D-Q Control System for Switched Reluctance Motor Torque Ripple
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Solution Overview
Problem
Switched reluctance motors (SRMs) face challenges with control complexity, torque ripple, and the need to adapt to operating parameter variations, limiting their use, and existing D-Q rotating reference frame control systems are not applicable due to uncoupled phases and unidirectional currents.
Innovation Solution
A D-Q rotating reference frame control system for SRMs is developed, incorporating a converter module that transforms torque command signals into sinusoidal signals, using a negativity removal module and a non-linear module to remove distortion and ensure positive signal components, allowing for retrofitting with existing synchronous motor control systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If D-Q rotating reference frame control is applied to SRM, then torque ripple is reduced and smooth torque output is achieved, but the control system complexity increases due to the need for converter modules and signal processing
Solution Approach 1:
The patent introduces converter modules (D-Q to ABC converter, negativity removal module, non-linear module) as intermediary components that transform the control signals between different reference frames and domains. These intermediaries enable the application of D-Q control to SRM by bridging the gap between the rotating reference frame and the motor's uncoupled phases, thereby reducing torque ripple while managing control complexity through structured signal transformation.
2Adaptability or versatility
If SRM control system is adapted to use D-Q rotating reference frame, then the motor can operate efficiently over wide speed range, but the existing control systems require significant modification
Solution Approach 1:
The patent creates a universal control architecture that can handle both the D-Q rotating reference frame requirements and the SRM's uncoupled phase characteristics. The converter modules are designed to be versatile, transforming signals between different domains while maintaining compatibility with existing SRM control systems, thereby enabling wide speed range operation without requiring complete system redesign.
Solution Approach 2:
The patent implements preliminary signal processing through the D-Q to ABC converter and negativity removal module, which pre-process the torque command signals before they are applied to the motor phases. This preliminary action ensures that the signals are properly formatted and distorted to account for SRM characteristics, facilitating easier integration with existing control systems while achieving wide speed range operation.
3Reliability
If converter module with negativity removal is used, then all signal components become positive values, but the signal processing complexity increases
Solution Approach 1:
The patent extracts and removes the negative components from the torque command signals through the negativity removal module. This extraction process separates the problematic negative signal components and redistributes them to maintain positive values only, ensuring signal validity for SRM operation while managing processing complexity through targeted component removal rather than complete signal redesign.
Data Source
AI summary
A D-Q or rotating reference frame control system for a switched reluctance motor (SRM) provides a negativity removal module and a non-linear model module. As such, the control system utilizes control inputs fq and fd, which are converted into the ABC domain as electrical current functions f′ix with negative values. The negativity removal module is configured to share the torque portion of the negative values of the electrical current functions f′ix for each of the three phases of the SRM motor to remove the negative values. The non-linear module corrects the non-linearity of the SRM to smooth the torque that is output. The control system also utilizes a phase advancing module, which outputs fd for achieving a wide range of operating speeds.