Linear Induction Motor Double Vector Model Predictive Thrust Control
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Solution Overview
Problem
Conventional control strategies for linear induction motors, such as vector control and direct torque control, fail to adequately account for the end effect, leading to significant thrust attenuation at high speeds due to drastic changes in mutual inductance, resulting in insufficient motor performance.
Innovation Solution
An arbitrary double vector and model prediction thrust control method is introduced, combining double vector modulation with model prediction thrust control, which involves sampling current and velocity, predicting thrust and conjugate thrust, solving for optimal voltage vectors, and calculating duty cycles to reduce thrust and flux linkage fluctuations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If conventional model prediction thrust control algorithms use only one voltage vector in one switching cycle, then the control algorithm is simple, but the thrust and flux linkage fluctuations are large
Solution Approach 1:
The patent segments the single voltage vector control into multiple voltage vectors within one switching cycle. Specifically, it divides the switching cycle into multiple segments where different voltage vectors are applied sequentially, thereby reducing thrust and flux linkage fluctuations while maintaining manageable algorithm complexity through structured segmentation
Solution Approach 2:
The patent implements periodic action by applying different voltage vectors in a periodic sequence within each switching cycle. The control algorithm periodically switches between multiple voltage vectors based on predetermined patterns, which smooths out thrust fluctuations and improves system stability without requiring overly complex real-time decision-making
2Measurement precision
If a double vector modulation strategy is combined with model prediction thrust control algorithm, then the modulation accuracy is improved and thrust fluctuations are reduced, but the calculation burden increases heavily
Solution Approach 1:
The patent applies preliminary action by pre-calculating and storing optimal voltage vector combinations and their corresponding duty cycles in lookup tables before operation. During real-time control, the system simply queries these pre-computed tables based on current operating conditions, thereby achieving high modulation accuracy without the heavy computational burden of real-time optimization calculations
Solution Approach 2:
The patent uses copying by creating pre-computed lookup tables that contain copies of optimal control solutions for various operating conditions. Instead of recalculating optimal voltage vectors in real-time, the system copies and applies pre-determined solutions from the lookup tables, significantly reducing calculation time while maintaining high modulation accuracy
3Reliability
If there are many combinations of two voltage vectors that need to be evaluated and compared one by one, then the optimal voltage vector combination can be found, but the calculation amount increases significantly
Solution Approach 1:
The patent performs preliminary evaluation and comparison of all possible voltage vector combinations offline, storing the optimal choices in lookup tables. During online operation, the system only needs to retrieve pre-determined optimal combinations based on current state, ensuring reliable optimal voltage vector selection while maintaining high calculation efficiency through avoidance of real-time exhaustive search
Solution Approach 2:
The patent extracts only the essential information needed for control from the exhaustive evaluation of all voltage vector combinations. By pre-computing and storing only the optimal voltage vector pairs and their duty cycles in lookup tables, the system extracts the critical control parameters without needing to perform the full evaluation process during real-time operation, thereby improving calculation efficiency while maintaining selection reliability
Data Source
AI summary
The present disclosure provides an arbitrary double vector and model prediction thrust control method and system, which belongs to the technical field of linear induction motor control. The present disclosure combines a double vector modulation algorithm to improve the modulation accuracy, in which two voltage vectors are used in one cycle, so that the amplitude of the fluctuation can be reduced, thereby improving the running performance of the motor. The addition of the double vector modulation strategy increases the complexity of the algorithm, and the calculation process is too complicated. The present disclosure further proposes a simplified search process instead of the traditional repeated calculation and comparison method, which eliminates the need for a complex online calculation process, thereby simplifying the implementation process of the algorithm in the actual system.