A Smooth Power Supply Switching Method of Segmented Long Primary Linear Motors for High-Speed Applications

To reduce capacity of converters, segmented power supply method is usually adopted for linear motors (LMs), and thyristor-based switches, which is composed of anti-parallel thyristors, are used to achieve power supply switching. However, thyristor-based switches can only be turned off at the moment of current zero crossing point, which may lead to overcurrent of LMs during power supply switching process. The operating characteristics of the LM is analyzed for the duration of the power supply switching, and the switching time is also derived. On this basis, a smooth power supply switching method is proposed in this paper. The proposed method can achieve thyristor-based switches of all phases turning off simultaneously, while also avoiding overcurrent. The effectiveness of the proposed method is verified by simulation results.