Motor control apparatus

Patent metadata

Field	Value
Publication number	US-9667187-B2
Application number	US-201314374242-A
Country	US
Kind code	B2
Filing date	Jan 30, 2013
Priority date	Jan 30, 2012
Publication date	May 30, 2017
Grant date	May 30, 2017

Abstract

A motor control apparatus includes a secondary-magnetic-flux-command calculating unit including a minimum-current-secondary-magnetic-flux-command calculating unit that calculates a secondary magnetic flux command for minimizing a current root-mean-square value due to a torque current and an excitation current and a PWM-signal generating unit that generates a torque current command for outputting a desired torque command and an excitation current command for outputting the secondary magnetic flux command, performs vector control such that a q-axis current, which is a detection value of the torque current, and a d-axis current, which is a detection value of the excitation current, respectively coincide with the torque current command and the excitation current command, and generates control signals for turning on and off a switching element in an inverter.

First claim

The invention claimed is:

1. A motor control apparatus that divides an electric current flowing into and out of a motor driven by an inverter into a torque current and an excitation current and individually controls the torque current and the excitation current on the basis of a torque current command obtained from a torque command and an excitation current command, the motor control apparatus comprising:
a secondary-magnetic-flux-command calculating unit including a first calculating unit that calculates a minimum current secondary magnetic flux command from the torque command under a condition that a current root-mean-square value due to the torque current command and the excitation current command is minimized; and
a PWM-signal generating unit that generates the torque current command and the excitation current command from the torque command and the minimum current secondary magnetic flux command, performs vector control such that a detection value of the torque current and a detection value of the excitation current respectively coincide with the torque current command and the excitation current command, and generates a control signal for turning on and off a switching element included in the inverter.

2. The motor control apparatus according to claim 1 , wherein the first calculating unit calculates the minimum current secondary magnetic flux command on the basis of secondary inductance and a number of pose pairs of the motor and the torque command.

3. The motor control apparatus according to claim 1 , wherein the switching element is formed of a wide band gap semiconductor.

4. The motor control apparatus according to claim 3 , wherein the wide band gap semiconductor is a semiconductor in which silicon carbide, a gallium nitride material, or diamond is used.

5. A motor control apparatus that divides an electric current flowing into and out of a motor driven by an inverter into a torque current and an excitation current and individually controls the torque current and the excitation current on the basis of a torque current command obtained from a torque command and an excitation current command, the motor control apparatus comprising:
a secondary-magnetic-flux-command calculating unit including a first calculating unit that calculates a minimum current secondary magnetic flux command from the torque command under a condition that a current root-mean-square value due to the torque current command and the excitation current command is minimized, the secondary-magnetic-flux-command calculating unit calculating, on the basis of an inverter frequency and the minimum current secondary magnetic flux command, a secondary magnetic flux command with which a total loss of a copper loss and an iron loss of the motor decreases to be smaller than the total loss that occurs when the minimum current secondary magnetic flux command is used; and
a PWM-signal generating unit that generates the torque current command and the excitation current command from the torque command and the secondary magnetic flux command, performs vector control such that a detection value of the torque current and a detection value of the excitation current respectively coincide with the torque current command and the excitation current command, and generates a control signal for turning on and off a switching element included in the inverter.

6. The motor control apparatus according to claim 5 , wherein the secondary-magnetic-flux-command calculating unit generates compensation for reducing a loss due to the iron loss on the basis of the inverter frequency and subtracts the compensation from the minimum current secondary magnetic flux command to calculate the secondary magnetic flux command.

7. The motor control apparatus according to claim 5 , wherein the first calculating unit calculates the minimum current secondary magnetic flux command on the basis of secondary inductance and a number of pole pairs of the motor and the torque command.

8. The motor control apparatus according to claim 5 , wherein the switching element is formed of a wide band gap semiconductor.

Assignees

• Mitsubishi Electric Corp

Inventors

• Yoshimoto Takuji
• Yamashita Yoshinori

Classifications

• H02P21/02

  specially adapted for optimising the efficiency at low load · CPC title

• H02P21/04

  specially adapted for very low speeds · CPC title

• H02P23/03 Primary

  specially adapted for very low speeds · CPC title

• H02P21/22

  Current control, e.g. using a current control loop · CPC title

• H02P23/02

  specially adapted for optimising the efficiency at low load · CPC title