基于DSP-FPGA的模块化多电平换流器PWM脉冲方案对比
A comparative study of PWM pulse schemes for modular multilevel converters based DSP-FPGA

摘要 由于MMC主控系统通信任务繁重、算法复杂,并且考虑到扩展性,通常采用一种基于数字信号处理器(DSP)和现场可编程门阵列(FPGA)的主控系统架构．为了研究DSP与FPGA产生的PWM脉冲对控制效果的影响，分析了MMC的基本结构和数学模型,在分析CPS-SPWM在MMC中应用特点的基础上,设计了两种PWM控制脉冲产生方案,并进行了仿真验证和实验对比．仿真结果表明:两种方案产生PWM控制脉冲的一致性;实验结果表明:两种方案在硬件中产生的实际PWM脉冲分配规律相同,但脉宽存在差异,从而导致控制效果不同．实验结论为工程设计提供了参考依据．
Abstract： The main control system usually takes a structure based on DSP and FPGA because of its characteristic of onerous communication tasks, complex control algorithm and redundancy. In order to research the influence that the PWM pulses generated by DSP or FPGA are used for modular multilevel converter (MMC), the basic structural characteristics and a simple mathematical model are analyzed. Two laws and realizations of PWM are proposed and analyzed based on the characteristics of CPS-SPWM(Carirer Phase Shifted Sinusoidal PWM) in MMC. Moreover, the two types of PWM pulse are compared by means of simulation and experiment. The simulation results show that the PWM pulse based on the two schemes is the same. Meanwhile, the experimental results suggest that the actual PWM pulse distribution rule in the hardware is consistent. However, the different pulse widths lead to different control effects. The experimental results provide references for engineering design.