ITER中性束注入器加速极需要一套逆变型直流高压电源系统。该电源采用三相三电平(TPTL)直流变换器作为基本单元, 通过占空比控制实现对输出电压的快速调节。针对三相三电平直流变换器在小占空比模式下输出电压纹波大的缺点, 提出了一种全新的控制策略。该策略通过协调直流母线电压的大小和逆变器占空比的变化对输出电压进行调节。为了验证新的控制策略的性能, 搭建了200 kV/60 A的MATLAB/Simulink仿真模型和400 V/6 A的原理样机。仿真结果和样机实验结果表明, 新的控制策略可以实现逆变型高压电源在输出电压快速可调的情况下降低输出电压纹波。

An inverter type high voltage power supply is required for the acceleration of ITER neutral beam injector (NBI) system. The power supply employs three-phase three-level DC/DC converter as its basic component. This type of power supply can regulate the output voltage rapidly by the duty cycle modulation of the inverter switches. However, when the duty cycle is very small, the output ripple will be large. A new control strategy has been studied for the power supply, the output voltage is regulated by inverter duty cycle combining with adjusting the dc-link voltage. In order to verify the control strategy, a 200 kV/60 A Simulink model and a 400 V/6 A prototype have been established. Simulation and experimental results demonstrate that the topology with this control strategy can limit the voltage ripple while maintain the rapid voltage response.