Three-level inverter circuit

Abstract

The invention discloses a three-level inverter circuit, belonging to the field of electric power electronics. The three-level inverter circuit comprises a circuit with power supply and a single-phase or three-phase inverter circuit, two switching tubes on an inverter bridge of the single-phase or three-phase inverter circuit are respectively connected with a first capacitor and a second capacitor in parallel, and intermediate nodes of the two switching tubes connected in series are connected with a first inductor in series. By adding the first capacitor, the second capacitor and the first inductor in the three-level inverter circuit, zero-voltage or zero-current on and off are realized between each switch tube and each inverse-parallel diode thereof, accordingly effect of a 'soft-switch' is achieved, and then loss of switches and electromagnetic interference are eliminated or reduced. The three-level inverter circuit can be applied to improve three-level T-type inverter circuit topologies and three-level I-type inverter circuit topologies.

Description

technical field [0001] The invention relates to the field of power electronics, in particular to a three-level inverter circuit including a soft switch. Background technique [0002] An inverter circuit is a conversion circuit used to convert direct current into alternating current. The existing inverter circuit is usually a circuit that converts the DC power outputted by the DC circuit into an AC power with adjustable frequency and voltage under the control of the control circuit. [0003] Please refer to figure 1 , which shows a schematic circuit diagram of an inverter circuit in the prior art. The inverter circuit mainly includes: a DC power source 112 , a capacitor C01 and a capacitor C02 connected in series, a first controllable switch Q1 and a second controllable switch Q2 connected in series, and a load 130 . Wherein, the positive pole of the DC power supply 112 is connected to the non-series end of the capacitor C01, and also connected to the non-series end of the...

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Problems solved by technology

[0005] In the process of realizing the present invention, the inventor found that the prior art has at least the following problems: since the power switch in the inverter circuit is not an ideal device in practice, its conduction and termination are not instantaneous but require a certain amount of time

With the continuous development of the inverter circuit to high frequency, the switching loss will rise linearly, the efficiency of the system will be seriously reduced, and serious electromagnetic interference will be generated, which has become the bottleneck that inhibits the efficiency of the inverter circuit.

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