提高PWM整流器抗负载扰动性能研究

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i*q≠0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.

Research on Improvement of Anti-Disturbance Performancefor Three-Phase PWM Rectifiers

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.