Grid-connected inverter

A grid-connected inverter comprises a DC power supply (11), a DC/DC converter (12), an inverter (13), a switching device (14), and a main controller (15). The DC power supply (11) consists of devices which can generate DC power, such as an accumulator battery, a photovoltaic cell, a wind-driven generator, and so on. The DC/DC converter (12) is connected between the DC power supply (11) and the inverter (13). The DC/DC converter (12) is used to boost the DC power and generate sinusoidal PWM voltage of double industrial frequency. The inverter (13) converts the sinusoidal PWM voltage of double industrial frequency to plus-minus half cycle sinusoidal PWM voltage, which is filtered and connected to a commercial supply network through the switching device (14). The main controller (15) is connected to the DC/DC converter (12) and the inverter (13) separately, and it controls the grid-on output current to be in-phase state to the voltage of the network, so effective power is exported. The DC power generated by various new energy resources is converted to AC power by the grid-connected inverter.