PWM整流器的双采样控制策略研究

Research of Double Update Control Strategy for PWM Rectifier

提出一种新的脉冲双采样控制策略与一个快速的相角估计器用于PWM整流器控制.常规的PWM控制策略只在一个开关周期内采样一次,而提出的双采样控制策略在一个开关周期内采样两次.双采样控制策略两次采样的特点保证了系统更加准确快速和很好的低频特性,能显著减少控制延迟时间与扩展最大允许控制带宽,虽然计算量增大,但采用高速数字信号处理器DSP可解决这一问题.同时,提出了一个快速的相角估计器,用于解决常规的相位检测器(如锁相环等)通常会产生明显的相位延迟而导致响应缓慢的缺点.该相角估计器即使在严重的电源电压失真或电源电压幅值、相角、频率突变的情况下,也能准确估计电网电压的相位角度与频率.实验结果验证了提出的控制策略的可行性,系统具有良好的动静态性能.

A novel dual update scheme and a very fast phase estimator for PWM rectifier are proposed.The proposed dual update scheme performances sampling and control calculation twice in a switch period,and conventional sampling scheme does only once.The dual update scheme sampling ensures that the control system gains fast response and good behavior in low frequency,reduces control delay significantly,and extends the allowable control bandwidth.Although the proposed dual update scheme increases calculation works,using high digital signal processor（DSP） can implement easily.Moreover,a very fast phase estimator is proposed to solve faults of normal phase detector such as a phase locked loop（PLL）,typically generating significant phase delay and resulting in a sluggish response.The proposed estimator can implement a very fast and robust phase angel estimation algorithm that operates well even under a distorted or sudden voltage changing condition,and a frequency estimation algorithm to accommodate a frequency vary environment.The experimental results verify feasibility of the proposed scheme,good dynamic and static behaviors of the system.