Insulated gate bipolar transistor IGBT drive protection circuit

Abstract

The invention relates to a protection circuit driven by insulated gate bipolar transistor (IGBT). It is composed of power supply, IGBT, a signal circuit driven by upper and lower bridges, light coupler, a control circuit with a switch triode, an amplifying circuit for driving signal, a protection circuit for detecting and adjusting the voltages between collector and emitter of IGBT. Said protection circuit includes a short circuit protection circuit, fault latching circuit and fault soft switch off circuit. When the voltage of collector-emitter of IGBT is abnormal, the voltage of insulated gate of IGBT is adjusted to lower than threshold voltage, by the operation of short circuit protection circuit as well as control and amplifying circuit. Thus the IGBT is cut-off and the close latching is realized by that fault latching circuit. It guarantees to close off IGBT before CPU receives the fault signal and closes off driving signal.

Description

technical field [0001] The invention relates to a drive protection circuit of an insulated gate bipolar transistor (IGBT--Insulated Gate Bipolar Transistor), in particular to a drive protection circuit of an insulated gate bipolar transistor IGBT used as a power switching device in a frequency converter. Background technique [0002] At present, because the insulated gate bipolar transistor IGBT is easy to drive and can handle large current and high voltage at a high switching frequency, the insulated gate bipolar transistor IGBT is mostly used in high-power inverters and switching power supplies at home and abroad. Switching devices, so the IGBT drive protection circuit has become an important circuit related to the reliability of the inverter. The IGBT drive protection circuit used by the existing inverter has a variety of forms due to different design ideas. Such as figure 1 and figure 2 Shown are two typical drive protection circuits, where figure 1 The circuit struc...

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Problems solved by technology

[0002] At present, because the insulated gate bipolar transistor IGBT is easy to drive and can handle large current and high voltage at a high switching frequency, the insulated gate bipolar transistor IGBT is mostly used in high-power inverters and switching power supplies at home and abroad. Switching devices, so the IGBT drive protection circuit has become an important circuit related to the reliability of the inverter. The IGBT drive protection circuit used by the existing inverter has a variety of forms due to different design ideas. like figure 1 and figure 2 Shown are two typical drive protection circuits, where figure 1 The circuit structure shown is simple and has the function of driving power supply undervoltage protection. figure 2 The circuit structure shown is a bit complicated, and it has the protection function of IGBT collector-emitter voltage Vce, but a comprehensive analysis of various current circuit schemes shows that various existing circuit schemes have their own design emphases, but None of the circuit schemes has a perfect protection function, resulting in low reliability of the inverter and inconvenience to use

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