Three-phase rotating machine controller

Patent metadata

Field	Value
Publication number	US-9985569-B2
Application number	US-201615132774-A
Country	US
Kind code	B2
Filing date	Apr 19, 2016
Priority date	Apr 22, 2015
Publication date	May 29, 2018
Grant date	May 29, 2018

Abstract

A three-phase rotating machine controller includes electric power converters that output, to the winding sets of a three-phase rotating machine, alternating currents having a same amplitude and a phase difference of (30 ±60*n) degrees from each other, n being an integer, and a control unit that reduces a peak of a phase current 1st order component applied to the rotating machine by superimposing therewith a phase current 5th order component and a phase current 7th order component, which have 5 times and 7 times the frequency of the phase current 1st order component, respectively. The control unit superimposes the phase current 5th and 7th order components having an optimum combination of amplitudes such that a peak reduction amount of the phase current 1st order component exceeds 5%, the amplitudes of the phase current 5th and 7th order components being with respect to the amplitude of the phase current 1st order component.

First claim

The invention claimed is:

1. A three-phase rotating machine controller for driving a three-phase rotating machine having two three-phase winding sets, comprising:
a first electric power converter and a second electric power converter corresponding to the two winding sets, the first electric power converter and the second electric power converter outputting, to the two winding sets, alternating currents having a same amplitude as each other and having a phase difference of (30 ±60*n) [degrees] from each other, n being an integer; and
a control unit that controls energizing of the three-phase rotating machine so as to reduce a peak of a phase current 1st order component applied to the three-phase rotating machine by superimposing a phase current 5th order component and a phase current 7th order component with the phase current 1st order component, the phase current 5th order component having 5 times the frequency of the phase current 1st order component, the phase current 7th order component having 7 times the frequency of the phase current 1st order component, wherein
the control unit superimposes the phase current 5th order component having an amplitude of 8.1 to 16.1 [%] and the phase current 7th order component having an amplitude of 0.6% to 11.1 [%], the amplitudes of the phase current 5th order component and the phase current 7th order component being defined with respect to the amplitude of the phase current 1st order component, and
the control unit superimposes the phase current 5th order component and the phase current 7th order component with a combination of amplitudes within a range surrounded by straight lines represented by the following five equations
x=8.1
x=16.1
y=0.54 x −3.8 (8.1≤x≤12.5)

y=1.14 x −11.3 (12.5≤x≤16.1)

y=1.00 x −5.0 (8.1≤x≤16.1)

where the amplitude of the phase current 5th order component is x [%], and the amplitude of the phase current 7th order component is y [%].

2. The three-phase rotating machine controller of claim 1 , wherein
the control unit calculates, on the q-d axis, a 6th order d-axis current and a 6th-order q-axis current which have a frequency 6 times that of the phase current 1st order component, such that the phase current 5th order component and the phase current 7th order component may be obtained by coordinate transformation.

3. The three-phase rotating machine controller of claim 1 , wherein the control unit calculates, on the d-q axis, a 6th order quasi-triangle wave d-axis current and a 6th axis q-axis current which have a frequency 6 times that of the phase current 1st order component, such that the phase current 5th order component and the phase current 7th order component may be obtained by coordinate transformation.

4. The three-phase rotating machine controller of claim 1 , wherein
each of the winding sets and the electric power converter corresponding to that winding set form a system, and
the control unit performs feedback control on actual currents flowing in the winding sets with respect to current command values for each system.

5. The three-phase rotating machine controller of claim 1 , wherein
each of the winding sets and the electric power converter corresponding to that winding set form a system, and
the control unit performs feedback control on sums and differences of actual currents flowing in the winding sets with respect to sums and differences of current command values of both systems.

6. The three-phase rotating machine controller of claim 1 , wherein
the control unit changes the amplitudes of the phase current 5th order component and the phase current 7th order component according to a rotation speed of the three-phase rotating machine.

7. The three-phase rotating machine controller of claim 1 , wherein
the control unit calculates, on the d-q axis, a d-axis current and a q-axis current such that such that the phase current 5th order component and the phase current 7th order component may be obtained by coordinate transformation, and
when the absolute value of a rotation speed of the three-phase rotating machine is below a predetermined value, a d-axis current command value is considered to be 0.

8. The three-phase rotating machine controller of claim 1 , wherein
the control unit considers the amplitude of the phase current 1st order component to be 0 when the amplitude of the phase current 1st order component is less than a predetermined value.

9. The three-phase rotating machine controller of claim 1 , wherein
the control unit compensates for the phases of the phase current 5th order component and the phase current 7th order component according to a rotation speed of the three-phase rotating machine.

10. The three-phase rotating machine controller of claim 1 , wherein
the control unit includes dead time compensators that perform voltage compensation according to a phase current polarity, so as to cancel out effects of dead time with respect to a voltage applied to the three-phase rotating machine.

11. The three-phase rotating machine controller of claim 10 , wherein
the dead time compensators determine the phase current polarity based on actual current.

12. The three-phase rotating machine controller of claim 10 , wherein
the dead time compensators determine the phase current polarity based on a current value calculated by adding the phase current 5th order component and the phase current 7th order component to the phase current 1st order component.

13. The three-phase rotating machine controller of claim 1 , wherein
each of the winding sets and the electric power converter corresponding to that winding set form a system, and
the control unit is configured to, when one system of the two systems fails, continue driving the three-phase rotating machine with the normally operating system and superimpose the phase current 5th order component and the phase current 7th order component having difference amplitudes than during dual system driving.

14. The three-phase rotating machine controller of claim 1 , wherein
each of the winding sets and the electric power converter corresponding to that winding set form a system, and
the control unit is configured to, when one system of the two systems fails, continue driving the three-phase rotating machine with the normally operating system and superimpose the phase current 5th order component and the phase current 7th order component having the same amplitudes as during dual system driving.

Assignees

• Denso Corp

Inventors

• Suzuki Takashi

Classifications

• H02P21/05

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

• H02P27/06 Primary

  using DC to AC converters or inverters (H02P27/05 takes precedence) · CPC title

• H02P29/50 Primary

  Reduction of harmonics · CPC title