级联H桥型静止无功补偿器(static synchronous compensator,STATCOM)通过调节单模块有功功率来达到均压的目的,但是会对输出无功电流产生影响。首先对单极倍频调制过程进行双重傅里叶分析,从理论上分析载波移相与单极倍频相结合的调制算法对单模块有功功率的影响,然后提出一种模块间载波轮换的新型调制算法,并且针对模块间如何进行同步切换以及在调制波过零点处切换的问题,给出一种在多DSP系统中的实现方案。该调制算法在不影响输出电压与输出电流质量的同时,从理论上解决了单模块有功功率不平衡的问题。仿真与实验结果验证了这种调制算法的正确性与可行性。
The cascade H-bridges STATCOM was to achieve the voltages balance by adjusting the active power of a single module, but would have an impact on output current surely. The paper firstly analyzed the unipolar SPWM process using double Fourier tools, which could give the theoretical analysis of active power for single modules on the carried phase-shift unipolar modulation, and then proposed a new modulation algorithm, the carrier rotation among single modules. The implementation of the new modulation under a multi-DSPs was described later especially for the synchronous rotation among different modules and the rotation occurring when the modulation wave passed zero point. This new modulation solves the problem of active power unbalance in a single module theoretically, and meanwhile does not affect the quality of output voltages and currents. Simulation and experiment results verified the theory analysis.