Research On Distributed Pulse Modulation Based On DSP For Inverters

Presently, with the rapid development of information technology, the research on the digital control scheme and its realization method of inverter systems has great significance in power electronics conversion techniques.The digital distributed pulse modulation (DPM) inverter based on digital signal processor (DSP) is mainly researched and analyzed in this dissertation. And the control manners to improve the static precision and the dynamic response of inverters, especially the capability in overcoming the repetitive distortion from rectifier-type loads are studied. The principle of DPM is introduced firstly. The variance law of filter inductance current in three-state hysteresis-band current control is analyzed and the digital DPM control method is realized. To perfect the output wave and limit two polarities modulation, a new variable hysteresis-band current control method is proposed. And the characteristics of digital DPM and Sinusoidal pulse width modulation (SPWM) are compared also. Based on the analysis of the principle and stability of repetitive control, a new hybrid control strategy with mixing repetitive control and DPM is proposed, which will efficiently improve the static precision and overcome the repetitive distortion. Then the theoretic analysis is carried out between inductance current feedback and capacitor current feedback in the hybrid control strategy. The analysis result indicates that capacitor current feedback is conducive to improve the performance of inverters.The validity and feasibility of the proposed control scheme are verified by the simulation and experiment results.