Large Excavator Automatic Excitation Control System Development

Electric excavator in the open pit mining, water conservancy construction and infrastructure construction and other fields to obtain a wide range of applications, is the main mechanical equipment of earth rock excavation, but also one of the sixteen major categories of construction machinery products. The excitation control system of the electric excavator is still partly used in analog circuit, which has the disadvantages of complex structure, anti-interference and flexibility.This paper first elaborated the excavator excitation regulation system in the domestic and foreign research situation, expounds the domestic and foreign researchers in the study of the full digital excitation regulator, using different types of microprocessor and control algorithm, the microprocessor main MCU, arm and DSP. According to different working conditions, the products are three kinds of single CPU, multi CPU and analog / digital hybrid system, which greatly improves the labor productivity. Control algorithm, the main PID algorithm, adaptive fuzzy PID algorithm, etc.. Finally, it is found that the full digital excitation regulator has become the research and development direction of the excitation regulation system for large excavators.The overall scheme of the system is composed of the main circuit, the control circuit, the armature voltage, armature voltage and current feedback loop and so on. The excitation main circuit routing of two single-phase half controlled bridge rectifier composition, respectively to the DC generator provides is reverse exciting current; control circuit to the main circuit to provide the corresponding control signal to achieve regulation of exciting current and to control the output voltage of the generator to meet the requirements of the corresponding operation conditions.Hardware circuit of the system with high performance C8051F330 microcontroller as the micro controller, design of the distribution of the minimum system of the one chip computer and PC function pin; at the same time, the design of the power supply circuit, signal sampling and trigger pulse and other peripheral circuit; software part adopts incremental intelligent PI control algorithm, completed the design flow chart of the main program and subprogram, code development, and combining with the prototype of software debugging, debugging results show, can better meet the design requirements.In this paper, the WK(E)-4C electric excavator as the test object, by regulating the generator excitation current to change its output voltage, so as to achieve the purpose of regulating the speed of the motor. Due to the on-site experimental condition limit, the rated voltage of the DC generator is 450 V, the rated current is 200 A, the load is a rated voltage 220 V, the current 100 A of the motor. Through the experiment can observe trigger waveform, adjustable precision voltage, voltage overshoot and speed of voltage regulator, commutation of the motor speed, zero generator output voltage. The experimental results show that can meet the design requirements.