ACS710 based frequency converter overcurrent protection circuit and method

Abstract

The invention discloses an ACS710 based frequency converter overcurrent protection circuit and method. The circuit comprises a frequency converter, a fault pull-up resistor, an enabling pull-up resistor, a first comparator, a second comparator, an eleventh resistor, a fourth resistor, a triode, a voltage stabilizing tube and a hardware lockout sub-circuit, wherein the first comparator is used for comparing pull-down voltage of a chip overcurrent fault pin with a reference voltage value, the second comparator is used for level overturn protection on overcurrent. The hardware overcurrent protection circuit is designed according to overcurrent signals of the overcurrent fault pin of an ACS710 Hall, so that a primary short-circuit priority protection circuit is added by output of the frequency converter, circuit protection signals are directly transmitted to the hardware lockout sub-circuit without being processed via a CPU (central processing unit) so as to shield drive PWM (pulse-width modulation) signals, delay of the circuit only includes ACS710 fault detection delay and overturn delay of the second comparator, delayed response time of the whole circuit is within 5us, and the shortcoming that a traditional circuit is not timely in short-circuit protection is eliminated thoroughly .

Description

[0001] technical field [0002] The invention relates to the field of power electronics, in particular to an ACS710-based frequency converter overcurrent protection circuit and method. [0003] Background technique [0004] 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 curre...

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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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