Improved residual current device (RCD) buffer circuit applied to direct tandem type insulated gate bipolar translator (IGBT)

Abstract

The invention provides an improved residual current device (RCD) buffer circuit applied to a direct tandem type insulated gate bipolar translator (IGBT). The improved RCD buffer circuit comprises an RCD buffer unit, a voltage sampling module, a comparator module, a pulse generation unit and an auxiliary switch unit. The RCD buffer unit comprises a resistor R, a diode D and a capacitor C. The resistor R is connected with the diode D in parallel, then connected with the capacitor C in series, and then connected with a collector electrode end and an emitting electrode end of the IGBT. The voltage sampling module divides the voltage of the collector electrode end and the emitting electrode end of the IGBT, and the comparator module compares the divided voltage of the two ends of the IGBT and a preset reference level. And input end of the pulse generation unit is connected with an output end of the comparator module. According to the improved RCD buffer circuit applied to the direct tandem type IGBT, when overvoltage is detected, the pulse generation unit generates short-time pulses to control and assist turning-on and turning-off of the IGBT so as to realize short-time leakage of overvoltage energy, the overvoltage on two ends of the IGBT can be quickly reduced to a normal range, and loss is greatly reduced.

Description

technical field [0001] The invention relates to the technical field of power electronics, in particular to an improved RCD snubber circuit applied to a direct series IGBT. Background technique [0002] IGBT (Isolated Gate Bipolar Transistor, Insulated Gate Bipolar Transistor) combines the advantages of GTR (Power Transistor) and MOSFET (Metal Oxide Semiconductor Field Effect Transistor, Metal Oxide Semiconductor Field Effect Transistor), with high input impedance and fast switching speed , simple drive, on-state voltage drop and many other excellent characteristics, so it has been widely used in the field of high-power electric energy conversion. However, due to the limitations of the current technology and manufacturing level, the withstand voltage level of a single IGBT device cannot meet the requirements in high-voltage and high-power electric energy conversion applications, and using multiple IGBTs directly in series is a relatively simple and economical solution. [00...

AI Technical Summary

Problems solved by technology

However, the circuit is complex, and the wiring of the circuit will introduce large stray inductance, which will affect the absorption effect

At the same time, it cannot be directly applied when high-voltage IGBTs are directly connected in series, because at this time the steady-state voltage of C on the snubber circuit corresponding to each IGBT is inconsistent, and additional steady-state voltage equalization processing is required, the structure is complex and the cost is also expensive.

At the same time, the wiring will be more complicated, not suitable for direct series IGBT applications

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