Multi-phase motor control apparatus and electric power steering apparatus using the same

• US 9,667,179 B2
• Filed: 05/04/2016
• Issued: 05/30/2017
• Est. Priority Date: 04/17/2013
• Status: Expired due to Fees

• Current Assignee: NSK Limited
• Original Assignee: NSK Limited
• Inventors: Sugawara, Takayoshi, Kumagai, Hiroyasu, Imamura, Yousuke
• Primary Examiner(s): Ip, Paul
• Application Number:
  US15/145,858
• Publication Number:
  US 20160248351A1
• Time in Patent Office: 391 Days
• Field of Search: 31840002, 31840004, 318432, 318443, 318446
• CPC Class Codes: B62D 5/046 Controlling the motor
• CPC Class Codes: B62D 5/0472 for damping vibrations
• CPC Class Codes: H02P 21/22 Current control, e.g. using a current control loop
• CPC Class Codes: H02P 23/14 Estimation or adaptation of motor parameters, e.g. rotor time constant, flux, speed, current or voltage
• CPC Class Codes: H02P 6/10 Arrangements for controlling torque ripple, e.g. providing reduced torque ripple
• CPC Class Codes: H02P 6/15 Controlling commutation time
• CPC Class Codes: H02P 6/28 Arrangements for controlling current H02P6/10 takes precedence

Abstract

A multi-phase motor control apparatus that reduces the occurrence of the vibrations and the noises by setting the shift amount per time more finely after realizing a reduction in processing ability of a CPU by using a one-shunt type current detection circuit and an electric power steering apparatus using the same. The apparatus includes a PWM-signal generating section that generates plural second each-phase PWM-signals within two control periods based on the current estimation value and the carrier signal, and in a case that a phase shift amount of a predetermined phase in a just before control period is zero and a phase shift amount of a predetermined phase in a present control period is not zero, the phase shift control section gradually increases the phase shift amount from zero in the present control period and a next control period, and uses the second each-phase PWM-signals in the next control period.

Claims

1. A multi-phase motor control apparatus comprising:

a driving section comprising pairs of upper-stage arm switching elements and lower-stage arm switching elements, and driving a multi-phase motor;

a single type current detection circuit detecting current values of said multi-phase motor;

a PWM-signal generating section generating a first each-phase PWM-signals in respective control periods within two control periods based on said current values detected by said current detecting circuit and a carrier signal;

a phase shift control section shifting a first PWM-signal of a predetermined phase, which is generated in said PWM-signal generating section, by gradually changing a phase shift amount within two control periods, and outputting said shifted first PWM-signal to said driving section; and

a current detection observer estimating a current estimation value of said multi-phase motor based on said current values detected by said current detection circuit;

wherein said PWM-signal generating section generates a second each-phase PWM-signals in respective control periods within two control periods based on said current estimation value and said carrier signal; and

said PWM-signal generating section drives at first said multi-phase motor using said first each-phase PWM-signals;

wherein in a case that a phase shift amount of a predetermined phase in a control period controlled by said first each-phase PWM-signals is zero and a phase shift amount of a predetermined phase in a control period controlled by next first each-phase PWM-signals is not zero, said phase shift control section gradually increases said phase shift amount from zero in a control period controlled by a second each-phase PWM-signals following said next first each-phase PWM-signals based on said phase shift amount calculated by said next first each-phase PWM-signals, and uses said second each-phase PWM-signals.

2. The multi-phase motor control apparatus according to claim 1, wherein said phase shift control section calculates a phase shift amount to a final shift position of said first PWM-signal, and shifts by “

phase shift amount/n”

as a shift number is n times.

3. The multi-phase motor control apparatus according to claim 2, wherein with respect to said phase shift of said determined phase, shift times m (<

n) are performed in said control period controlled by said first each-phase PWM-signals and phase shift of rest (n−

m) times are performed by control with the second each-phase PWM-signals following said control period of said first each-phase PWM-signals.

4. The multi-phase motor control apparatus according to claim 1, wherein said current detection observer estimates a current value in said control period of said second each-phase PWM-signals based on a current value detected in said control period of said first each-phase PWM-signals.

9. An electric power steering apparatus provided with said multi-phase motor control apparatus according to claim 1.

5. A multi-phase motor control apparatus comprising:

a driving section comprising pairs of upper-stage arm switching elements and lower-stage arm switching elements, and driving a multi-phase motor;

a single type current detection circuit detecting current values of said multi-phase motor;

a PWM-signal generating section generating a first each-phase PWM-signals in respective control periods within two control periods based on said current values detected by said current detecting circuit and a carrier signal;

a phase shift control section shifting a first PWM-signal of a predetermined phase, which is generated in said PWM-signal generating section, by gradually changing a phase shift amount within two control periods, and outputting said shifted first PWM-signal to said driving section; and

a current detection observer estimating a current estimation value of said multi-phase motor based on said current values detected by said current detection circuit;

wherein said PWM-signal generating section generates a second each-phase PWM-signals in respective control periods within two control periods based on said current estimation value and said carrier signal; and

said PWM-signal generating section drives at first said multi-phase motor using said first each-phase PWM-signals;

wherein in a case that a phase shift amount of a predetermined phase in a control period controlled by said first each-phase PWM-signals is not zero and a phase shift amount of a predetermined phase in a control period controlled by next first each-phase PWM-signals is zero, said phase shift control section gradually decreases said phase shift amount to zero in a control period controlled by a second each-phase PWM-signals following said next first each-phase PWM-signals based on said phase shift amount calculated by said next first each-phase PWM-signals, and uses said second each-phase PWM-signals.

6. The multi-phase motor control apparatus according to claim 5, wherein said phase shift control section calculates a phase shift amount to a final shift position of said first PWM-signal, and shifts by “

phase shift amount/n”

as a shift number is n times.

7. The multi-phase motor control apparatus according to claim 6, wherein with respect to said phase shift of said determined phase, shift times m (<

n) are performed in said control period controlled by said first each-phase PWM-signals and phase shift of rest (n−

m) times are performed by control with the second each-phase PWM-signals following said control period of said first each-phase PWM-signals.

8. The multi-phase motor control apparatus according to claim 5, wherein said current detection observer estimates a current value in said control period of said second each-phase PWM-signals based on a current value detected in said control period of said first each-phase PWM-signals.