Abstract:

The Fast Control Power Supply(FCPS) is employed to maintain the balance of plasma movement at vertical direction in the Experimental Advanced Superconducting Tokamak (EAST). FCPS is composed of H-bridge inverters. Phase shift is adopted to increase voltage levels and to guarantee that FCPS works safely and smoothly. The characteristics of PWM as well as the basic principle of phase shift were studied by introducing dual Fourier transform. The relationship between voltage levels and modulation ratio is also studied; meanwhile, a new modulation method is suggested to increase voltage levels. Simulation result using MATLAB verifies the validity of analysis.

Key words: Dual Fourier transform, Phase shift, Voltage levels

摘要：

EAST装置的快控电源是用来维持等离子体在垂直方向稳定性的，由H桥逆变电路组成。为了增加电平数，使快控电源安全平稳地进行，可以采取载波移相的方法。利用双重Fourier变换，讨论了PWM的特点，分析了载波移相的原理。研究了输出电压电平数与调制比的关系，对不同调制比下的输出电平数做了仿真分析。并且提出了一种同时增加电平数和消除谐波的新调制方法，通过MATLAB仿真验证了分析结果的正确性。

关键词: Dual Fourier transform, Phase shift, Voltage levels