JP2018166349A - Power conversion device and power conversion method - Google Patents

Abstract

An object of the present invention relates to driving a rotating electrical machine with high efficiency by reducing the total loss of copper loss and iron loss. When converting power supplied from a power source to power for driving an AC rotary motor, the present invention increases the output voltage according to the increase in the rotational speed of the AC rotary motor, and then It relates to lowering the output voltage as it rises. According to the present invention, the loss of the AC rotary motor can be minimized in the operating range where the rotational speed is high, and the AC rotary motor can be operated with high efficiency.

Description

  The present invention relates to a power conversion device that drives an AC rotary electric motor.

  In general, the output voltage output from the control device of the AC rotary motor increases in proportion to the speed of the rotating electrical machine at low speed, and increases to the maximum output voltage that can be output by the control device in the medium speed range. In the high speed range above the speed range, the maximum output voltage is constant, and the rotating electrical machine is driven. In this case, depending on the driving conditions, the vehicle is not necessarily operated at the maximum efficiency. In order to solve these problems, Patent Documents 1 to 4 are disclosed as changing the voltage applied to the rotary motor.

  Patent document 1 is for reducing the switching loss of an inverter when a high output is required for a rotary electric motor that generates a steering force. When the rotational speed or output of the rotary motor increases, the current flowing through the harness increases and the amount of voltage drop in the harness increases, thereby decreasing the input voltage. Thus, since the input voltage changes according to the rotational speed or output of the rotary motor, it is determined based on the input voltage whether the rotary motor is operating in a predetermined rotational speed region. When operating in the rotational speed region, the carrier frequency is set lower than when the rotary motor is operating in the low torque region.

  Further, in Patent Document 2, if the voltage fluctuation due to the decrease in the capacity of the smoothing capacitor becomes too large, the voltage cannot be sufficiently suppressed and an excessive voltage fluctuation occurs, and an overvoltage is applied to an electronic device connected to the output of the power supply source. This is to eliminate the possibility of the occurrence of the above. The electric drive control device includes: a DC voltage detection unit that detects a DC voltage applied to the smoothing unit; and an input characteristic of the power converter when the DC voltage detected by the DC voltage detection unit exceeds a predetermined voltage. And a motor control unit that corrects the input characteristics so that the DC voltage decreases. The operation of the motor control unit is configured to prevent the occurrence of overvoltage application to the device connected to the output of the power supply source.

  Further, Patent Document 3 discloses a motor drive system controller that controls an AC rotary motor according to a modulation method in which the fundamental component of a motor applied voltage is larger than that of a sine wave PWM control method. The current is appropriately controlled. In the control device of the motor drive system, the motor voltage correction means determines the correction degree of the applied voltage to the AC rotary motor with respect to the rotational speed difference when the rotational speed of the AC rotary motor is reduced, and the correction degree when the rotational speed of the AC rotary motor is increased. It is supposed to be set larger than.

  Patent Document 4 is for reducing the switching loss of an inverter circuit. The motor generator, which is a rotating electrical machine that supplies AC power, is controlled by the PWM method in an operation region where the motor generator is in a low speed operation state, and the operation is shifted to the PHM method in an operation region in which the rotational speed of the rotating electrical machine is higher than the low speed operation region. . This suppresses the influence of distortion as much as possible and realizes improvement in efficiency.

JP 2010-221856 A JP 2010-011687 A JP 2006-320039 A International Publication No. 2011/135621

  The inventor of the present application diligently studied to drive the AC rotary motor with high efficiency, and as a result, the following knowledge was obtained.

  In Patent Document 1, since the carrier frequency is set low, the iron loss generated in the iron core in the rotary motor increases as the applied voltage of the rotary motor increases. Further, by lowering the carrier frequency, the distortion of the applied voltage of the rotary motor increases, and the harmonic component of the loss generated in the rotary motor increases. Due to the increase in these losses, there is a problem that the efficiency of the rotary motor is reduced.

  In Patent Document 2, when the DC voltage becomes equal to or higher than a predetermined voltage, the input characteristics of the power conversion device are corrected to input characteristics that reduce the DC voltage, and the overvoltage to the device connected to the output of the power supply source is corrected. Generation of application can be prevented. However, since the voltage output from the power converter is driven by the allowable voltage of the power converter, there is a problem that the driven AC rotary motor is not operated under the maximum efficiency.

  In Patent Document 3, the degree of correction of the applied voltage to the AC rotary motor with respect to the rotational speed difference when the rotational speed of the AC rotary motor is reduced is set to be larger than the correction degree when the rotational speed of the AC rotary motor is increased. In this configuration, by suppressing the overcurrent of the AC rotary motor, the copper loss can be reduced and the efficiency can be improved as compared with the overcurrent. However, on the other hand, since the applied voltage of the AC rotary motor is corrected in order to suppress overcurrent, there is a problem that the AC rotary motor is not operated under the maximum efficiency.

  In Patent Literature 4, control is performed by the PWM method in the operation region in the low speed operation state, and the control shifts to the PHM method in the operation region in which the rotation speed of the rotating electrical machine is higher than the low speed operation region. In this configuration, the efficiency can be improved by reducing the switching loss of the inverter circuit. However, on the other hand, since the applied voltage of the AC rotary motor is the maximum value of the voltage output from the inverter circuit in both the PWM system and the PHM system, there is a problem that the AC rotary motor is not operated under the maximum efficiency. is there.

  An object of the present invention relates to driving a rotating electrical machine with high efficiency by reducing the total loss of copper loss and iron loss.

  In the present invention, when power supplied from a power source is converted into power for driving an AC rotary motor, the output voltage is increased according to the increase in the rotational speed of the AC rotary motor, and then the output voltage is increased according to the increase in the rotational speed. Related to lowering.

  According to the present invention, the loss of the AC rotary motor can be minimized in the operating range where the rotational speed is high, and the AC rotary motor can be operated with high efficiency.

1 is a circuit diagram of a power conversion device 1 according to a first embodiment. FIG. 3 is a block diagram for operating the inverter 2 according to the first embodiment. The graph which shows the rotation speed-torque characteristic of the motor 100 concerning Example 1. FIG. The graph which shows the conventional speed-alternating-current voltage pattern input into the motor 100 The graph which shows the copper loss and the iron loss which are the loss of the motor 100 in the conventional speed-alternating-current voltage pattern input into the motor 100 The graph which shows the speed-alternating-current voltage pattern input into the motor 100 concerning Example 1. FIG. Graph showing iron loss, copper loss and total loss (total value of iron loss and copper loss) of motor 100 in the AC voltage pattern shown in FIGS. 4 and 6 The graph which shows the speed-alternating-current voltage pattern concerning Example 2. The graph which shows the speed-alternating-current voltage pattern concerning Example 3. Circuit diagram of power conversion device 1 according to the fourth embodiment. Block diagram for operating the booster circuit 3 according to the fourth embodiment. The circuit diagram of the power converter device 1 concerning Example 5. FIG. The circuit diagram of the power converter device 1 concerning Example 6. FIG. The circuit diagram of the power converter device 1 concerning Example 7. FIG. The graph which shows the capacitor voltage-speed and alternating voltage-speed in the power converter device concerning Example 8 Configuration diagram of AC motor drive system for electric railway vehicle according to embodiment 9

  In the embodiment, the power conversion device drives the AC rotary motor by converting the power supplied from the power source, and after increasing the output voltage according to the increase in the rotational speed of the AC rotary motor, according to the increase in the rotational speed What lowers an output voltage is disclosed.

  Further, in the embodiment, the power conversion method converts power supplied from a power source into power for driving an AC rotary motor, and after the output voltage is increased according to the increase in the rotational speed of the AC rotary motor, the rotation is performed. Disclosed is an output voltage that decreases as the number increases.

  Further, the embodiment discloses that after the output voltage reaches the maximum value as the rotational speed of the AC rotary motor increases, the output voltage is decreased as the rotational speed increases.

  Further, in the embodiment, it is disclosed that the output voltage is decreased according to the increase in the rotation speed in the operation region where the output is decreased according to the increase in the rotation speed of the AC rotary motor.

  Moreover, in an Example, it discloses that a power converter device mounts a booster circuit. Also disclosed is that the power from the power source is boosted by a booster circuit and supplied to the inverter.

  Moreover, in an Example, it discloses that a power converter device mounts a step-down circuit. Moreover, it discloses that the power from the power source is stepped down by a step-down circuit and supplied to the inverter.

  Moreover, in an Example, it discloses that a power converter device mounts a storage battery. Moreover, applying the voltage of a storage battery to the electric power from a power supply and supplying to an inverter is disclosed.

  Moreover, in an Example, it discloses that the power converter device mounts the converter which converts the alternating current power supplied from the power supply into direct current power. Further, it discloses that AC power from a power source is converted into a DC voltage by a converter and supplied to an inverter.

  Moreover, in an Example, it discloses that the voltage of the capacitor | condenser connected in parallel with the inverter of a power converter device is dropped according to the raise of the rotation speed of an AC rotary motor. Further, it is disclosed that the voltage of the capacitor connected in parallel to the inverter for power conversion is lowered as the rotational speed of the AC rotating motor is increased.

  In addition, the embodiment discloses that the AC rotary motor is an induction machine, a permanent magnet synchronous motor, or a switched reluctance motor.

  Moreover, in an Example, an electric vehicle provided with a power converter device is disclosed. Also disclosed is a method for running an electric vehicle in which the electric power converted by the power conversion method is supplied to an AC rotary electric motor of the electric vehicle to run the electric vehicle.

  The above and other novel features and effects of the present invention will be described below with reference to the drawings. It should be noted that the drawings are used exclusively for understanding the invention and do not limit the scope of rights.

  A present Example is described based on FIG. 1 thru | or FIG.

  FIG. 1 is a circuit diagram of a power converter 1 according to the present embodiment. The power converter 1 includes a capacitor 5 that smoothes the voltage supplied from the DC power supply 4 and six switching elements 601. The capacitor 5 may be either an electrolytic capacitor or a film capacitor, and a large number of small capacitors may be connected in parallel to increase the capacity of the capacitor 5. The switching element 601 may be either an IGBT or a MOSFET. When the switching element 601 is an IGBT, diodes 901 are connected in parallel in the opposite direction to the IGBT, and when the switching element 601 is a MOSFET, a diode As 901, a MOSFET parasitic diode can be used. The semiconductor module 801 is a 2-in-1 module configured by connecting two switching elements 601 in series, but is not limited thereto, and a 1-in-1 module including only one switching element 601 may be combined. A connection point of the switching element 601 is an AC output point to the motor 100.

  FIG. 2 is a block diagram for operating the inverter 2 according to the present embodiment. The inverter 2 is controlled by the motor control unit 10 based on the position information θ of the rotor of the motor output from the inverter 2 and the AC currents Iu, Iv, Iw of the motor.

  FIG. 3 is a graph showing the rotational speed-torque characteristics of the motor 100 according to the present embodiment. When the motor 100 is operated at a variable speed, the motor 100 has an operation region where the torque is constant in the low speed region, and has a characteristic in which the output is constant or the output is reduced in the middle / high speed region where the speed is higher than the low speed region.

  FIG. 4 is a graph showing a conventional speed-AC voltage pattern input to the motor 100. Conventionally, as shown in FIG. 4, in the low speed region, the AC voltage is increased in proportion to the speed of the motor 100, and in the medium speed region, the AC voltage is increased to the maximum AC voltage that can be output. In the high speed region above the high speed region, the AC voltage is kept constant at the maximum value, and the motor 100 is driven.

FIG. 5 is a graph showing copper loss and iron loss, which are losses of the motor 100 in the conventional speed-AC voltage pattern input to the motor 100 shown in FIG. The copper loss is a Joule loss that occurs due to the current flowing in the winding of the motor 100, and the iron loss is a loss that occurs due to the time change of the magnetic flux generated inside the motor 100. In FIG. 5, the copper loss is larger than the iron loss in the low speed region, whereas the iron loss is larger than the copper loss in the medium speed region and the high speed region. Calculation formulas for copper loss and iron loss are shown below.
Copper loss Ws = R · I ² (1)
Iron loss Wi = Kh · (B) · f + Ke · (B) ² · f ² ... (2)
It is expressed.

Here, R is a resistance value of the winding of the motor 100, I is a current value for three phases flowing through the motor 100, Kh and Ke are coefficients determined by the internal structure of the motor 100, and B is a magnetic flux density inside the motor 100. , Φ is the amount of magnetic flux generated inside the motor 100, S is the area where the magnetic flux φ is linked, and f is the frequency of the AC voltage. The magnetic flux density and voltage are expressed by the following equations.
Magnetic flux density B = φ / S (3)
AC voltage V = N ・ (dφ / dt) (4)
Here, N is the number of windings of the motor 100, dφ is the time variation of the magnetic flux φ, and dt is the time variation. (2) From the equations (3) and (4), the iron loss Wi can be rewritten by the following equation.
Iron loss Wi = Kh ・ ((N∫Vdt)) / S) ・ f + Ke ・ ((N∫Vdt)) / S) ²・ f ²・ ・ ・ （5）
From equation (5), the iron loss Wi is proportional to the voltage and frequency in the first and second power. For this reason, since the iron loss increases as the rotational speed of the motor 100 increases, there is an operating region in which the iron loss of the motor 100 is dominant in the high speed region.

  FIG. 6 is a graph showing a speed-AC voltage pattern inputted to the motor 100 according to the present embodiment, and is an AC voltage pattern when the AC voltage is lowered in a high speed region. FIG. 7 is a graph showing the iron loss, copper loss, and total loss (total value of iron loss and copper loss) of motor 100 in the AC voltage patterns shown in FIGS. 4 and 6. By reducing the AC voltage in the high speed region, the total value of copper loss and iron loss can be minimized, and the motor 100 can be operated with high efficiency.

  In the present embodiment, after the AC voltage is increased according to the increase in the rotation speed of the motor 100, there is an operation area in which the AC voltage is decreased in a high speed area where the rotation speed of the motor 100 is further increased. According to the present embodiment, in the high speed region after the AC voltage is increased as the rotational speed of the motor 100 is increased, the AC voltage is decreased to minimize the total loss of the copper loss and the iron loss. Can be operated with high efficiency.

  Unlike the first embodiment, the present embodiment increases the AC voltage up to the maximum output voltage upper limit. Hereinafter, the difference from the first embodiment will be mainly described.

  FIG. 8 is a graph showing a speed-AC voltage pattern according to this example, and is an AC voltage pattern when the AC voltage is lowered in a high speed region. In the AC voltage pattern of this embodiment, after the AC voltage rises to the upper limit of the maximum output voltage of the control device according to the increase in the rotation speed of the motor 100, an operation region in which the AC voltage is decreased according to the increase in the rotation speed of the motor 100 is defined. Have.

  According to the present embodiment, when the torque output from the motor 100 is large, by outputting the output voltage of the control device 1 up to the maximum value, the current flowing through the motor 100 can be reduced, and the copper loss can be reduced. . In addition, by reducing the AC voltage in the high speed region, the total loss of copper loss and iron loss can be minimized, and the motor 100 can be operated with high efficiency.

  In this embodiment, there is a low speed region where the torque is constant, a medium speed region where the output is constant, and a high speed region where the output is reduced. Hereinafter, the difference from the first and second embodiments will be mainly described.

  FIG. 9 is a graph showing a speed-AC voltage pattern according to the present embodiment, which is a rotational speed-torque characteristic of the motor 100 and an AC voltage pattern input to the motor 100. In this embodiment, the motor 100 has a constant torque operation region in the low speed region, a medium output region where the speed is higher than the low speed region, and a low output in the operation region where the rotation speed is high. Has characteristics. On the other hand, the AC voltage applied to the motor 100 has an operation region in which the AC voltage increases according to the speed of the motor 100 in the low / medium speed region and decreases in the high speed region where the output decreases. doing.

  According to this embodiment, the AC voltage is increased as the number of rotations of the motor 100 is increased in the low / medium speed region where torque / output is required, and the AC voltage is decreased in the high speed region where output is not required. The motor 100 can be driven with high efficiency according to the speed.

  In the present embodiment, unlike the first embodiment, the power conversion device 1 includes an inverter 2 and a booster circuit 3. Hereinafter, the difference from the first to third embodiments will be mainly described.

  FIG. 10 is a circuit diagram of the power conversion apparatus 1 according to the present embodiment. The power conversion device 1 according to this embodiment includes an inverter 2 and a booster circuit 3.

  The booster circuit 3 includes a semiconductor module 802 and a reactor 15. The semiconductor module 802 is configured by connecting two switching elements 602 in series. A connection point of the switching element 602 is connected to the DC power supply 4 through the reactor 15. The semiconductor module 802 is connected in parallel with the inverter 2. Note that the semiconductor module 802 may be a single unit or a plurality of units, and a plurality of switching elements 602 and diodes 902 may be connected in parallel to increase the capacity.

FIG. 11 is a block diagram for operating the booster circuit 3 according to the present embodiment. Based on the voltage command value Ecf ^* , the AVR control unit adjusts the voltage to control the current command value Is *. The ACR control unit controls the current value Is such that the current command value Is ^* output from the AVR control unit. The gate driver 17 controls the booster circuit 3 according to Is output from the ACR control unit, and adjusts the voltage Ecf output from the booster circuit 3. Thereby, the booster circuit 3 is operated, and the DC voltage value input to the inverter 2 is adjusted.

  According to the present embodiment, since the power conversion device 1 is equipped with the booster circuit 3, when the rotational speed of the motor 100 is increased, the AC voltage can be reduced with low loss. Therefore, the motor 100 can be operated with high efficiency.

  In the present embodiment, unlike the first embodiment, the power conversion device 1 includes an inverter 2 and a step-down circuit 8. Hereinafter, the difference from the first to fourth embodiments will be mainly described.

  FIG. 12 is a circuit diagram of the power conversion device 1 according to the present embodiment. The power conversion device 1 according to this embodiment includes an inverter 2 and a step-down circuit 8.

  The step-down circuit 8 includes a semiconductor module 803 and a reactor 15. The semiconductor module 803 is configured by connecting two switching elements 603 in series. When the switching element 603 is an IGBT, it is necessary to connect the diodes 903 in parallel in the opposite direction to the IGBT. However, when the switching element 603 is a MOSFET, a parasitic diode of a MOSFET can be used as the diode 903. . A connection point between the two switching elements 603 is connected to the reactor 15, and the reactor 15 is connected to the inverter 2. Note that the semiconductor module 803 may be a plurality of semiconductor modules as well as a single unit, and a plurality of switching elements 803 and diodes 903 may be connected in parallel to increase the capacity. The inverter 2 is the same as the inverter 2 described in the above embodiment. The operation of the step-down circuit 8 is the same as the block diagram for operating the step-up circuit 3 according to the fourth embodiment shown in FIG. 11, and the Ecf output from the step-down circuit 8 and the input current of the gate driver 17 Based on the Is information, the voltage and current are controlled and the output voltage value is adjusted.

  According to this embodiment, when the rotational speed of the motor 100 is increased, the AC voltage can be reduced with low loss, so that the total loss of copper loss and iron loss can be minimized, and the motor 100 can be made highly efficient. I can drive.

  In the present embodiment, unlike the first embodiment, the power conversion device 1 includes an inverter 2 and a power storage device 9. Hereinafter, the difference from the first to fifth embodiments will be mainly described.

  FIG. 13 is a circuit diagram of the power conversion apparatus 1 according to the present embodiment. The power conversion device 1 according to this embodiment includes an inverter 2 and a power storage device 9, and the high voltage side of the power conversion device 1 is connected to the overhead wire 11 via a reactor 15. The inverter 2 is the same as the inverter 2 of the first embodiment. The power storage device 9 is connected to the ground side of the inverter 2, and a DC voltage output from the power storage device 9 is applied to the inverter 2 in addition to the DC voltage of the overhead wire 11. The operation of the power storage device 9 is the same as the block diagram for operating the booster circuit 3 according to the fourth embodiment shown in FIG. 11, and the Ecf output from the power storage device 9 and the input current of the gate driver 17 Based on the Is information, the voltage and current are controlled and the output voltage value is adjusted.

  According to the present embodiment, the AC voltage can be lowered when the rotation speed of the motor 100 is increased. Furthermore, the generated power generated when the motor 100 decelerates can be stored in the power storage device 9, and the motor 100 can be operated with high efficiency.

  In the present embodiment, unlike the first embodiment, the power conversion device 1 includes an inverter 2 and a converter 13. Hereinafter, the difference from the first to sixth embodiments will be mainly described.

  FIG. 14 is a circuit diagram of the power conversion device 1 according to the present embodiment. The power conversion apparatus 1 of the present embodiment supplies the voltage supplied from the AC power supply 18 to the converter 13 that converts the AC voltage into a DC voltage after changing the magnitude of the voltage by the transformer 16. The converter 13 is composed of four switching elements 604. When the switching element 604 is an IGBT, it is necessary to connect the diodes 904 in parallel in the opposite direction to the IGBT. However, when the switching element 604 is a MOSFET, a parasitic diode of the MOSFET can be used as the diode 904. . The semiconductor module 804 is configured by connecting switching elements 604 in series. The two semiconductor modules 804 are connected in parallel. The connection point of the switching element 604 of each of the two semiconductor modules 804 is connected to the transformer 16. The converter 13 is connected to the inverter 2. The inverter 2 is the same as the inverter 2 of the first embodiment.

  The power conversion device 1 according to the present embodiment includes an inverter 2 and a converter 13, and the operation of the converter 13 is a block diagram for operating the booster circuit 3 according to the fourth embodiment illustrated in FIG. 11. Similarly, based on Ecf output from the converter 13 and information on the input current Is of the gate driver 17, the voltage / current is controlled and the output voltage value is adjusted.

  According to the present embodiment, the AC voltage can be lowered when the rotation speed of the motor 100 is increased, and the motor 100 can be operated with high efficiency.

  In the present embodiment, unlike the first embodiment, the voltage Ecf of the capacitor 5 has an operation region that decreases when the rotation speed of the motor 100 increases. Hereinafter, the difference from the first to seventh embodiments will be mainly described.

  FIG. 15 is a graph showing capacitor voltage-speed and AC voltage-speed in the power converter according to the present embodiment, and the relationship between the voltage of the capacitor 5 mounted on the power converter 1 and the rotation speed of the motor 100. And the relationship of the alternating voltage of the motor 100 is shown. In the present embodiment, as means for changing the voltage of the capacitor 5 mounted on the power converter 1, the booster circuit 3 of the fourth embodiment, the step-down circuit 8 of the fifth embodiment, the storage battery of the sixth embodiment, or the seventh embodiment is applied. A power converter (converter) that converts AC to DC is used. The operation of the means for changing these voltages is the same as the block diagram for operating the booster circuit 3 according to the fourth embodiment shown in FIG.

  The voltage Ecf of the capacitor 5 according to the present embodiment has an operation region that decreases when the rotation speed of the motor 100 increases, and the AC voltage of the motor 100 also decreases in the same operation region.

  According to the present embodiment, the total loss of the copper loss and the iron loss can be minimized by reducing the AC voltage when the rotation speed of the motor 100 is increased, and the motor 100 can be operated with high efficiency.

  The present embodiment is a railway vehicle equipped with the power conversion device according to any one of the first to eighth embodiments. Hereinafter, the difference from the first to eighth embodiments will be mainly described.

  FIG. 16 is a configuration diagram of an AC motor drive system for an electric railway vehicle according to the present embodiment, and shows a railway vehicle using the AC motor drive system. In an AC motor drive system for a railway vehicle, electric power is supplied from an overhead wire 11 via a current collector, and AC power is supplied to the motor 100 via the power converter 1 to drive the motor 100. The motor 100 is connected to the axle of the railway vehicle, and the traveling of the railway vehicle is controlled by the motor 100. The electrical ground is connected via the rail 12. The voltage of the overhead wire 11 may be either direct current or alternating current.

  According to this embodiment, the railway vehicle can be driven with high efficiency.

  In the above embodiment, the induction motor has been described as an example. However, the present invention is not limited to this, and the present invention can also be applied to a permanent magnet motor, switched reluctance, and the like. In the above embodiment, the railway vehicle has been described as an example, but the present invention can also be applied to an electric vehicle, a hybrid car, and the like.

DESCRIPTION OF SYMBOLS 1 Power converter 2 Inverter 3 Booster circuit 4 DC power supply 5 Capacitor 8 Step-down circuit 9 Power storage device 10 Motor control part 11 Overhead wire 12 Rail 13 Converter 14 Wheel 15 Reactor 16 Transformer 17 Gate driver 18 AC power supply 100 Motor 601 Switching of inverter Element 602 Step-up circuit switching element 603 Step-down circuit switching element 604 Converter switching element 801 Inverter semiconductor module 802 Step-up circuit semiconductor module 803 Step-down circuit semiconductor module 804 Converter semiconductor module 901 Inverter diode 902 Step-up circuit diode 903 Step-down circuit diode 904 Converter diode

Claims (20)

A power conversion device that converts power supplied from a power source to drive an AC rotary motor,
The power converter according to claim 1, wherein after increasing the output voltage according to an increase in the rotational speed of the AC rotary motor, the output voltage is decreased according to the increase in the rotational speed. The power conversion device according to claim 1,
A power conversion device, wherein after the output voltage reaches a maximum value as the rotational speed of the AC rotary motor increases, the output voltage is decreased as the rotational speed increases. In the power converter device in any one of Claims 1-2,
The power converter according to claim 1, wherein the output voltage is decreased according to the increase in the rotation speed in an operation region where the output is decreased according to the increase in the rotation speed of the AC rotary motor. In the power converter device in any one of Claims 1-3,
The power converter is equipped with a booster circuit. In the power converter device in any one of Claims 1-3,
A power converter, wherein the power converter is equipped with a step-down circuit. In the power converter device in any one of Claims 1-3,
The said power converter device mounts a storage battery, The power converter device characterized by the above-mentioned. In the power converter device in any one of Claims 1-3,
The power source is an AC power source;
The said power converter device mounts the converter which converts the said alternating current power into direct-current power, The power converter device characterized by the above-mentioned. In the power converter device in any one of Claims 1-7,
The voltage of the capacitor | condenser connected in parallel with the inverter of the said power converter device is dropped according to the raise of the rotation speed of the said AC rotary motor, The power converter device characterized by the above-mentioned. In the power converter device in any one of Claims 1-8,
The AC rotating motor is an induction machine, a permanent magnet synchronous motor, or a switched reluctance motor. An electric vehicle comprising the power conversion device according to claim 1. A power conversion method for converting electric power supplied from a power source into electric power for driving an AC rotary motor,
A power conversion method comprising: increasing an output voltage according to an increase in the rotational speed of the AC rotating motor; and then decreasing the output voltage according to the increase in the rotational speed. The power conversion method according to claim 11,
A power conversion method characterized in that after the output voltage reaches a maximum value as the rotational speed of the AC rotary motor increases, the output voltage is decreased as the rotational speed increases. The power conversion method according to any one of claims 11 to 12,
A power conversion method, wherein an output voltage is decreased in accordance with an increase in the rotation speed in an operation region in which an output is decreased in accordance with an increase in the rotation speed of the AC rotary motor. In the power conversion method in any one of Claims 11-13,
A power conversion method comprising mounting the power from the power source after being boosted by a booster circuit. In the power conversion method in any one of Claims 11-13,
A power conversion method, wherein power from the power supply is stepped down and supplied by a step-down circuit. In the power conversion method in any one of Claims 11-13,
A power conversion method comprising applying a voltage of a storage battery to power from the power source and supplying the power. In the power conversion method in any one of Claims 11-13,
A power conversion method, wherein AC power from the power source is converted into a DC voltage by a converter and supplied. In the power conversion method in any one of Claims 11-17,
A power conversion method characterized in that the voltage of a capacitor connected in parallel to an inverter for power conversion is lowered as the rotational speed of the AC rotary motor increases. In the power conversion method in any one of Claims 11-18,
The AC rotating motor is an induction machine, a permanent magnet synchronous motor, or a switched reluctance motor. An electric vehicle traveling method in which electric power converted by the power conversion method according to any one of claims 11 to 19 is supplied to an AC rotary electric motor of an electric vehicle to cause the electric vehicle to travel.

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