Wound-Field Motor Control for High-Speed Field-Weakening Torque
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Solution Overview
Problem
Existing controllers for wound-field type rotating electric machines struggle to efficiently manage field current and stator current phases to optimize torque and reduce drive voltage, especially in high-rotation states where field-weakening is necessary.
Innovation Solution
A controller that adjusts the field current and stator current phase based on the rotor's rotation state, increasing the field current and setting the stator current phase to a field-weakening phase in high-rotation states to enhance torque output while reducing drive voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If field-weakening control is implemented in high-rotation states, then drive voltage is reduced, but torque output decreases
Solution Approach 1:
The controller dynamically adjusts the field current magnitude based on the rotation state. In high-rotation states where field-weakening is applied, the field current is increased compared to conventional control, while the stator current phase is shifted to a field-weakening phase. This dynamic adjustment allows the system to reduce drive voltage through phase shifting while compensating for torque loss by increasing field current magnitude.
Solution Approach 2:
The control method changes multiple parameters simultaneously: the phase angle of the stator current is shifted to achieve field-weakening effect for voltage reduction, while the magnitude of the field current is increased to compensate for torque reduction. This coordinated parameter change resolves the contradiction between voltage reduction and torque maintenance.
2Force
If field current is increased in high-rotation states, then torque output is maintained, but energy consumption increases
Solution Approach 1:
The controller predicts the need for field-weakening control based on the rotation state and proactively adjusts both the field current magnitude and stator current phase. By preparing the field current increase in advance when entering high-rotation states, the system maintains torque output while minimizing the energy penalty through coordinated phase shifting that reduces overall power requirements.
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 approach allows for increased output torque and reduced drive voltage in high-rotation states, improving the overall performance of the rotating electric machine by optimizing field and stator current management.
Implementation Method 1
A wound-field type rotating electric machine may have a stator including stator windings and a rotor including field windings
Implementation Method 2
the control unit controls the phase of the stator current to a phase for field-weakening that weakens a field flux of the field winding
Data Source
AI summary
A wound-field rotating electric machine includes: a stator including a stator winding; and a rotor having magnetic poles aligned in a circumferential direction and a field winding provided for each of the magnetic poles. A controller includes a control unit and an acquisition unit. The control unit controls a stator current through the stator winding and a field current through the field winding. The acquisition unit acquires a rotation parameter that indicates a rotation state of the rotor. When the rotor is in a high-rotation state in which a rotation speed of the rotor is higher than a predetermined rotation speed, the control unit controls the field current to be larger than in a state not being the high-rotation state, and controls the phase of the stator current to a field-weakening phase that weakens a field flux of the field winding.