基于PWM AC-AC变换的电压补偿器设计

介绍在配电系统中一种新型的电压补偿器,即在自耦变压器中集成PWM AC-AC变换器(每相4个IGBT元件)。其电压补偿控制模块根据系统控制对象的特点,选取数字化控制芯片TMS320LF2407,设计了基于DSP的PWM实现方式。在正常工作状况下,PWM变换器工作在旁路方式,电源功率直接传输给负荷,自耦变压器只吸收励磁电流;而当电压降低时,变换器将电压迭加(补偿)上去,以保持负荷端电压为额定值,同时通过自耦变压器增加一定的输出功率。在设计中没有使用诸如成组电容器/电感等这些储能元件,造价低,响应速度快。

Design of Voltage Compensator Based on PWM AC - AC Conversion

In this paper a new voltage compensator in electric distribution system is discussed,the design employs a PWM AC-AC converter(4,IGBTs per-phase) along with an auto-transformer.According to the features of control object,the proposed scheme employs TMS320LF2407,designing the PWM implement mode based on DSP.Under normal conditions the approach works in by-pass mode,delivering utility power directly to the load and the auto-trsformer draws only magnetizing current.During a disturbance such as voltage sag,the PWM converter adds the missing voltage and some amount of power is handled via the auto-trsformer,helps in maintaining rated voltage at the terminals of the critical load.The approach does not employ any energy storage components such as bulk capacitors/inductors and provides fast response at low cost.