提高PWM整流器抗负载扰动性能研究

Research on Improvement of Anti-Disturbance Performance for Three-Phase PWM Rectifiers

提高PWM整流器抗负载扰动能力、减少直流母线电容量是PWM整流器重要的研究内容。文章首先深入分析了PWM整流器在传统带负载前馈的双闭环控制方式下负载突变时动态 响应受限制的问题,提出了稳态采用带负载前馈的双闭环、瞬态采用0*qi变结构控制的改进方 案,有效地提高了PWM整流器抗负载扰动的能力。其次在对PWM整流器动态分析的基础上, 提出了直流母线电容准确计算的解析表达式。仿真结果验证了变结构控制的有效性和母线电容计算的正确性。

It is important to improve the anti-disturbance performance of three-phase voltage-source PWM rectifier and to reduce the capacitance of the dc-link capacitors. In this paper, the dynamic response limited problems of the PWM rectifier controlled by the traditional voltage and current doubly feed-back loops with the load current feed-forward compensation under output load sudden change was deeply examined and an improved control scheme was put forward firstly, in which the doubly feed-back control with load current feed-forward was used in the steady-state and the 0*qi structure-variable control was employed in the transient state in order to effectively enhance the anti-disturbance ability of the PWM rectifier. Secondly, based on the dynamic analysis of the PWM rectifier, a precise analytical expression for the computation of the dc-link capacitance was suggested. The effectiveness of the Structure-Variable Control Scheme and the correction of the dc-link capacitor computation were all verified by the computer simulation study.