Switched Reluctance Motor Torque Ripple Suppression
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Solution Overview
Problem
Conventional direct torque control of switched reluctance motors faces challenges in achieving smooth torque output due to the influence of main switch turn-off angles on torque control performance, requiring rigorous offline or online calculations to manage torque ripple effectively.
Innovation Solution
A method for two-level suppression of torque ripple in a three-phase switched reluctance motor, involving the setting of specific torque thresholds and excited states for phase A and phase B power supplies, allowing for a two-interval commutation process that automatically adjusts to maintain smooth torque control without considering the main switch turn-off angle, ensuring phase A and phase B switch between positive and negative voltage states to control total torque within defined thresholds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional direct torque control is used to eliminate torque ripple, then torque control performance can be improved, but the main switch turn-off angle must be precisely determined through offline calculation or online regulation, increasing system complexity
Solution Approach 1:
The patent segments the torque control range into multiple intervals with different torque thresholds (first group th1low/th1up and second group th2low/th2up). Each interval has its own control parameters, allowing simplified control within each segment while achieving overall smooth torque output without complex global optimization
Solution Approach 2:
The patent changes control parameters (torque thresholds and excited states) based on rotor position intervals. By switching between different threshold groups and excited states (SA and SB) at different intervals, the system achieves smooth torque control without requiring complex turn-off angle calculations
2Reliability
If the main switch turn-off angle is set to generate maximum smooth torque, then torque ripple is reduced, but current must be precisely controlled to avoid negative torque regions, increasing control difficulty
Solution Approach 1:
The patent dynamically switches between different excited states (SA and SB) and torque threshold groups based on rotor position and current torque levels. This dynamic adaptation allows the system to maintain optimal control without fixed, complex turn-off angle settings
Solution Approach 2:
The patent uses feedback control by comparing actual total torque with reference torque and adjusting excited states based on whether torque is above or below thresholds. This closed-loop feedback simplifies control by replacing complex open-loop turn-off angle calculations with adaptive threshold-based switching
3Measurement precision
If offline calculation or online regulation is used to determine turn-off angle, then torque control precision is improved, but computational requirements and processing time increase
Solution Approach 1:
The patent pre-defines torque thresholds and excited state combinations for different rotor position intervals. This preliminary preparation eliminates the need for complex real-time calculations, as the controller only needs to determine which pre-defined threshold group to apply based on current rotor position
Solution Approach 2:
The patent uses simple, discrete threshold values and excited state combinations instead of complex continuous calculations. These simplified control elements enable fast switching decisions with minimal computational resources, reducing processing time while maintaining adequate control precision
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 method effectively suppresses torque ripple by controlling total torque within specified thresholds, ensuring smooth torque output and reducing the need for complex calculations, applicable to various three-phase switched reluctance motor drive systems with minimal extra computational requirements.
Implementation Method 1
switched reluctance motor torque ripple
Data Source
AI summary
A three-phase switched reluctance motor torque ripple two-level suppression method. A first set of torque thresholds at rotor position interval [0°, θr/3]. A second set of torque thresholds at rotor position interval [θr/3, θr/2]. Power is supplied for excitation. The power supplied for excitation to phase A leads the power supplied for excitation to phase B by θr/3. Phase A is turned off, while phase B is turned on. An entire commutation process from phase A to phase B is divided. In rotor position interval [0°, θ1], phase A uses the second set of torque thresholds while phase B uses the first set. Critical position θ1 automatically appears in the commutation process. Total torque is controlled. In rotor position interval [θ1, θr/3], phase A uses the second set of torque thresholds, phase B uses the first set, and the total torque is controlled, suppressing torque ripples of a three-phase switched reluctance motor.