Line powered, primary side connected apparatus injecting voltage compensation into an electric power line using one transformer

摘要

DVRs and APLCs utilize a single transformer for injection of compensating voltages into an ac power line and for drawing power from or exchanging power with the ac power line. The poles of an inverter are connected in series with the wye connected transformer primary winding which is also connected to the source end of the power line. A first secondary winding is connected to the load end of the power line. A rectifier circuit or a power interface inverter in the DVR and APLC, respectively, is connected to a second secondary winding on the transformer. For high pulse numbers, the rectifier circuit or interface inverter can have additional rectifier bridges or inverter poles connected to additional transformer secondary windings phase shifted with respect to each other. The single transformer can be a load transformer already provided in the power line, thereby further reducing the cost of the arrangement.