A control method for the parallel-connected power converters includes a control
circuit comprising a voltage feedback circuit and a current feed-forward circuit.
The voltage feedback circuit, consisting of a voltage regulated control circuit
and a waveform control circuit, is used to control the power converter's output
voltage with constant amplitude and low total harmonic distortion. By adjusting
the gain of waveform control circuit, it can regulate the current distribution
among the parallel-connected power converters. The current feed-forward circuit
separates the power converter's output current into the fundamental component and
the harmonic component, and amplifies them by different gain. The amplified fundamental
component acts as a fundamental resistor to suppress the circulating current among
the parallel-connected power converters, and the amplified harmonic component acts
as a harmonic damper for preventing from high frequency oscillation generated by
the L-C filter.
