高变比脉冲变压器固态调制器的研制

固态半导体开关串联使用时要求均压和信号同步,导致固态半导体调制器的可靠性及稳定性降低.为解决该问题,对基于高变比脉冲变压器耦合全固态刚管调制器的设计原理、拓扑结构开展了研究.基于脉冲变压器等效电路模型,利用拉普拉斯变换法分析了脉冲变压器分布参数对输出波形的影响,并根据系统设计指标要求计算出过冲特征系数和上升时间系数,进而对脉冲变压器结构进行了优化设计.研究结果表明,输出波形的前沿与漏感和分布电容的乘积成正比,其过冲与漏感和分布电容的比值成正比;优化后脉冲变压器的变比从原来的1:30提高到1:70,其初级电压仅需1 kV即可达到设计要求,且保证了漏感和分布电容满足系统的需求.在此基础上研制的高变比脉冲变压器固态调制器在工作电压70 kV、负载阻抗1.4 k、脉冲宽度100 s的条件下,实现输出脉冲前沿2.8 s、脉冲后沿2 s,达到系统设计要求,且在100 Hz满功率条件下实现长时间稳定运行. 

Design of Solid State Modulator Coupled with Pulse Transformer of High-Turns Ratio

To improve the reliability and stability of solid-state modulator and avoid the plight that the semiconductor switch in series requires the voltage sharing and signal synchronization, a solid-state hard-tube modulator coupled with pulse transformer of high turns ratio was designed and its topology structure was presented. Based on the equivalent circuit model of pulse transformer, the effect of the distribution parameters of pulse transformer on the output waveform was analyzed using Laplace transform method. The characteristic coefficients of overshoot and rise time were calculated following the design requirements. Further, the structure of pulse transformer was optimized. The results show that the rise time change positively with the product of leakage inductance and parasitic capacitance, and the overshoot of the output waveform is directly proportional to the ratio of leakage inductance to parasitic capacitance. The optimized turn ratio of pulse transformer is increased from 1:30 to 1:70, and the primary voltage of 1 kV can meet the design requirements and ensure that the leakage inductance and parasitic capacitance also meet the demand of system. The experimental results show that rise time of high-voltage pulse waveform is 2.8 s, and the fall time is about 2 s when working voltage is 70 kV, load impendence is 1.4 k and the pulse width is 100 s; and the system can realize the stable operation for a long time in the 100 Hz full power conditions.