Three phase duplexing motor for electric power steering apparatus
To provide a three phase duplexing motor for electric power steering apparatus that can manage increase in a supply current and can manage influence on motor, when increasing a supply current to the three phase windings of the normal set. An three phase duplexing motor for electric power steering apparatus sets 0 to a supply current to three phase winding of abnormality occurrence set, and increases a supply current to three phase windings of the normal set, with a preliminarily set increase upper limit current value as an upper limit.
1. A three phase duplexing motor for an electric power steering apparatus comprising:
a motor which is provided with a stator equipped with 2 sets of three phase windings, and a rotor equipped with a permanent magnet, and drives a steering mechanism of a vehicle;
2 sets of inverters which supply AC power to each set of the three phase windings; and
a controller which controls the 2 sets of inverters,
wherein when abnormality occurs in a control system of the three phase windings of one set, the controller sets 0 to a supply current to the three phase windings of an abnormality occurrence set, and increases a supply current to the three phase windings of a normal set more than normal time, with a preliminarily set increase upper limit current value as an upper limit, and
wherein the increase upper limit current value is preliminarily set to a maximum value of a supply current range in which a demagnetizing factor of the permanent magnet becomes less than or equal to a preliminarily set allowable demagnetizing factor.
2. The three phase duplexing motor for the electric power steering apparatus according to claim 1 , wherein the increase upper limit current value is set to a rated current value of the three phase windings of each set.
3. The three phase duplexing motor for the electric power steering apparatus according to claim 1 , wherein the preliminarily set allowable demagnetizing factor is a demagnetizing factor at a maximum service temperature of the motor.
4. The three phase duplexing motor for the electric power steering apparatus according to claim 1 , wherein the increase upper limit current value is preliminarily set to a maximum value of a supply current range in which a temperature of the three phase windings of each set becomes less than or equal to a preliminarily set allowable temperature at a maximum service temperature of the motor.
5. The three phase duplexing motor for the electric power steering apparatus according to claim 1 , wherein the increase upper limit current value is set on a basis of an ampere turn value obtained by multiplying a number of turns of winding to current.
6. The three phase duplexing motor for the electric power steering apparatus according to claim 1 , wherein the permanent magnet is configured based on a condition in which the supply current to the three phase windings of the normal set was increased to the increase upper limit current value.
7. The three phase duplexing motor for the electric power steering apparatus according to claim 1 , wherein a coercive force of the permanent magnet is configured so that a demagnetizing factor becomes less than or equal to a preliminarily set allowable demagnetizing factor, when the supply current to the three phase windings of the normal set is increased to the increase upper limit current value at a maximum service temperature of the motor.
8. The three phase duplexing motor for the electric power steering apparatus according to claim 1 , wherein a permeance of an operating point of the permanent magnet is configured so that a demagnetizing factor becomes less than or equal to a preliminarily set allowable demagnetizing factor, when the supply current to the three phase windings of the normal set is increased to the increase upper limit current value at a maximum service temperature of the motor.
9. The three phase duplexing motor for the electric power steering apparatus according to claim 1 , wherein a cooling mechanism of the three phase windings is configured so that a temperature of the three phase windings of each set becomes less than or equal to a preliminarily set allowable temperature, when the supply current to the three phase windings of the normal set is increased to the increase upper limit current value at a maximum service temperature of the motor.
10. The three phase duplexing motor for the electric power steering apparatus according to claim 1 , wherein each set of the three phase windings is concentrated winding, and first set of the three phase windings and second set of the three phase windings are wound around different teeth of the stator with each other, and are not wound around the same teeth.
11. The three phase duplexing motor for the electric power steering apparatus according to claim 1 , wherein each set of the three phase windings is distributed winding; each phase winding is wound straddling plural slots; and about each phase, slots which first set of the three phase windings is straddling, and slots which second set of the three phase windings is straddling overlap with each other.