| 摘要 |
A grid-connected inverter circuit, provided with a half-bridge inverter or a three-level inverter (11) and two DC/DC converters (21,22) having no LC output filters, or provided with a single-phase inverter (12) and a DC/DC converter (23) having no LC output filter. When the absolute value of grid voltage (Vgrid) is less than the input voltage, the inverter performs SPWM modulation and the DC/DC converter is idle; when the grid voltage absolute value is greater than the input voltage, a DC/DC converter performs SPWM modulation, and the corresponding electronic switch in the inverter remains in a conductive state, thus transmitting energy directly to the electrical grid. At any time, the grid-connected inverter circuit actually only performs single-level SPWM conversion, thus greatly reducing switching loss throughout the entire circuit and improving conversion efficiency. |
