具有延时补偿的数字控制在PWM整流器中的应用

由零阶保持器及计算时间产生的控制延时是数字控制的主要缺点之一，这会导致系统振荡以至不稳定。为补偿延时，提出了一种基于状态反馈的新方法。该方法没有采用状态观测器，首先建立包含延时影响的PWM整流器的新数学模型，然后采用线性状态反馈，通过配置系统极点，得到新控制器。该方法消除延时影响不仅保证系统稳定而且对给定电流输入可取得无差拍响应。1kW的能量回馈型交流电子负载样机被用于验证新方法。样机采用20kHz的开关频率和TMS320F2812 DSP控制芯片。样机实验验证了理论分析的正确。

Digital Control With Compensation of Delay for PWM Rectifier

Control time delay induced by the zero-order-hold effect and the computational time delay was one of major disadvantages of digital control,which could induce system oscillation and even instability.To alleviate this problem,a new method based on state feedback was proposed.A new PWM rectifier model including delay effect was established,and then a new digital controller was designed according to linear state feedback and poles assignment.New method eliminates the delay impact so that not only stability is guaranteed but also deadbeat control is fully realized in current loop.A 1kW AC electric load prototype with power regeneration ability was set up for the proof of the control strategy.The prototype system was operated at 20kHz switching frequency and was controlled by TMS320F2812 DSP.Experimental results verify the validity of the proposed scheme.