Current Characteristics and Overcurrent Suppression in Segmented Power Switching Process of Long Primary Dual Three-Phase Linear Motors

In high-speed applications, thyristor-based switches are usually used to achieve fast power supply switching for segmented linear motors. However, thyristor-based switches can only be turned off at zero-crossing of currents, which makes stator currents seriously asymmetric during switching process, leading overcurrent. In this paper, the current dynamic characteristics of two segments involved in power supply switching are analyzed, and the analytical expressions of the both stators’ currents are also derived during switching process. Furthermore, the required electrical angle to complete turn-off and the maximum current at the converter side are obtained through numerical calculation method. Based on the aforementioned analysis, a power supply switching method is proposed, featuring both fast switching and overcurrent suppression. Simulation results verify the correctness of the presented analysis and the effectiveness of the proposed switching method.