Power conversion apparatus and electric power steering apparatus having the same

Patent metadata

Field	Value
Publication number	US-9520817-B2
Application number	US-201414489073-A
Country	US
Kind code	B2
Filing date	Sep 17, 2014
Priority date	Sep 18, 2013
Publication date	Dec 13, 2016
Grant date	Dec 13, 2016

Abstract

A power conversion apparatus includes: an inverter unit having high and low potential-side switching elements corresponding to each phase of a winding of a rotating electrical machine; a current detecting unit; and a control unit controlling the switching elements based on a PWM reference signal and a duty instruction value. The control unit includes: a phase current computing device; and a voltage instruction value computing device. The control unit computes an active voltage vector interval in first and second half periods of one or multiple cycles of the PWM reference signal to be a predetermined period or longer, and computes first and second half duty instruction values to set first and second voltage vector intervals equal to or longer than minimum time to be in the first or second half period.

First claim

What is claimed is:

1. A power conversion apparatus comprising:
an inverter unit having a plurality of high-potential-side switching elements disposed on a high-potential side and a plurality of low-potential-side switching elements disposed on a low-potential side, each of the high-potential-side switching elements and the low-potential-side switching elements corresponding to one of a plurality of phases of a winding of a rotating electrical machine;
a current detecting unit connected between the inverter unit and a positive side or a negative side of a DC power supply; and
a control unit controlling an on-operation and an off-operation of the high-potential-side switching elements and the low-potential-side switching elements based on a PWM reference signal and a duty instruction value,
wherein the control unit includes:
a phase current computing device computing a phase current of each phase, which flows through one of phases of the winding, based on a current detection value detected by the current detecting unit; and
a voltage instruction value computing device computing a voltage instruction value, which relates to a voltage applied to the winding, based on the phase current of each phase,

wherein the control unit computes an active voltage vector interval in both a first-half period and a second half period of the PWM reference signal to be longer or equal to a predetermined period required to obtain the current detection value,
wherein the control unit computes a first-half duty instruction value and a second-half duty instruction value as a duty instruction value based on the voltage instruction value in such a manner that a first voltage vector interval and a second voltage vector interval are equal to or longer than minimum time, and the first voltage vector interval and the second voltage vector interval are included in at least one of the first-half period and the second-half period,
wherein, in the first voltage vector interval, the low-potential-side switching elements of all of the phases turn on,
wherein, in the second voltage vector interval, the high-potential-side switching elements of all of the phases turn on,
wherein the minimum time is equal to or longer than a dead time period,
wherein, in the dead time period, both one high-potential-side switching element and one low-potential-side switching element corresponding to a same phase of the winding are turned off, and
wherein the second voltage vector interval in the first-half period and the first voltage vector interval in the second-half period are equal to the minimum time.

2. The power conversion apparatus according to claim 1 ,
wherein the active voltage vector interval is equal to or longer than the predetermined period required to obtain the current detection value in the first-half period and the second-half period of the one cycle of the PWM reference signal.

3. The power conversion apparatus according to claim 1 ,
wherein the control unit includes:
a duty converting device for converting the voltage instruction value to a duty conversion value;
a correcting device for computing a first half duty temporary value and a second half duty temporary value in a manner that the active voltage vector interval for obtaining the current detection value is equal to or longer than the predetermined period required to obtain the current detection value; and
an adjusting device for computing the first-half duty instruction value and the second-half duty instruction value from the first-half duty temporary value and the second-half duty temporary value so that the first voltage vector interval and the second voltage vector interval, which are equal to or longer than the minimum time, are included in at least one of the first-half period and the second-half period.

4. The power conversion apparatus according to claim 1 , further comprising:
a current obtaining unit for sampling and holding the current detection value with a fixed interval sampling timing,
wherein the control unit computes the first-half duty instruction value and the second-half duty instruction value so that phase current is obtained from the current detection value with the fixed interval sampling timing.

5. The power conversion apparatus according to claim 4 ,
wherein a value for computing the phase current of each phase is switched in accordance with an amplitude of the voltage instruction value, and
wherein the value is selected from the current detection values obtained by the current obtaining unit.

6. The power conversion apparatus according to claim 1 ,
wherein the inverter unit includes a first inverter unit and a second inverter unit, and
wherein the current detecting unit includes a first current detecting unit and a second current detecting unit,
wherein the first current detecting unit is connected between the first inverter unit and the positive side or the negative side of the DC power supply, and
wherein the second current detecting unit is connected between the second inverter unit and the positive side or the negative side of the DC power supply.

7. A power conversion apparatus comprising:
an inverter unit having a plurality of high-potential-side switching elements disposed on a high-potential side and a plurality of low-potential-side switching elements disposed on a low-potential side, each of the high-potential-side switching elements and the low-potential-side switching elements corresponding to one of a plurality of phases of a winding of a rotating electrical machine;
a current detecting unit connected between the inverter unit and a positive side or a negative side of a DC power supply; and
a control unit controlling an on-operation and an off-operation of the high-potential-side switching elements and the low-potential-side switching elements based on a PWM reference signal and a duty instruction value,
wherein the control unit includes:
a phase current computing device computing a phase current of each phase, which flows through one of phases of the winding, based on a current detection value detected by the current detecting unit; and
a voltage instruction value computing device computing a voltage instruction value, which relates to a voltage applied to the winding, based on the phase current of each phase,

wherein the control unit computes an active voltage vector interval in both a first-half period and a second half period of predetermined one cycle or multiple cycles of the PWM reference signal to be longer or equal to a predetermined period required to obtain the current detection value,
wherein the control unit computes a first-half duty instruction value and a second-half duty instruction value as a duty instruction value based on the voltage instruction value in such a manner that a first voltage vector interval and a second voltage vector interval are equal to or longer than minimum time, and the first voltage vector interval and the second voltage vector interval are included in at least one of the first-half period and the second-half period,
wherein, in the first voltage vector interval, the low-potential-side switching elements of all of the phases turn on,
wherein, in the second voltage vector interval, the high-potential-side switching elements of all of the phases turn on,
wherein the minimum time is equal to or longer than a dead time period,
wherein, in the dead time period, both one high-potential-side switching element and one low-potential-side switching element corresponding to a same phase of the winding are turned off,
wherein the inverter unit includes a first inverter unit and a second inverter unit,
wherein the current detecting unit includes a first current detecting unit and a second current detecting unit,
wherein the first curren

Assignees

• Denso Corp

Inventors

• Suzuki Takashi

Classifications

• B62D5/0463

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

• H02P6/10 Primary

  Arrangements for controlling torque ripple, e.g. providing reduced torque ripple · CPC title

• H02P21/05

  specially adapted for damping motor oscillations, e.g. for reducing hunting · CPC title

• B62D5/046 Primary

  Controlling the motor · CPC title

• H02M7/53875

  with analogue control of three-phase output · CPC title