IPM motor system and control method thereof
AssigneeMitsubishi Heavy Industries, Ltd.
InventorsMitsugu Nakamura, Shinichi Isobe, Takao Sakurai, Takaya Shirasu
Life of this patent
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Abstract
An IPM (Interior Permanent Magnet) motor system is provided with an IPM motor provided with a stator having slots and a rotor having poles, and a control unit which controls the rotor to the stator. An estimation precision of an initial angle position of the rotor to the stator is selected such that it is substantially the same as an angle unit precision of stable positions of the rotor to the stator which is based on a combination of the number of poles and the number of slots. In this way, the cheap IPM motor system with a high drive efficiency and a control method of the IPM motor system are provided.
Claims14
An IPM (Interior Permanent Magnet) motor system comprising:
- an IPM motor comprising a stator having slots and a rotor having poles;
- a control unit configured to control said IPM motor, said control unit estimates an initial position of said rotor to said stator in an angle estimation read precision, and said angle estimation read precision is equal to an angle unit precision of 360°/2 m, where m is the number of said slots in said stator;
- and
- a bearing sensor provided for a rotation axis which is connected with said rotor to detect a movement quantity from said initial position of said rotor to said stator;
- wherein said control unit comprises:
- a calculating section configured to output a number of rotations of said IPM motor and a measured phase angle from an output from said bearing sensor;
- a current command generating section configured to generate a d-axis current command and a q-axis current command based on the number of rotations and a torque command;
- a measuring section configured to generate a measured d-axis current and a measured q-axis current from a 3-phase motor current of said IPM motor;
- a voltage command generating section configured to generate a 2-phase voltage command from said d-axis current command, said q-axis current command, said measured d-axis current and said measured q-axis current;
- a command converting section configured to generate a 3-phase voltage command from a post correction phase angle and said 2-phase voltage command;
- a driving section configured to drive said IPM motor based on said 3-voltage command;
- and
- a correcting section configured to generate said post-correction phase angle from said measured phase angle, said d-axis current command, said q-axis current command, said measured d-axis current and said measured q-axis current.
A control method of an IPM (Interior Permanent Magnet) motor system, comprising:
- providing an IPM motor having a stator with slots and a rotor with poles and a control unit configured to control said IPM motor;
- estimating an initial position of said rotor to said stator in an angle estimation read precision by said control unit, said angle estimation read precision is equal to an angle unit precision of 360°/2 m, where m is the number of said slots in said stator;
- and
- detecting a movement quantity from said initial position of said rotor to said stator by a bearing sensor provided for a rotation axis which is connected with said rotor;
- wherein said estimating an initial position comprises:
- outputting a number of rotations of said IPM motor and a measured phase angle from an output from said bearing sensor;
- generating a d-axis current command and a q-axis current command based on the number of rotations and a torque command;
- generating a measured d-axis current and a measured q-axis current from a 3-phase motor current of said IPM motor;
- generating a 2-phase voltage command from said d-axis current command, said q-axis current command, said measured d-axis current and said measured q-axis current,
- generating a 3-phase voltage command from a post-correction phase angle and said 2-phase voltage command;
- driving said IPM motor based on said 3-phase voltage command;
- and
- generating said post-correction phase angle from said measured phase angle, said d-axis current command, said q-axis current command said measured d-axis current and said measured q-axis current.
Dependencies are inferred from the claim text.