Inverter and switching modulation method of ANPC type three-level inverter circuit

Abstract

The invention provides an inverter and a switching modulation method of an ANPC type three-level inverter circuit. In the switching modulation method of the inverter circuit, when the inverter circuit outputs a zero level, a closed circuit is not formed between a conducted outer tube and a current current path in the inverter circuit, so that zero-current turn-off of the outer tube can be realized; besides, after a double-follow-current loop is constructed in the inverter circuit, the output level of the inverter circuit cannot be changed when any clamping tube in the inverter circuit is turned off, so that zero-voltage turn-off of a clamping tube can be realized; in conclusion, according to the switching modulation method of the inverter circuit, the stress borne by the outer tube and the clamping tube in an output state switching process is reduced, so that overpressure of the outer tube and the clamping tube in the output state switching process can be avoided, the outer tube and the clamping tube can select a switching tube with lower withstand voltage, and therefore, the cost of the ANPC type three-level inverter circuit can be reduced.

Description

technical field [0001] The invention relates to the technical field of power electronics, in particular to an inverter and a switching modulation method for an ANPC type three-level inverter circuit. Background technique [0002] ANPC type three-level inverter circuit such as figure 1 As shown, wherein the first switching tube T1 and the fourth switching tube T4 are outer tubes, the second switching tube T2 and the third switching tube T3 are inner tubes, the fifth switching tube T5 and the sixth switching tube T6 are clamping tubes . At present, the modulation strategy of ANPC is relatively flexible, and the modulation strategy of inner tube high frequency and outer tube power frequency can be adopted. [0003] Although the modulation strategy makes the path of the commutation circuit longer, it can reduce the loss, so the modulation strategy is suitable for low power occasions. Usually, when this modulation strategy is adopted, the outer tube and the clamping tube switc...

AI Technical Summary

Problems solved by technology

Usually, when this modulation strategy is adopted, the outer tube and the clamping tube switch only at the zero-crossing point, and the output state of the ANPC type three-level inverter circuit is converted; during the switching process, the outer tube and the clamping tube The position tube has the possibility of overpressure. In order to avoid the outer tube and clamp tube from being damaged due to overpressure during the switching process, the outer tube and clamp tube with higher resistance are usually selected, so that the ANPC type three-level inverter The cost of changing the circuit increases

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