Instantaneous overcurrent detection circuit of optical fiber communication cascaded high voltage inverter

Abstract

The invention discloses an instantaneous overcurrent detecting circuit of an optical fiber communication cascade type high-voltage inverter. The instantaneous overcurrent detecting circuit of the optical fiber communication cascade type high-voltage inverter comprises an emitter follower, a voltage comparer and an optical couple isolation circuit. According to the instantaneous overcurrent detecting circuit of the optical fiber communication cascade type high-voltage inverter provided by the invention, three-phase current is detected by using a Hall sensor, and is converted into a voltage signal; the voltage signal is sent to a main control instantaneous overcurrent detecting circuit; whether an overcurrent condition exists or not can be judged by comparing the voltage signal with a configured voltage comparison value; and the voltage signal is output to a main control DSP (Digital Signal Processor) chip and a CPLD (Complex Programmable Logic Device) chip of an optical fiber board for judgment. Once the overcurrent condition occurs, two paths simultaneously act, so that quicker, more accurate and more reliable overcurrent halt can be realized. Furthermore, the instantaneous overcurrent detecting circuit of the optical fiber communication cascade type high-voltage inverter provided by the invention has the advantages of high input impedance, strong electric insulation capability and strong anti-jamming capability.

Description

technical field [0001] The invention relates to a frequency converter, in particular to an optical fiber communication cascaded high-voltage frequency converter instantaneous overcurrent detection circuit. Background technique [0002] With the development of power electronics technology and the deepening of high-voltage inverter technology research, high-voltage inverters are increasingly widely used in the drive systems of high-power mechanical equipment such as fans, water pumps, and compressors, especially cascaded high-voltage inverters. Frequency converters that are suitable for China's national conditions and have excellent performance are becoming more and more popular, which shows that they are in the ascendant. [0003] The over-current detection and protection circuit plays a vital role in the safety and stability of the entire high-voltage inverter. [0004] At present, the detection of the current signal mainly includes the direct series sampling resistor metho...

AI Technical Summary

Problems solved by technology

The direct series sampling resistor method is simple, reliable, undistorted, and fast; but it has loss and is not isolated, and is only suitable for small currents that do not require isolation, and is mostly used in small-capacity inverters

The current transformer method has low loss, is isolated from the main circuit, and is convenient and flexible to use; but the linearity is low, the working frequency band is narrow, and there is a certain hysteresis, and it is mostly used in high-voltage and high-current occasions

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