WO2022064673A1 - 電力変換装置 - Google Patents
電力変換装置 Download PDFInfo
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- WO2022064673A1 WO2022064673A1 PCT/JP2020/036540 JP2020036540W WO2022064673A1 WO 2022064673 A1 WO2022064673 A1 WO 2022064673A1 JP 2020036540 W JP2020036540 W JP 2020036540W WO 2022064673 A1 WO2022064673 A1 WO 2022064673A1
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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
- H02M7/483—Converters with outputs that each can have more than two voltages levels
- H02M7/487—Neutral point clamped inverters
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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
- H02M7/539—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 with automatic control of output wave form or frequency
- H02M7/5395—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 with automatic control of output wave form or frequency by pulse-width modulation
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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
- H02M1/00—Details of apparatus for conversion
- H02M1/0067—Converter structures employing plural converter units, other than for parallel operation of the units on a single load
- H02M1/007—Plural converter units in cascade
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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
- H02M1/00—Details of apparatus for conversion
- H02M1/08—Circuits specially adapted for the generation of control voltages for semiconductor devices incorporated in static converters
- H02M1/084—Circuits specially adapted for the generation of control voltages for semiconductor devices incorporated in static converters using a control circuit common to several phases of a multi-phase system
- H02M1/0845—Circuits specially adapted for the generation of control voltages for semiconductor devices incorporated in static converters using a control circuit common to several phases of a multi-phase system digitally controlled (or with digital control)
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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
- H02M1/00—Details of apparatus for conversion
- H02M1/12—Arrangements for reducing harmonics from ac input or output
- H02M1/123—Suppression of common mode voltage or current
-
- 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
- H02M7/483—Converters with outputs that each can have more than two voltages levels
- H02M7/4835—Converters with outputs that each can have more than two voltages levels comprising two or more cells, each including a switchable capacitor, the capacitors having a nominal charge voltage which corresponds to a given fraction of the input voltage, and the capacitors being selectively connected in series to determine the instantaneous output voltage
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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
- H02M7/53873—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 with digital control
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
- Y02B70/00—Technologies for an efficient end-user side electric power management and consumption
- Y02B70/10—Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes
Definitions
- the present disclosure relates to a power conversion device that converts DC power into AC power to the load and supplies it to the load while suppressing noise and harmonics.
- Patent Document 1 shows an example of a power conversion device that converts DC power into AC power to the load and supplies it to the load while suppressing noise and harmonics.
- the power conversion device described in Patent Document 1 is a device of a type called a cascade type multi-level inverter in which an H-bridge circuit is connected in series to each phase of a three-phase three-level inverter.
- the H-bridge circuit includes two legs in which two semiconductor switching elements are connected in series. According to this type of power conversion device, it is possible to reduce noise and harmonics of the output voltage as compared with the case of using only a three-phase three-level inverter.
- the cascade type multi-level inverter requires more semiconductor switching elements than the case of only the three-phase three-level inverter. Therefore, there is a problem that the switching loss increases and the efficiency of the power conversion device decreases as compared with the case of using only the three-phase three-level inverter.
- the present disclosure has been made in view of the above, and an object of the present disclosure is to obtain a power conversion device capable of efficiently controlling a power conversion device while reducing noise and harmonics.
- the power conversion device is a power conversion device that converts DC power output from a DC power source into AC power to the load and supplies it to the load.
- the power conversion device includes a three-phase inverter circuit connected to the positive and negative terminals of a DC power supply, three single-phase bridge circuits, and a controller.
- the single-phase bridge circuit has a first leg, a second leg connected in parallel to the first leg, and capacitors connected to both ends of the first and second legs, respectively.
- two semiconductor switching elements are connected in series, and the midpoint of their connection ends is connected to the AC end of one phase of the three-phase inverter circuit, which is different from each other.
- the controller controls the operation of the first gate signal that controls the operation of the three-phase inverter circuit based on the sinusoidal phase voltage command, and the second leg that controls the operation of the first and second legs in the three single-phase bridge circuits. Generates a gate signal.
- the controller divides a three-phase pulse voltage command that commands a sinusoidal phase voltage command to a three-phase inverter circuit and a first phase voltage command that commands each of the three single-phase bridge circuits. ..
- the controller generates a first gate signal based on the three-phase pulse voltage command.
- the controller calculates the first three-phase common voltage common to the three phases, and generates a second phase voltage command in which the calculated first three-phase common voltage is superimposed on the first phase voltage command. .. Further, the controller calculates the second three-phase common voltage common to the three phases, and generates a third phase voltage command in which the calculated second three-phase common voltage is superimposed on the second phase voltage command. do.
- the controller generates a second gate signal to be applied to one of the first and second legs based on the positive and negative polarities of the third phase voltage command, and the third phase voltage. Generates a second gate signal to be applied to any one of the first and second legs according to the command.
- the controller calculates the second three-phase common voltage so that the positive and negative polarities of the third phase voltage commands do not switch during the period when the sum of the three phases of the three-phase pulse voltage command is not zero.
- the power conversion device According to the power conversion device according to the present disclosure, there is an effect that the power conversion device can be efficiently controlled while reducing noise and harmonics.
- the figure which shows the waveform example for one phase of the three-phase pulse voltage command generated by the three-phase pulse voltage command calculator of FIG. A flowchart used to explain the operation of the first common voltage superimposition device in the first embodiment.
- the figure which shows the operation waveform when both the 1st common voltage superimposition and the 2nd common voltage superimposition are absent in the configuration of Embodiment 3 (modulation rate m 0.85).
- the figure which shows the relationship between the number of switchings and a modulation factor when the 2nd three-phase common voltage superimposition device in Embodiment 1 is used.
- the figure which shows the relationship between the number of switchings and a modulation factor when the 2nd three-phase common voltage superimposition device in Embodiment 2 is used.
- FIG. 1 is a circuit diagram showing the configuration of the power conversion device 1 according to the first embodiment.
- the power conversion device 1 according to the first embodiment is a power conversion device that converts the DC power output from the DC power supply 3 into AC power to the motor 2 which is a load and supplies it to the motor 2.
- the power conversion device 1 includes an inverter circuit 4, H-bridge circuits 5, 6 and 7 which are single-phase bridge circuits, and a power conversion controller 9A as a controller.
- An inverter circuit 4 is connected between the positive and negative terminals of the DC power supply 3, and an H bridge is connected between the AC ends 4a, 4b, 4c of one phase different from each other of the inverter circuit 4 and each phase of the motor 2.
- FIG. 1 illustrates a case where the inverter circuit 4 is a three-phase three-level inverter, but the present invention is not limited to this.
- the inverter circuit 4 may be a three-phase two-level inverter.
- the inverter circuit 4 may be a multi-phase, that is, a two-level inverter or a three-level inverter having four or more phases.
- each of the H-bridge circuits 5, 6 and 7 two semiconductor switching elements having a reverse conduction function are connected in series, and the middle points 5a1, 6a1, 7a1 which are the connection ends thereof are the AC ends 4a of the three-phase inverter circuit. It has 4b, 4c, a first leg connected to the AC end of one phase that is different from each other. Further, in each H bridge circuit 5, 6 and 7, two semiconductor switching elements having a reverse conduction function are connected in series, and the midpoints 5a2, 6a2 and 7a2 which are the connection ends thereof are the phase terminals of the motor 2. That is, it has a second leg connected to the terminals of one phase of the motor 2 that are different from each other. Further, each H-bridge circuit 5, 6 and 7 has capacitors Cs connected to both ends of the first and second legs.
- FIG. 1 as a semiconductor switching element having a reverse conduction function, an element provided with an insulated gate bipolar transistor (IGBT) and an antiparallel diode, or a metal oxide film semiconductor field effect transistor (Metal-Oxide-).
- IGBT Insulated gate bipolar transistor
- Metal-Oxide- metal oxide film semiconductor field effect transistor
- An example of an element including a Semiconductor (Field-Effective Transistor: MOSFET) and an antiparallel diode is illustrated.
- a reverse conducting (RC) IGBT may be used instead of the IGBT or MOSFET.
- the antiparallel diode may be omitted.
- an IGBT made of silicon (Si), which is a narrow band gap semiconductor element, is used for each semiconductor switching element of the inverter circuit 4. Further, an IGBT made of Si is also used for each semiconductor switching element of the first leg in the H-bridge circuits 5, 6 and 7, that is, the leg whose midpoint is connected to the inverter circuit 4.
- each semiconductor switching element of the second leg in the H-bridge circuits 5, 6 and 7, that is, the leg whose midpoint is connected to the motor 2 is a wide bandgap semiconductor element, for example, made of silicon carbide (SiC). MOSFET is used.
- SiC has the feature that it can form a semiconductor element with smaller on-voltage and switching loss than Si
- the element made of SiC is difficult to obtain and the price is higher than the element made of Si. be. Therefore, by using an IGBT made of Si for the first leg and a MOSFET made of SiC for the second leg, it is possible to achieve both the problems of manufacturing cost and difficulty in obtaining.
- the torque command T * is input to the motor controller 8.
- the motor controller 8 calculates a sinusoidal phase voltage command v su * , v sv * , v sw * so that the torque generated in the motor 2 becomes a desired torque based on the torque command T * , and is a power conversion controller. Output to 9A.
- the power conversion controller 9A has gate signals g mu1 to g mu4 , which are first gate signals, so that a voltage based on the sinusoidal phase voltage commands v su * , v sv * , and v sw * is applied to the motor 2.
- the gate signals g mu1 to g mu4 , g mv1 to g mv4 , and g mw1 to g mw4 are signals for controlling the operation of the inverter circuit 4, that is, gate signals for switching and controlling each semiconductor switching element of the inverter circuit 4. .. More specifically, it is as follows.
- the gate signal g mu1 is a signal applied to the gate of the first semiconductor switching element of the first phase (for example, u phase), and the gate signal g mu2 is the second semiconductor switching element of the first phase.
- the gate signal g mu3 is a signal applied to the gate
- the gate signal g mu3 is a signal applied to the gate of the third semiconductor switching element of the first phase
- the gate signal g mu4 is the fourth of the first phase. This is a signal applied to the gate of the semiconductor switching element.
- the gate signal g mv1 is a signal applied to the gate of the first semiconductor switching element of the second phase (for example, v phase), and the gate signal g mv2 is the second semiconductor switching element of the second phase.
- the gate signal g mv3 is a signal applied to the gate
- the gate signal g mv3 is a signal applied to the gate of the third semiconductor switching element of the second phase
- the gate signal g mv4 is the fourth of the second phase. This is a signal applied to the gate of the semiconductor switching element.
- the gate signal g mw1 is a signal applied to the gate of the first semiconductor switching element of the third phase (for example, w phase), and the gate signal g mw2 is the second semiconductor switching element of the third phase. It is a signal applied to the gate, the gate signal g mw3 is a signal applied to the gate of the third semiconductor switching element of the third phase, and the gate signal g mw4 is the fourth of the third phase. This is a signal applied to the gate of the semiconductor switching element.
- the gate signals g su1 to g su4 are signals for controlling the operation of the H-bridge circuit 5, that is, gate signals for switching and controlling each semiconductor switching element of the H-bridge circuit 5.
- the gate signal g su1 is a signal applied to the gate of the first semiconductor switching element located on the high potential side of the second leg
- the gate signal g su2 is the low potential of the first leg. It is a signal applied to the gate of the second semiconductor switching element on the side
- the gate signal g su3 is a signal applied to the gate of the third semiconductor switching element on the low potential side of the second leg, and is a gate.
- the signal g su4 is a signal applied to the gate of the fourth semiconductor switching element on the high potential side of the first leg.
- the gate signals g sv1 to g sv4 are signals for controlling the operation of the H-bridge circuit 6, that is, gate signals for switching and controlling the semiconductor switching element of the H-bridge circuit 6.
- the gate signal g sv1 is a signal applied to the gate of the first semiconductor switching element located on the high potential side of the second leg
- the gate signal g sv2 is the low potential of the first leg. It is a signal applied to the gate of the second semiconductor switching element on the side
- the gate signal g sv3 is a signal applied to the gate of the third semiconductor switching element on the low potential side of the second leg, and is a gate.
- the signal g sv4 is a signal applied to the gate of the fourth semiconductor switching element on the high potential side of the first leg.
- the gate signals g sw1 to g sw4 are signals for controlling the operation of the H-bridge circuit 7, that is, gate signals for switching and controlling the semiconductor switching element of the H-bridge circuit 7.
- the gate signal g sw1 is a signal applied to the gate of the first semiconductor switching element located on the high potential side of the second leg
- the gate signal g sw2 is the low potential of the first leg. It is a signal applied to the gate of the second semiconductor switching element on the side
- the gate signal g sw3 is a signal applied to the gate of the third semiconductor switching element on the low potential side of the second leg, and is a gate.
- the signal g sw4 is a signal applied to the gate of the fourth semiconductor switching element on the high potential side of the first leg.
- the voltage applied to the motor 2 is appropriately combined with the DC voltage of the DC power supply 3 and the capacitor voltages of the H-bridge circuits 5, 6 and 7, and is added or subtracted in consideration of the combination and polarity. It becomes a positive or negative DC voltage.
- the capacitor voltage is the voltage of the capacitors Cs.
- the DC voltage of the DC power supply 3 is referred to as “v dc ”, and the capacitor voltage is referred to as “v cs ”.
- the direction of the arrow attached next to the symbol v dc and the symbol v cs indicates the polarity. Further, in each embodiment, it is assumed that the capacitor voltage vcs is held within the step width of the phase voltage of the inverter circuit 4 or less.
- FIG. 2 is a block diagram showing the configuration of the power conversion controller 9A according to the first embodiment.
- the power conversion controller 9A according to the first embodiment has a three-phase pulse voltage command calculator 901, a dead time inserter 902, 907, a first common voltage superimposition device 903A, and a second common voltage. It includes a superimposition device 904A, a voltage polarity controller 905, a pulse width modulation (PWM) controller 906, and a subtractor 908.
- PWM pulse width modulation
- the three-phase pulse voltage command calculator 901 calculates the three-phase pulse voltage commands v sm * , v smv * , and v smw * commanded to the inverter circuit 4.
- FIG. 3 shows the waveforms of one phase of the three-phase pulse voltage command v sm * , v smv * , and v smw * .
- FIG. 3 is a diagram showing an example of a waveform for one phase of the three-phase pulse voltage command generated by the three-phase pulse voltage command calculator 901 of FIG.
- the voltage waveform shown in FIG. 3 has an absolute value that is half the DC voltage vdc of the DC power supply 3 and a positive polarity in the fundamental wave period of the sinusoidal phase voltage commands v su * , v sv * , and v sw * .
- it is a one-pulse voltage in which a negative voltage is repeated once each.
- the 1-pulse voltage is used, the number of switchings of the inverter circuit 4 is reduced, so that the switching loss is reduced and the efficiency of the power conversion device 1 can be improved.
- the three-phase pulse voltage command is represented by vsm * .
- V sm * is a general term for three-phase pulse voltage commands v sm * , v smv * , and v smw * .
- the same notation is used for the sinusoidal phase voltage command as appropriate.
- the horizontal axis of FIG. 3 represents the phase of the sinusoidal phase voltage command vs * .
- the one-pulse voltage representing the three-phase pulse voltage command vs m * is a voltage waveform that changes according to the phase and the phase angle ⁇ of the sinusoidal phase voltage command vs * . Details of the phase angle ⁇ will be described below.
- the value of one pulse voltage is a zero value in the range of the phase from zero to ⁇ , ⁇ - ⁇ to ⁇ + ⁇ , and 2 ⁇ - ⁇ to 2 ⁇ , and the phase is ⁇ to ⁇ - ⁇ . It is a positive value in the range and a negative value in the range of the phase from ⁇ + ⁇ to 2 ⁇ - ⁇ .
- the zero value referred to in this paper does not mean a completely zero value, and it is permissible to take a value close to zero. That is, the zero value referred to in this paper is a concept including a value considered to be zero.
- the amplitude of the sinusoidal phase voltage command vs * is defined as v * sphp .
- the phase angle ⁇ of is determined by the following equation (1).
- the inverter circuit 4 When the above equation (1) is satisfied, the inverter circuit 4 outputs the voltage of the fundamental wave component and shares all of the electric power of the fundamental wave component supplied to the motor 2. Therefore, when the above equation (1) is satisfied, a DC power supply is not required on the DC side of the H-bridge circuits 5, 6 and 7, and the power conversion device 1 can be miniaturized and reduced in cost. At this time, since the H-bridge circuits 5, 6 and 7 do not bear the active power, the capacitor voltage vcs is maintained at about 1/4 of the DC voltage vdc which is a specified value.
- the three-phase pulse voltage command calculator 901 generates the three-phase pulse voltage command v sm *, v smv *, v smw * , and at the same time, the three-phase pulse voltage command v sm * , v.
- Gate signals for outputting a voltage based on smv * and v smw * g mu1'to g mu4 ', g mv1'to g mv4 ', g mw1'to g mw4 ' are generated.
- the dead time for preventing the arm short circuit in the inverter circuit 4 is not inserted.
- Table 1 shows the relationship between the output voltage vsm output by the inverter circuit 4 and the gate signals g m1 to g m4 to the inverter circuit 4.
- the three-phase pulse voltage command calculator 901 uses the relationships in Table 1 to generate a gate signal to the inverter circuit 4.
- H represents “high” and means that it is a gate signal that controls the corresponding semiconductor switching element on.
- L represents “low” and means that it is a gate signal that controls the corresponding semiconductor switching element to be off.
- the three-phase pulse voltage command v sm * , v smv * , v smw * commanded to the inverter circuit 4 is subtracted from the sinusoidal phase voltage command v su * , v sv * , v sw * , and H
- the first phase voltage commands v ssu1 * , v ssv1 * , and v ssw1 * which are voltage commands commanded to the bridge circuits 5, 6 and 7, are generated.
- the sinusoidal phase voltage command v su * , v sv * , v sw * is the three-phase pulse voltage command v smu * , v smv * , v smw *.
- the first phase voltage command v ssu1 * , v ssv1 * , v ssw1 * is calculated by the subtractor 908 so that the change in the output voltage output by the inverter circuit 4 is offset.
- the first common voltage superimposition device 903A calculates the first three-phase common voltage common to the three phases based on the three-phase pulse voltage commands v sm * , v smv * , and v smw * .
- the first common voltage superimposition device 903A superimposes the calculated first three-phase common voltage on the first phase voltage commands v ssu1 * , v ssv1 * , v ssw1 * , and superimposes the superimposed voltage on each of the second. It is output to the second common voltage superimposition device 904A as the phase voltage command v ssu2 * , v ssv2 * , v ssw2 * .
- the capacitor voltage v cs is used to generate the second phase voltage commands v ssu2 * , v ssv2 * , v ssw2 * .
- the first three-phase common voltage is calculated so that the peak value of each of the second phase voltage commands v ssu2 * , v ssv2 * , and v ssw2 * is reduced.
- the second common voltage superimposition device 904A calculates the second three-phase common voltage common to the three phases based on the three-phase pulse voltage commands v sm *, v smv * , and v smw * .
- the second common voltage superimposition device 904A superimposes the calculated second three-phase common voltage on the second phase voltage commands v ssu2 * , v ssv2 * , v ssw2 * , and superimposes the superposed voltage on each of the third. It is output to the voltage polarity controller 905 as the phase voltage command v ssu3 * , v ssv3 * , v ssw3 * .
- FIG. 4 is a flowchart for explaining the operation of the first common voltage superimposition device 903A in the first embodiment.
- FIG. 5 is a flowchart for explaining the operation of the second common voltage superimposition device 904A in the first embodiment.
- the first common voltage superimposition device 903A rearranges the first phase voltage commands v ssu1 * , v ssv1 * , v ssw1 * into the maximum phase v max1 and the minimum phase v min1 .
- the common mode voltage v smcm * of the phase pulse voltage command v sm * , v smv * , v smw * is calculated using the following equation (2) (step 90301).
- step 90302 When the common mode voltage v smcm * of the three-phase pulse voltage command v sm *, v smv *, v smw * is positive (step 90302 , Yes), in order to reduce the voltage change of the common mode voltage v smcm * , The common mode voltage of each of the first phase voltage commands v ssu1 * , v ssv1 * , and v ssw1 * is operated so as to be negative. At this time, it is determined whether the minimum phase v min1 does not exceed the outputable minimum value ⁇ v cs , that is, whether the value of the minimum phase v min 1 is less than the minimum value ⁇ v cs (step 90305).
- the first three-phase common voltage v ofst1 is determined so that the minimum phase v min1 is the minimum value ⁇ v cs (step 90306).
- the minimum phase v min1 is not less than the minimum value ⁇ v cs (step 90305, No)
- the first three-phase common voltage v ofst1 0 (step 90307).
- step 90303 when the common mode voltage v smcm * of the three-phase pulse voltage command v sm *, v smv *, v smw * is negative (step 90303 , Yes), in order to reduce the voltage change of the common mode voltage v smcm * . Operates so that the common mode voltage of each of the first phase voltage commands v ssu1 * , v ssv1 * , and v ssw1 * becomes positive. At this time, it is determined whether or not the maximum phase v max1 does not exceed the maximum outputable value vcs (step 90308).
- the first three-phase common voltage v ofst1 is determined so that the maximum phase v max1 becomes the maximum value v cs (step 90309). ..
- the maximum phase v max1 does not exceed the maximum value vcs (step 90308, No)
- the first three-phase common voltage vofst1 0 (step 90310).
- the first common voltage superimposition device 903A superimposes the first three-phase common voltage v ofst1 on the first phase voltage commands v ssu1 * , v ssv1 * , v ssw1 * , and each of the second The phase voltage commands v ssu2 * , v ssv2 * , and v ssw2 * are generated (step 90311).
- the second phase voltage command v ssu2 * , v ssv2 * , v ssw2 * is a tentatively generated phase voltage command under correction.
- the second common voltage superimposition device 904A rearranges the second phase voltage commands v ssu2 * , v ssv2 * , v ssw2 * into the maximum phase v max2 and the minimum phase v min2 , and three.
- the common mode voltage v smcm * of the phase pulse voltage command v sm * , v smv * , v smw * is calculated using the above equation (2) (step 90401).
- the modulation factor m can be expressed by the following equation (3).
- the second common voltage superimposition device 904A superimposes the second three-phase common voltage v ofst2 on the second phase voltage commands v ssu2 * , v ssv2 * , v ssw2 * , and each of the third The phase voltage commands v ssu3 * , v ssv3 * , and v ssw3 * are generated (step 90413).
- the third phase voltage command v ssu3 * , v ssv3 * , v ssw3 * is the corrected phase voltage command generated by using the corrected phase voltage command. ..
- the common mode voltage v smcm * of the three-phase pulse voltage command v smu * , v smv * , v smw * that is, the three-phase of the three-phase pulse voltage command v smu * , v smv * , v smw * .
- the positive / negative properties in the third phase voltage commands v ssu3 * , v ssv3 * , and v ssw3 * are not switched.
- the third phase voltage command v ssu3 * , v ssv3 * , v ssw3 * is for the first phase voltage command v ssu1 * , v ssv1 * , v ssw1 * , which is the voltage command before correction.
- Positive and negative properties do not change.
- the number of switchings in the H-bridge circuits 5, 6 and 7 can be reduced, so that the switching loss in the power conversion device 1 can be reduced.
- the voltage polarity controller 905 is the first in the H-bridge circuits 5, 6 and 7 based on the polarities of the third phase voltage commands v ssu3 * , v ssv3 * and v ssw3 * .
- the leg that is, the gate signal g su2 ', g su4 ', g sv2 ', g sv4 ', g sw2 ', g sw4'for the leg whose midpoint is connected to the inverter circuit 4 is generated.
- the voltage polarity controller 905 is a second leg in the H-bridge circuits 5, 6 and 7, that is, a midpoint, based on the polarities of the third phase voltage commands v ssu3 * , v ssv3 * , and v ssw3 * .
- Each phase voltage command v ssu4 * , v ssv4 * , v ssw4 * is generated.
- the PWM controller 906 has a gate signal g su1 ', g su3 for the second leg in the H-bridge circuits 5, 6 and 7 based on the fourth phase voltage command v ssu4 * , v ssv4 * , v ssw4 * . ', g sv1 ', g sv3 ', g sw1 ', g sw3 ' are generated.
- FIG. 6 is a first diagram provided for explaining the operation of the voltage polarity controller 905 and the PWM controller 906 in the first embodiment.
- FIG. 7 is a second diagram for explaining the operation of the voltage polarity controller 905 and the PWM controller 906 according to the first embodiment.
- the horizontal axes of FIGS. 6 and 7 both represent time. Further, in FIGS. 6 and 7, from the upper side, the third phase voltage command vss3 * and the fourth phase voltage command vss4 * in any phase, the gate signals g s1 ', g s3 ', Each signal of g s2 ', g s4 ', and voltage command vssi * as an instantaneous value is shown by a thick line. Further, the waveform of the carrier signal c is shown by a thick line in the upper part. The carrier signal c is a triangular wave signal that changes between the zero voltage and the capacitor voltage v cs . The cycle of the carrier signal c may be referred to as a "carrier cycle".
- FIG. 6 shows an operation waveform when the third phase voltage command vss3 * ⁇ 0.
- FIG. 7 shows an operation waveform when the third phase voltage command vss3 * ⁇ 0. It should be noted that the value obtained by adding the capacitor voltage vcs to the value of the third phase voltage command vss3 * is the value of the fourth phase voltage command vss4 * . The addition of the capacitor voltage v cs is performed for the phase where vss3 * ⁇ 0.
- the voltage command vssi * as an instantaneous value becomes ⁇ v cs or 0 as shown in the lower part of FIG.
- the operation waveforms of the voltage polarity controller 905 and the PWM controller 906 output the third phase voltage command vss3 * as an average value.
- Table 2 shows the relationship between the output voltage Vss of the H-bridge circuits 5, 6 and 7 and the gate signals g s1 to g s4 to the H-bridge circuits 5, 6 and 7.
- the voltage polarity controller 905 and the PWM controller 906 use the relationships shown in Table 2 to generate gate signals to the H-bridge circuits 5, 6 and 7.
- H represents “high” and means that it is a gate signal that controls the corresponding semiconductor switching element on.
- L represents “low” and means that it is a gate signal that controls the corresponding semiconductor switching element to be off.
- the dead time inserter 902 inserts a new dead time into the gate signals g mu1 ' ⁇ g mu4 ', g mv1 ' ⁇ g mv4 ', g mw1 ' ⁇ g mw4 '.
- Gate signals g mu1 to g mu4 , g mv1 to g mv4 , and g mw1 to g mw4 are generated.
- the dead time inserter 907 inserts a dead time into the gate signals g mu1 ' ⁇ g mu4 ', g mv1 ' ⁇ g mv4 ', g mw1 ' ⁇ g mw4 ', and the new gate signal g mu1 ⁇ It produces g mu4 , g mv1 to g mv4 , and g mw1 to g mw4 .
- FIG. 8 shows a method of inserting a dead time.
- FIG. 8 is a diagram showing a method of inserting a dead time in the dead time inserters 902 and 907 of the first embodiment.
- the waveform of g'in the upper part shows the gate signal before the dead time is inserted
- the waveform of g in the lower part shows the gate signal after the insertion.
- the dead time t d is inserted so as to be delayed by the dead time t d at the timing when the gate signal changes from L to H. Note that FIG. 8 is an example, and the dead time t d may be inserted or set by a method other than that shown in FIG.
- FIG. 9 is a diagram showing an operation waveform when neither the first common voltage superimposition device 903A nor the second common voltage superimposition device 904A is present in the configuration of the first embodiment.
- the modulation factor m is 0.70.
- waveforms of (a) sinusoidal phase voltage command, (b) three-phase pulse voltage command, (c) H-bridge output voltage, and (d) phase voltage are shown in order from the top.
- (e) H-bridge voltage command, (f) corrected H-bridge voltage command, (g) corrected H-bridge voltage command, and (h) corrected H-bridge voltage command polarity are shown.
- the "H-bridge voltage command” represents the above-mentioned first phase voltage command v ssu1 * , v ssv1 * , v ssw1 *
- the "correcting H-bridge voltage command” is the above-mentioned second phase voltage command v ssu2. * , V ssv2 * , v ssw2 *
- the "corrected H-bridge voltage command” represents the above-mentioned third phase voltage command v ssu3 * , v ssv3 * , v ssw3 *
- the "corrected H-bridge voltage command polarity" represents the polarity of the corrected H-bridge voltage command.
- the "H-bridge output voltage” is the output voltage of the H-bridge circuits 5, 6 and 7.
- the "phase voltage” is a voltage output from each phase of the inverter circuit 4.
- Each operation waveform is normalized by "v dc / 2". Further, in each operation waveform, the U-phase waveform is shown by a solid line, the V-phase waveform is shown by a broken line, and the W-phase waveform is shown by a long-dotted line.
- the "sinusoidal phase voltage command” is calculated so that the motor 2 is operated by the desired torque command T * .
- the "pulse voltage command” is calculated by the three-phase pulse voltage command calculator 901
- the "H-bridge voltage command” is obtained by subtracting the "three-phase pulse voltage command” from the "sinusoidal phase voltage command”.
- the “H-bridge voltage command” becomes the “corrected H-bridge voltage command” as it is.
- the voltage polarity controller 905 generates the gate signal of the first leg in the H-bridge circuits 5, 6 and 7 based on the polarity of the "corrected H-bridge voltage command", and also generates the "H-bridge voltage” for PWM modulation. Generate a "command".
- the polarity of the “corrected H-bridge voltage command” changes 6 times in the fundamental wave period of the “sinusoidal phase voltage command”. There is. That is, the first leg of the H-bridge circuits 5, 6 and 7 is switched 6 times.
- the PWM controller 906 performs PWM control based on the fourth phase voltage command v ssu4 * , v ssv4 * , v ssw4 * for PWM modulation, and the H-bridge circuits 5, 6 and 7 perform "H-bridge output voltage". Is output.
- the "H-bridge output voltage” is an instantaneous voltage waveform of the H-bridge circuits 5, 6 and 7.
- the "phase voltage” output by the power conversion device 1 is the sum of the "three-phase pulse voltage command" and the "H-bridge output voltage", and has a quasi-sinusoidal waveform. As a result, a "phase voltage” with less noise and harmonic components can be obtained.
- FIG. 10 shows an operation waveform when the first common voltage superimposition device 903A is added. That is, FIG. 10 is a diagram showing an operation waveform in the case where the second common voltage superimposition device 904A is not provided in the configuration of the first embodiment.
- the first common voltage superimposition device 903A calculates the first three-phase common voltage and superimposes it on the "H-bridge voltage command". As a result, a "correcting H-bridge voltage command” that does not exceed the maximum and minimum values that can be output by the H-bridge circuits 5, 6 and 7 can be obtained.
- the “corrected H-bridge voltage command” becomes the “corrected H-bridge voltage command” as it is. Since the "corrected H-bridge voltage command” does not exceed the maximum and minimum values that can be output, a "phase voltage” with few harmonic components is obtained.
- FIG. 11 shows an operation waveform when the second common voltage superimposition device 904A is added. That is, FIG. 11 is a diagram showing an operation waveform of the configuration of FIG. 2 in the first embodiment.
- the second common voltage superimposition device 904A is common to the second three-phase so that the positive and negative characteristics of the "corrected H-bridge voltage command" do not switch during the period when the sum of the three phases of the "three-phase pulse voltage command” is not zero.
- the voltage is calculated and superimposed on the "correcting H-bridge voltage command".
- the modulation factor is 0.70, when the common mode voltage of the “three-phase pulse voltage command” is positive, the maximum value of the three phases in the “correcting H-bridge voltage command” is zero or negative.
- the second three-phase common voltage is calculated so as to be.
- the second three-phase common voltage is calculated so that the maximum value of the three phases in the "correcting H-bridge voltage command" becomes zero or positive. ..
- the positive and negative polarities of the "corrected H-bridge voltage command” do not switch during the period when the sum of the three phases of the "three-phase pulse voltage command” is not zero.
- the positive / negative polarity of the "corrected H-bridge voltage command” does not change with respect to the "H-bridge voltage command" before the correction.
- the polarity change of the "corrected H-bridge voltage command" is reduced to 6 times in the fundamental wave period of the "sinusoidal phase voltage command". That is, since the number of switchings of the first leg of the H-bridge circuits 5, 6 and 7 is reduced, the switching loss is also reduced. Therefore, according to the first embodiment, the H-bridge circuit 5, while suppressing the output of the voltage exceeding the maximum value and the minimum value that can be output by the "H-bridge voltage command" and suppressing the distortion of the "phase voltage". It is possible to reduce the switching loss of the first leg of 6 and 7.
- FIG. 12 is a diagram showing an operation waveform when neither the first common voltage superimposition device 903A nor the second common voltage superimposition device 904A is present in the configuration of the first embodiment.
- the polarity of the “corrected H-bridge voltage command” changes 6 times in the fundamental wave period of the “sinusoidal phase voltage command”, and is H.
- the first leg of the bridge circuits 5, 6 and 7 will be switched 6 times.
- FIG. 13 shows an operation waveform when the first common voltage superimposition device 903A is added. That is, FIG. 13 is a diagram showing an operation waveform when there is no second common voltage superimposition device 904A in the configuration of the first embodiment.
- FIG. 14 shows an operation waveform when a second common voltage superimposition device 904A is further added. That is, FIG. 14 is a diagram showing an operation waveform of the configuration of FIG. 2 in the first embodiment.
- the polarity change of the "corrected H-bridge voltage command" is reduced to 6 times in the fundamental wave period of the "sinusoidal phase voltage command". That is, since the number of switchings of the first leg of the H-bridge circuits 5, 6 and 7 is reduced, the switching loss is also reduced. Therefore, the output of the voltage exceeding the maximum value and the minimum value that can be output by the "H-bridge voltage command” is suppressed, and the distortion of the "phase voltage” is suppressed, and the first of the H-bridge circuits 5, 6 and 7. Switching loss can be reduced.
- FIG. 15 is a diagram showing an operation waveform when neither the first common voltage superimposition device 903A nor the second common voltage superimposition device 904A is present in the configuration of the first embodiment.
- the polarity of the “corrected H-bridge voltage command” changes 10 times in the fundamental wave period of the “sinusoidal phase voltage command”, and is H.
- the first leg of the bridge circuits 5, 6 and 7 will be switched 10 times.
- FIG. 16 shows an operation waveform when the first common voltage superimposition device 903A is added. That is, FIG. 16 is a diagram showing an operation waveform when there is no second common voltage superimposition device 904A in the configuration of the first embodiment.
- FIG. 17 shows an operation waveform when a second common voltage superimposition device 904A is further added. That is, FIG. 17 is a diagram showing an operation waveform of the configuration of FIG. 2 in the first embodiment.
- the power conversion controller calculates the first three-phase common voltage common to the three phases, and calculates the calculated first three-phase common voltage. Is superimposed on the first phase voltage command to generate a second phase voltage command. Further, the power conversion controller calculates the second three-phase common voltage common to the three phases, and superimposes the calculated second three-phase common voltage on the second phase voltage command. To generate. The power conversion controller generates a second gate signal to be applied to either one of the first leg and the second leg based on the positive and negative polarities of the third phase voltage command, while generating each of the third. Based on the phase voltage command, a second gate signal to be applied to any one of the first and second legs is generated.
- the power conversion controller calculates the second three-phase common voltage so that the positive / negative characteristics of each of the third phase voltage commands do not switch during the period when the sum of the three phases of the three-phase pulse voltage command is not zero.
- the switching loss of the leg can be reduced by reducing the number of switchings of the switching element of either the first leg or the second leg. This makes it possible to efficiently control the power conversion device while reducing noise and harmonics.
- the capacitor voltage which is the voltage of the capacitor
- the capacitor voltage is one half or less of half the step width of the phase voltage of the inverter circuit, that is, one quarter or less of the voltage of the DC power supply. Is preferable. With this setting, harmonics are suppressed and an output voltage closer to a sine wave can be obtained.
- the power conversion controller is a first three-phase so that the absolute value of the voltage value of each phase in the second phase voltage command does not exceed the capacitor voltage. Calculate the common voltage. As a result, the output of the voltage of the portion exceeding the maximum value and the minimum value that can be output by the first phase voltage command is suppressed, so that the distortion of the phase voltage can be suppressed.
- the power conversion controller has a modulation factor m of 0.61 or more and 0.79 or less, or 0.90 or more and 0.99 or less.
- m the modulation factor
- the power conversion controller is common to the second three phases so that the minimum value of the three phases of each second phase voltage command becomes zero or positive. Calculate the voltage.
- the number of switchings of the first leg of the single-phase bridge circuit is reduced, so that the switching loss of the single-phase bridge circuit can be reduced.
- a semiconductor switching element formed of a narrow band gap semiconductor is used for the inverter circuit, and a semiconductor switching formed of a wide band gap semiconductor is used for the single-phase bridge circuit. Elements can be used.
- the switching loss of one of the first and second legs can be reduced, and the cost of the other leg of the first and second legs can be reduced. be able to. This makes it possible to suppress an increase in the manufacturing cost of the power conversion device while improving the efficiency of the operation of the power conversion device. In addition, it is possible to achieve both the problems of manufacturing cost and difficulty in obtaining.
- the leg controlled by the second gate signal generated based on the positive / negative properties of the third phase voltage command may be used for this.
- the capacitor voltage of the single-phase bridge circuit is preferably half or less than the step width of the phase voltage of the inverter circuit. With this setting, it is possible to obtain an output voltage closer to a sine wave while suppressing harmonics. Further, by lowering the capacitor voltage of the single-phase bridge circuit, the effect of reducing the switching loss in the single-phase bridge circuit can be obtained.
- Embodiment 2 In a general inverter circuit, the rated voltage is often set when the amplitude of the output line voltage is equal to the DC voltage.
- FIG. 18 shows an operation waveform when neither the first common voltage superimposition device 903A nor the second common voltage superimposition device 904A is present. That is, FIG. 18 is a diagram showing an operation waveform when neither the first common voltage superimposition device 903A nor the second common voltage superimposition device 904A is present in the configuration of the first embodiment.
- the polarity of the “corrected H-bridge voltage command” changes 10 times in the fundamental wave period of the “sinusoidal phase voltage command”, and is H.
- the first leg of the bridge circuits 5, 6 and 7 will be switched 10 times.
- the magnitude of the "sinusoidal phase voltage command" for driving that is, the magnitude of the modulation factor m is proportional to the rotation speed of the motor 2. Therefore, when the modulation factor m is smaller than 1.15, the rotation speed of the motor 2, that is, the fundamental frequency of the "sinusoidal phase voltage command” is low. Therefore, when the modulation factor m is smaller than 1.15, it can be said that the first leg of the H-bridge circuits 5, 6 and 7 may be switched 10 times in the fundamental wave period.
- FIG. 19 is a circuit diagram showing the configuration of the power conversion device 10 according to the second embodiment.
- the power conversion controller 9A is replaced with the power conversion controller 11B in the configuration of the power conversion device 1 according to the first embodiment shown in FIG. There is.
- the other configurations are the same as or equivalent to the configurations of the first embodiment, and the same or equivalent components are designated by the same reference numerals, and duplicate description will be omitted.
- FIG. 20 is a block diagram showing the configuration of the power conversion controller 11B according to the second embodiment.
- the second common voltage superimposition device 904A is the second common voltage superimposition device. It has been replaced by 904B.
- Other configurations are the same as or equivalent to the configuration of the first embodiment, and the same or equivalent components are designated by the same reference numerals, and duplicate description will be omitted.
- FIG. 21 is a flowchart for explaining the operation of the second common voltage superimposition device 904B in the second embodiment.
- the processing when the modulation factor m is 0.61 or more and 0.79 or less, or 1.23 or more is the same as the flowchart shown in FIG. Yes, duplicate explanations are omitted.
- step 90802, step 90805 to 9083 and step 90823 in FIG. 21 correspond to step 90402, step 90404 to 90412 and step 90413 in FIG. 5, respectively.
- step 90803 when the condition of step 90803 is satisfied (step 90803, Yes), the second common voltage superimposition device 904B has a positive common mode voltage v smcm * (step 90814), or is negative or zero (step 90814). Step 90818) is determined.
- the common mode voltage v smcm * is zero (step 90814, No, and step 90818, No)
- step 90818 it is determined whether or not the minimum phase v min 2 exceeds zero.
- the minimum phase v min2 exceeds zero (step 90819, Yes)
- the second three-phase common voltage v ofst2 ⁇ v min2 (step 90820)
- the minimum phase v min2 does not exceed zero (step 90820).
- the second three-phase common voltage volt2 0 (step 90821).
- the minimum phase v min2 is controlled to be zero or negative.
- the second common voltage superimposition device 904B superimposes the second three-phase common voltage v ofst2 on the second phase voltage commands v ssu2 * , v ssv2 * , v ssw2 * , and each of the third The phase voltage commands v ssu3 * , v ssv3 * , and v ssw3 * are generated (step 90823).
- the "corrected H-bridge voltage command” allows a change in positive / negative polarity with respect to the "H-bridge voltage command” before correction.
- the polarity change of the "corrected H-bridge voltage command” is 10 times in the fundamental wave period of the "sinusoidal phase voltage command”. This is an increase from 6 times in FIG. 14, which is the result of the first embodiment, but it is the same 10 times as when the power conversion device 10 is operated at a modulation factor of 1.15, which is an approximate rated voltage. be.
- the power conversion controller has a three-phase pulse voltage command three-phase when the modulation factor is 0.90 or more and 0.99 or less.
- the second three-phase common voltage is calculated so that the maximum value of the three phases of each second phase voltage command becomes zero or positive.
- the power conversion controller is common to the second three phases so that the minimum value of the three phases of each second phase voltage command becomes zero or negative. Calculate the voltage.
- control can be performed by maximizing the allowable number of switchings, so that noise and harmonics can be reduced while reducing the switching loss of the single-phase bridge circuit.
- it has a remarkable effect that has never been seen before, such as being able to supply a voltage with less distortion to the load.
- the first common voltage superimposition device 903A of the first embodiment and the second embodiment has a first common voltage superimposition device 903A so that the peak value of each phase voltage command v ssu2 * , v ssv2 * , v ssw2 * is reduced.
- the three-phase common voltage is calculated. That is, the first three-phase common voltage is calculated so as not to exceed the maximum value v cs and the minimum value ⁇ v cs that can be output by the first phase voltage commands v ssu1 * , v ssv1 * , v ssw1 * .
- the peak value can be further reduced, the switching loss of the H-bridge circuits 5, 6 and 7 can be further reduced. Therefore, in the third embodiment, the peak values of the second phase voltage commands v ssu2 * , v ssv2 * , and v ssw2 * are further reduced to further reduce the switching loss of the H-bridge circuits 5, 6 and 7. Disclose the power conversion device for the purpose.
- FIG. 23 is a circuit diagram showing the configuration of the power conversion device 12 according to the third embodiment.
- the power conversion controller 9A is replaced with the power conversion controller 13C in the configuration of the power conversion device 1 according to the first embodiment shown in FIG. There is.
- v dc v dc / 4
- Other configurations are the same as or equivalent to the configuration of the first embodiment, and the same or equivalent components are designated by the same reference numerals, and duplicate description will be omitted.
- FIG. 24 is a block diagram showing the configuration of the power conversion controller 13C according to the third embodiment.
- the first common voltage superimposition device 903A is the first common voltage superimposition device. It has been replaced by the 903B, and the second common voltage superimposition device 904A has been replaced by the second common voltage superimposition device 904C.
- Other configurations are the same as or equivalent to the configuration of the first embodiment, and the same or equivalent components are designated by the same reference numerals, and duplicate description will be omitted.
- the first common voltage superimposition device 903B calculates the first three-phase common voltage so as to reduce the peak value of each of the second phase voltage commands v ssu2 * , v ssv2 * , v ssw2 * .
- the first common voltage superimposition device 903B superimposes the calculated first three-phase common voltage on the first phase voltage commands v ssu1 * , v ssv1 * , v ssw1 * , and superimposes the superimposed voltage on each of the second. It is output to the second common voltage superimposition device 904C as the phase voltage command v ssu2 * , v ssv2 * , v ssw2 * .
- FIG. 25 is a flowchart for explaining the operation of the first common voltage superimposition device 903B in the third embodiment.
- the first common voltage superimposition device 903B rearranges the first phase voltage commands v ssu1 * , v ssv1 * , v ssw1 * into the maximum phase v max1 and the minimum phase v min1 (step 90901). ).
- the first common voltage superimposition device 903B uses the following equation (4) to set the polarity of the first three-phase common voltage vofst1 to the average value of the maximum phase v max1 and the minimum phase v min1 . Calculate as an inverted value (step 90902).
- v ofst1 -0.5 ⁇ (v max1 + v min1 ) ... (4)
- the first common voltage superimposition device 903B superimposes the first three-phase common voltage v ofst1 on the first phase voltage commands v ssu1 * , v ssv1 * , v ssw1 * , and each of the second The phase voltage commands v ssu2 * , v ssv2 * , and v ssw2 * are generated (step 90903).
- FIG. 26 is a flowchart for explaining the operation of the second common voltage superimposition device 904C in the third embodiment.
- the second common voltage superimposition device 904C rearranges the second phase voltage commands v ssu2 * , v ssv2 * , v ssw2 * into the maximum phase v max2 and the minimum phase v min2 , and three.
- the common mode voltage v smcm * of the phase pulse voltage command v sm * , v smv * , v smw * is calculated using the above equation (2) (step 91001).
- Step 91008 it is determined whether or not the minimum phase v min 2 is less than zero.
- Step 91090 it is determined whether or not the minimum phase v min 2 is less than zero.
- the minimum phase v min2 is less than zero (step 9109, Yes)
- the second three-phase common voltage v ofst2 ⁇ v min2 (step 91010), and when the minimum phase v min2 is zero or more (step 9109, Yes). No)
- the second three-phase common voltage vofst2 0 (step 91011).
- the minimum phase v min2 is controlled to be zero or positive.
- the second common voltage superimposition device 904C superimposes the second three-phase common voltage v ofst2 on the second phase voltage commands v ssu2 * , v ssv2 * , v ssw2 * , and each of the third The phase voltage commands v ssu3 * , v ssv3 * , and v ssw3 * are generated (step 91013).
- the common mode voltage v smcm * of the three-phase pulse voltage command v smu * , v smv * , v smw * that is, the three-phase of the three-phase pulse voltage command v smu * , v smv * , v smw * .
- the positive / negative properties in the third phase voltage commands v ssu3 * , v ssv3 * , and v ssw3 * are not switched.
- the third phase voltage command v ssu3 * , v ssv3 * , v ssw3 * is for the first phase voltage command v ssu1 * , v ssv1 * , v ssw1 * , which is the voltage command before correction.
- Positive and negative properties do not change.
- the number of switchings in the H-bridge circuits 5, 6 and 7 can be reduced, so that the switching loss in the power conversion device 12 can be reduced.
- FIG. 27 is a diagram showing an operation waveform when both the first common voltage superimposition device 903B and the second common voltage superimposition device 904C are not present in the configuration of the third embodiment.
- the modulation factor m is 0.85.
- the "H-bridge voltage command” becomes the "corrected H-bridge voltage command” as it is.
- the polarity of the “corrected H-bridge voltage command” changes 6 times in the fundamental wave period of the “sinusoidal phase voltage command”. There is. That is, the first leg of the H-bridge circuits 5, 6 and 7 is switched 6 times.
- FIG. 28 shows an operating waveform when the first common voltage superimposition device 903B is added. That is, FIG. 28 is a diagram showing an operation waveform when there is no second common voltage superimposition device 904C in the configuration of the third embodiment.
- the first common voltage superimposition device 903B calculates the first three-phase common voltage so as to reduce the peak value of the “H-bridge voltage command” and superimposes it on the “H-bridge voltage command”. ..
- the “corrected H-bridge voltage command” becomes the “corrected H-bridge voltage command” as it is. Since the peak value of the "corrected H-bridge voltage command” is reduced, the capacitor voltage of the H-bridge circuits 5, 6 and 7 can be lowered to reduce the switching loss.
- FIG. 29 shows an operation waveform when the second common voltage superimposition device 904C is added. That is, FIG. 29 is a diagram showing an operation waveform of the configuration of FIG. 24 in the third embodiment.
- the second common voltage superimposition device 904C is common to the second three-phase so that the positive and negative characteristics of the "corrected H-bridge voltage command" do not switch during the period when the sum of the three phases of the "three-phase pulse voltage command" is not zero.
- the voltage is calculated and superimposed on the "correcting H-bridge voltage command".
- the modulation factor is 0.85, so when the common mode voltage of the “three-phase pulse voltage command” is positive, the maximum value of the three phases in the “correcting H-bridge voltage command” is zero or negative.
- the second three-phase common voltage is calculated so as to be.
- the second three-phase common voltage is calculated so that the maximum value of the three phases in the "correcting H-bridge voltage command" becomes zero or positive. ..
- the positive and negative polarities of the "corrected H-bridge voltage command” do not switch during the period when the sum of the three phases of the "three-phase pulse voltage command” is not zero.
- the positive / negative polarity of the "corrected H-bridge voltage command” does not change with respect to the "H-bridge voltage command" before the correction.
- the polarity change of the "corrected H-bridge voltage command” is reduced to 6 times in the fundamental wave period of the "sinusoidal phase voltage command". That is, since the number of switchings of the first leg of the H-bridge circuits 5, 6 and 7 is reduced, the switching loss is also reduced. Therefore, according to the third embodiment, by reducing the peak value of the "H-bridge voltage command", the capacitor voltages of the H-bridge circuits 5, 6 and 7 are lowered to reduce the switching loss. This makes it possible to further reduce the switching loss of the H-bridge circuits 5, 6 and 7.
- FIG. 30 is a diagram showing an operation waveform when neither the first common voltage superimposition device 903B nor the second common voltage superimposition device 904C is provided in the configuration of the third embodiment.
- the polarity of the “corrected H-bridge voltage command” changes 10 times in the fundamental wave period of the “sinusoidal phase voltage command”, and is H.
- the first leg of the bridge circuits 5, 6 and 7 will be switched 10 times.
- FIG. 31 shows an operation waveform when the first common voltage superimposition device 903B is added. That is, FIG. 31 is a diagram showing an operation waveform when there is no second common voltage superimposition device 904C in the configuration of the third embodiment.
- FIG. 32 shows an operation waveform when a second common voltage superimposition device 904C is further added. That is, FIG. 32 is a diagram showing an operation waveform of the configuration of FIG. 24 in the third embodiment.
- the polarity change of the “corrected H-bridge voltage command” is reduced to 10 times in the fundamental wave period of the “sinusoidal phase voltage command”. That is, since the number of switchings of the first leg of the H-bridge circuits 5, 6 and 7 is reduced, the switching loss is also reduced. Therefore, according to the third embodiment, by reducing the peak value of the "H-bridge voltage command", the capacitor voltages of the H-bridge circuits 5, 6 and 7 are lowered to reduce the switching loss. This makes it possible to further reduce the switching loss of the H-bridge circuits 5, 6 and 7.
- the power conversion controller does not change the positive / negative properties of the third phase voltage command with respect to the first phase voltage command. Calculate the second three-phase common voltage. As a result, the switching loss can be further reduced as compared with the first embodiment and the second embodiment, and a more efficient power conversion device can be configured, which is an unprecedented remarkable effect.
- the power conversion controller sets a value obtained by inverting the polarity of the average value of the maximum value and the minimum value of each of the first phase voltage commands as the first three-phase. Generated as a common voltage. As a result, the peak value of each of the first phase voltage commands can be reduced, so that the power conversion device can be efficiently controlled while reducing the distortion of the output phase voltage.
- the power conversion controller has a three-phase pulse when the modulation factor m is 0.67 or more and 0.97 or less, or 1.11 or more.
- the second three-phase common voltage is calculated so that the maximum value of each second phase voltage command becomes zero or negative.
- the power conversion controller calculates the second three-phase common voltage so that the minimum value of each second phase voltage command becomes zero or positive. do. As a result, the number of switchings of the first leg of the single-phase bridge circuit is reduced, so that the switching loss of the single-phase bridge circuit can be reduced.
- the peak value is considerably larger than the "corrected H-bridge voltage command”.
- the peak value of the “corrected H-bridge voltage command” is further reduced by maximizing the allowable number of switchings, and the switching loss of the H-bridge circuits 5, 6 and 7 is reduced.
- a power conversion device for further reduction is disclosed.
- FIG. 33 is a circuit diagram showing the configuration of the power conversion device 14 according to the fourth embodiment.
- the power conversion controller 13C in the configuration of the power conversion device 12 according to the third embodiment shown in FIG. 23, the power conversion controller 13C is replaced with the power conversion controller 15D.
- Other configurations are the same as or equivalent to the configuration of the first embodiment, and the same or equivalent components are designated by the same reference numerals, and duplicate description will be omitted.
- FIG. 34 is a block diagram showing the configuration of the power conversion controller 15D according to the fourth embodiment.
- the second common voltage superimposition device 904C is the second common voltage superimposition device. It has been replaced by 904D.
- Other configurations are the same as or equivalent to the configuration of the first embodiment, and the same or equivalent components are designated by the same reference numerals, and duplicate description will be omitted.
- the second common voltage superimposition device 904D is a third phase voltage command v ssu3 * , v ssv3 during the period when the sum of the three phases of the three-phase pulse voltage command v sm * , v smv * , v smw * is not zero.
- the second three-phase common voltage is calculated and superimposed on the second phase voltage commands v ssu2 * , v ssv2 * , and v ssw2 * so that the positive / negative characteristics in * and v ssw3 * are not switched.
- FIG. 35 is a flowchart for explaining the operation of the second common voltage superimposition device 904D in the fourth embodiment.
- the second common voltage superimposition device 904D sets the second phase voltage commands v ssu2 * , v ssv2 * , v ssw2 * to the maximum phase v max2 , the intermediate phase v mid2 , and the minimum phase v min 2.
- the common mode voltage v smcm * of the three-phase pulse voltage command v sm * , v smv * , v smw * is calculated using the above equation (2) (step 91101).
- the second common voltage superimposition device 904D determines whether or not the modulation factor m is 0.67 or more and less than 0.86, or whether or not it is 1.11 or more (step 91102). If none of these conditions are met (step 91102, No), the process proceeds to step 91103. On the other hand, if one of the conditions is met (step 91102, Yes), the second common voltage superimposition device 904D has a positive common mode voltage v smcm * (step 91105), or is negative or zero. (Step 91109).
- Step 91110 it is determined whether or not the minimum phase v min 2 is less than zero.
- Step 91110 it is determined whether or not the minimum phase v min 2 is less than zero.
- the minimum phase v min2 is less than zero (step 91110, Yes)
- the second three-phase common voltage v ofst2 ⁇ v min2 (step 91111)
- the minimum phase v min2 is zero or more (step 91110,).
- the second three-phase common voltage vofst2 0 (step 91112).
- the minimum phase v min2 is controlled to be zero or positive.
- the second common voltage superimposition device 904D issues the second three-phase common voltage to the second phase voltage commands v ssu2 * , v ssv2 * , and v ssw2 * .
- v ssu2 * the second phase voltage commands
- v ssv3 * the third phase voltage command
- v ssw3 * the third phase voltage command
- Step 91118 it is determined whether or not the intermediate phase v mid2 is less than zero.
- the intermediate phase v mid2 is controlled to be zero or negative.
- the second common voltage superimposition device 904D superimposes the second three-phase common voltage v ofst2 on the second phase voltage commands v ssu2 * , v ssv2 * , v ssw2 * , and each of the third The phase voltage commands v ssu3 * , v ssv3 * , and v ssw3 * are generated (step 91123).
- FIG. 36 is a diagram showing the operation waveform of the configuration of FIG. 24 in the third embodiment as a comparison target.
- FIG. 37 is a diagram showing an operation waveform of the configuration of FIG. 34 in the fourth embodiment.
- the number of times of the polarity change of the “corrected H-bridge voltage command” is 6 times, which is sufficiently reduced. ing.
- the peak value of the "corrected H-bridge voltage command” is considerably larger than that of the "corrected H-bridge voltage command”. That is, in the "corrected H-bridge voltage command", there is an overmodulation component exceeding the maximum value and the minimum value that can be output by the "H-bridge voltage command”. Therefore, the "phase voltage” output by the power conversion device 12 is distorted.
- FIG. 37 which is the operation waveform of the fourth embodiment, it can be seen that the peak value of the “corrected H-bridge voltage command” is reduced as compared with FIG. 36.
- the second three-phase common voltage vofst2 is set so that the intermediate value of the three phases of the "correcting H-bridge voltage command" becomes zero or positive. It is calculated. As a result, the positive / negative polarity of the "corrected H-bridge voltage command" does not switch during the period when the sum of the three phases of the three-phase pulse voltage command is not zero.
- the "corrected H-bridge voltage command” allows a change in positive / negative polarity with respect to the "H-bridge voltage command” before correction.
- the polarity change of the "corrected H-bridge voltage command” is 10 times in the fundamental wave period of the "sinusoidal phase voltage command”. This is an increase from the 6 times shown in FIG. 36, which is the result of the third embodiment, but it is the same 10 times as when the power conversion device 14 is operated at a modulation factor of 1.15, which is an approximate rated voltage. be.
- the power conversion controller has a three-phase pulse voltage command three-phase when the modulation factor is 0.86 or more and 0.97 or less.
- the second three-phase common voltage is calculated so that the intermediate value of the three phases of each second phase voltage command becomes zero or negative.
- the power conversion controller is common to the second three phases so that the intermediate value of the three phases of each second phase voltage command becomes zero or positive. Calculate the voltage.
- control can be performed by maximizing the allowable number of switchings, so that noise and harmonics can be reduced while reducing the switching loss of the single-phase bridge circuit.
- it has a remarkable effect that has never been seen before, such as being able to supply a voltage with less distortion to the load.
- FIG. 38 is a diagram showing the relationship between the number of switching times of the first leg and the modulation factor when the second common voltage superimposition devices 904A and 904B are not used in the first and second embodiments.
- the horizontal axis X represents the modulation factor
- the vertical axis Y represents the number of switchings. Further, in the figure, the X-axis value (modulation rate) and the Y-axis value (switching frequency) at the plotted points are described.
- the number of switching times at a modulation factor m 1.15, which is the rated voltage, is 10.
- the modulation factor m is 0.45 or less, or 0.61 or more, and 0.79 or less, or 0.90 or more, and 0.99 or less, or 1. In the case of 23 or more, it is more than 10 times.
- the modulation factor m is as small as 0.45 or less, no special processing is performed in each embodiment for the reason described at the beginning of the second embodiment. Therefore, the conditions of the modulation factor m on which the second three-phase common voltage vost2 is superimposed are 0.61 or more, 0.79 or less, 0.90 or more, 0.99 or less, and 1.23 or more. Become.
- FIG. 39 is a diagram showing the relationship between the number of switchings and the modulation factor when the second three-phase common voltage superimposition device 904A in the first embodiment is used. According to FIG. 39, it can be confirmed that the number of switchings can be reduced in the modulation factor region where the number of switchings has increased.
- FIG. 40 is a diagram showing the relationship between the number of switchings and the modulation factor when the second three-phase common voltage superimposition device 904B in the second embodiment is used.
- the number of switchings increases in the range where the modulation factor is 0.90 or more and 0.99 or less.
- This characteristic is due to the fact that, as described in the second embodiment, control is performed to obtain an output voltage with less distortion by making maximum use of the allowable number of switching times. That is, the allowable number of switchings can be fully utilized in the range of the modulation factor of 0.90 or more and 0.99 or less.
- FIG. 41 shows the number of switching times and modulation of the first leg when the first common voltage superimposition device 903B of the third embodiment and the fourth embodiment is used and the second common voltage superimposition devices 904C and 904D are not used. It is a figure which shows the relationship of rates.
- the modulation factor m is 0.66 or less, 0.67 or more, and 0.97 or less, or 1.11 or more, the number of switchings becomes more than 10 times, which is the rated voltage in a general inverter circuit. There is.
- the modulation factor m is as small as 0.66 or less, no special processing is performed in each embodiment for the reason described at the beginning of the second embodiment. Therefore, the conditions of the modulation factor for superimposing the second three-phase common voltage are 0.67 or more, 0.97 or less, and 1.11 or more.
- FIG. 42 is a diagram showing the relationship between the number of switchings and the modulation factor when the second three-phase common voltage superimposition device 904C in the third embodiment is used. According to FIG. 42, the number of switchings can be reduced in the modulation factor region where the number of switchings is large.
- FIG. 43 is a diagram showing the relationship between the number of switchings and the modulation factor when the second three-phase common voltage superimposition device 904D in the fourth embodiment is used. According to FIG. 43, the allowable number of switchings can be fully utilized in the range of the modulation factor of 0.86 or more and 0.97 or less.
- FIG. 44 is a diagram showing an example of a hardware configuration that realizes each function of the power conversion controller according to the first to fourth embodiments.
- FIG. 45 is a diagram showing another example of a hardware configuration that realizes each function of the power conversion controller according to the first to fourth embodiments.
- the functions of the power conversion controller include the three-phase pulse voltage command calculator 901, the dead time inserter 902, 907, and the first common voltage superimposition included in the power conversion controllers 9A, 11B, 13C, and 15D. It refers to the functions of the devices 903A, 903B, the second common voltage superimposition device 904A, 904B, 904C, 904D, the voltage polarity controller 905, the PWM controller 906, and the subtractor 908.
- Each function of the power conversion controller can be realized by using a processing circuit.
- the power conversion controllers 9A, 11B, 13C, 15D in the configurations of the first to fourth embodiments are replaced with the dedicated processing circuit 16.
- the dedicated processing circuit 16 is a single circuit, a composite circuit, a programmed processor, a parallel programmed processor, an ASIC (Application Specific Integrated Circuit), an FPGA (Field Programmable Gate Array), or these. The combination of is applicable.
- Each function of the power conversion controller may be realized by a processing circuit, or may be collectively realized by a processing circuit.
- the power conversion controllers 9A, 11B, 13C, 15D in the configurations of the first to fourth embodiments are replaced with the processor 17 and the storage device 18.
- the processor 17 may be an arithmetic unit, a microprocessor, a microcomputer, a CPU (Central Processing Unit), or a DSP (Digital Signal Processor).
- the storage device 18 a non-volatile or volatile semiconductor such as a RAM (Random Access Memory), a ROM (Read Only Memory), a flash memory, an EPROM (Erasable Project ROM), and an EPROM (registered trademark) (Electrically EPROM). Can be exemplified.
- each function of the power conversion controller is realized by software, firmware, or a combination thereof.
- the software or firmware is described as a program and stored in the storage device 18.
- the processor 17 reads out and executes the program stored in the storage device 18. It can also be said that these programs cause the computer to execute the procedure and method of each function of the power conversion controller.
- Each function of the power conversion controller may be partially realized by hardware and partly realized by software or firmware.
- the functions of the dead time inserter 902, 907 and the PWM controller 906 are realized by using dedicated hardware, and the three-phase pulse voltage command processor 901, the first common voltage superimposition device 903A, 903B, and the second
- the functions of the common voltage superimposition device 904A, 904B, 904C, 904D, the voltage polarity controller 905, and the subtractor 908 may be realized by using the processor 17 and the storage device 18.
- the load is a motor, and the case of torque control of the motor in the operating waveform etc. has been described as an example, but the present invention is not limited to this.
- the motor may be speed controlled.
- the load may be other than the motor.
- the power conversion device may be connected to a system power supply or another power converter to control active power and reactive power.
- the DC power supply has been described by the symbol of the voltage source, a battery may be used, or a voltage rectified from the power system by using a transformer or a semiconductor element may be used.
- the three-phase three-level inverter exemplified as the inverter circuit has been described by exemplifying a diode clamp type, it may be a capacitor clamp type or both between the output terminal of each phase and the DC neutral point. It may be the one using the direction switch.
- the semiconductor switching element used for the three-phase inverter circuit and the single-phase bridge circuit is described by the symbol of the IGBT or MOSFET, but any semiconductor element that can be turned on and off can be used.
- the wide bandgap semiconductor element an element using GaN can be used in addition to SiC, and the selection of the DC voltage and the withstand voltage of the element can be freely set without being limited to the values of the embodiment.
- a Si element is used for the three-phase inverter circuit, and a SiC element is used for the H-bridge circuit, but this can also be reversed. By using the element made of SiC on the high voltage side in this way, it is possible to configure a power conversion device having a higher DC voltage.
- the voltage waveform of the three-phase inverter circuit has been described as a one-pulse voltage, it is not limited to the number of these pulses. Further, the voltage of a plurality of pulse numbers may be generated by PWM control comparing the voltage command and the carrier, or the phase angle ⁇ may be generated by using an inverter or a pulse pattern optimized to minimize the load loss. You may.
- the configuration shown in the above embodiments is an example, and can be combined with another known technique, can be combined with each other, and does not deviate from the gist. It is also possible to omit or change a part of the configuration.
- 1,10,12,14 Power converter 2 motor, 3 DC power supply, 4 inverter circuit, 4a, 4b, 4c AC end, 5,6,7 H bridge circuit, 5a1,5a2,6a1,6a2,7a1,7a2 Midpoint, 8 motor controller, 9A, 11B, 13C, 15D power conversion controller, 16 dedicated processing circuit, 17 processor, 18 storage device, 901 three-phase pulse voltage command calculator, 902,907 dead time inserter, 903A , 903B 1st common voltage superimposition, 904A, 904B, 904C, 904D 2nd common voltage superimposition, 905 voltage polarity controller, 906 PWM controller, 908 subtractor.
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Abstract
Description
図1は、実施の形態1に係る電力変換装置1の構成を示す回路図である。実施の形態1に係る電力変換装置1は、直流電源3から出力される直流電力を負荷であるモータ2への交流電力に変換して、モータ2に供給する電力変換装置である。電力変換装置1は、図1に示すように、インバータ回路4と、単相ブリッジ回路であるHブリッジ回路5,6,7と、制御器としての電力変換制御器9Aを備えている。直流電源3の正負端子間には、インバータ回路4が接続され、インバータ回路4の互いに異なる1つの相の交流端4a,4b,4cと、モータ2の各相との間には、それぞれHブリッジ回路5,6,7が直列に挿入されるように接続されている。なお、図1では、インバータ回路4が三相3レベルインバータである場合を例示しているが、これに限定されない。インバータ回路4は、三相2レベルインバータであってもよい。或いは、インバータ回路4は、多相、即ち4相以上の、2レベルインバータもしくは3レベルインバータであってもよい。
である。電力変換装置1が出力する「相電圧」は、「三相パルス電圧指令」と「Hブリッジ出力電圧」との和となり、準正弦波状の波形になる。これにより、ノイズ及び高調波成分の少ない「相電圧」が得られる。
一般的なインバータ回路では、出力線間電圧の振幅が直流電圧と等しくなる場合を定格電圧とすることが多い。このときの変調率mは、m=1.15である。この場合について、第1の共通電圧重畳器903A及び第2の共通電圧重畳器904Aが両方とも無い場合の動作波形を図18に示す。即ち、図18は、実施の形態1の構成において、第1の共通電圧重畳器903A及び第2の共通電圧重畳器904Aが両方とも無い場合の動作波形を示す図である。
実施の形態1及び実施の形態2の第1の共通電圧重畳器903Aは、第2の各相電圧指令vssu2 *,vssv2 *,vssw2 *の波高値が低減されるように第1の三相共通電圧を演算している。即ち、第1の三相共通電圧は、第1の各相電圧指令vssu1 *,vssv1 *,vssw1 *によって出力可能な最大値vcs及び最小値-vcsを超えないように演算される。しかしながら、実施の形態1及び実施の形態2の制御には、改善の余地がある。波高値を更に低減できれば、Hブリッジ回路5,6,7のスイッチング損失を更に低減することができる。そこで、実施の形態3では、第2の各相電圧指令vssu2 *,vssv2 *,vssw2 *の波高値を更に低減して、Hブリッジ回路5,6,7のスイッチング損失の更なる低減を図る電力変換装置を開示する。
実施の形態3において、図29の動作波形、即ち変調率m=0.85で動作する場合、Hブリッジ回路5,6,7の第1のレグのスイッチング回数は6回である。これは、一般的なインバータ回路で定格電圧とされる変調率m=1.15におけるスイッチング回数である10回に比べて少ない。その一方で、図29(g)の「補正後Hブリッジ電圧指令」の波形を参照すると、その波高値は「補正中Hブリッジ電圧指令」よりもかなり大きくなっている。そこで、実施の形態4では、許容されるスイッチング回数を最大限に利用して、「補正後Hブリッジ電圧指令」の波高値を更に低減して、Hブリッジ回路5,6,7のスイッチング損失の更なる低減を図る電力変換装置を開示する。
Claims (12)
- 直流電源から出力される直流電力を負荷への交流電力に変換して前記負荷に供給する電力変換装置であって、
前記直流電源の正負端子に接続された三相インバータ回路と、
2つの半導体スイッチング素子が直列に接続され、それらの接続端である中点が前記三相インバータ回路の互いに異なる1つの相の交流端に接続される第1のレグと、前記第1のレグに並列に接続され、2つの半導体スイッチング素子が直列に接続され、それらの接続端である中点が前記負荷における互いに異なる1つの相の端子に接続される第2のレグと、前記第1及び第2のレグのそれぞれの両端に接続されるコンデンサとを有する3つの単相ブリッジ回路と、
正弦波状相電圧指令に基づいて前記三相インバータ回路の動作を制御する第1のゲート信号と、3つの前記単相ブリッジ回路における前記第1及び第2のレグの動作を制御する第2のゲート信号とを生成する制御器と、
を備え、
前記制御器は、
前記正弦波状相電圧指令を前記三相インバータ回路に指令する三相パルス電圧指令と、3つの前記単相ブリッジ回路のそれぞれに指令する電圧指令である第1の各相電圧指令とに分割し、
前記三相パルス電圧指令に基づいて前記第1のゲート信号を生成し、
三相で共通の第1の三相共通電圧を演算し、演算した前記第1の三相共通電圧を前記第1の各相電圧指令に重畳した第2の各相電圧指令を生成し、
更に前記三相で共通の第2の三相共通電圧を演算し、演算した前記第2の三相共通電圧を前記第2の各相電圧指令に重畳した第3の各相電圧指令を生成し、
前記第3の各相電圧指令の正負極性に基づいて前記第1及び第2のレグのうちの何れか一方のレグに付与する前記第2のゲート信号を生成しつつ、前記第3の各相電圧指令に従って前記第1及び第2のレグのうちの何れか他方のレグに付与する前記第2のゲート信号を生成し、
前記三相パルス電圧指令の三相の和がゼロでない期間は、前記第3の各相電圧指令の正負極性が切り替わらないように前記第2の三相共通電圧を演算する
ことを特徴とする電力変換装置。 - 前記制御器は、前記第3の各相電圧指令の正負極性が前記第1の各相電圧指令に対して変化しないように前記第2の三相共通電圧を演算する
ことを特徴とする請求項1に記載の電力変換装置。 - 前記コンデンサの電圧であるコンデンサ電圧は、前記直流電源の電圧の4分の1以下である
ことを特徴とする請求項1又は2に記載の電力変換装置。 - 前記制御器は、前記第2の各相電圧指令における各相の電圧値の絶対値が前記コンデンサ電圧を超えないように前記第1の三相共通電圧を演算する
ことを特徴とする請求項3に記載の電力変換装置。 - 変調率を前記正弦波状相電圧指令の振幅を前記直流電源の電圧の半分の値で除した値と定義するとき、
前記制御器は、
前記変調率が、0.61以上、且つ0.79以下の場合、又は0.90以上、且つ0.99以下の場合、又は1.23以上の場合、
前記三相パルス電圧指令の三相の和が正のときには、前記第2の各相電圧指令の最大値がゼロ又は負になるように前記第2の三相共通電圧を演算し、
前記三相パルス電圧指令の三相の和が負のときには、前記第2の各相電圧指令の最小値がゼロ又は正になるように前記第2の三相共通電圧を演算する
ことを特徴とする請求項1から4の何れか1項に記載の電力変換装置。 - 変調率を前記正弦波状相電圧指令の振幅を前記直流電源の電圧の半分の値で除した値と定義するとき、
前記制御器は、
前記変調率が、0.90以上、且つ0.99以下の場合、
前記三相パルス電圧指令の三相の和が正のときには、前記第2の各相電圧指令の最大値がゼロ又は正になるように前記第2の三相共通電圧を演算し、
前記三相パルス電圧指令の三相の和が負のときには、前記第2の各相電圧指令の最小値がゼロ又は負になるように前記第2の三相共通電圧を演算する
ことを特徴とする請求項1、3、4又は5に記載の電力変換装置。 - 前記制御器は、前記第1の各相電圧指令の最大値と最小値との平均値の極性を反転した値を前記第1の三相共通電圧として生成する
ことを特徴とする請求項1又は2に記載の電力変換装置。 - 変調率を前記正弦波状相電圧指令の振幅を前記直流電源の電圧の半分の値で除した値と定義するとき、
前記制御器は、
前記変調率が、0.67以上、且つ0.97以下の場合、又は1.11以上の場合、
前記三相パルス電圧指令の三相の和が正のときには、前記第2の各相電圧指令の最大値がゼロ又は負になるように前記第2の三相共通電圧を演算し、
前記三相パルス電圧指令の三相の和が負のときには、前記第2の各相電圧指令の最小値がゼロ又は正になるように前記第2の三相共通電圧を演算する
ことを特徴とする請求項1、2又は7に記載の電力変換装置。 - 変調率を前記正弦波状相電圧指令の振幅を前記直流電源の電圧の半分の値で除した値と定義するとき、
前記制御器は、
前記変調率が、0.86以上、且つ0.97以下の場合、
前記三相パルス電圧指令の三相の和が正のときには、前記第2の各相電圧指令の中間値がゼロ又は負になるように前記第2の三相共通電圧を演算し、
前記三相パルス電圧指令の三相の和が負のときには、前記第2の各相電圧指令の中間値がゼロ又は正になるように前記第2の三相共通電圧を演算する
ことを特徴とする請求項1、7又は8に記載の電力変換装置。 - 前記三相インバータ回路には、ナローバンドギャップ半導体で形成された半導体スイッチング素子を用い、
前記単相ブリッジ回路には、ワイドバンドギャップ半導体で形成された半導体スイッチング素子を用いる
ことを特徴とする請求項1から9の何れか1項に記載の電力変換装置。 - 前記単相ブリッジ回路を構成する前記第1及び第2のレグのうち、前記第3の各相電圧指令の正負極性に基づいて生成される前記第2のゲート信号によって制御されるレグには、ナローバンドギャップ半導体で形成された半導体スイッチング素子を用いる
ことを特徴とする請求項1から10の何れか1項に記載の電力変換装置。 - 前記第3の各相電圧指令による正負極性の切り替え回数は、前記正弦波状相電圧指令の基本波周期において10回以下である
ことを特徴とする請求項1から11の何れか1項に記載の電力変換装置。
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JP2000166251A (ja) * | 1998-12-01 | 2000-06-16 | Fuji Electric Co Ltd | 電力変換装置 |
JP2004120979A (ja) * | 2002-09-30 | 2004-04-15 | Mitsubishi Electric Corp | 電力変換装置 |
WO2010103600A1 (ja) | 2009-03-09 | 2010-09-16 | 三菱電機株式会社 | 電力変換装置 |
JP6682049B1 (ja) * | 2019-06-25 | 2020-04-15 | 三菱電機株式会社 | 電力変換装置 |
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WO2014125697A1 (ja) * | 2013-02-15 | 2014-08-21 | 三菱電機株式会社 | 三相電力変換装置 |
CN104283432B (zh) * | 2013-07-03 | 2017-12-26 | 通用电气公司 | 联合共模电压注入系统和方法 |
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JP2000166251A (ja) * | 1998-12-01 | 2000-06-16 | Fuji Electric Co Ltd | 電力変換装置 |
JP2004120979A (ja) * | 2002-09-30 | 2004-04-15 | Mitsubishi Electric Corp | 電力変換装置 |
WO2010103600A1 (ja) | 2009-03-09 | 2010-09-16 | 三菱電機株式会社 | 電力変換装置 |
JP6682049B1 (ja) * | 2019-06-25 | 2020-04-15 | 三菱電機株式会社 | 電力変換装置 |
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