磁性源电磁法发射电流分段控制方法

Piecewise control method of emission current of magnetic source transient electromagnetic interference

针对磁性源发射系统中脉冲宽度调制(PWM)控制方法电磁干扰强及上升沿、下降沿拖尾严重的问题,提出一种磁性源电磁法发射电流分段控制的方法。将发射电流分为4段精确控制,即通过引进高压辅助电源的方法控制发射电流的上升沿、平顶段与下降沿,并利用软硬件相结合的方法消除下降沿过冲。讨论供电电压与波形线性度、延迟时间的关系,给出具体设计方案及电路参数计算,采用仿真和实验的方法与PWM控制方法所得电流波形进行对比分析。研究结果表明:通过输出电流分段控制方法得到的输出电流波形的上升沿时间小于1.5 ms;下降沿时间小于0.5 ms,过冲电流小于3 A,线性度大于0.875,与PWM控制方法所得波形相比,其上升沿提升速度快,下降沿延迟时间短,线性度高,反向过冲电流小。

A piecewise control method of emission current used in the magnetic source electromagnetic interference（TEM） transmitting system was proposed to solve the problems caused by pulse width modulation（PWM） control method, i.e. serious electromagnetic interference（EMI） and large trailing currents during ascending and turn-off time. The current was divided into four segments and accurately controlled. The ascending segment, turn-off segment and flat segment were controlled through the introduction of high voltage auxiliary power supply and a method combining the use of hardware and software was used to eliminate current over-shot. The relationships among the supply voltage, waveform linearity and turn-off time was discussed. The specific design scheme was put forward and circuit parameter calculation was done. The results show that the ascending time of the proposed circuits is lower than 1.5 ms, turn-off time is lower than 0.5 ms; the amplitude of the current over-shot is lower than 3 A and the linearity of the waveform is larger than 0.875. Compared with the waveform obtained from the PWM control technology, the proposed rectifying circuits have less turn-off time and ascending time. The current over-shot is eliminated and the turn-off consistency is improved.