

In the motor driving device according to the next invention, the motor is a DC brushless motor using a concentrated winding stator.

In the motor driving device according to the next invention, when the motor is stopped, the voltage control function of the power storage means is stopped to supply power to a low load.

A motor drive device according to the next invention is a motor for a compressor in which the motor is mounted on a refrigeration / air conditioner.

[0024] An air conditioner according to the next invention has the motor drive device according to the above invention, and the drive of the compressor motor is controlled by the motor drive device.

In the air conditioner according to the next invention, the refrigerant is H
The FC-based refrigerant is used.

[0026]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing an embodiment of a motor driving apparatus and an air conditioner according to the present invention.

FIG. 1 shows an embodiment of a motor driving device according to the present invention. In particular, as a motor driving device mounted on an air conditioner, a secondary motor is used to convert a motor of a compressor into an inverter. FIG. 3 is a circuit block diagram for driving. This motor drive device is mounted on an outdoor unit of an air conditioner.

The motor driving apparatus according to the present invention includes a rectifier circuit 1 composed of a diode, a power factor improving reactor 2 for shaping an output waveform of the rectifier circuit 1, a smoothing circuit 3 for smoothing a DC voltage, and an inverter circuit 4. A bus voltage detecting circuit 5 for detecting voltages at both ends of the smoothing circuit 3, an inverter control circuit 6, a storage battery 7, a converter circuit (voltage control means) 8 on the storage battery side, a converter control circuit 9, a DC switch 10, a storage battery voltage detection circuit 11 for detecting a voltage between both ends of the storage battery 7, a motor control circuit 12, and an indicator 13. The compressor receives a power supply from a commercial power supply 60 as a primary power supply. The power supplied to the driving motor 50 is controlled. The electric motor 50 can be constituted by a DC-brushless motor using a concentrated winding stator.

The inverter circuit 4 includes a MOSFET, an IG
It is composed of a switching element such as a BT or a bipolar transistor and a diode, and is connected to the smoothing circuit 3 to receive supply of DC power. Storage battery 7 is 1
It is configured by connecting the battery cells in series. For example, 1
Assuming that the output voltage of the battery cells is 4 (V), a storage battery 7 having 108 (V) output can be obtained by connecting 27 cells in series.
The converter circuit 8 includes a transistor, a diode, and a reactor, is connected to the storage battery 7, and is connected to the smoothing circuit 3 via the DC switch 10.
The drive signal output from the converter control circuit 9 is input.
The motor control circuit 12 inputs the output signals of the bus voltage detection circuit 5 and the storage battery voltage detection circuit 11 and outputs command signals to the converter control circuit 9 and the inverter control circuit 6.

In the motor driving device having the above-described configuration, the AC commercial power supply 60 is converted into DC by the rectifier circuit 1,
After the waveform is shaped by the power factor improving reactor 2, the smoothing circuit 3 smoothes the waveform to a DC voltage with little pulsating flow. The inverter circuit 4 modulates a DC voltage by a drive signal from the inverter control circuit 6, and modulates a fundamental wave voltage of a PWM control method at a high carrier frequency, as shown in FIG. The motor 50 is converted to an arbitrary frequency and an AC voltage, and is driven at a variable speed. Motor 50 is D
In the case of the C-brushless motor, the inverter control circuit 6 calculates the position of the magnetic pole of the rotor from the induced voltage of the DC-brushless motor, sets the energization timing, and controls the switching elements of the inverter circuit 4 to turn on and off the motor 50. The rotation speed control is performed so as to match the target rotation speed.

The converter circuit 8 is a bidirectional chopper circuit for controlling the output DC voltage by the operation of the switching element such as a transistor by the operation of accumulating and releasing the energy of the reactor 2. And a discharging operation in which the direct current of the storage battery 7 is boosted to a voltage necessary for driving the electric motor 50 by the inverter circuit 4 and discharged to the smoothing circuit 3.

Next, the charging operation of the storage battery 7 will be described. When a charge command is input to the motor control circuit 12,
The DC switch 10 is turned on, and the target voltage value command is output from the motor control circuit 12 to the converter control circuit 9. The converter control circuit 9 performs an operation of storing energy in the reactor and releasing energy from the reactor by driving a switching element of the converter circuit 8. The on / off of the switching element of the converter circuit 8 is controlled so that the DC bus voltage value matches the target voltage suitable for charging the storage battery 7 while the storage battery voltage detection circuit 11 detects the storage battery voltage. The storage battery 7 is charged using an inexpensive time zone such as midnight power.

FIG. 3 shows the relationship between the DC bus voltage Vdc and the duty ratio D of the inverter with respect to the air conditioning load (rotational speed of the electric motor). Vbat is a DC bus voltage (for example, 108 V) when the voltage of the storage battery 7 is directly supplied to the smoothing circuit 3.
V) and Vmax are the DC bus voltage upper limit (for example, 350 V) when the voltage of the storage battery 7 is boosted by the converter circuit 8 and supplied to the smoothing circuit 3. PWM control is performed when the air conditioner is under a low load (low-speed rotation of the motor 50), and PAM (Pulse is performed when the load is high (the high-speed rotation of the motor 50).
The motor is operated under Amplitude Modulation control. At the time of the switching operation between the operation and the stop of the converter circuit 8, although not shown, a hysteresis is provided for the duty ratio D or the DC bus voltage Vdc of the inverter to prevent unstable operation of the device due to frequent switching operation. I have.
FIG. 2B shows an output voltage waveform of the inverter based on the PAM control method.

FIG. 4 shows average voltage and current waveforms during PWM control of induction motor driving. The voltage applied to the induction motor is a high-frequency rectangular wave (FIG. 2A).
Since the current waveform does not include a low-order harmonic component, torque ripple is small and driving with low vibration can be performed.

FIG. 5 shows voltage and current waveforms during the PAM control of the induction motor drive. Since the voltage applied to the induction motor is a low-frequency rectangular wave, the current waveform includes a low-order harmonic component, the torque ripple is large, and the vibration of the motor is large.

The above-described motor driving device can be operated when the power supply voltage detected by the bus voltage detection circuit 5 is equal to or lower than a predetermined value. At this time, a signal notifying this is output and the display 13 is displayed.

FIG. 6 shows a refrigeration cycle device such as an air conditioner to which the motor driving device according to the present invention is applied. The refrigeration cycle apparatus includes a compressor 20, an outdoor heat exchanger 21, an indoor heat exchanger 22, a capillary tube 23 for throttling,
The compressor 20 includes an accumulator 24, a four-way valve 25, and a refrigerant pipe 26 for connecting these components. The compressor 20 is driven by the electric motor 50 described above.

With respect to the operation of the refrigeration cycle apparatus such as an air conditioner, the operation of the refrigeration cycle apparatus during cooling will be described. The arrows in the figure indicate the direction in which the refrigerant flows. The refrigerant is compressed by the compressor 21 to become a high-temperature and high-pressure gaseous refrigerant, guided to the outdoor heat exchanger (condenser) 21 through the four-way valve 25, and then outdoor by the outdoor heat exchanger (condenser) 21. , And is cooled by the outside air and converted into a high-pressure liquid refrigerant.

The high-pressure liquid refrigerant converted by the outdoor heat exchanger (condenser) 21 passes through the capillary tube 23 to become a low-pressure liquid refrigerant, and the indoor heat exchanger (evaporator) 22 operates as a cooler during cooling. And heat exchange with room air to cool the room. As a result, the refrigerant liquid is heated and becomes a two-phase refrigerant close to a low-pressure gas. The two-phase refrigerant flows into the accumulator 24 through the four-way valve 25. Here, the capacity of the refrigeration cycle can be made variable in proportion to the rotation speed of the electric motor 50 built in the compressor 20. Although the cooling operation has been described here, the heating operation can be performed by switching the four-way valve 25.

Therefore, when an operation command of the air conditioner is input to the motor control circuit 12 shown in FIG. 1, a rotation speed command value is output to the inverter control circuit 6, and an actuator (necessary for the air conditioner) is output. The motor 50 is controlled so as to match the rotation speed command value together with the operation of the refrigerant circuit (not shown).

Next, the operation of performing the air conditioning operation using the commercial power supply 60 and the secondary power supply of the storage battery 7 will be described. When an air-conditioning operation command is input to the motor control circuit 12, the DC switch 10 is turned on, and the motor control circuit 12 outputs a target voltage value command to the converter control circuit 9. The converter control circuit 9 drives the switching element of the converter circuit 8 to detect the bus voltage by the bus voltage detection circuit 5, and to store the energy in the reactor and release the energy from the reactor, the voltage of the storage battery 7 is increased. Of the switching element of the converter circuit 8 is controlled so as to match the target DC bus voltage value. The electric power of the storage battery 7 is supplied to the smoothing circuit 3, and the electric power is supplied to the electric motor 50 by the PWM drive of the inverter circuit 4.
It also supplies power to circuits required for air conditioners.

Since the air conditioner uses the secondary power supply of the storage battery 7, a peak cut operation in which the storage battery 7 is charged with electric power at night and the air conditioning operation is performed only by the secondary power from the storage battery 7 during a predetermined time period in the daytime. Alternatively, any of the peak shift operation in which the air conditioning operation is performed from the commercial power source 60 and the secondary power of the storage battery 7 during a predetermined time period in the daytime is possible.

Next, an operation of performing an air-conditioning operation using only the secondary power supply of the storage battery 7 will be described. Storage battery 7-2
As a method of using only the secondary power supply, the voltage of the storage battery 7 is increased to a DC bus voltage value obtained by rectifying the commercial power supply 60 or higher, and the voltage of the storage battery 7 is reduced when the power supply voltage of the commercial power supply 60 is reduced or the power failure occurs. May be used.

When the voltage of the storage battery 7 is boosted to a value equal to or higher than the DC bus voltage obtained by rectifying the commercial power supply 60, the inverter circuit 4 does not perform PWM control, but sets the voltage by the converter circuit 8 and sets the frequency by the inverter circuit. P set in 4
The rotation speed of the electric motor 50 is controlled by the AM control. The output voltage waveform of the inverter circuit 4 at this time is shown in FIG. The basic operation such as the converter circuit 8 after the input of the air-conditioning operation command to the motor control circuit 12 is the same as described above. In addition to the above case, the user of the air conditioner may forcibly perform the air-conditioning operation using only the secondary power supply of the storage battery 7. If there is no problem such as a leakage current, the inverter circuit 4 may perform PWM control.

In the air-conditioning operation of the commercial power supply 60 when the power supply voltage drops or the power failure occurs, the power failure of the commercial power supply 60 is detected by the bus voltage detection circuit 5 and the rotation speed of the motor 50 is controlled. After inputting the air-conditioning operation command to the motor control circuit 12,
The DC switch 10 is closed. At this time, if the load on the air conditioner (motor 50) is small, the converter circuit 8
Are turned on continuously, and are electrically connected to the smoothing circuit 3, and the inverter circuit 4 performs PWM control.
The motor 50 is controlled to a desired target rotation speed. When the load on the air conditioner (motor 50) increases and the voltage applied to the motor 50 needs to be equal to or higher than the voltage of the storage battery 7, the output voltage is controlled by the converter circuit 8, and the output frequency is controlled by the inverter circuit 4. The number of revolutions of the electric motor 50 is controlled by the PAM control to be controlled.

When the commercial power supply 60 is cut off during the air-conditioning operation and the high-load motor 50 is stopped, the DC switch 10 is closed and the switching element of the converter circuit 8 is turned on continuously to connect the storage battery 7 with the storage battery 7. The smoothing circuit 3 is electrically connected. At this time, electric power for operating a low load such as a fan motor connected to the smoothing circuit 3 is supplied from the storage battery 7.

Here, in the PWM control, since the switching element of the inverter circuit 4 operates at a high frequency, a low-order harmonic component close to a fundamental frequency component is suppressed, and the low-order harmonic generated when the motor 50 is driven is suppressed. Since the torque ripple can be removed, the vibration of the electric motor 50 can be suppressed. However, since the switching element is operated many times, the loss due to switching increases. In addition, leakage current from the electric motor 50 and the air conditioner also increases, and the cost of countermeasures increases.

On the other hand, in the PAM control, the switching element of the inverter circuit 4 is not operated at a high frequency, so that the switching loss can be reduced and the leakage current from the motor 50 can be reduced. When the motor 50 is a DC-brushless motor, there is no particular problem such as vibration and noise, but when the motor 50 is an induction motor, the current waveform includes torque ripple due to low-order harmonics as shown in FIG. Because
The vibration and noise of the electric motor 50 increase. Therefore, the vibration and noise of the air conditioner also increase, and the cost of materials such as soundproofing materials is added or increased as a measure.

As for the refrigerant used in the air conditioner, the HCFC system, which has been conventionally used, is being switched to the HFC system in consideration of the environment. The electric motor 50 mounted on the compressor 20 is immersed in the refrigerant, and the leakage current tends to increase when switching to the HFC-based refrigerant. However, the motor 50
Uses a stator with concentrated winding.
The stray capacity between the winding and the compressor shell is smaller than that of the distributed winding stator, and the leakage current can be reduced when the HFC-based refrigerant is used when the motor is driven.

[0050]

As can be understood from the above description, according to the motor driving apparatus of the present invention, the DC power supply voltage is boosted to an arbitrary voltage by the power storage means, and power is supplied to the inverter circuit. The AC power of any frequency is supplied to the motor to perform variable speed control, so it is possible to increase the output of the motor by boosting the voltage of the storage battery to a DC bus voltage value obtained by rectifying the commercial power supply Becomes

According to the motor drive device of the next invention, the DC power supply voltage is boosted to a voltage value obtained by rectifying the commercial power supply by the power storage means, and power is supplied to the inverter circuit. Since variable speed control is performed by supplying AC power of an arbitrary frequency to the motor, the number of operations of the switching elements of the inverter circuit and the motor current can be reduced to reduce the loss occurring in the circuit and the motor, and Efficiency can be improved. Further, it is possible to extend the operation time of the device using the storage battery without increasing the capacity of the storage battery. Further, since the number of times of switching in the inverter circuit is reduced, leakage current from the motor is also reduced.

According to the motor drive device of the next invention, the voltage control function of the power storage means is selectively stopped to supply power to the inverter circuit. The power supply to the inverter circuit from the commercial power supply that performs variable speed control by supplying AC power to the motor is stopped, the storage battery and the smoothing circuit are electrically connected without chopper control, and the inverter circuit connects to the motor. Variable speed control can be performed by converting to the required voltage and frequency, and the loss of the chopper circuit can be reduced.

According to the motor driving device of the next invention, the switching of the operation of the voltage control function by the power storage means is performed based on the output of the motor, and the switching is provided with hysteresis. It is possible to prevent unstable operation of the control accompanying the switching.

According to the motor driving device of the present invention, the motor operates when the power supply voltage detected by the power supply voltage detecting means is equal to or lower than the predetermined value. Becomes possible.

According to the motor driving device of the present invention, when the power supply voltage detected by the power supply voltage detecting means is equal to or lower than a predetermined value, a signal is output and displayed to notify the user of the power supply voltage. Or, in the event of a power failure such as a power outage, it can be notified that the operation is performed by secondary power supply from the storage battery, and it is possible to reduce the output of the device and operate it for a long time. Can be avoided.

According to the motor driving device of the next invention, since the DC-brushless motor is used as the motor, the vibration of the motor during the PAM control can be reduced, and the operating noise can be reduced.

According to the motor driving device of the next invention, since the DC brushless motor using the concentrated winding stator is used as the motor, the capacitance between the winding of the motor and the outer casing of the compressor can be reduced, and the leakage current can be reduced. It is possible to reduce it.

According to the motor driving device of the next invention, when the motor is stopped, the voltage control function of the power storage means is stopped to supply power to a low load, so that the electric power can be supplied without chopper control between the storage battery and the smoothing circuit. Can be connected to drive a fan motor or an actuator, the loss of the chopper circuit can be reduced, and high efficiency and energy saving can be achieved. In addition, the secondary power of the storage battery can be extracted to the maximum, and the storage battery can be used effectively.

According to the motor driving device of the next invention, since the motor is a compressor motor mounted on a refrigeration / air conditioner, it is possible to increase the compressor output during rapid heating or rapid cooling. As a result, the capacity of the air conditioner can be increased and energy can be saved. In addition, since the efficiency of the air conditioner can be improved, long-term operation using the storage battery is possible, and leakage current from the air conditioner can be reduced.

According to the air conditioner of the next invention, since the drive of the compressor motor is controlled by the motor drive device of the above invention, the output of the compressor can be increased during rapid heating or rapid cooling. Thus, the capacity of the air conditioner can be increased and energy can be saved.

According to the air conditioner of the next invention, H
Since the FC-based refrigerant is used, the ozone layer can be prevented from being destroyed.

[Brief description of the drawings]

FIG. 1 is a circuit block diagram showing one embodiment of a motor driving device according to the present invention.

FIGS. 2A and 2B are diagrams showing voltage waveforms of PWM control and PAM control.

FIG. 3 is a graph showing a relationship between a DC bus voltage and a duty ratio of an inverter circuit with respect to an air conditioning load (rotation speed).

FIG. 4 is a diagram showing voltage and current waveforms of an induction motor under PWM control.

FIG. 5 is a diagram showing voltage and current waveforms of an induction motor under PAM control.

FIG. 6 is a block diagram illustrating a configuration of a refrigeration cycle device.

FIG. 7 is a block diagram showing a circuit configuration of a conventional motor driving device.

[Explanation of symbols]

1 rectifier circuit, 3 smoothing circuit, 4 inverter circuit, 5
Bus voltage detection circuit, 6 inverter control circuit, 7 storage battery, 8 converter circuit, 9 converter control circuit,
Reference Signs List 10 DC switch, 11 Battery voltage detection circuit, 12
Motor control circuit, 13 display, 50 motor, 60
Commercial power supply.

Continued on the front page (72) Inventor Shinya Nishida 2-3-2 Marunouchi, Chiyoda-ku, Tokyo Mitsubishi Electric Corporation F-term (reference) 3L061 BA07 5H007 BB05 BB06 CA01 CC23 DA03 DC05 EA01 EA02 5H560 AA01 AA02 BB04 BB12 DA13 DC13 EB01 EC01 EC02 EC07 EC10 JJ20 RR01 RR10 TT20 UA03 UA05 UA06 XA08 XA11 XA12 5H576 AA09 AA10 BB02 BB04 BB05 BB06 CC05 DD02 DD07 EE11 EE18 EE30 GG07 HA02 HA03 HA04 HB02 MM10 MM09 LL09

Claims (12)

[Claims] 1. A rectifier circuit for converting an alternating current of a commercial power supply into a direct current, a smoothing circuit for smoothing the direct current, and frequency control means for converting the smoothed direct current into an alternating current of an arbitrary frequency and supplying power to the electric motor. An inverter circuit, and power storage means having voltage control means for supplying a secondary power supply to the smoothing circuit, wherein the power storage means boosts a DC power supply voltage to an arbitrary voltage to supply power to the inverter circuit, An electric motor drive device characterized in that an inverter circuit supplies AC electric power of an arbitrary frequency and voltage to the electric motor to perform variable speed control. 2. The method according to claim 1, wherein said power storage means boosts a DC power supply voltage to a voltage value obtained by rectifying a commercial power supply and supplies power to an inverter circuit. The electric motor drive device according to claim 1, wherein the electric motor is supplied to the electric motor to perform variable speed control. 3. A power supply to the inverter circuit by selectively stopping a voltage control function of the power storage means,
2. The motor drive device according to claim 1, wherein the inverter circuit supplies AC power of an arbitrary frequency and voltage to the motor to perform variable speed control. 4. The motor driving device according to claim 2, wherein the switching of the operation of the voltage control function by the power storage means is performed based on the output of the motor, and the switching is provided with hysteresis. 5. The power supply according to claim 1, further comprising a power supply voltage detecting means for detecting a voltage value of a commercial power supply, wherein the apparatus operates when a power supply voltage detected by the power supply voltage detecting means is equal to or lower than a predetermined value. The electric motor drive device according to any one of the above. 6. The motor drive device according to claim 5, wherein when the power supply voltage detected by said power supply voltage detection means is equal to or lower than a predetermined value, a signal output and display for notifying the power supply are displayed. 7. The electric motor drive device according to claim 1, wherein the electric motor is a DC brushless motor. . 8. A DC motor using a concentrated winding stator.
The motor drive device according to claim 7, wherein the motor drive device is a brushless motor. 9. The motor driving device according to claim 1, wherein when the motor is stopped, the voltage control function of the power storage unit is stopped to supply power to a low load. 10. The motor according to claim 1, wherein the motor is a compressor motor mounted on a refrigeration / air conditioner.
The electric motor drive device according to any one of claims 9 to 9. 11. An air conditioner comprising the motor drive device according to claim 1, wherein the drive of the compressor motor is controlled by the motor drive device. 12. The air conditioner according to claim 11, wherein an HFC-based refrigerant is used as the refrigerant.