上海质子治疗装置项目中质子注入系统凸轨磁铁需要脉冲电源励磁,要求两台电源脉冲峰值幅度可调和波形一致,且运行可靠.本文介绍了凸轨磁铁脉冲电源的设计和测试.脉冲电源电路采用LC串联谐振作为脉冲成形发生电路,电路设计可调电感用于调整波形脉宽.晶闸管为电流开关,快恢复二极管串联晶闸管弥补大功率晶闸管的关断延迟和下冲,并增加饱和电抗器抑制励磁电流反向电流尖峰.测试结果表明,当励磁电流峰值为3732 A时,励磁电流触发抖动小于±25 ns,励磁电流峰值重复稳定度小于0.1%,反向电流尖峰下降为峰值电流的3.75%,快恢复二极管和饱和电感器对抑制励磁电流反冲的效果明显,满足了设计要求.%Background:Proton therapy centers have been operated worldwide recently. The central rationale for proton therapy is its superior spatial dose distribution in the patient. Injection system of synchronous storage ring in Shanghai proton therapy equipment requires two bump magnets.Purpose:Two new pulsed power supplies of the same parameters used in the bump magnet have been proposed and developed.Methods:The principle of pulse forming circuit is thatLC series resonance generates when thyristor is turned on by trigger signals. Energy storage capacitor is charged to the setting voltage which determines the amplitude of the pulse waveform based on constant current by charging power supply. The main circuit employs variable inductance to adjust the pulse width. Fast recovery diode in series of thyristor could compensate for the turn-off delay of the thyristor while the peak of reverse current decreases due to saturable inductor.Results:Test results showed that when the half-sineexcitation current peak was set to 3732 A, its trigger jitter and reproducibility were less than ±25 ns and 0.1%, respectively. Reverse current could be reduced to 3.75% of the peak current.Conclusion:Experimental results indicate that the pulse power supply reaches the design requirements and saturable inductor restrains reverse current effectively.
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