Single-phase inverter

A single phase inverter comprising,

• a bridge circuit including a series connection between a first main switching element and a second main switching element and a series connection between a third main switching element and a fourth main switching element, the series connections being connected in parallel with respect to a DC power source, and each of the main switching elements being connected to a diode in parallel, reverse-biased with respect to the DC power source,
• a smoothing circuit, an auxiliary switching circuit, and a resonant capacitor, being connected in that order from the DC power source, between the DC power source and the bridge circuit, and
• a resonant inductor being connected between a connection point of the first main switching element and the second main switching element, and a connection point of the third main switching element and the fourth main switching element in the bridge circuit, wherein,
• the resonant capacitor and the resonant inductor form a resonance circuit, when an open operation by the auxiliary switching circuit disconnects the smoothing circuit from the resonant capacitor, and
• a) in a switching operation by the main switching elements, from an off-state to an on-state,
• a resonance current of the resonance circuit passes through the diodes of the bridge circuit being connected in parallel with the main switching elements, thereby achieving zero current switching for the main switching elements, and passing of the resonance current through the resonance circuit makes voltage across the main switching elements to be zero voltage so as to achieve zero voltage switching, thereby achieving the zero current switching and zero voltage switching for the switching operation by the main switching elements from the off-state to the on-state;
• and
• b) in the switching operation by the main switching elements, from the on-state to the off-state,
• discharging of the resonant capacitor with the resonance current makes a voltage across the capacitor to be zero voltage, and a voltage across the main switching elements becomes zero voltage, thereby achieving the zero voltage switching for the switching operation by the main switching elements from the on-state to the off-state, and
• the switching operation by the main switching elements is performed by soft switching.