Abstract: The power supply of fishtail divertor magnet in EAST is multi frequency LC resonant power. In the experiment, the change of magnetic field will cause the current skin effect of the load magnet of the divertor,leading to the shift of resonant frequency and the attenuation of current. Therefore, the feedback control strategy based on the resonant frequency identification is adopted to ensure the output amplitude of the resonant current.As the resonant quality factors Q of the high frequency working point is larger than the low one, the current amplitude attenuation caused by the shift of resonant frequency at the high frequency point is much greater than the low point. The resonant current error will increase greatly when the frequency of working point increases due to the resonant frequency identification control with fixed scanning space and number. Therefore, a frequency scanning strategy based on multi-spaces is proposed to improve the output current feedback control accuracy. The effect of this frequency feedback optimal control strategy is verified by modeling and simulation.

Key words: EAST, Divertor, Resonant, Frequency feedback

摘要： EAST 装置中鱼尾偏滤器磁体线圈电源采用多频率谐振技术方案以实现 3.5 kHz/5000 A 的正弦电流输出。而在实验中，环境磁场的变化会引起鱼尾偏滤器负载磁体的电流趋肤效应的变化，从而引起谐振网络频率的偏移和谐振电流的衰减。为了保证谐振电流的输出幅值，采用了基于谐振频率辨识的反馈控制策略。由于高频工作点的谐振品质因数 Q 要大于低频工作点，高频点谐振频率偏移引起的电流幅值衰减远大于低频点。当工作点频率值增加时，采用固定扫描间隔和扫描次数的谐振频率辨识控制导致的谐振电流误差会大大增加。因此，为了提高输出电流反馈控制精度，提出了一种基于多种间隔的频率扫描策略。根据工作点的频率高低，该控制策略优化了频率反馈范围和频率反馈间隔，可以有效提高反馈控制精度。通过建模和仿真，验证了该频率反馈优化控制策略的效果。

关键词: EAST, 偏滤器, 谐振, 频率反馈