分析了導致SPWM 逆變器輸出變壓器偏磁的幾種主要因素：控制系統引起的偏磁，驅動電路元件參數的分散性引起的偏磁和主電路引起的偏磁以及偏磁對逆變器的影響，其中控制系統所引起的偏磁是主要因素。在此基礎上提出基于DSP的單相逆變器直流偏磁抑制技術，通過檢測變壓器原邊的直流電流并進行閉環數字PI控制，可使原邊的直流電流值穩態下近似為0。仿真和實驗結果表明, 所提出的方案可以有效地抑制逆變器變壓器的直流偏磁。
關鍵詞： SPWM 逆變器； 偏磁；PI控制；DSP
Abstract：The key factors which result in output transformer bias magnetic in SPWM inverter are analyzed.These factors include control system, the difference between the device parameters of drive circuit and the main circuit. And the first factor is main. An anti-bias-magnetic method used in single phase inverter based on DSP digital control is presented. The direct current of transformer primary windings is sensed. Under the PI closed-loop control, the stable state direct current of transformer primary windings will be approximately 0.Simulation and experimental results show the proposed method is simple and effective, and the magnetic bias in the transformer of inverter can be restricted.
Key words: SPWM inverter; magnetic bias;PI control ; DSP