Patent ID: 6906501
Filing Date: 2005-06-14
Classification: H02M

Abstract:
1. A control arrangement for parallel-connected power converters, each of said power converters comprising: a voltage feedback circuit adapted to retrieve a power converter's output voltage and output current and to control the power converter in a voltage control mode for supplying a high quality ac voltage, said parallel-connected power converters being commonly and directly connected with at least one load for supplying said controlled high quality ac voltage and a distribution current to the load; a current feed-forward circuit adapted to retrieve the output current of the power converter, said current feed-forward circuit being adapted to be operated as an equivalent impedance serially connected to the output of the power converter, said equivalent impedance thereby suppressing a circulating current oscillation, wherein a magnitude of power converter's output current is used to determine a gain of the voltage feedback circuit for balancing the distribution current among said parallel-connected power converters; and a modulation circuit adapted to add the outputs of the voltage feedback circuit and the current fee-forward circuit to generate a modulation signal, which is sent to a pulse-width modulator to generate driving signals for switching devices of the power converter.