Frequency converter overcurrent protection circuit and method based on acs710

Abstract

The invention discloses an ACS710-based frequency converter overcurrent protection circuit and method. The circuit includes a frequency converter, a fault pull-up resistor, an enable pull-up resistor, a pull-down voltage and a reference voltage value for the chip over-current fault pin The first comparator for comparison, the second comparator for level inversion protection for overcurrent, the eleventh resistor, the fourth capacitor, the triode, the regulator tube and the hardware blocking sub-circuit. In the present invention, a hardware overcurrent protection circuit is designed for the overcurrent signal of the overcurrent fault pin of ACS710 Hall, so that the output of the frequency converter is increased by a first-level short-circuit priority protection circuit, and the circuit protection signal is directly sent to the hardware blockade without CPU processing. The circuit shields the drive PWM signal. The delay of this circuit is only the fault detection delay of ACS710 and the flip delay of the second comparator. The delay response time of the whole circuit is within 5us, which completely eliminates the short circuit protection of traditional circuits. Shortcomings.

Description

technical field [0001] The invention relates to the field of power electronics, in particular to an ACS710-based frequency converter overcurrent protection circuit and method. Background technique [0002] At this stage, the following two schemes are often used for short-circuit overcurrent protection of low-power machines in the inverter industry; scheme 1: current detection circuit for current detection and short-circuit protection; current signal is added after the detection device (Hall, current detection resistor, etc.) The amplification circuit and filter circuit are then sent to the CPU for processing. Current detection devices, amplifier circuits, filter circuits and CPU processing all inevitably have delays, especially when low-power machines have a large magnification factor and high filtering effect requirements, the response time of the circuit in this solution is above 10us. When the inverter output is short-circuited, the instantaneous current is several times...

AI Technical Summary

Problems solved by technology

When the inverter output is short-circuited, the instantaneous current is several times or even dozens of times the nominal rated current of the IGBT, and the ability of the IBGT to withstand ten times the rated current is within 10us, which makes the IGBT very easy to fail when the inverter is short-circuited

Solution 2: Add a current detection circuit on the bus; this solution has obvious effects, but it needs to add a linear optocoupler for isolation, which is contrary to the development trend of small power machines with small size and low cost

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