Improved performance of linear induction motors based on optimal duty cycle finite-set model predictive thrust...

Area of Science:

• Electrical Engineering
• Control Systems
• Electromechanical Systems

Background:

• Linear induction machines (LIMs) are crucial for applications like linear metros due to their advantages.
• LIMs suffer from reduced thrust at higher speeds (end effects) and normal force fluctuations, impacting efficiency and stability.
• Existing control methods often struggle to mitigate these performance degradations.

Purpose of the Study:

• To propose a novel Finite-Set Model Predictive Thrust Control (FS-MPTC) strategy for LIM drive systems.
• To enhance operational efficiency and system stability by addressing speed-dependent thrust reduction and normal force variations.
• To optimize the voltage vector duty cycle for improved LIM performance.

Main Methods:

• Developed an FS-MPTC strategy that optimizes active and zero voltage vector duty cycles.
• Incorporated the deadbeat concept and electromagnetic thrust derivative for duty cycle calculation.
• Utilized a two-term cost function in the prediction stage, considering thrust and flux linkage errors.
• Validated the approach using parameters from a Japanese 12000 linear induction machine.

Main Results:

• The proposed FS-MPTC with an optimal duty cycle demonstrated superior performance compared to a fixed duty cycle approach.
• Effective mitigation of speed-dependent thrust reduction and improved system stability were observed.
• Enhanced operational efficiency of the LIM drive system was achieved.

Conclusions:

• The FS-MPTC offers a robust and effective solution for improving LIM performance.
• Optimizing voltage vector duty cycles is key to enhancing efficiency and stability in LIM applications.
• This control strategy presents a promising advancement for LIM-based drive systems, particularly in demanding applications like linear metros.