Additional-voltage-free zero voltage switch energy-storing semi-bridge type inverter and modulation method

Abstract

The invention provides an additional-voltage-free zero voltage switch energy-storing semi-bridge type inverter and a modulation method. The inverter comprises a direct current side storage battery, a direct current side voltage division capacitor, an alternating current side filtering inductor and a single-phase bridge arm formed by two full control main switches with antiparallel diodes. An auxiliary switch of the antiparallel diodes is connected between direct current buses of the voltage division capacitor and the single-phase bridge arm. Capacitors are connected at two ends of the main switches and the auxiliary switch, and a resonant branch formed by connecting a resonant inductor and a clamping capacitor is connected at two ends of the auxiliary switch in bridge mode. The inverter runs independently with load or in grid-connection mode. The main switches adopt a sine wave pulse width modulation method, and modulation signals of the auxiliary switch are synchronous with modulation signals of the main switches. In each on-off period, the auxiliary switch can achieve zero voltage opening of the main switches by simply acting once, reverse current restoring of the antiparallel diodes of the main switches is restrained, and the switch voltage stress is equal to the direct current side voltage of the inverter. The inverter is small in switch consumption, high in circuit efficiency and favorable for improving working efficiency and further improves power density.

Description

technical field [0001] The invention relates to a half-bridge inverter, in particular to a circuit topology and a modulation method of a zero-voltage switching battery energy storage half-bridge inverter without additional voltage stress. Background technique [0002] A battery energy storage single-phase half-bridge inverter with the functions of grid-connected power generation and independent operation with load, its circuit is as follows figure 1 As shown, it consists of two fully controlled main switches S with antiparallel diodes 1 ~S 2 The single-phase bridge arm is connected to the output filter inductance L between the midpoint of the bridge arm and the load or the AC grid. This kind of inverter can realize independent inverter function, and can also realize grid-connected power generation operation, but the circuit works in a hard switching state, there is a problem of reverse recovery of the diode, and the switching loss of the device is large, which limits the i...

AI Technical Summary

Problems solved by technology

This kind of inverter can realize independent inverter function, and can also realize grid-connected power generation operation, but the circuit works in a hard switching state, there is a problem of reverse recovery of the diode, and the switching loss of the device is large, which limits the increase of the operating frequency and reduces the The circuit efficiency is improved and there is a large electromagnetic interference

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