基于PWM电抗器的静态无功功率补偿器的仿真研究

Simulation of PWM-Reactor-Based Static V ar Compensator

提出了一种新的静态无功功率补偿装置,该装置较好地解决了低次谐波和同步电路的问题.利用PWM逆变器技术,根据无方向自动换向开关的不同选通信号控制电抗器的单向电流,当工作周期D≤0.65时,输入电流的谐波分量is,h逐渐增大,谐波畸变率也随之增大;当工作周期D>0.65时,is,h逐渐减小,其谐波畸变率也随之减小.建立了该装置的数学模型,完成了理论分析,得出了相应的设计公式.仿真结果表明在不同的开关频率或周期下,可以获得超前或滞后的无功功率,从而有效地削弱输入电流中的谐波,改善电力系统的功率因数.

To overcome the shortcomings of large low -order harmo nics and slow response associated with conventional thyristor-controlled-react or -based compensator, and in order to satisfy the requirement of synchronizing ci rcuit in a pulse -width-modulated (PWM) static var compensator (SVC), a new SVC, a PWM AC inver te r, is used to control the reactors according to different selecting signal. When duty-cycle D≤0.65, the harmonic elements of input current are continuousl y inc reasing and total harmonic distortion increase with them; when duty-cycle  D >0.65, the results are reversed. Based on the mathematical model of this devi ce, i ts corresponding design formula were deduced and verified by means of simul a tion. The simulation results show that it can obtain either ahead or lag var power in different switching frequencies, thus eliminating harmo nics in input currents efficiently and improving the power factor of power syst em.