Permanent magnet motor controller

Patent metadata

Field	Value
Publication number	US-9793844-B2
Application number	US-201214368451-A
Country	US
Kind code	B2
Filing date	Oct 10, 2012
Priority date	Dec 27, 2011
Publication date	Oct 17, 2017
Grant date	Oct 17, 2017

Abstract

An object is to provide a permanent magnet motor controller capable of suppressing the rotary bending vibration that occurs in the permanent magnet motor effectively with simple configuration. A permanent magnet motor controller uses the dq coordinate conversion. A dq target current setting part adds the current component (i* da ) that cancels the magnetic attractive force acting in the radial direction of the rotational shaft of the rotor of the permanent magnet motor to the d-axis target current value, whereby the eccentricity of the rotational shaft of the rotor is reduced.

First claim

The invention claimed is:

1. A permanent magnet motor controller including a rotor rotational shaft rotatably supported by a bearing, the permanent magnet controller comprising:
a current detecting part configured to detect a phase current flowing through a permanent magnet motor;
a three-phase/dq coordinate converting part configured to convert the phase current detected by the current detecting part into a current value of an orthogonal coordinate system (hereinafter, referred to as “dq coordinate system”) that rotates in synchronization with a rotation of a motor;
a dq target current setting part configured to set a target current value of the dq coordinate system based on a rotation speed of the motor;
a dq target voltage generating part configured to generate a target voltage value of the dq coordinate system based on the current value of the dq coordinate system converted by the three-phase/dq coordinate converting part and the target current value of the dq coordinate system set by the dq target current setting part;
a dq/three-phase coordinate converting part configured to convert the target voltage value of the dq coordinate system generated by the dq target voltage generating part into a three-phase target voltage value;
a power converting part configured to convert the three-phase target voltage value generated by the dq/three-phase coordinate converting part into a three-phase motor driving current;
a rotation angle detecting part configured to detect a rotation angle of the rotor; and
a table configured to define in advance a displacement in a radial direction of the rotor based on the rotation angle of the rotor rotational shaft,
wherein a cyclic displacement having an eccentric frequency is defined in the table, the eccentric frequency being determined by a pole number of the permanent magnet motor and a slot number of the permanent magnet motor, and
wherein the dq target current setting part is configured to estimate a displacement corresponding to a detected value of the rotation angle detecting part based on the table and add a current component which is obtained from the estimated displacement and cancels a magnetic attractive force to a d-axis target current value set in the dq target current setting part so as to reduce an eccentricity of the rotor rotational shaft, the magnetic attractive force acting in a radial direction of a rotor rotational shaft of the permanent magnet motor and having cyclic behavior every electric angle of the rotor.

2. The permanent magnet motor controller according to claim 1 ,
wherein the rotor is connected to a rotational shaft of an electric supercharger or a rotational shaft of a generator.

3. The permanent magnet motor controller according to claim 2 ,
wherein the rotor is rotatably supported by a sliding bearing.

4. A permanent magnet motor controller including a rotor rotational shaft rotatably supported by a bearing, the permanent magnet motor controller comprising:
a current detecting part configured to detect a phase current flowing through a first stator winding wound around a stator iron core of a permanent magnet motor;
a three-phase/dq coordinate converting part configured to convert the phase current detected by the current detecting part into a current value of an orthogonal coordinate system (hereinafter, referred to as “dq coordinate system”) that rotates in synchronization with a rotation of a motor;
a dq target current setting part configured to set a target current value of the dq coordinate system based on a rotation speed of the motor;
a dq target voltage generating part configured to generate a target voltage value of the dq coordinate system based on the current value of the dq coordinate system converted by the three-phase/dq coordinate converting part and the target current value of the dq coordinate system set by the dq target current setting part;
a dq/three-phase coordinate converting part configured to convert the target voltage value of the dq coordinate system generated by the dq target voltage generating part into a three-phase target voltage value;
a power converting part configured to convert the three-phase target voltage value generated by the dq/three-phase coordinate converting part into a three-phase motor driving current;
a second stator winding wound around the stator iron core of the permanent magnet motor independently of the first stator winding;
a rotation angle detecting part configured to detect a rotation angle of the rotor; and
a table configured to define in advance a displacement in a radial direction of the rotor based on the rotation angle of the rotor rotational shaft,
wherein a cyclic displacement having an eccentric frequency is defined in the table, the eccentric frequency being determined by a pole number of the permanent magnet motor and a slot number of the permanent magnet motor,
wherein the displacement of the radial direction of the rotor based on the rotation angle of the rotor rotational shaft is estimated based on the table, and
wherein a current which is obtained from the estimated displacement and cancels a magnetic attractive force is applied to the second stator winding so as to reduce an eccentricity caused on the rotor rotational shaft, the magnetic attractive force acting in a radial direction of the rotor rotational shaft of the permanent magnet motor and having cyclic behavior every electric angle of the rotor.

5. The permanent magnet motor controller according to claim 4 ,
wherein the rotor is connected to a rotational shaft of an electric supercharger or a rotational shaft of a generator.

6. The permanent magnet motor controller according to claim 5 ,
wherein the rotor is rotatably supported by a sliding bearing.

7. A permanent magnet motor controller comprising:
a current detecting part configured to detect a current which flows through a magnet bearing rotatably supporting a rotor rotational shaft of a permanent magnet motor;
a displacement sensor configured to detect a displacement amount in a radial direction of the rotor rotational shaft;
a target current value setting part configured to set a target current value flowing through the magnet bearing based on a detected value of the displacement sensor;
a current control part configured to control the current flowing through the magnet bearing so that the current becomes the target current value;
a rotation angle detecting part configured to detect a rotation angle of the rotor; and
a table configured to define in advance a displacement in a radial direction of the rotor based on the rotation angle of the rotor rotational shaft,
wherein a cycle displacement having an eccentric frequency is defined in the table, the eccentric frequency being determined by a pole number of the permanent magnet motor and a slot number of the permanent magnet motor, and
wherein the target current setting part is configured to estimate a displacement corresponding to a detected value of the rotation angle detecting part based on the table and add a current component which is obtained from the estimated displacement and cancels a magnet attractive force to the target current value so as to reduce an eccentricity of the rotor rotational shaft, the magnet attractive force acting in a radial direction of the rotor rotational shaft of the permanent magnet motor and having cyclic behavior every electric angle of the rotor.

8. The permanent magnet motor controller according to claim 7 ,
wherein the rotor is connected to a rotational shaft of an electric supercharger or a rotational shaft of a generator.

Assignees

• Mitsubishi Heavy Ind Ltd

Inventors

• Yamashita Yukio
• Hayashi Noriyuki

Classifications

• H02P21/05 Primary

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

• H02P21/22

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

• H02P2207/05

  Synchronous machines, e.g. with permanent magnets or DC excitation · CPC title

• H02P21/50

  Vector control arrangements or methods not otherwise provided for in H02P21/00- H02P21/36 · CPC title

• H02P29/032

  Preventing damage to the motor, e.g. setting individual current limits for different drive conditions · CPC title