IGBT overcurrent protection apparatus and method of PFC circuit

Abstract

The invention discloses an IGBT overcurrent protection apparatus and method of a PFC circuit. The IGBT overcurrent protection apparatus comprises: a PWM control module; an input voltage detection module detecting an input voltage, setting a hardware protection voltage, comparing the input voltage with the hardware protection voltage, generating a hardware voltage protection signal and outputting the hardware voltage protection signal to the PWM control module; an output voltage detection module detecting an output voltage; a current detection module detecting an input current; a current overcurrent protection module setting a hardware protection current, comparing the input current with the hardware protection current, generating a first hardware current protection signal and a second hardware current protection signal and transmitting the second hardware current protection signal to the PWM control module, wherein the PWM control module outputs a PWMout signal according to the hardware voltage protection signal and the second hardware current protection signal; and a PFC control module separately connected with the above modules, receiving the input voltage, the input current, thefirst hardware current protection signal and the output voltage, setting a software protection current, outputting a PWM signal to the PWM control module according to various values, and controllingthe PWM control module to output the PWMout signal.

Description

technical field [0001] The invention relates to the technical field of household appliances, in particular to an IGBT overcurrent protection device and method for a PFC circuit. Background technique [0002] At present, most household and similar frequency conversion appliances such as frequency conversion air conditioners and refrigerators are designed with a PFC circuit after the rectifier circuit and before the inverter circuit in order to improve the power factor. Household appliances usually use Boost-type PFC circuits, mainly including PFC inductors, IGBTs (Insulated Gate Bipolar Transistors, insulated gate bipolar transistors), and fast recovery diodes. IGBT is a key device for correcting current waveform, improving power factor, and increasing DC voltage. Overcurrent, overvoltage, and overheating damage are the main damage mechanisms of IGBT, and overcurrent damage accounts for the highest proportion. Therefore, it is necessary to design a fast response, with It is ...

AI Technical Summary

Problems solved by technology

However, the logic of this method is not refined, and it is easy to cause secondary overcurrent in the current cycle or the PWM can only be enabled when overcurrent occurs again. out Signal output is zero

[0004] Existing protection methods are not perfect enough to prevent IGBT overcurrent caused by AC power interference

The surge voltage of the AC power supply will cause a sudden increase in the current flowing through the IGBT; the voltage drop of the input power supply will cause a sudden increase in the duty cycle d of the IGBT in the next cycle, and then the current increment △Iin of the next switching cycle will suddenly increase , even overcurrent

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