Isolation buffer tri-level inversion circuit

Abstract

The invention discloses an isolation buffer tri-level inversion circuit, which comprises a direct current unit, an inversion unit and a controller, wherein the direct current unit is connected with the inversion unit; an isolation buffer driving unit is arranged between the inversion unit and the controller; the inversion unit is connected with the controller through the isolation buffer driving unit; the isolation buffer driving unit comprises a buffer unit, a conditioning unit and a driving unit; a control signal output end of the controller is connected with a gate pole of an IGBT switching tube of the inversion unit through the buffer unit, the conditioning unit and the driving unit in turn; and one control signal output end correspondingly controls one gate pole of the IGBT switchingtube. The isolation buffer tri-level inversion circuit has safe and reliable insulated isolation and flexible and convenient overall layout, reduces the requirement on the voltage stress of isolationdevices on the premise of not losing the performance, reduces the requirement of the whole circuit isolation security on the devices, and is a product design with low cost and high performance.

Description

technical field [0001] The invention relates to an inverter circuit with a three-level structure, in particular to an isolation buffer type three-level inverter circuit which utilizes the structural characteristics of the three-level inverter circuit itself to reduce the voltage stress of an isolation device. Background technique [0002] The middle-point clamped high-voltage three-level inverter has shown a good application prospect in the field of inverters due to its advantages such as fewer components required, wide speed range, bidirectional energy flow, small size, and light weight. In particular, the advent of integrated gate commutated thyristors (IGCTs) has added another ideal choice for medium and high voltage inverter switching devices. According to the current withstand voltage level of IGCT and high-voltage IGBT, the highest output voltage level of the three-level inverter in the frequency converter can reach 4.16kV, which greatly expands the application range o...

AI Technical Summary

Problems solved by technology

The voltage stress of the IGBT switching tube in the inverter unit 300 in the three-level inverter constructed by this direct coupling method is low, and the voltage stress borne by the switching tube is half of that of the two-level inverter. However, the direct coupling connection The voltage stress borne by the devices in the unit 400 should still be considered according to the full bus voltage. Therefore, low withstand voltage devices cannot be used in the direct coupling connection unit 400, which requires high requirements on the devices and the insulation safety of the entire device. High design and manufacturing costs

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