Research Of Mine Electric Locomotive DC Chopper Speed-governing Controller

Currently, most of speed regulationare based on series resistance in mine electric locomotive.Though the method is relative maturely, there are a lot of energy consumption in the resistors, and it leads to a great waste of energy.This paper research a speed controller base on DC chopper speed-governing, the system used full-controlled switching devices, and there are many advantages ,such as the more bandwidth of the system frequency, the faster response, the stronger ability of dynamic anti-interference.The DC chopper speed-governing controller of mine electric locomotive has two parts of hardware circuits , respectivly , the major points of circuit and control circuit . Firstly,it designs the main circuit, and then chooses the type of IGBT power switches. Finally, it designs the control circuit and it uses ATmega 16 microcontroller as the main chip.The control circuit includes the power circuit, sampling circuit, the speed reference circuits, M57962L drive circuit, undervoltage protection circuit, overcurrent protection circuit, the reset circuit, alarm circuit and extension circuit etc. Control circuit principle:First, the MCU of Atmega16 work stably in a stable supply of power ,when the speed controlled, it transform the PWM waveform in accordance with the input changes, and then the signals are amplified by the power drive module M57962L of IGBT, and finally they are sent to the switching element IGBT, so as to realize the chopper speed-governing, As the speed-governing , the MCU sample with the main circuit current and battery voltage, such as over-current needs over-current protection, under-voltage needs under-voltage protection. In order to prevent voltage surge from the motor , a soft-starting program is designed by the method of stall scanning, and it has practical value and applicative prospect.Finally, it proved that the stability and reliability of the DC chopper speed-governing controller by a large number of experimentations. The results show that: the system's performance is stable and reliable and it achieved the desired design requirements.