# US 7,078,874 B2 · Control device for alternating-current motor

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- Number: US 7,078,874 B2
- Document ID: US7078874B2
- Status: Granted
- Kind: B2
- Application number: 11/203,175
- Filed: 2005-08-15
- Published: 2006-03-09
- Granted: 2006-07-18
- Earliest claimed: 2004-09-06
- Assignees: Toyota Jidosha Kabushiki Kaisha
- Inventors: Hideo Nakai; Hiroki Ohtani; Yukio Inaguma; Katsuhiro Asano; Hideto Hanada; Masaki Okamura
- Web page: https://patentgrep.com/patent/US7078874B2

## CPC

- H02P 21/06: Rotor flux based control involving the use of rotor position or rotor speed sensors
- H02P 2207/05: Synchronous machines, e.g. with permanent magnets or DC excitation
- H02P: CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS

## Abstract

In one coordinate system of arbitrary rectangular coordinate systems including a coordinate system in which the position of a stator is fixed, a coordinate system in which the position of a rotor is fixed, and a coordinate system which rotates at a rotational frequency which is n times (n is an integer which is not 0 or 1) that of the rotor, a filter on any other coordinate system is defined. Further, driving of a motor is controlled by utilizing this filter. As a result, a coordinate transformation operation need not be individually performed with respect to control variables.

## Claims

### Claim 1

A control device for an alternating-current motor including a rotor and a stator, wherein
in one coordinate system of arbitrary rectangular coordinate systems including a coordinate system fixed to the stator, a coordinate system fixed to the rotor and a coordinate system which rotates at a rotational frequency which is n times (n is an integer which is not 0 or 1) that of the rotor, a filter on any other coordinate system is defined, and driving of the motor is controlled by utilizing the filter.

### Claim 2

A control device for an alternating-current motor including a rotor and a stator,
the control device comprising:
a fundamental wave current control circuit which obtains a current control output which controls a fundamental wave component of a motor current in an axis coordinate system which rotates in synchronization with the rotor with respect to a d axis current which is mainly an exciting current component of a phase current of the alternating-current motor and a q axis current which is mainly a torque current component of the same;
a higher harmonic current control circuit which controls an e axis current and an f axis current, the e axis current and the f axis current having a frequency which is an integer multiple of a frequency of the fundamental wave component of the alternating motor, the higher harmonic current control circuit realizing the e and f axes current controls on the d axis current control and the q axis current control;
an addition circuit which adds an output from the fundamental wave current control circuit and an output from the higher harmonic current control circuit; and
an inverter circuit which receives an output from the addition circuit and outputs a motor driving current,
wherein PI control in the higher harmonic current control circuit is also executed as current control on the d and q axes.

### Claim 3 (depends on 2)

The apparatus according to claim 2, wherein the higher harmonic current control circuit comprises:
a first operation unit which performs subtraction or addition with respect to a constant multiple of an output from an f axis current error integration controller and an e axis current error;
a second operation unit which performs addition or subtraction with respect to a constant multiple of an output from an e axis current error integration controller and the e axis current error;
an e axis current error proportional controller which subjects an output from the first operation unit to proportional multiplication;
an f axis current error proportional controller which subjects an output from the second operation unit to proportional multiplication;
an e axis higher harmonic controller which adds a constant multiple of the e axis current error and an output from the e axis current error proportional controller; and
an f axis higher harmonic controller which adds a constant multiple of the f axis current error and an output from the f axis current error proportional controller;
wherein the e axis current error integration controller subjects an output from the first operation unit to integration; and
the f axis current error integration controller subjects an output from the second operation unit to integration and proportional multiplication.

### Claim 4 (depends on 3)

The control device for an alternating-current motor according to claim 3, wherein the constants are the same value and the value is a product of n−1 and a rotation angular velocity based on an electric angle,
wherein n is a rotation order of the e and f axes which rotate at a rotation frequency which is n times that of the d and q axes, wherein n is an integer which is not 0 or 1.

### Claim 5 (depends on 2)

The control device for an alternating-current motor according to claim 2, wherein the higher harmonic current control circuit realizes on the d and q axes PI control on the e and f axes by utilizing expressions obtained by transforming expressions of the PI control on the e and f axes into expressions on the d and q axes.

### Claim 6

A current control circuit which separates an α phase current and a β phase current as current components of axes which are fixed to a stator and orthogonal to each other with respect to an alternating-current motor including a rotor and the stator, and controls the respective phase currents based on an α phase current error and a β phase current error which are errors from command values of motor currents of the α phase current and the β phase current,
the current control circuit comprising:
an α phase proportional unit which multiplies the α phase current error by a predetermined proportional coefficient to obtain an α phase proportional control component;
an α phase integrator which integrates a difference value between the α phase current error and a coefficient multiple based on a rotational frequency of the rotor as an output from a β phase integrator;
a β phase integrator which integrates an added value of the β phase current error and a coefficient multiple based on a rotational frequency as an output from the α phase integrator;
an α phase voltage command unit which adds an α phase integration control component obtained by multiplying an output from the α phase integrator by a predetermined proportional coefficient and an α phase proportional control component as an output from the α phase proportional unit, and outputs an α phase voltage command;
a β phase voltage command unit which adds a β phase integration control component obtained by multiplying an output from the β phase integrator by a predetermined proportional coefficient and a β phase proportional control component as an output from the β phase proportional unit, and outputs a β phase voltage command; and
an inverter circuit which drives the alternating-current motor based on the α phase voltage command and the β phase voltage command from the α phase voltage command unit and the β phase voltage command unit.