Switched Reluctance Motor Torque Ripple Reduction via Current Lookup
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Solution Overview
Problem
Switched reluctance motors (SRMs) produce high torque ripple and acoustic noise, which are undesirable in electric power steering (EPS) applications where low torque ripple and noise are required.
Innovation Solution
A motor control system that includes a position sensor, current sensor, and control module, which uses a lookup table to determine phase current commands based on rotor position and phase current to generate torque ripple within a predefined range, thereby reducing torque ripple and acoustic noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a switched reluctance motor is used, then the motor structure is simple and rugged with high operational temperature tolerance, but the motor produces high torque ripple and acoustic noise
Solution Approach 1:
The patent applies parameter changes by modifying the phase current waveform parameters (magnitude, duration, timing) based on rotor position to control the torque output. By adjusting current parameters dynamically, the system reduces torque ripple while maintaining the simple SRM construction.
Solution Approach 2:
The control system implements feedback by continuously monitoring rotor position and phase current, then using this information to adjust current commands via lookup tables. This closed-loop feedback mechanism enables precise torque control that minimizes ripple and noise while preserving the motor's structural simplicity.
2Power
If phase current is applied to generate output torque in an SRM, then mechanical power is produced, but torque ripple increases
Solution Approach 1:
The system applies dynamics by continuously adjusting phase current parameters based on real-time rotor position feedback. The lookup tables store pre-calculated current commands that dynamically adapt to changing operating conditions, enabling smooth torque production with minimized ripple.
Solution Approach 2:
The control system employs periodic action by applying phase current in controlled pulses synchronized with rotor position cycles. The periodic current application follows optimal timing patterns stored in lookup tables, producing continuous torque while reducing ripple through rhythmic, precisely-timed excitation.
Data Source
AI summary
A motor control system is provided. The motor control system includes a motor, a position sensor, a current sensor, and a control module. The motor has a rotor and a stator. The motor generates an output torque based on a phase current applied to the motor. The output torque generated by the motor creates a torque ripple that is within a predefined range. The position sensor monitors the motor to determine a rotor position. The current sensor monitors the motor to determine the phase current. The control module is in communication with the motor, the position sensor, and the current sensor. The control module includes a lookup table that stores values of phase current commands. The control module determines a phase current command from the lookup table based on the rotor position and the phase current.