基于DSP的有效消除数字控制延时的UPS逆变器多环控制策略

摘要

This paper presents the design of a digital multiple-loop control strategy for high performance UPS inverters based on a discrete-time dynamic model. In digital control implement for UPS inverters, one of the most important factors, which limit the dynamic performance, is the control delay. The effects of different control delays in multiple-loop control system are investigated and resolved through adopting improved pulse-width modulation (PWM) methods which contributes to improve stability and robustness of the inverter system. The control method is implemented on a 16-bit single chip DSP-controller and tested on a single-phase 3.3kVA IGBT-based inverter prototype. Both the simulation and experimental results verify that the system with proposed control strategy achieves low THD (＜1.9%) with nonlinear load, possesses very fast dynamic response and lends itself to linear and nonlinear load applications.%基于逆变器离散动态模型提出了一种高性能UPS逆变器多环控制方案,在数字控制UPS逆变器中,控制延时是限制其动态性能的一个重要因素,本文详细分析了不同控制延时对多环控制逆变器性能的影响,比较了各种消除逆变器控制延时的方法,采用了更改PWM有效模式的方法以有效消除控制延时,该方法简单可靠,不会涉及预测误差,并且很容易用DSP控制器实现.控制延时的有效消除极大改进了逆变器系统的稳定性和鲁棒性.此外,内外环增益通过无差拍控制理论确定以实现快速动态响应.将本文提出的控制策略应用于16位定点DSP控制的3.3kVA的逆变器样机中,并对比了传统的多环控制逆变器系统,仿真和实验结果表明,本文提出的控制方法能实现非线性负载下低THD (＜1.9%),快速动态响应,适用于线性和非线性负载.