Motor control apparatus, power conversion device, auxiliary power source device, and method for controlling auxiliary power source device

Patent metadata

Field	Value
Publication number	US-10158316-B2
Application number	US-201715429170-A
Country	US
Kind code	B2
Filing date	Feb 10, 2017
Priority date	Feb 10, 2016
Publication date	Dec 18, 2018
Grant date	Dec 18, 2018

Abstract

A motor control apparatus includes an AC-DC converter, an auxiliary power source, and an inverter. The AC-DC converter converts AC power into DC power and feeds the DC power to a DC bus bar. DC power is fed from the auxiliary power source to the DC bus bar and from the DC bus bar to the auxiliary power source. The inverter converts the DC power of the DC bus bar into the AC power and feeds the AC power to a motor. The auxiliary power source includes a capacitor, a DC-DC converter, and circuitry. The DC-DC converter performs conversion between a first DC voltage of the DC bus bar and a second DC voltage applied between both terminals of the capacitor or inside of the capacitor. The circuitry is configured to control the DC-DC converter to maintain positive correlation between the second DC voltage and the first DC voltage.

First claim

What is claimed is:

1. A motor control apparatus comprising:
an AC-DC converter to convert AC power into DC power and to feed the DC power to a DC bus bar;
an auxiliary power source, DC power being fed from the auxiliary power source to the DC bus bar and from the DC bus bar to the auxiliary power source, the auxiliary power source comprising:
a capacitor;
a DC-DC converter to perform conversion between a first DC voltage of the DC bus bar and a second DC voltage applied between both terminals of the capacitor; and
circuitry configured to control the DC-DC converter to maintain directly proportional relation that the second DC voltage is a value obtained by multiplying the first DC voltage by a predetermined first coefficient; and

an inverter to convert the DC power of the DC bus bar into AC power and to feed the AC power to a motor.

2. The motor control apparatus according to claim 1 ,
wherein the DC-DC converter includes a chopper circuit comprising a semiconductor switching element, a diode, and an inductor, and
wherein the circuitry is configured to perform PWM control on the semiconductor switching element.

3. The motor control apparatus according to claim 2 ,
wherein the circuitry comprises:
a first voltage detector to detect the first DC voltage of the DC bus bar; and
a current detector to detect a capacitor current flowing through the capacitor, and
wherein the circuitry is configured to perform the PWM control in accordance with a duty ratio calculated based on the first DC voltage and the capacitor current.

4. A motor control apparatus comprising:
an AC-DC converter to convert AC power into DC power and to feed the DC power to a DC bus bar;
an auxiliary power source, DC power being fed from the auxiliary power source to the DC bus bar and from the DC bus bar to the auxiliary power source, the auxiliary power source comprising:
an electric double-layer capacitor;
a DC-DC converter to perform conversion between a first DC voltage of the DC bus bar and a second DC voltage applied inside of the electric double-layer capacitor; and
circuitry configured to control the DC-DC converter to maintain directly proportional relation that the second DC voltage is a value obtained by multiplying the first DC voltage by a predetermined second coefficient; and

an inverter to convert the DC power of the DC bus bar into AC power and to feed the AC power to a motor.

5. The motor control apparatus according to claim 4 ,
wherein the DC-DC converter includes a chopper circuit comprising a semiconductor switching element, a diode, and an inductor, and
wherein the circuitry is configured to perform PWM control on the semiconductor switching element.

6. The motor control apparatus according to claim 5 ,
wherein the circuitry comprises:
a first voltage detector to detect the first DC voltage of the DC bus bar; and
a current detector to detect a capacitor current flowing through the capacitor, and
wherein the circuitry is configured to perform the PWM control in accordance with a duty ratio calculated based on the first DC voltage and the capacitor current.

7. The motor control apparatus according to claim 6 ,
wherein the circuitry is configured to calculate the duty ratio to maintain proportional relation of the second DC voltage to the first DC voltage through feedback control of the capacitor current.

8. The motor control apparatus according to claim 7 ,
wherein the circuitry comprises:
an inter-terminal voltage detector to detect a voltage between both terminals of the electric double-layer capacitor;
an internal voltage command generator to generate an internal voltage command by multiplying the first DC voltage detected by the first voltage detector by a function coefficient corresponding to a predetermined set value;
a second DC voltage command generator to generate a second DC voltage command by adding, to the internal voltage command, a multiplication value of the capacitor current detected by the current detector and an internal resistance value of the electric double-layer capacitor;
a capacitor current command generator to generate a capacitor current command based on a deviation between the second DC voltage command and the voltage between the both terminals detected by the inter-terminal voltage detector;
a duty ratio command generator to generate a duty ratio command based on a deviation between the capacitor current command and the capacitor current detected by the current detector; and
a PWM controller configured to perform the PWM control based on the duty ratio command.

9. A power conversion device comprising:
an AC-DC converter to convert AC power into DC power and to feed the DC power to a DC bus bar; and
an auxiliary power source, DC power being fed from the auxiliary power source to the DC bus bar and from the DC bus bar to the auxiliary power source, the auxiliary power source comprising:
a capacitor;
a DC-DC converter to perform conversion between a first DC voltage of the DC bus bar and a second DC voltage applied between both terminals of the capacitor; and
circuitry configured to control the DC-DC converter to maintain directly proportional relation that the second DC voltage is a value obtained by multiplying the first DC voltage by a predetermined first coefficient.

10. An auxiliary power source device, DC power being fed from the auxiliary power source device to a DC bus bar and from the DC bus bar to the auxiliary power source device, the auxiliary power source device comprising:
a capacitor;
a DC-DC converter to perform conversion between a first DC voltage of the DC bus bar and a second DC voltage applied between both terminals of the capacitor; and
circuitry configured to control the DC-DC converter to maintain directly proportional relation that the second DC voltage is a value obtained by multiplying the first DC voltage by a predetermined first coefficient.

11. A method for controlling an auxiliary power source device including a capacitor and a DC-DC converter, the method comprising:
performing conversion in the DC-DC converter between a first DC voltage of a DC bus bar and a second DC voltage applied between both terminals of the capacitor; and
controlling the DC-DC converter to maintain directly proportional relation that the second DC voltage is a value obtained by multiplying the first DC voltage by a predetermined first coefficient.

12. A power conversion device comprising:
an AC-DC converter to convert AC power into DC power and to feed the DC power to a DC bus bar; and
an auxiliary power source, DC power being fed from the auxiliary power source to the DC bus bar and from the DC bus bar to the auxiliary power source, the auxiliary power source comprising:
an electric double-layer capacitor;
a DC-DC converter to perform conversion between a first DC voltage of the DC bus bar and a second DC voltage applied inside of the electric double-layer capacitor; and
circuitry configured to control the DC-DC converter to maintain directly proportional relation that the second DC voltage is a value obtained by multiplying the first DC voltage by a predetermined second coefficient.

13. An auxiliary power source device, DC power being fed from the auxiliary power source device to a DC bus bar and from the DC bus bar to the auxiliary power source device, the auxiliary power source device comprising:
an electric double-layer capacitor;
a DC-DC converter to perform conversion between a first DC voltage of the DC bus bar and a second DC voltage applied inside of the electric double-layer capacitor; and
circuitry configured to control the DC-DC converter to maintain direct

Assignees

• Yaskawa Electric Corp

Inventors

• Sawamura Mitsujiro
• Kaku Yasuhiko

Classifications

• H02M7/537

  using semiconductor devices only, e.g. single switched pulse inverters · CPC title

• H02M5/458 Primary

  using semiconductor devices only · CPC title

• H02M7/06

  using discharge tubes without control electrode or semiconductor devices without control electrode · CPC title

• H02M3/158

  including plural semiconductor devices as final control devices for a single load · CPC title

• H02P6/14

  Electronic commutators · CPC title