Motor control device and electric power steering device using same

Patent metadata

Field	Value
Publication number	US-9575127-B2
Application number	US-201214114576-A
Country	US
Kind code	B2
Filing date	May 7, 2012
Priority date	Jun 24, 2011
Publication date	Feb 21, 2017
Grant date	Feb 21, 2017

Abstract

Provided are a motor control device ( 1 ) for controlling a motor ( 2 ) having a plurality of phases, for quickly and accurately detecting a phase in which an open-state fault has occurred when the open-state fault occurs in a target phase. When a power-supply voltage (Vb) is equal to or higher than a predetermined voltage (Vthr), a motor rotation speed (ω) is equal to or lower than a predetermined speed (ωthr), a target x-phase voltage command (Vx*) is not in the vicinity of zero, a current (Ix) of the target x-phase is equal to or lower than a predetermined current (Iu_thr), and a state in which a control error is equal to or larger than a predetermined error is detected over a predetermined time period or longer, occurrence of an open-state fault in the target phase is determined.

First claim

The invention claimed is:

1. A motor control device for controlling a current and an applied voltage to a motor having a plurality of phases, comprising:
an inverter for supplying electric power from a power supply to the motor;
current control means for generating a voltage command in accordance with a current command to control the current to the motor;
an inverter driving circuit for driving the inverter in accordance with the voltage command to control the applied voltage to the motor; and
fault detecting means for detecting a fault occurrence state based on the voltage command, a power-supply voltage of the power supply, a motor rotation speed of the motor, and currents in the plurality of phases,
wherein when the power-supply voltage is equal to or higher than a predetermined voltage,
when the motor rotation speed is equal to or lower than a predetermined speed,
when a voltage command in a target phase is not in a vicinity of zero,
when a phase current of the target phase is equal to or lower than a predetermined current, and
when a state in which a control error with respect to the current command or the voltage current is equal to or larger than a predetermined error is detected over a predetermined time period or longer,
the fault detecting means determines occurrence of an open-state fault in the target phase.

2. The motor control device according to claim 1 , wherein a value of the control error comprises a value in accordance with the current command.

3. The motor control device according to claim 2 , wherein a value of the control error comprises a value in accordance with a current deviation between a value of the current command and the current.

4. The motor control device according to claim 1 , wherein a value of the control error comprises a value in accordance with a voltage deviation between a value of the voltage command and the applied voltage.

5. The motor control device according to claim 4 , wherein a value of the applied voltage comprises an estimated value.

6. The motor control device according to claim 5 , wherein the value of the applied voltage comprises an estimated value in accordance with at least one of the current and the motor rotation speed.

7. The motor control device according to claim 1 , wherein a condition that the voltage command in the target phase is not in the vicinity of zero is set based on a condition that the voltage command in the target phase is larger than that of another phase.

8. A motor control device for controlling a current and an applied voltage supplied from a power supply for a motor including a plurality of systems of winding sets each including windings of a plurality of phases, comprising:
inverters of the plurality of systems comprising a plurality of switching elements for controlling applied voltages to the plurality of respective phases of the winding sets of the plurality of systems, for controlling currents to be supplied from the power supply to the plurality of respective phases of the winding sets of the plurality of systems;
current control means for generating a plurality of sets of voltage commands corresponding to the applied voltages to the respective inverters of the plurality of systems in accordance with a plurality of sets of current commands corresponding to the currents to be supplied to the plurality of respective phases of the winding sets of the plurality of systems so as to control the currents to flow through the plurality of respective phases of the winding sets of the plurality of systems; and
fault detecting means for detecting disconnection of a wiring of any one of the plurality of respective phases of the winding sets of the plurality of systems or the inverters of the plurality of systems or an open fault of any one of the plurality of switching elements,
wherein the fault detecting means is configured to:
perform abnormality doubt determining processing for determining which system in which there is a doubt about abnormality among the plurality of systems respectively including the inverters of the plurality of systems and the winding sets of the plurality of systems; and
determine that an open-state fault in the target phase is occurred, when it is determined that there is a doubt about abnormality and when a state in which a phase current of a target phase is equal to or lower than a predetermined current is detected over a predetermined time period or longer.

9. The motor control device according to claim 8 , wherein, in the abnormality doubt determining processing:
the fault detecting means determines whether or not conditions that a power-supply voltage of the power supply is equal to or higher than a predetermined voltage and that a motor rotation speed of the motor is equal to or lower than a predetermined speed are satisfied, in common to the plurality of systems; and
when the conditions are satisfied, in a case where a condition that a control error with respect to the current command or the voltage command is equal to or larger than a predetermined error or that the voltage command in the target phase is equal to or larger than a predetermined phase voltage is satisfied, the fault detecting means determines that there is a doubt about abnormality in the target system.

10. The motor control device according to claim 8 , wherein:
the fault detecting means performs the abnormality doubt determining processing for each of the plurality of systems; and
when a power-supply voltage of the power supply is equal to or higher than a predetermined voltage and when a motor rotation speed of the motor is equal to or lower than a predetermined speed, in a case where a condition that a control error with respect to the current command or the voltage command is equal to or larger than a predetermined error or that the voltage command in the target phase is equal to or larger than a predetermined phase voltage is satisfied, the fault detecting means determines that there is a doubt about abnormality in the target system.

11. The motor control device according to claim 8 , wherein:
the fault detecting means performs the abnormality doubt determination processing for each of the plurality of systems; and
in a case where a control error in a target system of the plurality of systems is equal to or larger than a predetermined error and where a control error in another system falls within an appropriate error range, the fault detecting means determines that there is a doubt about abnormality in the target system.

12. The motor control device according to claim 8 , wherein:
the fault detecting means performs the abnormality doubt determination processing for each of the plurality of systems; and
in a case where the phase current of a corresponding phase in another system which is not a target system among the plurality of systems is equal to or larger than a predetermined normal current and where a control error in the another system falls within an appropriate error range, the fault detecting means determines that there is a doubt about abnormality in the target system.

13. The motor control device according to claim 8 , wherein:
the fault detecting means performs the abnormality doubt determination processing for each of the plurality of systems; and
in a case where a sum of a control error in a target system of the plurality of systems and a control error in another system is equal to or larger than a predetermined added error and where the control error in the another system falls within an appropriate error range, the fault detecting means determines that there is a doubt about abnormality in the target system.

14. The mot

Assignees

• Kezobo Isao
• Iezawa Masahiro
• Zeniya Susumu
• Iwami Eiji
• Fujiki Yusuke
• Kishioka Hiroyuki
• Kamei Sadaaki
• Kimpara Yoshihiko
• Okada Jiro
• Mitsubishi Electric Corp

Inventors

• Kezobo Isao
• Iezawa Masahiro
• Zeniya Susumu
• Iwami Eiji
• Fujiki Yusuke
• Kishioka Hiroyuki
• Kamei Sadaaki
• Kimpara Yoshihiko
• Okada Jiro

Classifications

• H02P29/0243

  the fault being a broken phase · CPC title

• B62D5/0487 Primary

  detecting motor faults (B62D5/0496 takes precedence) · CPC title

• H02P29/0241

  the fault being an overvoltage · CPC title

• B62D5/0463

  calculating assisting torque from the motor based on driver input · CPC title

• G01R31/343 Primary

  in operation · CPC title