基于IGBT的大功率H桥快控电源控制策略

为了控制快速变化的等离子体垂直位移，研制了基于IGBT的大功率H桥快速可控电源，额定参数为500 V/3 kA。旧的快控电源由于结构以及控制策略的原因，导致IGBT关断过电压高、工作频率低、续流过程不可控产生的电压宽脉冲等问题。针对这些不足，新的H桥快速控制电源首先重新设计了电源的结构，使其更加紧凑，减小了电源的寄生电感，从而降低了IGBT的关断过电压。其次，通过改变电源的控制方式，电源的工作频率达到IGBT开关频率的2倍，增大了电源输出电压的频率，等效提高了电源的快速响应能力。同时，为电源重新设计了一种可控的续流方式，通过对IGBT的控制改变电路的续流回路，使续流过程可控。通过实验研究可知，电源的响应时间为125 s，在等离子体位移发生变化时电流能够快速响应，控制等离子体位移，保证托卡马克装置的正常放电，并且通过新的续流控制方式，使电源在续流时不会再出现续流不可控导致的宽电压脉冲问题，输出电压能够有效地跟踪给定电压值变化。

Control strategy for high power H-bridge quick response power supply based on IGBT

In order to track the plasma rapid change in the vertical displacement, an H-bridge quick response power supply based on IGBT has been developed, rating of the power supply parameters for +500 V/+3 kA. Due to the structure and control strategy, the old quick response power supply has some deficiencies such as IGBT turn-off overvoltage, low working frequency, wide pulse voltage of uncontrolled flyback process. Aiming to solve these deficiencies, firstly, a new H-bridge quick response power supply redesigns the structure to reduce the power of the parasitic inductance, which brings down the IGBT turn-off overvoltage. Secondly, through changing the control mode of power supply, the working frequency of the power supply is two times the IGBT switch frequency, and the frequency of the power supply output voltage is increased, equivalent to improve the fast response ability of the power supply. At the same time, a kind of controllable flyback mode is designed, which changes the flyback circuit with IGBT to make the flyback process under control. Tested by the experimental study, the response time of the power supply is 125 s. The power supply has a quick response when the displacement of plasma changes, ensuring the normal discharge of tokamak, and with the new freewheeling control mode, the wide voltage pulse will not happen again, thus the output voltage can effectively track the given voltage change.