提高动态电压恢复器控制性能的立即刷新方法

A Method With Immediate Refreshing to Improve the Control Performance of Dynamic Voltage Regulator

数字控制系统因其固有的控制延时问题,严重影响了控制系统的稳定性及带宽。动态电压恢复器(DVR)需要对系统的电压暂降进行毫秒级的快速补偿,对系统的动态特性和鲁棒性的要求尤其严格。此处提出一种双采样单立即刷新的方法,可以有效地消除计算延时,并将数字控制延时减小到0.5拍脉宽调制(PWM)更新延时,提高了系统的控制性能和鲁棒性。重点分析了双采样单立即刷新方法在三相三电平拓扑中的应用,并建立了DVR系统的数学模型,对采用双采样单立即刷新方法的数字控制延时特性进行了研究,并分析了其对控制系统稳定性和动态特性的影响。最后搭建了一台100kW三相三电平DVR样机,实验结果验证了提出的方法的有效性。

The stability and bandwidth of digital control system are seriously affected by its inherent control delay.The dynamic voltage regulator(DVR)needs to compensate the voltage sag of the system rapidly at ms level,which has strict requirements on the dynamic characteristics and robustness of system.A method of double sampling and single immediate refreshing is proposed,which can effectively eliminate the calculation delay,reduce the digital control delay to 0.5 beat pulse width modulation(PWM)update delay,and improve the control performance and robustness of the system.It focuses on the application of double sampling and single immediate refreshing method in three-phase threelevel topology,establishes the mathematical model of DVR system,studies the delay characteristics of digital control using double sampling and single immediate refreshing method,and analyzes its influence on stability and dynamic characteristics of control system.Finally,a 100 kW three-phase three-level DVR prototype is built,and the experimental results verify the effectiveness of the proposed method.