Abstract:

This paper proposed a dual power supply circuit to increase the system reliability of the electronic controller.Based on the low-power design concept from the aspects of device selection and software design,the electronic controller system is designed,including a high-accuracy multi-channel AC signal acquisition module,magnetically isolated RS-485 communication module,LCD display and input module,central controller module and so on.The power consumption of the tested system is 0.79 W,which is 71% higher than that of the conventional products,and the current accuracy is 48% higher.The system adopts a multi-tasking real-time operating system,and samples current and voltage signals through multiple acquisition modules to calculate current and voltage values in real time.Considering the controller’s thermal memory function,the 12-order harmonic analysis of the three-phase current signal is realized,and the MODBUS communication protocol is supported.

Key words: air circuit breaker(ACB), inverse time, instantaneous protection characteristic, dual power supply