WO2023281668A1 - 電力変換装置、航空機及び電力変換方法 - Google Patents
電力変換装置、航空機及び電力変換方法 Download PDFInfo
- Publication number
- WO2023281668A1 WO2023281668A1 PCT/JP2021/025656 JP2021025656W WO2023281668A1 WO 2023281668 A1 WO2023281668 A1 WO 2023281668A1 JP 2021025656 W JP2021025656 W JP 2021025656W WO 2023281668 A1 WO2023281668 A1 WO 2023281668A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- inverter
- sub
- voltage
- controlled
- main
- Prior art date
Links
- 238000006243 chemical reaction Methods 0.000 title claims abstract description 49
- 238000000034 method Methods 0.000 title claims description 9
- 239000003990 capacitor Substances 0.000 claims abstract description 129
- 239000004065 semiconductor Substances 0.000 claims description 54
- 238000001514 detection method Methods 0.000 claims description 10
- 230000000630 rising effect Effects 0.000 claims description 4
- 238000010586 diagram Methods 0.000 description 45
- 239000000446 fuel Substances 0.000 description 3
- 230000002123 temporal effect Effects 0.000 description 2
- 240000007594 Oryza sativa Species 0.000 description 1
- 235000007164 Oryza sativa Nutrition 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- 230000002457 bidirectional effect Effects 0.000 description 1
- JJWKPURADFRFRB-UHFFFAOYSA-N carbonyl sulfide Chemical compound O=C=S JJWKPURADFRFRB-UHFFFAOYSA-N 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000000605 extraction Methods 0.000 description 1
- 238000010304 firing Methods 0.000 description 1
- 230000007274 generation of a signal involved in cell-cell signaling Effects 0.000 description 1
- 238000009413 insulation Methods 0.000 description 1
- 239000012212 insulator Substances 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000007935 neutral effect Effects 0.000 description 1
- 230000002265 prevention Effects 0.000 description 1
- 230000001141 propulsive effect Effects 0.000 description 1
- 235000009566 rice Nutrition 0.000 description 1
- 239000007858 starting material Substances 0.000 description 1
- 230000001360 synchronised effect Effects 0.000 description 1
Images
Classifications
-
- 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
- H02M1/0095—Hybrid converter topologies, e.g. NPC mixed with flying capacitor, thyristor converter mixed with MMC or charge pump mixed with buck
-
- 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
- H02M1/0003—Details of control, feedback or regulation circuits
- H02M1/0029—Circuits or arrangements for limiting the slope of switching signals, e.g. slew rate
-
- 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
-
- 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
- H02M7/4833—Capacitor voltage balancing
-
- 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
-
- 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
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03K—PULSE TECHNIQUE
- H03K17/00—Electronic switching or gating, i.e. not by contact-making and –breaking
Definitions
- the present disclosure relates to a power conversion device, an aircraft equipped with the power conversion device, and a power conversion method.
- the inverter which is one of the power conversion devices, generates noise due to switching.
- a gradation-controlled inverter in which a sub-inverter is connected in series with a main inverter is known.
- a gradation control type inverter has a capacitor in a sub-inverter, and controls the capacitor of the sub-inverter to a predetermined voltage.
- the sub-inverter is equipped with an initial charging circuit composed of a current limiting resistor, a switch, etc., in order to prevent overcurrent from flowing during the initial charging of the capacitor.
- the gradation control type inverter performs gradation operation by adding or subtracting the output voltage of the sub-inverter to the output voltage of the main inverter.
- the gradation-controlled inverter can reduce the switching frequency more than a general inverter composed only of a main inverter. Therefore, the gradation-controlled inverter can reduce noise.
- Patent Document 1 discloses a gradation-controlled inverter that is not equipped with an initial charging circuit for the capacitor of the sub-inverter.
- the gradation-controlled inverter described in Patent Document 1 controls the pulse width and pulse period of the pulse voltage output by the main inverter to suppress the rush current flowing through the capacitor of the sub-inverter, thereby initial charging the capacitor of the sub-inverter. conduct.
- the capacitor of the sub-inverter can be initially charged without providing an initial charging circuit for the capacitor of the sub-inverter, so that the size of the gradation control inverter can be reduced.
- the main inverter starts switching when the capacitor of the sub-inverter is not controlled to a predetermined voltage, such as at startup.
- a predetermined voltage such as at startup.
- the gradation-controlled inverter outputs a large amount of voltage change due to the main inverter to the load, large noise is generated.
- the present disclosure has been made in order to solve the above-described problems. , a power conversion device capable of reducing noise caused by a main inverter, an aircraft equipped with the power conversion device, and a power conversion method.
- a power conversion device includes a main inverter connected to a power source side and having a gate drive circuit capable of changing gate impedance, and a sub-inverter having a capacitor connected in series to the main inverter and connected to a load side.
- a voltage detecting means for detecting the capacitor voltage of the sub-inverter
- a voltage detecting means for controlling the capacitor voltage of the sub-inverter detected by the voltage detecting means to a predetermined voltage
- a control unit controls the gate impedance so that the capacitor voltage of the sub-inverter becomes higher than the gate impedance of the main inverter after being controlled to a predetermined voltage.
- a power conversion method includes a main inverter connected to a power source side and having a gate drive circuit capable of changing gate impedance, and a sub-inverter having a capacitor connected in series to the main inverter and connected to a load side. and a step of controlling the detected capacitor voltage of the sub-inverter to a predetermined voltage, detecting the capacitor voltage of the sub-inverter, and before the capacitor voltage of the sub-inverter is controlled to the predetermined voltage and controlling the gate impedance of the main inverter to be higher than the gate impedance of the main inverter after the capacitor voltage of the sub-inverter is controlled to a predetermined voltage.
- noise caused by the main inverter can be reduced when the capacitor of the sub-inverter is not controlled to have a predetermined voltage.
- FIG. 1 is a circuit diagram showing the configuration of a power converter according to Embodiment 1.
- FIG. FIG. 2 is a circuit diagram showing a gate drive circuit provided with gate impedance changing means for the main inverter according to the first embodiment.
- FIG. 3 is a flow chart showing the operation of the gradation control inverter according to the first embodiment.
- FIG. 4 is an output voltage waveform diagram of the gradation control inverter in step S301 of the first embodiment.
- FIG. 5 is an output voltage waveform diagram of the gradation control inverter in step S301 of the first embodiment.
- FIG. 6 is an output voltage waveform diagram of the gradation control inverter in step S301 of the first embodiment.
- FIG. 1 is a circuit diagram showing the configuration of a power converter according to Embodiment 1.
- FIG. FIG. 2 is a circuit diagram showing a gate drive circuit provided with gate impedance changing means for the main inverter according to the first embodiment.
- FIG. 3 is a flow chart showing the
- FIG. 7 is an output voltage waveform diagram of the gradation control inverter in step S501 of the first embodiment.
- FIG. 8 is an output voltage waveform diagram of the gradation control inverter in step S501 of the first embodiment.
- FIG. 9 is a schematic diagram showing temporal changes in the output voltage of the main inverter according to the first embodiment.
- FIG. 10 is an output voltage waveform diagram of the gradation control inverter according to the first embodiment.
- FIG. 11 is a circuit diagram showing the configuration of a gradation-controlled inverter according to the second embodiment.
- FIG. 12 is a flow chart showing the operation of the gradation control inverter according to the second embodiment.
- FIG. 13 is an output voltage waveform diagram of the gradation control inverter in step S302 of the second embodiment.
- FIG. 14 is a flow chart showing the operation of the gradation control inverter according to the third embodiment.
- FIG. 15 is an explanatory diagram for explaining step S603 of the third embodiment.
- FIG. 16 is a circuit diagram showing the configuration of a gradation-controlled inverter according to the fourth embodiment.
- FIG. 17 is a flow chart showing the operation of the gradation control inverter according to the fourth embodiment.
- FIG. 18 is a schematic diagram of an aircraft in Embodiment 5.
- FIG. FIG. 19 is a schematic diagram of an aircraft in Embodiment 6.
- FIG. 1 is a circuit diagram showing the configuration of a gradation-controlled inverter 2 according to the first embodiment.
- the power conversion device 1 of the present embodiment is a DC/AC gradation control type inverter 2 that converts DC power from a first DC power source 3, which is a DC power source, into AC required to drive a load 4. An example is given.
- a gradation-controlled inverter 2 is connected between a first DC source 3 and a load 4 .
- the first DC source 3 will be described as being supplied by DC wiring as an example, but it may be a separate DC power supply system, solar battery, or the like.
- a DC/DC power conversion device capable of stepping up, stepping down or stepping up and down and an AC/DC power conversion device are provided on the DC wiring side to supply the DC voltage.
- a DC/DC power conversion device may be provided between the first DC source 3 and the power conversion device 1 .
- the load 4 is, for example, a load composed of at least one passive component such as a resistor, an inductor, and a capacitor. Also, the load 4 may be an electric motor or the like.
- the gradation-controlled inverter 2 includes an input noise filter 10, two series capacitors 11 and 12, a main inverter 20, a sub-inverter 30, an output noise filter 13, and a control section . Each configuration of the gradation control type inverter 2 will be described below.
- the main inverter 20 is connected to the first DC power source 3 side, which is a DC power source, rather than the sub-inverter 30 .
- the main inverter 20 will be described as an example of a three-phase, three-level inverter.
- the main inverter 20 is not limited to a three-phase inverter, and may have a plurality of output phases other than a single-phase inverter and three phases, for example. Further, the main inverter 20 is not limited to a three-level inverter, and may be a multi-level inverter with other number of output levels.
- the main inverter 20 is a three-phase inverter and is composed of three output phases 21, 22, and 23 of a U-phase main inverter arm 21, a V-phase main inverter arm 22, and a W-phase main inverter arm 23.
- the main inverter 20 includes semiconductor switches such as IGBTs and MOSFETs having four switching capabilities, diodes having two rectifying capabilities, and a gate drive circuit 24 for each output phase 21 , 22 , 23 . IGBTs, MOSFETs, etc. may be used instead of diodes.
- the gate drive circuit 24 can change the gate impedance of the circuit elements of the gate drive circuit 24 .
- the gate drive circuit 24 will be described later.
- the main inverter 20 is a three-level inverter and is connected to the midpoint of two series capacitors 11 and 12 that divide the voltage of the first DC source 3 .
- the DC bus voltage value of the main inverter 20, which is the voltage of the first DC source 3 is referred to as VDCM.
- the high potential side capacitor of the two series capacitors 11 and 12 is referred to as P bus capacitor 11, its voltage value is VDCMP, the low potential side capacitor is referred to as N bus capacitor 12, and its voltage value is VDCMN.
- Main inverter 20 has semiconductor switches driven and controlled by control unit 14, voltage VDCMP of P-bus capacitor 11, voltage VDCMN of N-bus capacitor 12, and neutral voltage which is a connection point between P-bus capacitor 11 and N-bus capacitor 12. Output one of the point voltages.
- FIG. 1 shows the main inverter 20 as a diode-clamped three-level inverter, it may be configured as a flying capacitor type, or as a T-type three-level inverter using a bidirectional switch.
- the main inverter 20 also includes voltage detection means for detecting the voltage VDCMP of the P-bus capacitor 11 and the voltage VDCMN of the N-bus capacitor 12 of the main inverter 20 .
- a well-known means may be used as the voltage detection means.
- the voltage between terminals may be stepped down by a resistance voltage dividing circuit, and the stepped-down voltage may be detected by receiving the stepped-down voltage in a differential amplifier circuit.
- the sub-inverter 30 is a single-phase inverter connected in series with the main inverter 20 and connected closer to the load 4 than the main inverter 20 and having a capacitor 35 .
- the sub-inverters 30 are connected in series to respective terminals of the U-phase main inverter arm 21, the V-phase main inverter arm 22, and the W-phase main inverter arm 23 of the main inverter 20, respectively.
- the sub-inverters 30 connected in series to the output phases 21, 22, 23 of the main inverter 20 are called a U-phase sub-inverter 31, a V-phase sub-inverter 32, and a W-phase sub-inverter 33, respectively.
- the sub-inverter 30 is a full-bridge inverter, with semiconductor switches such as IGBTs and MOSFETs with two switching capabilities per bridge.
- Each of the U-phase sub-inverter 31, the V-phase sub-inverter 32, and the W-phase sub-inverter 33 includes a capacitor 35 and a gate drive circuit 34 capable of changing the gate impedance.
- the gate drive circuit 34 can change the gate impedance of the circuit elements of the gate drive circuit 34 .
- the gate drive circuit 34 will be described later.
- the voltage values of the capacitors 35 of the U-phase sub-inverter 31, V-phase sub-inverter 32, and W-phase sub-inverter 33 are referred to as VDCSU, VDCSV, and VDCSW, respectively.
- Capacitor voltages VDCSU, VDCSV, and VDCSW of the output phases 31, 32, and 33 are collectively referred to as a capacitor voltage VDCS of the sub-inverter 30.
- the sub-inverter 30 has voltage detection means for detecting the capacitor voltage VDCS of the sub-inverter 30 .
- a well-known means may be used as the voltage detection means.
- Capacitor voltage VDCS of sub-inverter 30 is controlled to a predetermined voltage by control unit 14 .
- the predetermined voltage is set lower than the voltage of the first DC source 3 which is the DC bus voltage VDCM of the main inverter 20 .
- the capacitor voltage VDCS of the sub-inverter 30 is 1 ⁇ 4 of the DC bus voltage VDCM of the main inverter 20 will be described.
- the predetermined voltage is not limited to 1/4 voltage of the DC bus voltage VDCM of the main inverter 20 as long as it is lower than the voltage of the first DC source 3 .
- Each of the semiconductor switches and diodes described above may be composed of Si semiconductors, or any of the semiconductor switches and diodes may be composed of wide bandgap semiconductors such as SiC and GaN.
- a wide bandgap semiconductor can reduce loss more than a Si semiconductor.
- the main inverter 20 includes a gate drive circuit 24 having gate impedance changing means for each semiconductor switch of each output phase 21, 22, 23 in order to change the switching speed of each semiconductor switch.
- the sub-inverter 30 comprises a gate drive circuit 34 with gate impedance changing means for each semiconductor switch of each output phase 31, 32, 33 in order to change the switching speed of each semiconductor switch.
- FIG. 2 is a circuit diagram showing the gate drive circuit 24 provided with the gate impedance changing means of the main inverter 20 of the first embodiment.
- FIG. 2 shows a gate drive circuit 24 for driving the semiconductor switches of the U-phase main inverter arm 21 indicated by A in FIG.
- the gate drive circuit 24 shown in FIG. 2 will be described as an example, the other semiconductor switches and the gate drive circuits 24 and 34 connected to the semiconductor switches have the same circuit configuration.
- the gate drive circuit 24 comprises four bridge-connected transistors 41, 42, 43, 44.
- Transistor 41 and transistor 42 are connected in series via impedance components 45, 46 of the two circuit elements.
- Transistors 43 and 44 are connected in series via impedance components 47, 48 of the two circuit elements.
- a connection point between the impedance components 45 and 46 of the circuit element and a connection point between the impedance components 47 and 48 of the circuit element are connected, and the output terminal thereof is connected to the gate of the semiconductor switch.
- the output part of the gate drive circuit 24 is composed of a totem-pole circuit (also called a push-pull circuit), and the number of parallel gate impedances is changed according to the number of parallel totem-pole circuits.
- a gate resistor is generally used for the gate impedance of each circuit element, but it may be configured by combining a resistor and a passive component such as an inductor.
- the gate drive circuit 24 also includes a switching speed switching unit 52 that switches the speed when driving the semiconductor switch.
- the switching speed switching unit 52 is configured by, for example, a logic circuit.
- the gate drive circuit 24 includes a second DC source 61 and a third DC source 62 .
- a second DC source 61 and a third DC source 62 are connected to the transistors 41 , 42 , 43 , 44 and the insulator 51 .
- the insulating unit 51 is a circuit that isolates the signal received from the signal generating unit 50, and may use, for example, a photocoupler and an insulating IC.
- the switching speed switching unit 52 controls the on/off of the transistors 41, 42, 43, and 44 to change the parallel connection of the totem pole circuits and change the magnitude of the gate impedance. By increasing the gate impedance, the switching speed of the semiconductor switch can be slowed down. On the other hand, by reducing the gate impedance, the switching speed of the semiconductor switch can be increased.
- a totem-pole type gate impedance changing means has been described, but the configuration of the gate driving circuit 24 is not limited to that described above, and the gate driving circuit 24 capable of changing the gate impedance using other known techniques. , 34 may be constructed.
- the magnitude of the gate impedance is changed by parallel connection, it may be configured by serial connection, or by adding a plurality of circuits to increase the number of parallel or series connections and switching the connection. .
- a high-speed relay or the like may be used instead of semiconductor switches such as the transistors 41, 42, 43, and 44.
- the gate drive circuits 24 and 34 may be configured by combining diodes for gate impedance.
- the input noise filter 10 is connected between the first DC source 3 and two series capacitors 11 and 12 .
- the output noise filter 13 is connected between the sub-inverter 30 and the load 4 .
- the input noise filter 10 and the output noise filter 13 are composed of at least one of a common mode filter and a normal mode filter to suppress noise, surge voltage, and the like.
- the gradation control type inverter 2 may be provided with only one of the input noise filter 10 and the output noise filter 13 in order to reduce the number of components and reduce noise.
- the control unit 14 outputs control signals to the main inverter 20 and the sub-inverter 30 .
- the control unit 14 includes a CPU (Central Processing Unit), a DSP (Digital Signal Processor), an FPGA (Field-Programmable Gate Array), and the like.
- the control unit 14 detects the voltage VDCMP of the P-bus capacitor 11 of the main inverter 20, the voltage VDCMN of the N-bus capacitor 12 of the main inverter 20, and the capacitor voltage VDCS of each phase of the sub-inverter 30 detected by the voltage detection means. Based on this, the output voltages of the main inverter 20 and the sub-inverter 30 are controlled. Specifically, the control unit 14 controls the output voltages of the main inverter 20 and the sub-inverter 30 so that the differential voltage between the voltage VDCMP of the P-bus capacitor 11 and the voltage VDCMN of the N-bus capacitor 12 of the main inverter 20 becomes zero. , the capacitor voltage VDCS of the sub-inverter 30 is set to a predetermined voltage.
- Each voltage control by the control unit 14 is PI control or the like that brings the voltage detected by the voltage detection means closer to the target voltage to be output. Further, in order to control the load current, the control unit 14 may detect the phase current of the gradation control inverter 2 and control the load current based on the phase current. For example, the current may be controlled by detecting the phase current of the gradation-controlled inverter 2, dq-converting it, and PI-controlling the dq-converted current. The control unit 14 also controls gate impedance changing means of the gate drive circuits 24 and 34 of the main inverter 20 and the sub-inverter 30 . The operation of the control unit 14 will be described in the operation of the gradation control inverter 2, which will be described later.
- the gradation control type inverter 2 performs gradation operation by adding or subtracting the output voltage of the sub-inverter 30 to the output voltage of the main inverter 20 .
- the gradation control type inverter 2 is not equipped with an initial charging circuit for initially charging the capacitor voltage VDCS of the sub-inverter 30, but by switching the semiconductor switches of the main inverter 20 and the sub-inverter 30, the capacitor of the sub-inverter 30 is charged. Voltage VDCS is initially charged, and capacitor voltage VDCS of sub-inverter 30 is controlled to a predetermined voltage.
- FIG. 3 is a flow chart showing the operation of the gradation control inverter 2 of the first embodiment.
- step S101 the control unit 14 determines whether the capacitor voltage VDCS of the sub-inverter 30 detected by the voltage detection means of the sub-inverter 30 is controlled to a predetermined voltage.
- step S101 determines in step S101 that the capacitor voltage VDCS of the sub-inverter 30 is not controlled to the predetermined voltage (NO in S101) will be described.
- the capacitor voltage VDCS of the sub-inverter 30 is not initially charged at the time of start-up, the capacitor voltage VDCS of the gradation control inverter 2 is not controlled to a predetermined voltage.
- control unit 14 controls the gate impedance changing means of the gate drive circuits 24 and 34 to increase the gate impedances of the main inverter 20 and the sub-inverter 30 (S201).
- increasing the gate impedance of the main inverter 20 and the sub-inverter 30 means that the gate impedance of the main inverter 20 and the sub-inverter 30 after the capacitor voltage VDCS of the sub-inverter 30 is controlled to a predetermined voltage in step S601 to be described later. means big. Details of step S201 will be described later.
- step S301 the control unit 14 causes the main inverter 20 and the sub-inverter 30 to perform PWM (pulse width modulation) operation in order to output the target voltage.
- PWM pulse width modulation
- the control unit 14 controls the sub-inverter 30 having a small capacitor voltage VDCS to perform switching at a higher frequency than the main inverter 20 .
- the control unit 14 may operate the switching of the main inverter 20 at a high frequency equal to or higher than that of the sub-inverter 30 .
- the control unit 14 causes the sub-inverter 30 to output the difference between the target voltage of the gradation-controlled inverter 2 and the output voltage of the main inverter 20 .
- Step S201 and step S301 may be performed simultaneously.
- FIG. 4 to 6 are output voltage waveform diagrams of the gradation control inverter 2 in step S301 of the first embodiment. That is, this is the initial charging stage in which the capacitor voltage VDCS of the sub-inverter 30 is not controlled to a predetermined voltage, and the transitional gradation in which the capacitor voltage VDCS of the sub-inverter 30 gradually increases from 0 voltage to a predetermined voltage.
- 4 is an output voltage waveform diagram of the controlled inverter 2.
- FIG. The vertical axis is output voltage and the horizontal axis is time. In FIGS.
- the upper output voltage waveform is the U phase
- the middle output voltage waveform is the V phase
- the lower output voltage waveform is the W phase
- the left output voltage waveform is the output voltage waveform of the main inverter 20.
- the output voltage waveform diagram in the middle is the output voltage waveform of the sub-inverter 30
- the output voltage waveform diagram on the right is the output voltage of the gradation control type inverter 2, which is the phase voltage of the output voltage of the main inverter 20 and the output voltage of the sub-inverter 30.
- the DC bus voltage VDCM of the main inverter 20 is 1.5 kV
- the predetermined voltage is 375V, which is 1/4 of the VDCM voltage.
- FIG. 5 is an enlarged output voltage waveform at time t1-t2 when the capacitor voltage VDCS of the sub-inverter 30 is near zero voltage, and FIG. It is an expanded output voltage waveform.
- the main inverter 20 when the capacitor voltage VDCS of the sub-inverter 30 is near zero voltage, the amount of voltage change in the output voltage of the main inverter 20 is applied to the load 4 as the output of the gradation control inverter 2 . Since the main inverter 20 is a three-level inverter in this embodiment, the main inverter 20 applies 750 V, which is half the VDCM voltage, to the load 4 .
- the capacitor voltage VDCS of the sub-inverter 30 is higher than during the time t1-t2 shown in FIG. Therefore, the amount of voltage change of the gradation control inverter 2 is slightly smaller in FIG. 6 than in FIG.
- the control unit 14 applies approximately half the voltage of the VDCM voltage, which is a large amount of voltage change in the output voltage of the main inverter 20 , to the load 4 as the output of the gradation control type inverter 2 .
- step S401 the control unit 14 determines whether or not the capacitor voltage VDCS of the sub-inverter 30 is controlled to a predetermined voltage. As shown in FIG. 4, the control unit 14 switches the main inverter 20 and the sub-inverter 30 to gradually increase the capacitor voltage VDCS of the sub-inverter 30 to a predetermined voltage for initial charging. After the capacitor voltage VDCS of the sub-inverter 30 rises to the predetermined voltage and is initially charged, the control unit 14 controls the capacitor voltage VDCS of the sub-inverter 30 to the predetermined voltage. That is, the control unit 14 controls the capacitor voltage VDCS of the sub-inverter 30 to maintain a predetermined voltage. When the controller 14 determines that the capacitor voltage VDCS of the sub-inverter 30 is not controlled to the predetermined voltage (NO in S401), the process returns to step S301.
- the control unit 14 causes the main inverter 20 to perform PWM operation or one-pulse operation, and causes the sub-inverter 30 to perform PWM operation (S501).
- the main inverter 20 performs PWM operation or 1-pulse operation for switching at a lower frequency than the sub-inverter 30 does.
- the sub-inverter 30 performs PWM operation in which switching is performed at a higher frequency than the main inverter 20.
- FIG. As a result, a highly accurate output voltage can be output as the output voltage of the gradation control type inverter 2 .
- step S501 the case where the main inverter 20 is PWM-operated and the case where the main inverter 20 is operated for one pulse will be described with reference to FIGS. 7 and 8, respectively.
- 7 and 8 are output voltage waveform diagrams of the gradation control inverter 2 in step S501 of the first embodiment.
- the vertical axis is output voltage and the horizontal axis is time.
- the upper output voltage waveform diagram is the U phase
- the middle output voltage waveform diagram is the V phase
- the lower output voltage waveform diagram is the W phase
- the left output voltage waveform diagram is the output voltage of the main inverter 20.
- the output voltage waveform diagram in the middle is the output voltage waveform of the sub-inverter 30, and the output voltage waveform diagram on the right is the output voltage of the gradation control type inverter 2, which is the phase voltage of the output voltage of the main inverter 20 and the output voltage of the sub-inverter 30.
- Voltage waveforms are shown respectively. 7 and 8, the DC bus voltage VDCM of the main inverter 20 is 1.5 kV, and the predetermined voltage is 375V, which is 1/4 of the VDCM voltage.
- the waveform of the target voltage is superimposed on the output voltage waveform of the gradation control inverter 2 shown on the right side of FIGS.
- FIG. 7 shows the case where the capacitor voltage VDCS of the sub-inverter 30 is controlled to a predetermined voltage, and the main inverter 20 is PWM-operated by the control unit 14 in order to output the target voltage. Further, the sub-inverter 30 is PWM-operated by the control unit 14 , and the sub-inverter 30 performs switching at a higher frequency than the main inverter 20 . Sub-inverter 30 outputs the difference between the target voltage of gradation control type inverter 2 and the output voltage of main inverter 20 . In step S501, since the capacitor voltage VDCS of the sub-inverter 30 is controlled to a predetermined voltage, the sub-inverter 30 can output a desired output voltage.
- control unit 14 adjusts the large amount of voltage change by the main inverter 20 with the output voltage of the sub-inverter. As a result, the control unit 14 causes the load 4 to output, as the output of the gradation control type inverter 2, a voltage change amount that is 1/4 voltage of the bus voltage value VDCM of the main inverter 20.
- FIG. 1 the control unit 14 causes the load 4 to output, as the output of the gradation control type inverter 2, a voltage change amount that is 1/4 voltage of the bus voltage value VDCM of the main inverter 20.
- FIG. 8 shows a case where the capacitor voltage VDCS of the sub-inverter 30 is controlled to a predetermined voltage, and shows a case where the control unit 14 operates the main inverter 20 by one pulse.
- the switching frequency when the main inverter 20 performs one-pulse operation is about the same as the fundamental frequency (the frequency of the target voltage) output by the power conversion device 1, and the control unit 14 causes the main inverter 20 to switch positive and negative once per cycle. switch one by one.
- the sub-inverter 30 performs PWM operation, and the sub-inverter 30 performs switching at a higher frequency than the main inverter 20 does.
- the sub-inverter 30 outputs the difference between the target voltage of the gradation control inverter 2 and the output voltage of the main inverter 20 . That is, the one-pulse output voltage of the main inverter 20 and the output voltage of the sub-inverter 30 are adjusted and output as the output voltage of the gradation control type inverter 2 . Therefore, as shown in the output voltage waveform diagram on the right side of FIG. 8, the output voltage waveform of the gradation control inverter 2 can be a multi-level waveform close to a sine wave. In FIG. 8, the output voltage of the gradation-controlled inverter 2 shows a five-level waveform, but by increasing the target voltage, a maximum of seven-level waveform output is possible.
- step S601 the control section 14 controls the gate impedance changing means of the gate drive circuits 24 and 34 to reduce the gate impedances of the main inverter 20 and the sub-inverter 30.
- FIG. Step S601 is performed for a predetermined period after the capacitor voltage VDCS of sub-inverter 30 is controlled to a predetermined voltage.
- the predetermined period is after the capacitor voltage VDCS of the sub-inverter 30 is controlled to the predetermined voltage (after YES in S101 or YES in S401), and the loss of the semiconductor switch reaches the allowable limit. do.
- the allowable limit of the loss of the semiconductor switch is set, for example, to a temperature obtained by derating the maximum junction temperature of the semiconductor switch. Therefore, the order of steps S501 and S601 is not limited to the above description, and may be reversed or performed simultaneously. Thus, the operation of the gradation control type inverter 2 is finished.
- step S201 in FIG. 3 will be described in detail.
- the amount of noise with respect to the voltage change associated with switching increases as the voltage change width ⁇ V and the slope of dV/dt increase.
- the surge voltage increases as the slope of dV/dt increases. Therefore, when the capacitor voltage VDCS of the sub-inverter 30 is not controlled to a predetermined voltage as shown in FIG. rice field.
- the noise standard is often defined not only by the average noise value but also by the peak value and peak value. Therefore, if the gradation-controlled inverter 2 is designed with consideration given to the case where a large amount of voltage change occurs at startup as described above, the size of the input noise filter 10 and the output noise filter 13 may become large.
- step S201 of FIG. 3 the control unit 14 increases the gate impedance of the main inverter 20 to slow down the switching speed of each semiconductor switch of the main inverter 20 and reduce noise.
- FIG. 9 is a schematic diagram showing temporal changes in the output voltage of the main inverter 20 of the first embodiment.
- the vertical axis is output voltage and the horizontal axis is time. It shows that when the magnitude of the gate impedance is different, the time change of the rise and fall of the output voltage of the main inverter 20 is also different.
- the solid line is for the case where the gate impedance is small
- the broken line is for the case where the gate impedance is large.
- the slope of dv/dt is gentler than when the gate impedance is small and the switching speed is fast.
- control unit 14 increases the gate impedance of the main inverter 20 and slows down the switching speed, thereby reducing noise and surge voltage.
- FIG. 10 is an output voltage waveform diagram of the gradation control inverter 2 according to the first embodiment.
- 10A to 10D show output voltage waveform diagrams of the main inverter 20 in the upper stages, output voltage waveform diagrams of the sub-inverter 30 in the middle stages, and output voltage waveform diagrams of the gradation control type inverter 2 in the lower stages.
- the vertical axis is output voltage and the horizontal axis is time.
- FIG. 10 shows an output voltage waveform diagram when the main inverter 20 outputs a positive voltage.
- the main inverter 20 When the main inverter 20 outputs a negative voltage, the positive and negative directions of the voltage are reversed.
- 10A shows the case where the switching speeds of the main inverter 20 and the sub-inverter 30 are both slow
- FIG. 10B shows the case where the switching speeds of the main inverter 20 and the sub-inverter 30 are both fast
- FIG. FIG. 10D shows a case where the switching speed of the main inverter 20 is fast and the switching speed of the sub inverter 30 is slow.
- the output of the gradation control inverter 2 is a thin signal at the timing when the main inverter 20 outputs. It can be seen that a pulse is generated and a large amount of voltage change is generated. This narrow pulse is caused by, for example, the time lag between the switching timings of the main inverter 20 and the sub-inverter 30, the slow/fast switching speed lag, and dead time generation for arm short-circuit prevention.
- the control unit 14 similarly controls the gate impedances of the main inverter 20 and the sub-inverter 30 at the same timing to switch the switching speeds of the main inverter 20 and the sub-inverter 30 at approximately the same speed.
- step S601 as in step S201 described above the control unit 14 similarly reduces the gate impedances of the main inverter 20 and the sub-inverter 30 for the same predetermined period, thereby increasing the switching speed and realizing low-loss operation. can do.
- the gradation-controlled inverter 2 which is the power conversion device 1 in the present embodiment, sets the gate impedance of the main inverter 20 before the capacitor voltage VDCS of the sub-inverter 30 is controlled to a predetermined voltage to the sub-inverter 30 is controlled to be higher than the gate impedance of the main inverter 20 after the capacitor voltage VDCS is controlled to a predetermined voltage.
- noise caused by the main inverter 20 can be reduced when the capacitor voltage VDCS of the sub-inverter 30 is not controlled to a predetermined voltage.
- the conventional gradation-controlled inverter generates large noise when the capacitor voltage VDCS of the sub-inverter 30 is not controlled to a predetermined voltage, such as at startup. Therefore, if the noise filter is designed so as to satisfy the noise standard including the operating mode such as startup, the input noise filter 10 and the output noise filter 13 may become large and heavy. On the other hand, since the gradation-controlled inverter 2 in this embodiment can reduce noise as described above, the input noise filter 10 and the output noise filter 13 can be made smaller and lighter.
- the sub-inverter 30 before the capacitor voltage VDCS of the sub-inverter 30 is controlled to a predetermined voltage similarly to the gate impedance of the main inverter 20. is controlled to be larger than the gate impedance of the sub-inverter 30 after the capacitor voltage VDCS of the sub-inverter 30 is controlled to a predetermined voltage. That is, control unit 14 similarly controls the gate impedances of main inverter 20 and sub-inverter 30 to be large for a predetermined period after capacitor voltage VDCS of sub-inverter 30 is controlled to a predetermined voltage.
- the gradation control inverter 2 similarly controls the gate impedances of the main inverter 20 and the sub-inverter 30 in the same predetermined period, so that the output of the gradation control inverter 2 does not produce a narrow pulse. , the amount of voltage change can also be reduced. Therefore, noise and surge voltage can be suppressed, and the size of the input noise filter 10 and the output noise filter 13 can be reduced.
- the control unit 14 causes the main inverter 20 to perform one-pulse operation, so that only the sub-inverter 30 with a low capacitor voltage VDCS is switched at high frequencies. Therefore, the switching frequency of the main inverter 20 with a high DC bus voltage VDCM can be minimized, and the switching loss can be reduced. In particular, the switching loss can be reduced by performing one-pulse operation at high load such as rated operation with a large current. Furthermore, since multi-level voltage output can be realized by gradation operation, the change width of the voltage change amount can be reduced stepwise, and noise can be reduced. Therefore, the gradation control type inverter 2 is superior to the general inverter composed only of the main inverter 20 .
- the power conversion device 1 when the power conversion device 1 is mounted on an automobile, ship, aircraft, etc., it is desirable that it be small and lightweight. Since the power conversion device 1 of the present embodiment can reduce noise caused by the main inverter 20 as described above, the output noise filter 13 can be made smaller and lighter. The power conversion device 1 does not require an initial charging circuit for the capacitor 35 of the sub-inverter 30, which is composed of a current-limiting resistor, a switch, and the like. Furthermore, since the power conversion device 1 has a low loss, the cooler can be made smaller and lighter, and the output noise filter 13 by the multi-level voltage can be made smaller and lighter. Therefore, the power conversion device 1 mounted on an automobile, a ship, an aircraft, or the like can be made small and light.
- the main inverter 20 has been described as an example of a diode-clamped three-level inverter.
- the 3-level inverter increases the number of voltage levels that can be output to the load 4 side compared to the 2-level inverter. for that reason. Harmonic components contained in the output voltage can be suppressed without increasing the switching frequency.
- the size of the input noise filter 10 and the output noise filter 13 can be reduced, and the voltage applied to the semiconductor switches of the sub-inverter 30 can be halved. can.
- the power conversion device 1 when the power conversion device 1 is mounted on an aircraft, it is required to provide a larger voltage margin for the semiconductor switch than on the ground because the altitude is high and the use environment is greatly affected by cosmic rays. Therefore, by using a diode-clamped three-level inverter for the main inverter 20, low voltage elements can be used instead of large and expensive high voltage elements.
- the main inverter 20 has been described with a three-phase inverter as an example.
- the three-phase inverter can use ⁇ 3 times more power than the single-phase inverter. Also, considering that the power and voltage are the same, the current is less, so the efficiency is good.
- FIG. 11 is a circuit diagram showing the configuration of the gradation control type inverter 2 of the second embodiment.
- the gradation-controlled inverter 2 according to the second embodiment is characterized in that it does not include the gate drive circuit 34 having gate impedance changing means.
- Other configurations of the gradation control type inverter 2 are the same as those of the first embodiment.
- the same reference numerals are assigned to the same configurations as in the first embodiment.
- the main inverter 20 is provided with a gate drive circuit 24 having gate impedance changing means
- the sub-inverter 30 is provided with a gate drive circuit 34 having gate impedance changing means. Not prepared.
- FIG. 12 is a flow chart showing the operation of the gradation control inverter 2 of the second embodiment.
- step S102 the control unit 14 determines whether the capacitor voltage VDCS of the sub-inverter 30 detected by the power detection means of the sub-inverter 30 is controlled to a predetermined voltage.
- step S202 when the control unit 14 determines that the capacitor voltage VDCS of the sub-inverter 30 is not controlled to the predetermined voltage (NO in S102), the control unit 14 controls the gate impedance changing means of the gate drive circuit 24. , the gate impedance of the main inverter 20 is increased.
- increasing the gate impedance of the main inverter 20 means that the gate impedance of the main inverter 20 after the capacitor voltage VDCS of the sub-inverter 30 in step S602 described later is controlled to a predetermined voltage is greater.
- control unit 14 causes the main inverter 20 and the sub-inverter 30 to perform PWM operation.
- control unit 14 determines whether or not the capacitor voltage VDCS of the sub-inverter 30 is controlled to a predetermined voltage.
- step S502 when the capacitor voltage VDCS of the sub-inverter 30 is controlled to a predetermined voltage (YES in S102, YES in S402), the main inverter 20 is PWM-operated or one-pulse-operated, and the sub-inverter 30 is PWM-operated.
- step S602 after the capacitor voltage VDCS of the sub-inverter 30 has been controlled to a predetermined voltage, the control unit 14 controls the gate impedance changing means of the gate drive circuit 24 until the loss of the semiconductor switch reaches the allowable limit. , the gate impedance of the main inverter 20 is reduced. Thus, the operation of the gradation control type inverter 2 is finished.
- the gradation-controlled inverter 2 of the present embodiment is characterized in that the sub-inverter 30 does not include a gate drive circuit 34 having gate impedance changing means. Therefore, the gradation-controlled inverter 2 of the present embodiment controls the gate impedance changing means of the main inverter 20 and the sub-inverter 30 as in the gradation-controlled inverter 2 of the first embodiment. and the switching speed of the sub-inverter 30 cannot be made comparable. In this case, in step S202, as shown in FIG. 10C, it is necessary to suppress the generation of narrow pulses as the output of the gradation control inverter 2 and to reduce the amount of voltage change. The operation of the gradation control inverter 2 of this embodiment for solving this problem will be described with reference to FIG.
- FIG. 13 is an output voltage waveform diagram of the gradation control inverter 2 in step S302 of the second embodiment.
- 13 shows the output voltage waveform diagram of the main inverter 20, the middle stage shows the output voltage waveform diagram of the sub-inverter 30, and the lower stage shows the output voltage waveform diagram of the gradation control type inverter 2.
- FIG. The vertical axis is output voltage and the horizontal axis is time.
- FIG. 13 shows an output voltage waveform diagram when the main inverter 20 outputs a positive voltage. When the main inverter 20 outputs a negative voltage, the positive and negative directions of the voltage are reversed.
- step S202 the control unit 14 increases the gate impedance of the main inverter 20, slows the switching speed, and moderates the slope of dv/dt, which is the rising edge of the output voltage waveform.
- the sub-inverter 30 has a faster switching speed than the main inverter 20 because the sub-inverter 30 does not have the gate drive circuit 34 having the gate impedance changing means.
- step S302 the control unit 14 causes the sub-inverter 30 to switch the output voltage from positive to negative at the switching timing (t5) when the output voltage of the main inverter 20 rises, as shown in FIG. 10(C).
- the sub-inverter 30 is controlled to output 0 voltage without outputting a large amount of voltage change.
- the control unit 14 causes the sub-inverter 30 to output a negative voltage in the middle of the rising timing of the output voltage of the main inverter 20 (t6).
- the control unit 14 controls the sub-inverter 30 to output 0 voltage at the timing (t7) when the output voltage of the main inverter 20 falls, and to output a positive voltage in the middle of the rising timing (t8). do.
- step S602 after controlling the gate impedance of the main inverter 20 to be small for a predetermined period after the capacitor voltage VDCS of the sub-inverter 30 is controlled to a predetermined voltage, the control unit 14 performs the following operations as shown in FIG. 10B. Control is performed so that the sub-inverter 30 cancels the voltage of the main inverter 20 .
- the gate impedance of the main inverter 20 before the capacitor voltage VDCS of the sub-inverter 30 is controlled to a predetermined voltage is The capacitor voltage VDCS of the sub-inverter 30 is controlled to be higher than the gate impedance of the main inverter 20 after being controlled to a predetermined voltage. Thereby, noise caused by the main inverter 20 can be reduced when the capacitor voltage VDCS of the sub-inverter 30 is not controlled to a predetermined voltage.
- the control unit 14 controls the output voltage of the sub-inverter 30 to be 0 voltage at the switching timings when the output voltage of the main inverter 20 rises and falls. to control.
- the control unit 14 controls the output voltage of the sub-inverter 30 to be 0 voltage at the switching timings when the output voltage of the main inverter 20 rises and falls. to control.
- the gradation control inverter 2 which is the power conversion device 1 in the present embodiment, does not require gate impedance changing means in the sub-inverter 30, it can be made smaller and lighter.
- Embodiment 3 The gradation-controlled inverter 2, which is the power conversion device 1 according to the third embodiment, has the same circuit configuration as the gradation-controlled inverter 2 according to the first or second embodiment.
- step S601 of FIG. 3 of Embodiment 1 after the capacitor voltage VDCS of the sub-inverter 30 has been controlled to a predetermined voltage, the controller 14 controls the gate drive circuit 24 before the loss of the semiconductor switch reaches the allowable limit. , 34 to reduce the gate impedances of the main inverter 20 and the sub-inverter 30 .
- the period during which the gate impedances of the gate drive circuits 24 and 34 are reduced is further optimized.
- FIG. 14 is a flow chart showing the operation of the gradation control inverter 2 of the third embodiment.
- Steps S103 to S403 are the same as steps S101 to S401 of the first embodiment or steps S102 to S402 of the second embodiment.
- step S503 the control unit 14 causes the main inverter 20 to operate for one pulse, and causes the sub-inverter 30 to perform PWM operation. That is, the control unit 14 switches the main inverter 20 from PWM operation to 1-pulse operation.
- step S603 the control unit 14 controls the gate impedance changing means of the gate drive circuits 24 and 34 to reduce the gate impedances of the main inverter 20 and the sub-inverter 30.
- the predetermined period for changing the gate impedances of the main inverter 20 and the sub-inverter 30 in step S603 is from the time when the capacitor voltage VDCS of the sub-inverter 30 is controlled to the predetermined voltage to the allowable limit of the semiconductor switch loss, and the main inverter 20 is the non-switching output voltage 0 voltage point period.
- a more preferable predetermined period is the period during which the main inverter 20 is switched from the PWM operation to the 1-pulse operation in step S503 described above.
- the control section 14 controls the gate impedance changing means of the gate drive circuit 24 to reduce the gate impedance of the main inverter 20 .
- FIG. 15 is an explanatory diagram for explaining step S603 of the third embodiment.
- the solid line is the waveform of the output voltage of the main inverter 20
- the broken line is the waveform of the target voltage.
- the lower part of FIG. 15 shows the magnitude of the gate impedance of the main inverter 20 .
- Time t9 in FIG. 15 is the time at which the main inverter 20 is switched from PWM operation to 1-pulse operation in step S503.
- Time t9 is a period when the main inverter 20 is not switching and the output voltage is 0 voltage point.
- the control unit 14 controls the gate impedance changing means of the gate drive circuit 24 of the main inverter 20 to change the gate impedance of the main inverter 20 from high to low.
- the control unit 14 may control the gate impedance changing means of the gate drive circuit 34 of the sub-inverter 30 to change the gate impedance of the sub-inverter 30 from high to low at time t9.
- the gate impedance may be changed from small to large.
- the gradation-controlled inverter 2 which is the power conversion device 1 in the present embodiment, sets the gate impedance of the main inverter 20 before the capacitor voltage VDCS of the sub-inverter 30 is controlled to a predetermined voltage to
- the capacitor voltage VDCS of the sub-inverter 30 is controlled to be higher than the gate impedance of the main inverter 20 after being controlled to a predetermined voltage.
- the gradation control inverter 2 which is the power conversion device 1 in the present embodiment, has the impedance is characterized by changing Effects of this configuration will be described below.
- the gradation control type inverter 2 especially the main inverter 20, outputs a large voltage even if the gate impedance is increased and the slope of the dv/dt of the output voltage during switching is moderated.
- the output voltage of the sub-inverter 30 is smaller than the output voltage of the main inverter 20 , it is synchronized with the timing of the output voltage of the main inverter 20 and is output so as to cancel the output voltage of the main inverter 20 .
- the output timing of the sub-inverter 30 is slightly different from that of the main inverter 20, but the sub-inverter 30 operates at the rise and fall of the main inverter 20, and during the rise and fall of the main inverter 20. , operate almost synchronously.
- the gradation control type inverter 2 reduces the amount of noise to the load 4 by controlling the synchronization of the main inverter 20 and the sub-inverter 30 .
- each semiconductor switch of the main inverter 20 and the sub-inverter 30 gives noise to the adjacent gate drive circuits 24 and 34 by switching itself. Therefore, it should be avoided to change the gate impedance of the gate drive circuit 24 of the main inverter 20 at the switching timing of the semiconductor switch of the main inverter 20 that outputs a large voltage.
- the gate impedances of the main inverter 20 and the sub-inverter 30 are changed by the control unit 14 at the timing when the semiconductor switches of the main inverter 20 and the sub-inverter 30 switch high voltage and high current.
- the gate drive circuits 24, 34 are subject to noise generated by high voltage and high current switching.
- the transistors 41 to 44 of the gate drive circuits 24, 34 do not fire, and at different timings. There is a risk that the transistors 41 to 44 will be erroneously fired.
- the transistors 41 to 44 of the gate drive circuits 24, 34 are not fired at all due to noise, they are operated with a large gate impedance under the worst conditions. This results in excessive switching losses. Moreover, if only one of the gate impedances of the main inverter 20 and the sub-inverter 30 is switched, there is a possibility that the intended tuning control cannot be realized.
- the time width of the 0 voltage point in 1-pulse operation and PWM operation will be explained.
- positive and negative pulses are output around the peak of the target voltage waveform in one cycle, so the duration of the 0 voltage point is long.
- the PWM operation distributes and outputs the pulse voltage multiple times with respect to the target voltage waveform in one cycle, so the duration of the 0 voltage point is short.
- the control unit 14 changes the impedance of the gate drive circuit 24 of the main inverter 20 during a predetermined period when the main inverter 20 is not switching and the output voltage is 0 voltage point. This prevents unintended erroneous firing due to self-poisoning or the like. Further, as described above, during the PWM operation period, the time width of the 0 voltage point is shortened depending on the switching carrier frequency. Therefore, the control unit 14 does not change the gate impedance of the main inverter 20 and the sub-inverter 30 during the period of the 0 voltage point during PWM operation, but changes the gate impedance during the period of switching the main inverter 20 from the PWM operation to the 1-pulse operation. should be changed.
- the gradation control inverter 2 can prevent the gate impedance from being changed at the switching timing that causes a large voltage change amount. Then, the gate impedance can be reliably changed without being affected by noise. Moreover, it is possible to easily change the gate impedance in synchronization with the switching timing from the PWM operation to the 1-pulse operation without providing a special switching sequence means.
- FIG. 16 is a circuit diagram showing the configuration of the gradation control type inverter 2 of the fourth embodiment.
- the gradation-controlled inverter 2 of the fourth embodiment has means for detecting failure of each semiconductor switch of the sub-inverter 30. .
- the x mark in FIG. 16 indicates the position where the semiconductor switch of the sub-inverter 30 of the gradation-controlled inverter 2 has failed.
- the means for detecting the failure of the semiconductor switch detects, for example, the drain-source voltage Vds of the semiconductor element, and determines the failure based on the Vds voltage.
- Other publicly known means that are open to the public may be used as the means for detecting the failure of the semiconductor switch.
- FIG. 17 is a flow chart showing the operation of the gradation control inverter 2 of the fourth embodiment.
- START in FIG. 17 is after the operation processing of steps S601, S602, and S603 of the first to third embodiments.
- step S704 the control unit 14 determines whether or not the semiconductor switches of the sub-inverter 30 have failed using the means for detecting that each semiconductor switch of the sub-inverter 30 has failed.
- the control unit 14 sets the through mode in which the output voltage of the main inverter 20 is directly output to the load 4 (S804). Specifically, the control unit 14 always turns on the two semiconductor switches on the high potential side of the capacitor 35 of the sub-inverter 30, or turns on both the switches on the low potential side. Then, the control unit 14 controls the gate drive circuit 24 of the main inverter 20 to slow down the switching speed by increasing the gate impedance of the main inverter 20 (S904).
- increasing the gate impedance of the main inverter 20 means making the gate impedance larger than the gate impedance of the main inverter 20 before the failure of the semiconductor switch of the sub-inverter 30 is detected in S704.
- the gradation control type inverter 2 performs PWM operation only with the main inverter 20 .
- the main inverter 20 can be operated with reduced noise.
- the gradation-controlled inverter 2 which is the power conversion device 1 in the present embodiment, sets the gate impedance of the main inverter 20 before the capacitor voltage VDCS of the sub-inverter 30 is controlled to a predetermined voltage to
- the capacitor voltage VDCS of the sub-inverter 30 is controlled to be higher than the gate impedance of the main inverter 20 after being controlled to a predetermined voltage.
- the gradation-controlled inverter 2 of the present embodiment further includes means for detecting that the semiconductor switch of the sub-inverter 30 has failed. After the gate impedance of the main inverter 20 is controlled to be small (steps S601, S602, and S603), the gradation-controlled inverter 2 detects that the semiconductor switch of the sub-inverter 30 has failed. mode. Then, the gradation-controlled inverter 2 makes the gate impedance of the main inverter 20 larger than before the semiconductor switch of the sub-inverter 30 fails. As a result, even if the sub-inverter 30 fails, the gradation-controlled inverter 2 can continue to operate using the main inverter 20 without increasing noise.
- the semiconductor element that caused the short-circuited failure may be used to put the sub-inverter 30 into the through mode. It is possible. However, since a short-circuit failure results in operation in an unexpected mode, it is preferable to avoid operating by utilizing the short-circuit failure. However, if there is a need for continuous operation beyond stopping, such as in an aircraft, the short-circuit failure may be used to operate.
- Embodiment 5 is aircraft 100 on which power converter 1 according to Embodiments 1 to 4 is mounted.
- the aircraft 100 of this embodiment is, for example, an airplane, a helicopter, a drone, a flying car, or the like.
- FIG. 18 is a schematic diagram of aircraft 100 according to the fifth embodiment.
- the aircraft 100 includes a gradation control inverter 2 that is the power conversion device 1 according to the first to fourth embodiments.
- the aircraft 100 is an electric aircraft, and its propulsion power system 90 includes a power source 92, a first DC source 3 connected to the power source 92, a step-down power source 3 connected to the first DC source 3 and converted to a predetermined voltage.
- a step-up or buck-boost DC/DC converter 91 which is a power conversion device 1 that converts the DC power stepped down or stepped down by the DC/DC converter 91 into AC power
- the gradation control type inverter 2 It comprises a load 4 to which power is supplied.
- the control unit 14 controls the DC/DC converter 91 and the gradation control inverter 2 .
- the controller 14 may be provided inside the gradation-controlled inverter 2 or may be provided in a device separate from the gradation-controlled inverter 2 .
- a load 4 is a propulsion system load for obtaining propulsive force, such as an electric motor.
- the power converter 1 according to Embodiments 1 to 4 is used as the gradation control type inverter 2 for the electric aircraft of the propulsion system power system 90 mounted on the aircraft 100 .
- the power conversion device 1 according to Embodiments 1 to 4 can reduce noise caused by the main inverter 20 as described above. Further, the power conversion device 1 according to Embodiments 1 to 4 does not require an initial charging circuit for the capacitor 35 of the sub-inverter 30 as described above, reduces the size and weight of the cooler, and suppresses noise caused by multi-level voltages. The size and weight of the filter can be reduced. Therefore, by installing the power conversion device 1 in the propulsion power system 90 of the aircraft 100, the gradation control type inverter 2 for electric aircraft can be made low noise, compact, and lightweight. Thereby, the fuel efficiency of the aircraft 100 is improved.
- Embodiment 6 The present embodiment is aircraft 100 on which power converter 1 according to Embodiments 1 to 4 is mounted.
- Aircraft 100 is, for example, an airplane, a helicopter, a drone, a flying car, or the like.
- FIG. 19 is a schematic diagram of aircraft 100 according to the sixth embodiment.
- the aircraft 100 includes a gradation control inverter 2 that is the power conversion device 1 according to the first to fourth embodiments.
- the aircraft 100 is an electric aircraft, and its equipment system 94 includes a power source 92, an AC/DC converter 93 connected to the power source 92 for converting AC power to DC power, and a second AC/DC converter 93 connected to the AC/DC converter 93.
- 1 DC source 3 a step-down, step-up or buck-boost DC/DC converter 91 connected to the first DC source 3 and converting to a predetermined voltage, and the DC power stepped down by the DC/DC converter 91 is converted to AC power.
- the control section 14 controls the DC/DC converter 91 , the gradation control inverter 2 and the AC/DC converter 93 .
- the controller 14 may be provided inside the gradation-controlled inverter 2 or may be provided in a device separate from the gradation-controlled inverter 2 .
- a load 4 is an equipment load, such as an air conditioner, an engine starter, and an electric motor used to drive an auxiliary power device.
- the aircraft 100 of the present embodiment uses the power conversion device 1 of Embodiments 1 to 4 as the gradation control type inverter 2 for the electric aircraft of the equipment power system 94 mounted on the aircraft 100 .
- the gradation control inverter 2 for an electric aircraft can be made low noise, compact, and lightweight. Thereby, the fuel efficiency of the aircraft 100 is improved.
- the aircraft 100 may be equipped with storage batteries. If the aircraft 100 were to run only on storage batteries instead of fuel, the smaller size and lighter weight would improve power consumption.
Landscapes
- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Inverter Devices (AREA)
Abstract
Description
実施の形態1における電力変換装置1である階調制御型インバータ2について図1を用いて説明する。図1は実施の形態1の階調制御型インバータ2の構成を示す回路図である。本実施の形態の電力変換装置1は、直流電力源である第1の直流源3からの直流電力を負荷4の駆動に必要な交流に変換するDC/ACの階調制御型インバータ2である例を説明する。階調制御型インバータ2は第1の直流源3と負荷4との間に接続される。
ステップS201及びステップS301は同時に行ってもよい。
図4~6は、実施の形態1のステップS301における階調制御型インバータ2の出力電圧波形図である。すなわち、サブインバータ30のコンデンサ電圧VDCSが所定電圧に制御されていない初期充電段階であり、サブインバータ30のコンデンサ電圧VDCSが0電圧から所定電圧まで徐々に電圧が上昇していく過渡状態の階調制御型インバータ2の出力電圧波形図である。縦軸は出力電圧、横軸は時間である。図4~6において、上段の出力電圧波形図はU相、中段の出力電圧波形図はV相、下段の出力電圧波形図はW相、左の出力電圧波形図はメインインバータ20の出力電圧波形、中央の出力電圧波形図はサブインバータ30の出力電圧波形、右の出力電圧波形図はメインインバータ20の出力電圧とサブインバータ30の出力電圧の相電圧である階調制御型インバータ2の出力電圧波形をそれぞれ示している。図4~6において、メインインバータ20のDC母線電圧VDCMは1.5kVであり、所定電圧はVDCM電圧の1/4である375Vとする。また、図4において初期充電段階を時刻t1、t2、t3、t4で区切る。図5はサブインバータ30のコンデンサ電圧VDCSが0電圧付近の時間t1-t2における拡大出力電圧波形であり、図6はサブインバータ30のコンデンサ電圧VDCSが時間t1-t2より上昇した時間t3-t4の拡大出力電圧波形である。
以上により、階調制御型インバータ2の動作を終了する。
一般的に、スイッチングに伴う電圧変化に対するノイズ量は、電圧変化量として電圧変化幅ΔVの大きさ、及びdV/dtの傾きが大きくなるほどノイズが大きくなる。また、dV/dtの傾きが大きくなるほどサージ電圧も大きくなる。そのため、図4に示すようにサブインバータ30のコンデンサ電圧VDCSが所定電圧に制御されていない場合に、メインインバータ20による大きな電圧変化量を負荷4に印加させると、ノイズが大きくなるという課題があった。そして、ノイズ規格はノイズの平均値だけではなく、ピーク値及び尖頭値で規定されることが多い。よって、上述のように起動時において大きな電圧変化量が発生する場合も考慮して階調制御型インバータ2を設計すると、入力ノイズフィルタ10及び出力ノイズフィルタ13が大きくなる虞がある。
図10(A)はメインインバータ20とサブインバータ30のスイッチング速度が共に遅い場合、図10(B)はメインインバータ20とサブインバータ30のスイッチング速度が共に速い場合、図10(C)はメインインバータ20のスイッチング速度が遅く、サブインバータ30のスイッチング速度が速い場合、図10(D)はメインインバータ20のスイッチング速度が速く、サブインバータ30のスイッチング速度が遅い場合である。
サブインバータ30のコンデンサ電圧VDCSが所定電圧に制御される前は、ゲートインピーダンスを大きくするためスイッチング損失は大きくなる。しかし、起動時等の投入電力が少なくてよい場合、メインインバータ20及びサブインバータ30のスイッチング損失が大きくても問題はない。さらに、起動時にサブインバータ30のコンデンサ電圧VDCSが所定電圧に制御されるまでの時間も短いため問題ない。
例えば航空機に電力変換装置1を搭載する場合、高度が高く宇宙線の影響が大きい使用環境であるため、地上より半導体スイッチの電圧マージンを大きく設ける必要がある。そこで、メインインバータ20にダイオードクランプ型の3レベルインバータを用いることにより、大型で高価な高電圧素子ではなく、低電圧素子を使用することができる。
実施の形態2における電力変換装置1である階調制御型インバータ2について図11を用いて説明する。図11は実施の形態2の階調制御型インバータ2の構成を示す回路図である。実施の形態2における階調制御型インバータ2は、ゲートインピーダンス変更手段を備えたゲート駆動回路34を備えないことを特徴とする。その他の階調制御型インバータ2の構成は実施の形態1と同様である。実施の形態1と同様の構成については、同一符号が付されている。
以上により、階調制御型インバータ2の動作を終了する。
実施の形態3における電力変換装置1である階調制御型インバータ2は、実施の形態1又は実施の形態2の階調制御型インバータ2と同様の回路構成である。
また、上述のように、PWM動作期間においては、スイッチングのキャリア周波数次第で0電圧点の時間幅が短くなる。そのため、制御部14は、PWM動作時の0電圧点の期間でメインインバータ20とサブインバータ30のゲートインピーダンスを変更するのではなく、メインインバータ20をPWM動作から1パルス動作に切り替える期間でゲートインピーダンスを変更させるとよい。これにより、階調制御型インバータ2は、大きな電圧変化量を生じるスイッチングタイミングでゲートインピーダンスを変更することを防ぐことができる。そして、ノイズの影響を受けずゲートインピーダンスを確実に変更できる。また、特別な切り替えシーケンス手段を備えなくともよく、PWM動作から1パルス動作への切り替えタイミングに同期して容易にゲートインピーダンスを変更することが可能である。
実施の形態4における電力変換装置1である階調制御型インバータ2について図16を用いて説明する。図16は実施の形態4の階調制御型インバータ2の構成を示す回路図である。実施の形態1及び実施の形態2の階調制御型インバータ2に対して、実施の形態4の階調制御型インバータ2は、サブインバータ30の各半導体スイッチが故障したことを検知する手段を備える。
本実施の形態は、実施の形態1から実施の形態4における電力変換装置1が搭載された航空機100である。本実施の形態の航空機100は、例えば飛行機、ヘリコプター、ドローン、空飛ぶ自動車等である。
本実施の形態は、実施の形態1から実施の形態4における電力変換装置1が搭載された航空機100である。航空機100は、例えば飛行機、ヘリコプター、ドローン、空飛ぶ自動車等である。
Claims (10)
- 電力源側に接続され、ゲートインピーダンスを変更可能なゲート駆動回路を有するメインインバータと、
前記メインインバータに直列に接続され負荷側に接続された、コンデンサを有するサブインバータと、
前記サブインバータのコンデンサ電圧を検知する電圧検知手段と、
前記電圧検知手段により検知した前記サブインバータの前記コンデンサ電圧を所定電圧に制御し、前記サブインバータの前記コンデンサ電圧が前記所定電圧に制御される前の前記メインインバータの前記ゲートインピーダンスを、前記サブインバータの前記コンデンサ電圧が前記所定電圧に制御された後の前記メインインバータの前記ゲートインピーダンスより大きくなるように制御する制御部と、
を備える電力変換装置。 - 前記サブインバータはゲートインピーダンスを変更可能なゲート駆動回路を有し、
前記制御部は、前記サブインバータの前記コンデンサ電圧が前記所定電圧に制御される前の前記サブインバータの前記ゲートインピーダンスを、前記サブインバータの前記コンデンサ電圧が前記所定電圧に制御された後の前記サブインバータの前記ゲートインピーダンスより大きくなるように制御することを特徴とする請求項1に記載の電力変換装置。 - 前記メインインバータの前記ゲートインピーダンスは、前記メインインバータの前記ゲートインピーダンスを前記サブインバータの前記コンデンサ電圧が前記所定電圧に制御された後の所定期間に制御され、
前記所定期間は前記メインインバータがスイッチングしていない出力電圧が0電圧点の期間、又は前記メインインバータがPWM動作と1パルス動作とを切り替える期間であることを特徴とする請求項1又は請求項2に記載の電力変換装置。 - 前記サブインバータの前記ゲートインピーダンスは、前記メインインバータの前記ゲートインピーダンスを前記サブインバータの前記コンデンサ電圧が前記所定電圧に制御された後の所定期間に制御され、
前記所定期間は前記メインインバータがスイッチングしていない出力電圧が0電圧点の期間、又は前記メインインバータがPWM動作と1パルス動作とを切り替える期間であることを特徴とする請求項2又は請求項3に記載の電力変換装置。 - 前記サブインバータは、前記サブインバータの半導体スイッチが故障したことを検知する手段を備え、
前記制御部は、前記メインインバータの前記ゲートインピーダンスが制御された後に前記サブインバータの前記半導体スイッチが故障した場合、前記サブインバータを前記メインインバータの出力電圧を前記負荷に直接出力するスルーモードにし、前記メインインバータの前記ゲート駆動回路の前記ゲートインピーダンスを前記半導体スイッチが故障する前より大きくすることを特徴する請求項1から4のいずれか一項に記載の電力変換装置。 - 前記制御部は、前記メインインバータの前記ゲートインピーダンスが制御される前は、前記メインインバータの出力電圧の立ち上がり時、及び立ち下がり時のスイッチングタイミングにおいて、前記サブインバータの出力電圧が0電圧となるように制御することを特徴とする請求項1に記載の電力変換装置。
- 前記メインインバータは単相又は複数の出力相であることを特徴とする請求項1から6のいずれか一項に記載の電力変換装置。
- 前記メインインバータはマルチレベルインバータであることを特徴とする請求項1から7のいずれか一項に記載の電力変換装置。
- 電力源と、
推進力を得るための推進系又は装備品系の負荷と、
前記電力源と前記負荷とに接続された、請求項1から8のいずれか一項に記載の電力変換装置と、
を備える航空機。 - 電力源側に接続され、ゲートインピーダンスを変更可能なゲート駆動回路を有するメインインバータと、前記メインインバータに直列に接続され負荷側に接続された、コンデンサを有するサブインバータとを用いた電力変換方法であって、
前記サブインバータのコンデンサ電圧を検知するステップと、
検知した前記サブインバータの前記コンデンサ電圧を所定電圧に制御し、前記サブインバータの前記コンデンサ電圧が前記所定電圧に制御される前の前記メインインバータの前記ゲートインピーダンスを、前記サブインバータの前記コンデンサ電圧が前記所定電圧に制御された後の前記メインインバータの前記ゲートインピーダンスより大きくなるように制御するステップと、
を備える電力変換方法。
Priority Applications (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
EP21949302.0A EP4369582A1 (en) | 2021-07-07 | 2021-07-07 | Power conversion device, aircraft, and power conversion method |
PCT/JP2021/025656 WO2023281668A1 (ja) | 2021-07-07 | 2021-07-07 | 電力変換装置、航空機及び電力変換方法 |
JP2023532957A JPWO2023281668A1 (ja) | 2021-07-07 | 2021-07-07 |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
PCT/JP2021/025656 WO2023281668A1 (ja) | 2021-07-07 | 2021-07-07 | 電力変換装置、航空機及び電力変換方法 |
Publications (1)
Publication Number | Publication Date |
---|---|
WO2023281668A1 true WO2023281668A1 (ja) | 2023-01-12 |
Family
ID=84801444
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/JP2021/025656 WO2023281668A1 (ja) | 2021-07-07 | 2021-07-07 | 電力変換装置、航空機及び電力変換方法 |
Country Status (3)
Country | Link |
---|---|
EP (1) | EP4369582A1 (ja) |
JP (1) | JPWO2023281668A1 (ja) |
WO (1) | WO2023281668A1 (ja) |
Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2011142740A (ja) | 2010-01-07 | 2011-07-21 | Mitsubishi Electric Corp | 電力変換装置 |
JP2012222854A (ja) * | 2011-04-04 | 2012-11-12 | Mitsubishi Electric Corp | 電力変換装置 |
WO2020261384A1 (ja) * | 2019-06-25 | 2020-12-30 | 三菱電機株式会社 | 電力変換装置 |
-
2021
- 2021-07-07 EP EP21949302.0A patent/EP4369582A1/en active Pending
- 2021-07-07 JP JP2023532957A patent/JPWO2023281668A1/ja active Pending
- 2021-07-07 WO PCT/JP2021/025656 patent/WO2023281668A1/ja active Application Filing
Patent Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2011142740A (ja) | 2010-01-07 | 2011-07-21 | Mitsubishi Electric Corp | 電力変換装置 |
JP2012222854A (ja) * | 2011-04-04 | 2012-11-12 | Mitsubishi Electric Corp | 電力変換装置 |
WO2020261384A1 (ja) * | 2019-06-25 | 2020-12-30 | 三菱電機株式会社 | 電力変換装置 |
Also Published As
Publication number | Publication date |
---|---|
JPWO2023281668A1 (ja) | 2023-01-12 |
EP4369582A1 (en) | 2024-05-15 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
AU2012339926B2 (en) | Power converter based on H-bridges | |
US8462524B2 (en) | 3-level pulse width modulation inverter with snubber circuit | |
US8711586B2 (en) | Power converter and method including noise suppression by controlling phase shifting of converter cells | |
JP6206502B2 (ja) | 電力変換装置及び電力変換方法 | |
WO2011033698A1 (ja) | 電力変換装置 | |
JP5755930B2 (ja) | 単位セルとこれを用いた交直変換装置 | |
US20190013743A1 (en) | Three-level two-stage decoupled active npc converter | |
EP3651341A1 (en) | Driving power supply device | |
US20180219501A1 (en) | Control Method for Power Converters with Inverter Blocks with Silicon Carbide Mosfets | |
US7199622B2 (en) | Interleaving control type inverter | |
Ma et al. | Open-circuit fault-tolerant control strategy based on five-level power converter for SRM system | |
JP5362657B2 (ja) | 電力変換装置 | |
WO2019167244A1 (ja) | 電力変換装置および電動機システム | |
WO2023281668A1 (ja) | 電力変換装置、航空機及び電力変換方法 | |
JP4178331B2 (ja) | 直列多重パルス幅変調サイクロコンバータ装置およびその制御方法 | |
US9325273B2 (en) | Method and system for driving electric machines | |
JP6594566B2 (ja) | 電力変換装置およびこれを用いた電動機駆動装置 | |
JP4069460B2 (ja) | 直列多重3相pwmサイクロコンバータ | |
Vinodkumar et al. | Modeling of new multilevel inverter topology with reduced number of power electronic components | |
Kim et al. | Commutation technique for high frequency link inverter without operational limitations and dead time | |
US20220393614A1 (en) | Power supply system and moving body | |
WO2024105872A1 (ja) | 電力変換装置、および飛行物体 | |
JP7051600B2 (ja) | 多段変換器の制御装置 | |
Sravani et al. | Performance analysis of a multilevel inverter topology with reduced switches |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
121 | Ep: the epo has been informed by wipo that ep was designated in this application |
Ref document number: 21949302 Country of ref document: EP Kind code of ref document: A1 |
|
ENP | Entry into the national phase |
Ref document number: 2023532957 Country of ref document: JP Kind code of ref document: A |
|
WWE | Wipo information: entry into national phase |
Ref document number: 2021949302 Country of ref document: EP |
|
ENP | Entry into the national phase |
Ref document number: 2021949302 Country of ref document: EP Effective date: 20240207 |
|
NENP | Non-entry into the national phase |
Ref country code: DE |