IGBT cycle-by-cycle current-limiting protection circuit

Abstract

The invention discloses an IGBT cycle-by-cycle current-limiting protection circuit, and the circuit comprises a sampling circuit which is used for detecting a sampling voltage corresponding to an IGBT current signal, an amplification circuit for amplifying the sampling voltage, a comparison circuit which is used for comparing the amplified sampling voltage with a comparison reference voltage, and a drive circuit which is used for cutting off a IGBT drive signal in a current control cycle when the amplified sampling voltage is greater than the comparison reference voltage. The protection circuit does not depend on a main control board, can detect the current signal of each IGBT in real time, carries out the overcurrent protection of each IGBT according to the current signal in one cycle, and improves the reliability and accuracy of an IGBT control system.

Description

technical field [0001] The invention relates to the technical field of IGBT overcurrent protection, in particular to an IGBT cycle-by-cycle current limiting protection circuit. Background technique [0002] The DC-DC step-up part of the front stage of the photovoltaic combiner box uses IGBT to boost and stabilize the voltage of the battery string. When there are multiple photovoltaic combiner boxes, each photovoltaic combiner box needs such a booster circuit, and each circuit is independent of each other. , the working state of the IGBT is an important factor to ensure the normal operation of these circuits. At present, the general control method is to judge and protect the IGBT overcurrent through the current detection signal of the sensor. However, when there are many circuits (8 or more), it is necessary to monitor the current flowing through each IGBT in real time. Monitoring and protection will occupy a large amount of controller resources and greatly increase the cost...

AI Technical Summary

Problems solved by technology

At present, the general control method is to judge and protect the IGBT overcurrent through the current detection signal of the sensor. However, when there are many circuits (8 or more), it is necessary to monitor the current flowing through each IGBT in real time. Monitoring and protection will occupy a large amount of controller resources and greatly increase the cost

[0003] Generally, a strobe is used to control the current signals of each channel in turn. Although this reduces the cost, the disadvantages cannot be ignored. The detected current signals are not real-time. Taking the 8-way photovoltaic combiner box as an example, the final The maximum delay time of the current signal detected along the way can reach 8 switching cycles. If an overcurrent phenomenon occurs, the drive signal cannot be detected and turned off in time, which will cause the current accumulation to increase, and even damage IGBT and other devices, which greatly reduces the control System reliability and accuracy

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