Three Phase Duplexing Motor Torque Compensation
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Solution Overview
Problem
Existing three-phase duplexing motors for electric power steering face challenges in managing temperature increases and magnetic demagnetization when increasing supply current to compensate for torque reduction during abnormality occurrences, with existing technologies lacking solutions for these issues.
Innovation Solution
A three-phase duplexing motor with two sets of three-phase windings, a rotor with a permanent magnet, and a controller that sets the supply current to zero for the abnormal set while increasing the supply current to the normal set beyond normal levels, with a preliminarily set upper limit to manage temperature and demagnetization risks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the supply current to the normal set of windings is increased to compensate for torque reduction, then the torque output is improved, but the temperature of the windings increases and the permanent magnet may be demagnetized
Solution Approach 1:
The patent applies parameter changes by establishing an upper limit current value that defines the maximum supply current to the normal set of windings during abnormality occurrence. This parameter setting allows torque compensation while preventing excessive temperature increase and magnetic demagnetization, resolving the contradiction between maintaining power output and controlling thermal effects.
2Power
If the supply current to the normal set of windings is increased significantly to compensate for torque reduction, then the torque output is improved, but the permanent magnet experiences increased magnetic field that can cause demagnetization
Solution Approach 1:
The patent uses parameter changes by setting an upper limit current value that restricts the supply current to the normal set of windings. This parameter control prevents the magnetic field from exceeding levels that would cause permanent magnet demagnetization, while still allowing sufficient current to maintain required torque output during abnormal operation.
3Power
If the supply current to the normal set of windings is increased beyond normal levels, then the torque reduction is compensated, but the endurance of the winding is deteriorated
Solution Approach 1:
The patent applies parameter changes by establishing an upper limit current value that defines the maximum supply current during abnormality occurrence. This parameter setting balances torque compensation needs with winding endurance protection, allowing temporary overcurrent operation without significantly degrading winding reliability or causing excessive temperature increase.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration effectively compensates for torque reduction while limiting the adverse effects of increased current on winding temperature and permanent magnet demagnetization, allowing for designed cooling performance and coercive force management within predetermined ranges.
Implementation Method 1
a motor which is provided with a stator equipped with 2 sets of three phase windings, and a rotor equipped with a permanent magnet
Implementation Method 2
the windings of the stator and the permanent magnet of the rotor generate torque
Implementation Method 3
there is a possibility that an endurance of winding is deteriorated by increase in a temperature of the normal set of the windings
Implementation Method 4
the permanent magnet is demagnetized by increase in an magnetic field which acts in the direction which demagnetizes the permanent magnet of the rotor
Data Source
AI summary
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.