Current detection circuit based on Hall sensor

Abstract

The invention discloses a current detection circuit based on a Hall sensor, and belongs to the technical field of current detection. The current detection circuit comprises a current sensor desymbolization circuit, an upper limit voltage generation circuit, a return difference analog-to-digital conversion circuit and a relay control circuit; the input end of the current sensor desymbolization circuit is connected with a converter; the output end of the current sensor desymbolization circuit is connected with the return difference analog-to-digital conversion circuit; the current sensor desymbolization circuit is used for collecting converter current and outputting a negative value of a potential absolute value; the input end of the upper limit voltage generation circuit is connected with input voltage, and the output end of the upper limit voltage generation circuit is connected with the return difference analog-to-digital conversion circuit; the upper limit voltage generation circuit is used for generating upper limit voltage; the output end of the return difference analog-to-digital conversion circuit is connected with the relay control circuit, and the return difference analog-to-digital conversion circuit is used for generating lower limit voltage, comparing the potential absolute value with the lower limit voltage and the upper limit voltage and outputting a digital quantity for controlling a relay to be opened and closed; and the relay control circuit is used for outputting an alarm signal to the outside. The detection circuit can adapt to the characteristic that the features of detected current are variable; an alarm signal is sent out when a power module is over-current, so that devices are prevented from being damaged.

Description

technical field [0001] The invention relates to the technical field of current detection, in particular to a current detection circuit based on a Hall sensor. Background technique [0002] The IGBT power module is a power module composed of insulated gate bipolar transistors. Because of its simple driving and high switching frequency, it is widely used in the field of medium voltage driving. The conduction loss of the IGBT during normal operation is very small, but when the application module overcurrent occurs, its transistor leaves the safe operating area, which will generate a large instantaneous power and needs to be shut down in time. However, in the application environment of IGBT, such as converters, the power characteristics change frequently, and it is easy to over-current. In order to avoid damage to devices in extreme conditions such as short circuit and overcurrent, on the one hand, overcurrent protection needs to be added, and on the other hand, current informa...

AI Technical Summary

Problems solved by technology

For the IGBT power module in the converter measured in this example, these two methods have disadvantages. The former will have very small resistance selection when the current is high, which is not easy to choose, and there are also problems with heat generation and accuracy. It is not very simple to consider the magnetic saturation and waveform distortion when designing

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