基于晶闸管二进制补偿器和PWM-IGBT有源功率滤波器组合的普通负载全补偿系统

A Full Compensating System for General Loads, Based on a Combination of Thyristor Binary Compensator, and a PWM-IGBT Active Power Filter

介绍用于分布网络中能够消除谐波,平衡负载和产生或吸收无功功率的全补偿系统。该系统基于晶闸管二进制补偿器(TBC)和PWM-IGBT有源功率滤波器(APF)相级联的组合。TBC能补偿基波无功功率,平衡连接到系统的负载。APF能消除谐波,补偿少量的负载不平衡或由于TBC二进制条件而不能消除的功率因数。TBC由一串被标定的二进制电容器和每相一个电感器构成。该拓扑允许采用数量合适的电容器,也允许无功功率补偿的软变化,其产生的谐波可忽略。当线电压达到电压峰值时,电容器接通,以避免产生浪涌电流。必要时,电感器可帮助平衡负载和吸收无功功率。APF的作用是测试电源电流,迫使电源电流为正弦电流。这2个变流器(TBC和APF)工作独立,使系统控制简单可靠。仿真表明,在只有一个循环耦合中,系统能够响应许多种瞬时干扰。文章分析了所提出的电路和它的工作方法,并给出了工作时的一些实验结果。

A full compensating system for distribution networks, able to eliminate harmonics, correct unbalanced loads, and generate or absorb reactive power,is presented. The system is based on a combination of a thyristor binary compensator(TBC), and a pulsewidth- modulation insulated gate bipolar transistor active power filter(APF) connected in cascade. The TBC compensates the fundamental reactive power and balances the load connected to the system. The APF eliminates the harmonics and compensates the small amounts of load unbalances of power factor that the TBC cannot eliminate due to its binary condition. The TBC is based on a chain of binary-scaled capacitors and one inductor per phase. This topology allows, with an adequate number of capacitors, a soft variation of reactive power compensation and a negligible generation of harmonics. The capacitors are switched on when the line voltage reaches its peak value, avoiding inrush currents generation. The inductor helps to balance the load, adn absorbs reactive power when required. The APF works measuring the source currents, forcing them to be sinusoidal. The two converters(TBC and APF)work independently, making the control of the system simpler and more reliable. Simulations show that the system is able to respond to many kinds of transient perturbations in no more than a couple of cycles. The paper analyzes the circuit proposed, the way it works and shows some experimental results obtained under operation.