Electric Power Steering Torque Ripple Compensation
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Solution Overview
Problem
Existing methods for reducing torque ripple in electric power steering (EPS) systems, such as using antiphase torque generation, are ineffective in eliminating residual torque fluctuations, leading to steering heterogeneity and increased manufacturing and processing costs due to the need for additional sensors and complex arithmetic processing.
Innovation Solution
An apparatus and method that calculates a compensation current value for torque ripple based on predetermined motor information and sensing data, without requiring a separate device, by collecting steering and motor position information, calculating a target torque, determining a compensation torque, and generating a current control signal to reduce torque ripple.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If antiphase torque generation method is used to reduce torque ripple, then torque ripple can be partially canceled, but residual torque fluctuation remains causing steering heterogeneity
Solution Approach 1:
The patent changes the parameters of the compensation torque by calculating it based on actual motor information (torque constant, phase, harmonic order) and operating conditions (steering angle, steering speed) rather than using a fixed constant waveform. This allows the compensation torque to dynamically match the actual torque ripple characteristics, eliminating residual fluctuations.
Solution Approach 2:
The patent implements feedback by continuously monitoring motor position, steering angle, and steering speed to calculate the compensation torque in real-time. The compensation current is adjusted based on the actual operating state, ensuring the compensation torque accurately counteracts the torque ripple under varying conditions.
2Object-generated harmful factors
If sensor and lookup table are added to calculate antiphase torque, then torque ripple compensation can be improved, but manufacturing cost and arithmetic processing burden increase
Solution Approach 1:
The patent replaces the need for additional torque ripple sensors with a calculation-based approach. Instead of mechanically sensing the torque ripple and then compensating for it, the system calculates the compensation torque directly from motor parameters and operating conditions, substituting physical sensing with computational methods.
Solution Approach 2:
The patent enables the motor control system to self-compensate for torque ripple using its own existing sensors (motor position sensor, steering angle sensor, steering speed sensor) and predetermined motor information. No external sensing devices are needed, as the system uses its own operational data to generate the compensation torque.
Data Source
AI summary
The disclosure provides an apparatus and method of compensating for a torque of a motor. The apparatus includes a torque information collector configured to collect steering information, motor position information, and predetermined motor information, a torque ripple calculator configured to determine a target torque based on the steering information and to determine a compensation torque for torque ripple based on the target torque and the motor information, a compensation current calculator configured to determine a compensation current value based on the motor information and the compensation torque, a current value generator configured to convert the target torque into a target current value and to generate an output current value based on the target current value and the compensation current value, and a current signal output configured to output a current control signal corresponding to the output current value.