The invention belongs to the field of
photovoltaic power generation, applies a power decoupling circuit to reduce the capacity of a
capacitor at the side of a DC (
Direct Current)
bus for prolonging the service life and improving the reliability of the
inverter, replaces an
electrolytic capacitor with high capacity and a short service life with a thin
film capacitor with low capacity and a long service life and designs a miniature photovoltaic grid-connected
inverter. To fulfill the aims, the invention adopts the technical scheme that the miniature photovoltaic grid-connected
inverter with an optimized
DC bus capacitor comprises a main circuit and a control and
driving circuit, wherein the main circuit is formed by a photovoltaic
cell panel, a phase-shift full-
bridge circuit, a
high frequency transformer, a full-bridge rectifying circuit, the
DC bus capacitor, the power decoupling circuit and an inverter circuit which are sequentially connected; the control and
driving circuit comprises a photovoltaic output current sampling circuit, a photovoltaic output
voltage sampling circuit, a
power MOSFET (
Metal Oxide Semiconductor Field Effect Transistor)
driving circuit, a
capacitor voltage sampling circuit, a grid-connected current sampling circuit, a phase-locked loop circuit and a DSP (
Digital Signal Processor) controller. The miniature photovoltaic grid-connected inverter is mainly applied to
photovoltaic power generation.