Current detection apparatus and control apparatus of rotary electric machine

Patent metadata

Field	Value
Publication number	US-10432124-B2
Application number	US-201816170533-A
Country	US
Kind code	B2
Filing date	Oct 25, 2018
Priority date	Oct 26, 2017
Publication date	Oct 1, 2019
Grant date	Oct 1, 2019

Abstract

In a current detection apparatus, a corrector obtains first current-value pairs of the plural values of the corrective first phase current and the respective plural values of the corrective first phase bus-based current synchronized with the plural values of the corrective first phase current. The corrector obtains second current-value pairs of the plural values of the corrective second phase current and the respective plural values of the corrective second phase bus-based current synchronized with the plural pairs of the corrective second phase current. The corrector corrects at least target first and second phase currents detected by a first current detector based on the obtained first current-value pairs and the second current-value pairs to thereby align amplitudes of the respective target first and second phase currents with each other.

First claim

What is claimed is:

1. A current detection apparatus applicable to a system including an inverter including plural pairs of series-connected upper-arm switches and lower-arm switches, and a multi-phase rotary electric machine including multiphase windings, the upper- and lower-arm switches of each pair being connected to a corresponding phase winding of the multi-phase rotary electric machine, an upper set of the upper-arm switches being connected to a direct-current power supply via a first bus, a lower set of the lower-arm switches being connected to the direct-current power supply via a second bus, the current detection apparatus comprising:
a first current detector configured to repeatedly detect at least:
a corrective first phase current flowing through a corresponding first phase winding of the multiphase windings to thereby obtain plural values of the corrective first phase current; and
a corrective second phase current flowing through a corresponding second phase winding of the multiphase windings to thereby obtain plural values of the corrective second phase current;

a second current detector configured to repeatedly detect at least:
a corrective first phase bus-based current flowing through one of the first and second buses to thereby obtain plural values of the corrective first phase bus-based current, the corrective first phase bus-based current having the same phase as the phase of the corrective first phase current, the plural values of the corrective first phase bus-based current being synchronized with the respective plural values of the corrective first phase current; and
a corrective second phase bus-based current flowing through one of the first and second buses to thereby obtain plural values of the corrective second phase bus-based current, the corrective second phase bus-based current having the same phase as the phase of the corrective second phase current, the plural values of the corrective second phase bus-based current being synchronized with the respective plural values of the corrective second phase current; and

a corrector configured to:
obtain:
first current-value pairs of the plural values of the corrective first phase current and the respective plural values of the corrective first phase bus-based current; and
second current-value pairs of the plural values of the corrective second phase current and the respective plural values of the corrective second phase bus-based current; and

correct at least target first and second phase currents detected by the first current detector based on the obtained first current-value pairs and the second current-value pairs to thereby align amplitudes of the respective target first and second phase currents detected by the first current detector with each other.

2. The current detection apparatus according to claim 1 , wherein:
first and second phase switches selected in one of the upper set of the upper-arm switches and the lower set of the lower-arm switches are respectively defined as first and second detection switches;
the first current detector is configured to repeatedly detect at least:
the corrective first phase current based on a potential difference between input and output terminals of the first detection switch while only the first detection switch is on in the first and second detection switches; and
the corrective second phase current based on a potential difference between input and output terminals of the second detection switch while only the second detection switch is on in the first and second detection switches;

the second current detector configured to repeatedly detect at least:
the corrective first phase bus-based current flowing through one of the first and second buses while only the first detection switch is on in the first and second detection switches; and
the corrective second phase bus-based current flowing through one of the first and second buses while only the second detection switch is on in the first and second detection switches; and

the corrector is configured to obtain:
the first current-value pairs of the plural values of the corrective first phase current and the respective plural values of the corrective first phase bus-based current while the plural values of the corrective first phase bus-based current are synchronously detected with the respective plural values of the corrective first phase current while only the first detection switch is on in the first and second detection switches; and
the second current-value pairs of the plural values of the corrective second phase current and the respective plural values of the corrective second phase bus-based current while the plural values of the corrective second phase bus-based current are synchronously detected with the respective plural values of the corrective second phase current while only the second detection switch is on in the first and second detection switches.

3. The current detection apparatus according to claim 2 , wherein:
the corrector is configured to:
calculate, based on the obtained first current-value pairs and the second current-value pairs, correction gains for aligning the amplitudes of the respective target first and second phase currents detected by the first current detector; and
multiply the correction gains to the respective target first and second phase currents detected by the first current detector to thereby align the amplitudes of the respective target first and second phase currents detected by the first current detector with each other,

the current detection apparatus further comprising:
a temperature estimator configured to estimate a temperature of each of the first and second detection switches based on the correction gain of the corresponding one of the correction gains.

4. The current detection apparatus according to claim 1 , wherein:
the corrector is configured to:
correct, based on the obtained first current-value pairs, the target first phase current detected by the first current detector to thereby zero an offset error of the target first phase current relative to the center of a peak-to-peak variation of the target first phase current; and
correct, based on the obtained second current-value pairs, the target second phase current detected by the first current detector to thereby zero an offset error of the target second phase current relative to the center of a peak-to-peak variation of the target second phase current.

5. The current detection apparatus according to claim 2 , wherein:
the first current detector is configured to repeatedly detect at least:
the corrective first phase current while the first detection switch is in an on state for a predetermined first reference period; and
the corrective second phase current while the second detection switch is in an on state for a predetermined second reference period; and

the second current detector is configured to repeatedly detect at least:
the corrective first phase bus-based current for the predetermined first reference period; and
the corrective second phase bus-based current for the predetermined second reference period,

each of the first and second reference periods being a period in which an on resistance of the corresponding one of the first and second detection switches increases from an initial value at a current detection start timing up to 10% of the initial value due to an increase of a temperature of the corresponding one of the first and second detection switches.

6. The current detection apparatus according to claim 5 , further comprising:
a timing controller configured to:
determine whether a period, during which the corrective first phase current detected by the first current detector and the corrective first phase bus-based current detected by the second current detector are the

Assignees

• Denso Corp

Inventors

• Aoki Yasuaki

Classifications

• H02M7/5395

  by pulse-width modulation · CPC title

• H02P21/22 Primary

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

• H02M7/53871

  with automatic control of output voltage or current · CPC title

• H02P27/12

  pulsing by guiding the flux vector, current vector or voltage vector on a circle or a closed curve, e.g. for direct torque control · CPC title

• H02P21/16

  Estimation of constants, e.g. the rotor time constant · CPC title