基于虚拟磁链的PWM整流器直接功率控制研究

Study on direct power control of PWM rectifier based on virtual flux

以虚拟磁链为核心,建立三相Boost型脉冲宽度调制(PWM)整流器直接功率控制系统的模型结构.应用矢量空间变换方法及数字信号处理(DSP)技术,给出控制系统中交流电压、虚拟磁链和瞬时功率估计的数字化算法,探讨PWM调制开关表与功率滞环控制器的构成机制,并在实验平台上对所设计的基于虚拟磁链的三相Boost型PWM整流器直接功率控制系统进行实时控制试验。为检验控制系统性能,试验时在电源电压中注入5%基波幅值的5次谐波.试验结果表明,与传统的直接功率控制方法相比较,基于虚拟磁链的三相Boost型PWM整流器直接功率控制系统结构简单,能有效减少传感器的数量,且抗干扰能力强,电网输入电流的畸变较小,具有更优的瞬时功率静动态控制特性.

A model structure of the direct power control system of three-phase Boost type pulse width modulation (PWM) rectifier which focused on virtual flux was established. The digital arithmetic for estimating AC voltage, virtual flux and instantaneous power was proposed with the help of the space-vector-transformations and the digital signal processing (DSP) technology. The constitutions of the PWM modulation switch-table and the power hysteresis controllers were also studied. A real-time experiment on the designed direct power control system of three-phase Boost type PWM rectifier based on virtual flux was conducted. In order to verify the characteristics of the control system, the 5% the 5th harmonic voltage was added to the power supply. The experimental results show that compared with the traditional method of direct power control system of three-phase Boost type PWM rectifier, the direct power control system based on virtual flux has simpler structure, fewer sensors, stronger anti-jamming ability, less input current distort and better static and dynamic control performances of instantaneous power.