Motor Control Decoupling for NVH Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Electric Power Steering (EPS) systems using permanent magnet synchronous motors (PMSMs) face challenges in maintaining consistent torque control and noise reduction due to coupling between d-axis and q-axis voltage commands, which affects motor performance and introduces NVH-related disturbances.
Innovation Solution
A motor control system that decouples d-axis and q-axis portions of the voltage command using a set of gain factors and an inverse transfer matrix, filtering NVH-related disturbances while preserving decoupling to reduce the influence of operating parameter variations and ensure consistent high performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If d-axis and q-axis voltage commands are coupled in traditional FOC, then the control structure is simpler, but motor performance deteriorates and NVH disturbances increase
Solution Approach 1:
The patent divides the voltage command into separate d-axis and q-axis components that are independently controlled. By segmenting the control into decoupled axes with separate filtering and gain application, the system achieves better performance consistency without requiring complete redesign of the control structure.
Solution Approach 2:
The patent introduces an intermediary decoupling control module between the current feedback and voltage command generation. This intermediary layer applies gain factors and filtering to preserve decoupling between d-axis and q-axis, acting as a mediator that maintains performance while managing complexity.
2Object-affected harmful factors
If filtering is applied to reduce NVH disturbances, then noise reduction improves, but decoupling between d-axis and q-axis is lost
Solution Approach 1:
The patent applies filtering with different characteristics to different axes based on their specific requirements. By tailoring the filtering approach locally to each axis while maintaining the decoupling structure, the system reduces NVH disturbances without sacrificing the decoupling relationship between d-axis and q-axis control.
3Reliability
If parameter variations are compensated, then performance consistency improves, but control complexity increases
Solution Approach 1:
The patent compensates for parameter variations by dynamically adjusting gain factors in the decoupling control. Instead of complex adaptive algorithms, the system changes parameters (gain factors) based on operating conditions to maintain performance consistency, achieving robustness through parameter adjustment rather than structural complexity.
Data Source
AI summary
A method of controlling a motor that generates an output current from an input voltage command. The method receives, from the motor, the output current that includes a direct-axis portion and a quadrature-axis portion, the output current being received as feedback current. The method determines a compensated voltage command by applying, to the feedback current, first gain factors and an inverse of second gain factors. The first gain factors decouple the d-axis portion and the q-axis portion of the compensated voltage command. The inverse of the second gain factors allow the compensated voltage command to be filtered in a manner that preserves decoupling between the d-axis and q-axis. The method determines the input voltage command for the motor by applying the second gain factors to the compensated voltage command to cause the motor to generate the output current with reduced influence of variations of operating parameters of the motor.