CN108736754B - Power conversion device and air conditioner - Google Patents
Power conversion device and air conditioner Download PDFInfo
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- CN108736754B CN108736754B CN201810348596.2A CN201810348596A CN108736754B CN 108736754 B CN108736754 B CN 108736754B CN 201810348596 A CN201810348596 A CN 201810348596A CN 108736754 B CN108736754 B CN 108736754B
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- 238000006243 chemical reaction Methods 0.000 title claims abstract description 24
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- 238000007906 compression Methods 0.000 description 4
- 238000009499 grossing Methods 0.000 description 4
- 238000012937 correction Methods 0.000 description 3
- 230000001360 synchronised effect Effects 0.000 description 3
- 230000006837 decompression Effects 0.000 description 2
- 239000004065 semiconductor Substances 0.000 description 2
- 239000003638 chemical reducing agent Substances 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 230000006698 induction Effects 0.000 description 1
- 230000010354 integration Effects 0.000 description 1
- WABPQHHGFIMREM-UHFFFAOYSA-N lead(0) Chemical compound [Pb] WABPQHHGFIMREM-UHFFFAOYSA-N 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M7/00—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output
- H02M7/42—Conversion of dc power input into ac power output without possibility of reversal
- H02M7/44—Conversion of dc power input into ac power output without possibility of reversal by static converters
- H02M7/48—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
- H02M7/53—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
- H02M7/537—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only, e.g. single switched pulse inverters
- H02M7/5387—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only, e.g. single switched pulse inverters in a bridge configuration
- H02M7/53871—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only, e.g. single switched pulse inverters in a bridge configuration with automatic control of output voltage or current
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
- H02P21/00—Arrangements or methods for the control of electric machines by vector control, e.g. by control of field orientation
- H02P21/22—Current control, e.g. using a current control loop
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
- H02P21/00—Arrangements or methods for the control of electric machines by vector control, e.g. by control of field orientation
- H02P21/24—Vector control not involving the use of rotor position or rotor speed sensors
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
- H02P27/00—Arrangements or methods for the control of AC motors characterised by the kind of supply voltage
- H02P27/04—Arrangements or methods for the control of AC motors characterised by the kind of supply voltage using variable-frequency supply voltage, e.g. inverter or converter supply voltage
- H02P27/06—Arrangements or methods for the control of AC motors characterised by the kind of supply voltage using variable-frequency supply voltage, e.g. inverter or converter supply voltage using dc to ac converters or inverters
- H02P27/08—Arrangements or methods for the control of AC motors characterised by the kind of supply voltage using variable-frequency supply voltage, e.g. inverter or converter supply voltage using dc to ac converters or inverters with pulse width modulation
- H02P27/085—Arrangements or methods for the control of AC motors characterised by the kind of supply voltage using variable-frequency supply voltage, e.g. inverter or converter supply voltage using dc to ac converters or inverters with pulse width modulation wherein the PWM mode is adapted on the running conditions of the motor, e.g. the switching frequency
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
- H02P2203/00—Indexing scheme relating to controlling arrangements characterised by the means for detecting the position of the rotor
- H02P2203/09—Motor speed determination based on the current and/or voltage without using a tachogenerator or a physical encoder
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- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Inverter Devices (AREA)
- Rectifiers (AREA)
- Control Of Ac Motors In General (AREA)
Abstract
The invention relates to a power conversion device and an air conditioner, comprising: a diode series circuit; a capacitor series circuit connected in parallel with the series circuit; a switch module having three switch leads, consisting of a single module, connected in parallel with the diode series circuit; an alternating voltage detector for detecting a voltage of a single-phase alternating current power supply connected to a common connection point of the 1 st lead and a common connection point of the diode series circuit; a current detector for detecting the current flowing through each switch lead; a direct current voltage detector for detecting a direct current voltage which is a terminal voltage of the diode series circuit; and a control unit that performs PWM control of the leads based on the current, the AC voltage, and the DC voltage, wherein the control unit performs switching control using the 1 st lead as a lead for power factor control, connects a common connection point of the 2 nd and 3 rd leads and a common connection point of the capacitor series circuit to a 3-phase load, and performs switching control using the 2 nd and 3 rd leads as a lead for load control.
Description
Technical Field
Embodiments of the present invention relate to a power conversion device that converts a commercial ac power supply into a dc power supply and then into an ac power supply, and an air conditioner that uses a motor driven by the ac power supply obtained by the power conversion device as a power source.
Background
For example, in order to drive an ac motor such as a permanent magnet synchronous motor, it is necessary to convert electric power obtained from a dc power supply into 3-phase ac electric power using a power converter such as an inverter. A system in which an inverter is mounted is equipped with a power supply device for obtaining dc power from a commercial ac power supply.
As a Power supply device for obtaining dc Power from ac Power, for example, as shown in fig. 9, a Power supply device including a diode rectifier circuit and a Power Factor Correction (Power Factor Correction) circuit is generally known. Hereinafter, the power factor correction circuit is referred to as a PFC circuit. The diode rectifier circuit rectifies the alternating-current voltage and converts the alternating-current voltage into direct-current voltage. Since the voltage rectified by the diode rectifier has a large amplitude variation as in the case of the ac voltage, a smoothing capacitor is connected to the output side to smooth the voltage.
When the smoothing capacitor is connected, the diode of the rectifier is turned on and operates only when the ac voltage is larger than the smoothing capacitor. Therefore, the current flowing from the ac power supply to the rectifier has a waveform with a low power factor, which exhibits an amplitude only in the vicinity of the peak of the ac voltage. Therefore, a PFC circuit is connected between a diode rectifier circuit and a smoothing capacitor to improve a power factor, and the obtained dc power is supplied to an inverter circuit to control a 3-phase ac current to drive a motor.
In the above configuration, a rectifier circuit and a PFC circuit are required to convert electric power from ac to dc, and an inverter circuit for converting electric power into 3-phase ac is also required, which has a problem of increasing the size and cost of the entire system.
On the other hand, as a configuration for realizing the miniaturization of the 3-phase inverter, for example, as disclosed in japanese patent application laid-open No. 2008-295161 in patent document 1, a V-junction inverter in which 1 phase of the 3 phases is connected to a neutral point of a dc voltage generated using a series capacitor or the like is proposed. Thus, the number of power devices required for the 3-phase inverter can be reduced from 6 to 4, and miniaturization can be achieved.
However, although the inverter circuit can be miniaturized by the V-junction inverter, further miniaturization is desired for the entire system including the conversion portion from the ac power supply to the dc power supply. In general, in an inverter having an ac power of 100V to 200V and an output of several kW or less, an ipm (intelligent power module) in which a plurality of power devices are integrated is often used. On the other hand, the rectifier circuit and the PFC circuit are formed of a plurality of discrete components, which hinders miniaturization.
Disclosure of Invention
Therefore, a power conversion device that can be miniaturized even including a conversion unit from an ac power supply to a dc power supply, and an air conditioner configured using the power conversion device are provided.
The power conversion device of the embodiment includes:
a diode series circuit composed of two diodes connected in series;
a capacitor series circuit including two capacitors connected in series and connected in parallel to the diode series circuit;
a switch module having three switch leads composed of six switching elements, composed of a single module, and connected in parallel to the diode series circuit;
an alternating-current voltage detector that detects a voltage of a single-phase alternating-current power supply connected to a common connection point of the 1 st lead wire, which is one of the three switching lead wires, and a common connection point of the diode series circuit;
a current detector for detecting the current flowing through each of the switch leads;
a dc voltage detector for detecting a dc voltage which is a terminal voltage of the diode series circuit; and
a control unit for performing PWM control of the switching of each switching element based on the current, the AC voltage, and the DC voltage,
the control part controls the switch of the 1 st lead as a lead for power factor control,
the common connection point of the 2 nd and 3 rd lead wires and the common connection point of the two capacitors, which are the other two switching leads, are connected to a 3-phase load, and the control unit performs switching control using the 2 nd and 3 rd lead wires as load control leads.
Drawings
Fig. 1 is a circuit configuration diagram of a motor control device including a power conversion device according to embodiment 1.
Fig. 2 is a functional block diagram showing the configuration of the control unit.
Fig. 3 is a functional block diagram showing the configuration of the 2-phase/3-phase conversion unit and the modulation unit.
Fig. 4 is a functional block diagram showing the configuration of the motor control unit.
Fig. 5 is a functional block diagram showing the configuration of the power factor control unit.
Fig. 6 is a diagram showing modulation ratios of the switching leads 8(2) and 8(3) and waveforms of 3-phase currents applied to the motor.
Fig. 7 is a diagram showing signal waveforms of respective portions in the power factor control unit.
Fig. 8 is a diagram showing the configuration of an air conditioner according to embodiment 2.
Fig. 9 is a diagram showing an example of a conventional power supply device for obtaining dc power from ac power.
Detailed Description
(embodiment 1)
Hereinafter, embodiment 1 will be described with reference to fig. 1 to 7. Fig. 1 is a circuit configuration diagram of a power conversion device or a motor drive device according to the present embodiment. The motor 1 as a load is, for example, a 3-phase permanent magnet synchronous motor, an induction motor, or the like. In the present embodiment, a permanent magnet synchronous motor is used for convenience. The ac power supply 2 is a single-phase 100V or 200V system.
Current detectors 10(1), 10(2), and 10(3) are connected in series to the source side of the lower FET7(-) of the leads 8(1), 8(2), and 8(3), respectively. The current detector 10 is, for example, a shunt resistor or a current sensor. That is, the power module 9 and the current detector 10 are connected in parallel to a series circuit of the diodes 3 and 4 and the capacitors 5 and 6.
One end of ac power supply 2 is connected to a common connection point of diodes 3 and 4 via reactor 11, and the other end of ac power supply 2 is connected to a common connection point of lead 8 (1). The common connection points of the capacitors 5 and 6 and the lead wires 8(2) and 8(3) are connected to one end of U, V, W-phase stator coils, not shown, of the motor 1.
A dc voltage detector 12 is connected in parallel to the series circuit of the diodes 3 and 4, and an ac voltage detector 13 is connected in parallel to the ac power supply 2. The dc voltage detector 12 detects a terminal voltage of the diode series circuit, and the ac voltage detector 2 detects a voltage of the ac power supply 2 and outputs the detected voltage to the control unit 14. Instead of the ac voltage detector 13, a detector that detects only the phase of the ac power supply or only the polarity of the ac power supply may be used.
The control unit 14 receives detection signals from the current detector 10 and the voltage detectors 12 and 13. Current detector 10(1) current I flowing through reactor 11ACThe current detectors 10(2) and 10(3) detect the V-phase and W-phase currents of the motor 1, respectively. Further, a speed command and a dc voltage command of the motor 1 are input to the control unit 14 from a higher-level control device not shown. The control unit 14 outputs the PWM signal as the drive signal to the gates of the upper and lower FETs 7(+), 7(-) constituting the leads 8(1), (8), (2), and 8(3) based on the input signals and the like. The lead 1, the lead 2, and the lead 3 shown in fig. 1 and the like mean leads 8(1), 8(2), and 8(3), respectively.
The control unit 14 includes a motor control unit 15 and a PFC control unit 16. The PFC controller 16 corresponds to a power factor controller. As shown in fig. 2, the motor control unit 15 controls the speed of the motor 1 and a speed command ω given from a system that drives the motor 1, for example, an air conditioner system or the likeRefAnd (5) the consistency is achieved. Further, the application to the air conditioner system will be described in detail in embodiment 2. The speed control unit 21 receives the speed command ωRefAnd a slave position estimating unit22 output estimated speed ω of motor 1cGenerating a q-axis current command IqRefAnd outputs the result to the current control unit 23.
The 3-phase/2-phase converter 24 first calculates the U-phase current by calculation on the basis of the V, W-phase currents detected by the current detectors 10(2) and 10(3) on the condition that the sum of the 3-phase currents is zero. Then, the 3-phase current is converted into currents Id, Iq of dq-axis coordinates for vector control. The current control unit 23 receives the dq-axis current command IdRef、IqRefAnd the currents Id and Iq generate and output dq-axis voltage commands Vd and Vq. The low-field control unit 25 generates the d-axis current command Id as a low-field currentRefAnd outputs the dq axis voltage commands Vd and Vq so as not to exceed the DC voltage VDC。
As shown in fig. 3, the 2-phase/3-phase converter 26 converts the dq-axis voltage commands Vd and Vq into 2-phase motor voltages V α and V β in the dq/αβ converter 26A, and converts the converted voltages into 2-phase motor voltages V α and V β in the dq/αβ converter 26A
In the converter 26B, the modulation control unit 27 for converting the voltages V α and V β into the motor voltage commands Vu, Vv, and Vw. of 3 phases first generates, from the 3-phase voltage commands Vu, Vv, and Vw, 2-phase voltage commands Vv ', Vw' output to the leads 8(2), 8(3) by the subtracters 27A and 27B, and the duty ratio determination unit 27C generates the voltage commands Vv ', Vw' of 2 phases from the voltage signals Vv ', Vw' and the dc voltage VDCThe PWM duty ratios Dv and Dw of the 2 phases are determined, and four PWM signals to be given to 8(2), 8(3) are generated. This process will be described later. The reason why "0.5" is added to the right side of the formula for determining the duty ratios Dv and Dw in the duty ratio determination unit 27C is to set the modulation rate to a range of 0 to 1.0.
The position estimating unit 22 obtains an estimated rotation speed ω of the motor 1 from the dq-axis currents Id and Iq and the d-axis voltage VdcEstimating the rotational position θcAnd a position estimation error Δ θ. Fig. 4 shows a detailed configuration of the position estimating unit 22. The induced voltage calculation unit 31 calculates the d-axis induced voltage Ed based on the resistance R, dq of the stator coil, which is a constant of the motor 1, the axis inductances Ld and Lq, and the above parametersAnd (6) performing row operation. The PI operation unit 32 performs PI (Proportional-Integral) operation on the induced voltage Ed, and the subtractor 33 outputs a speed command ω from the speed command ωRefSubtracting the result of the above calculation to output an estimated rotation speed ωc. Integrator 34 calculates the estimated rotation speed ωcPerforms integration to output an estimated rotational position θc。
Next, the PFC control unit 16 shown in fig. 5 will be described. The dc voltage control unit 37 controls the dc voltage V applied from the subtractor 36DCAnd a DC voltage command value VDC_RefPerforming PI operation on the difference to generate an amplitude command value I of the reactor currentAC_amp_Ref. A PLL (phase Locked Loop) unit 38 for receiving the single-phase AC voltage VACThe phase ω t (═ θ) of the voltage is detected. The sine calculator 39 calculates the sine sin θ of the phase ω t. Multiplier 40 pair reactor current command value IAC_amp_RefThe product of sine and sine is calculated to obtain the instantaneous command value I of the AC currentAC_Ref。
The current control unit 42 controls the instantaneous current command value I given by the subtractor 41AC_RefWith reactor current IACThe difference of (3) is subjected to PI calculation to obtain an output voltage. The output voltage is divided by a dc voltage V by a divider 43DCThereby obtaining the PWM duty ratio Du.
The polarity determination unit 44 determines the alternating current I detected by the current detector 10(1)ACOutputs "1" if it is positive, and outputs "0" if it is negative. The subtractor 45 subtracts the PWM duty Du from the polarity determination result, thereby correcting the output duty Du. The duty ratio Du corrected by the comparator 46 is compared with a carrier such as a triangular wave, for example, and generates a PWM signal to be output to the upper and lower arms of the lead 8(1) together with the output of the inverter gate 47. The lead 8(1) corresponds to a power factor control lead. In the configuration shown in fig. 1, the configuration other than the motor 1 and the ac power supply 2 corresponds to a power conversion device or a load driving device.
Next, the operation of the present embodiment will be described. The motor control unit 15 controls the motor based on the speed command ωRefDetermining a current command value Iq_RefVoltage commands Vd and Vq are generated based on the detected currents Id and Iq. Here, although the 3-phase voltage commands Vu, Vv, Vw are determined in the 2-phase/3-phase converting unit 26, the applied voltage is equivalent to zero since the 1 phase of the 3 phases is connected to the neutral point, which is the common connection point of the capacitors 5 and 6. Therefore, the U-phase voltage command Vu is equivalent to zero, and the command value Vu is subtracted from the full phase, and new V, W-phase voltage command values Vv 'and Vw' are obtained as shown in expression (1).
Vv’＝Vv-Vu
Vw’＝Vw-Vu……(1)
As shown in fig. 6, the voltage commands Vv ', Vw' are commands having a phase difference of 60 degrees from each other. By dividing these voltage commands by the DC voltage VDCAnd compared with the triangular wave carrier, thereby obtaining PWM signals output to leads 8(2), 8 (3). By performing the processing of expression (1), the neutral point of the capacitor at which the voltage becomes zero and the line-to-line voltages of the leads 8(2), 8(3) become 3-phase sine waves. Therefore, as shown in fig. 6, currents having a phase difference of 120 degrees flow through the 3-phase motor 1, and sinusoidal drive is possible. The leads 8(2), 8(3) correspond to load control leads.
The PFC control unit 16 controls the DC voltage command V based on the target voltageDC_RefThe duty ratio Du is controlled. By flowing DC voltage VDCFollowing DC voltage command VDC_RefSuch a reactor current IACThereby, the AC power supply 2 and the reactor current I can be realizedACThat is, the ac current is identical in phase and the power factor is "1", that is, 100%.
Here, attention is paid to the lead 8(1) and the diodes 3 and 4 constituting the PFC circuit. The PFC controller 16 adjusts the amplitude and phase of a sinusoidal voltage, which is a difference voltage between the intermediate potential of the lead 8(1) and the intermediate potential of the diodes 3 and 4, thereby adjusting the current I flowing from the ac power supply 2ACAnd (5) controlling. However, depending on the characteristics of the diodes, the intermediate potential of the diodes 3 and 4 changes to the positive side potential or the negative side potential of the dc part according to the polarity of the flowing current. Thus, the difference voltage of the two circuits is controlled toThe potential of the lead 8(1) is a signal in consideration of the potential on the diode side, though it has a sine wave shape.
That is, the polarity determination unit 44 determines the reactor current IACAnd the duty ratio Du is subtracted from the diode modulation ratio obtained by converting the voltage of the diode into the modulation ratio according to the positive or negative polarity of the polarity. This enables the current of the ac power supply 2 to be controlled in a sinusoidal wave form. FIG. 7 shows an AC voltage VACAC current IACA duty ratio Du, which is a modulation ratio between the diode and the lead 8(1) as an output of the current control unit, a diode modulation ratio, and a modulation ratio finally output to the lead 8 (1).
Since the power factor "1" is set as the control target, the voltage V is usedACPhase and current I ofACIs controlled so that the phases of (1) are identical. The line-to-line modulation rate obtained as a result of thus controlling the current becomes sinusoidal. On the other hand, the terminal voltage and current I of the diode series circuitACIs correspondingly changed into a direct current voltage VDCOr 0V, and thus the diode modulation rate changes to "1" or "0". Therefore, the modulation factor of the lead 8(1) is the shape as shown in fig. 7 obtained by subtracting the line-to-line modulation factor from the diode modulation factor. By controlling the lead 8(1) in this manner, an operation to obtain a power factor "1" can be realized.
As described above, according to the present embodiment, the power conversion device includes the series circuit of the diodes 3 and 4, the series circuit of the capacitors 5 and 6 connected in parallel to the series circuit, and the power module 9 having the switching leads 8(1) to 8(3), and the 3-phase motor 1 is connected to the common connection point of the leads 8(2) and 8(3) and the common connection point of the capacitors 5 and 6. The ac voltage detector 13 detects the voltage of the ac power supply 2 connected to the common connection point of the lead wires 8(1) and the common connection point of the diodes 3 and 4. The current detectors 10(1) to 10(3) detect the currents flowing through the leads 8(1) to 8(3), respectively, and the dc voltage detector 12 detects the dc voltage, which is the terminal voltage of the diode series circuit. The control unit 14 performs switching control using the lead 8(1) as a power factor control lead and the leads 8(2) and 8(3) as load control leads based on the detected current, ac voltage, and dc voltage.
Specifically, the motor control unit 15 of the control unit 14 controls the motor based on the input speed command ωRefWhen generating the 3-phase voltage commands Vu, Vv, Vw, these commands are converted into 2-phase voltage commands Vv ', Vw' corresponding to leads 8(2) and 8(3), and based on the conversion result and the dc voltage VDCTo generate PWM duty ratios Dv, Dw.
The PFC control unit 16 is configured to control the phase θ of the ac voltage and the dc voltage V based on the phaseDCAnd a current I flowing through the lead 8(1)ACWhen the PWM duty ratio Du is generated, the duty ratio Du is modulated in accordance with the polarity of the ac power supply, that is, the modulation rate based on the diode series circuit, and the modulated duty ratio Du is used for switching control and PWM control of the lead 8 (1).
With this configuration, the leads 8(2) and 8(3) can operate as a V-junction inverter to drive the motor 1, and can be controlled so that the power factor becomes "1" by the leads 8 (1). Further, since the power module 9 is configured by integrating the lead wires 8(1) for power factor control and the lead wires 8(2) and 8(3) for motor control, the power conversion device can be downsized.
Further, a reactor 11 is inserted between the ac power supply 2 and a common connection point of the diode series circuit, and the PFC control unit 16 responds to the input dc voltage command VDC_RefAnd a DC voltage VDCThe difference generates a PWM duty Du of the lead 8(1) to provide a DC voltage VDCThe boosting function of (1). Thus, when the lead wires 8(2) and 8(3) are operated, the drive voltage is not limited to V unlike the V-junction inverterDCAnd/2, the driving voltage can be boosted as necessary as in the case of rotating the motor 1 at a high speed.
(embodiment 2)
Fig. 8 shows embodiment 2, in which the power conversion device according to embodiment 1 is applied to a compressor motor of an air conditioner. The compressor 52 constituting the heat pump system 51 is configured by housing a compression unit 53 and a motor 54 in the same iron-made sealed container 55, and a rotor shaft of the motor 54 is coupled to the compression unit 53. The compressor 52, the four-way valve 56, the indoor-side heat exchanger 57, the pressure reducer 58, and the outdoor-side heat exchanger 59 are connected to each other by pipes as heat transfer medium flow paths so as to form a closed circuit. The compressor 52 is, for example, a rotary compressor, and the motor 54 is, for example, a 3-phase ipm (internal Permanent magnet) motor. Further, the motor 54 is a brushless DC motor. The air conditioner 50 includes the heat pump system 51 described above.
During heating, the four-way valve 56 is in a state shown by solid lines, and the high-temperature medium compressed by the compression portion 55 of the compressor 52 is supplied from the four-way valve 56 to the indoor-side heat exchanger 57, condensed, decompressed by the decompression device 58, becomes low-temperature, flows to the outdoor-side heat exchanger 59, evaporated there, and returns to the compressor 52. On the other hand, during cooling, the four-way valve 56 is switched to the state shown by the broken line. Therefore, the high-temperature medium compressed by the compression unit 53 of the compressor 52 is supplied from the four-way valve 6 to the outdoor heat exchanger 59, condensed, decompressed by the decompression device 8, turned into a low temperature, flows to the indoor heat exchanger 57, evaporated there, and returned to the compressor 52. The fans 60 and 61 blow air to the indoor-side and outdoor- side heat exchangers 57 and 59, respectively, and heat exchange between the indoor air and outdoor air is efficiently performed by the blown air in the heat exchangers 57 and 59. The motor 54 is driven and controlled by the motor control device according to embodiment 1.
According to embodiment 2 configured as described above, the operation efficiency of the air-conditioner 50 can be improved by controlling the driving of the motor 54 of the compressor 52 constituting the heat pump system 51 in the air-conditioner 50 by the power conversion device of embodiment 1.
(other embodiments)
The switching element is not limited to the N-channel MOSFET, and a P-channel MOSFET, a wide band gap semiconductor such as an IGBT, a power transistor, SiC, or GaN, or the like may be used for the upper arm.
The boost function of the control unit may be provided as needed, and the reactor 11 may be omitted.
It can also be applied to 3-phase loads other than motors.
It can also be applied to electric equipment other than air conditioners.
Several embodiments of the present invention have been described, but these embodiments are presented as examples and are not intended to limit the scope of the invention. These new embodiments can be implemented in other various ways, and various omissions, substitutions, and changes can be made without departing from the spirit of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the scope equivalent thereto.
Claims (3)
1. A power conversion device is provided with:
a diode series circuit composed of two diodes connected in series;
a capacitor series circuit including two capacitors connected in series and connected in parallel to the diode series circuit;
a switch module having three switch leads composed of six switching elements, composed of a single module, and connected in parallel to the diode series circuit;
an ac voltage detector that detects a voltage of a single-phase ac power supply connected to a neutral point of a 1 st lead that is one of the three switching leads and a neutral point of the diode series circuit;
a current detector for detecting the current flowing through each of the switch leads;
a dc voltage detector for detecting a dc voltage which is a terminal voltage of the diode series circuit; and
a control unit for performing PWM control of the switching of each switching element based on the current, the AC voltage, and the DC voltage,
the control part controls the switch of the 1 st lead as a lead for power factor control,
neutral points of the other two switching leads, i.e., the 2 nd lead and the 3 rd lead, and neutral points of the two capacitors are connected to a 3-phase load, whereby the control unit performs switching control using the 2 nd lead and the 3 rd lead as load control leads,
the control unit converts the 3-phase voltage command into a 2-phase voltage command corresponding to the 2 nd lead and the 3 rd lead when generating a 3-phase voltage command based on the input speed command, and generates a PWM duty of the load control lead based on the conversion result and the DC voltage,
when the PWM duty of the power factor control lead is generated based on the phase of the ac voltage, the dc voltage, and the current flowing through the 1 st lead, the PWM duty is modulated according to the polarity of the ac power source, and the modulated PWM duty is used for switching control.
2. The power conversion apparatus according to claim 1,
a reactor interposed between the single-phase AC power supply and a neutral point of the diode series circuit,
the control unit generates a PWM duty of the power factor control lead based on a difference between the input dc voltage command and the dc voltage, and has a dc voltage boosting function.
3. An air conditioner is provided with:
the power conversion device of claim 1 or 2; and
the motor as the 3-phase load is driven by the AC power converted by the power conversion device,
the air conditioner uses the driving force generated by the motor as a power source.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2017-085330 | 2017-04-24 | ||
| JP2017085330A JP2018186595A (en) | 2017-04-24 | 2017-04-24 | Power conversion device, and air conditioner |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN108736754A CN108736754A (en) | 2018-11-02 |
| CN108736754B true CN108736754B (en) | 2020-09-01 |
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| CN201810348596.2A Expired - Fee Related CN108736754B (en) | 2017-04-24 | 2018-04-18 | Power conversion device and air conditioner |
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| Country | Link |
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| JP (1) | JP2018186595A (en) |
| CN (1) | CN108736754B (en) |
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| JP7255475B2 (en) * | 2019-12-18 | 2023-04-11 | 株式会社明電舎 | Power converter control system |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2001238452A (en) * | 2000-02-23 | 2001-08-31 | Matsushita Electric Ind Co Ltd | Converter circuit |
| CN101592970A (en) * | 2009-06-18 | 2009-12-02 | 魏晓亮 | AC voltage stabilizer circuit and three-phase AC voltage stabilizer |
| CN101682269A (en) * | 2007-05-23 | 2010-03-24 | 大金工业株式会社 | Power conversion device |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2007053881A (en) * | 2005-08-19 | 2007-03-01 | Daikin Ind Ltd | Voltage converter |
| WO2017037791A1 (en) * | 2015-08-28 | 2017-03-09 | 三菱電機株式会社 | Motor drive device, and heat pump device and refrigerating and air-conditioning device using said motor drive device |
-
2017
- 2017-04-24 JP JP2017085330A patent/JP2018186595A/en active Pending
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2018
- 2018-04-18 CN CN201810348596.2A patent/CN108736754B/en not_active Expired - Fee Related
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2001238452A (en) * | 2000-02-23 | 2001-08-31 | Matsushita Electric Ind Co Ltd | Converter circuit |
| CN101682269A (en) * | 2007-05-23 | 2010-03-24 | 大金工业株式会社 | Power conversion device |
| CN101592970A (en) * | 2009-06-18 | 2009-12-02 | 魏晓亮 | AC voltage stabilizer circuit and three-phase AC voltage stabilizer |
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| Publication number | Publication date |
|---|---|
| JP2018186595A (en) | 2018-11-22 |
| CN108736754A (en) | 2018-11-02 |
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