大功率有源滤波器的并联变流器电路

提出了有效应用并联变流器作为大功率负载时的无功补偿器以及有源滤波器(APF)新拓扑.由于单个器件功率容量有限,要将功率电路结构的谐波电流总畸变率保持在规定的标准内,并联是增加设备定额的一种选择.有文献报导把几个变流器而非开关并联在一起,在分担负载时更可靠.从这个角度来看,多电平变流器很重要,因为其典型功率电路结构能把单个器件的应力限制在适当的范围.另一方面,多电平变流器具有开关频率低和能有效利用开关器件的优点,这在大功率应用中非常关键.这些优点在与一个小功率、高频的电流控制的有源滤波器并联后得到了充分利用,消除了高次谐波.提出了一种由一个三点式中点箝位变流器和一个辅助电流控制电压型逆变器组成的新的并联拓扑结构及其控制技术,并在SABER仿真平台对线性与非线性负载进行了广泛的仿真研究.

Parallel converter scheme for high-power active power filters

A new topology for efficient utilization of parallel converters as VAR compensators and active power filters (APF) for high power loads is proposed. As a result of the limited power handling capacity of individual devices, paralleling is the choice to increase rating of equipment, while keeping the THD of the current at the PCC within the agency specified standards. It has been reported in the literature that paralleling several converters, rather than switches, is more reliable in sharing of loads. From this perspective, multilevel converters carry lot of weight, as their typical power circuit configuration limits the stress on individual devices to an appreciable extent. Also, they have the advantage of low switching frequency and full utilization of switching devices, which is essential in high-power applications. These advan- tages have been utilized in parallel combination with a low-power high-frequency current controlled APF, such that the higher order harmonics can be eliminated. A new parallel converter topology with a three-level neutral point clamped (NPC) converter and an auxiliary current- controlled VSI has been proposed and control techniques have been developed. Extensive simulation study have been carried out in a SABER simulator for linear and non-linear loads.