The Research On The Application Of Frequency Conversion Speed Control For Battery Locomotive

Mine electric locomotive is an important conveyance of coal mine. Now it has still used DC adjustable-speed control method based on DC series motor. But in this mode a lot of electric energy is consumed on resistance in series and the storage battery is frequently charged so that its life-span is shorter. DC motor has a complicated structure, low efficiency and large maintenance. Asynchronous motor can run under abominable operating condition because of its simple structure, high efficiency and small maintenance, and also it is cheap. While AC adjustable-speed technology is getting more advanced, DC electric locomotive will be displaced by AC electric locomotive.This paper applies direct torque control (DTC) to Asynchronous motor to control its speed. The technology of direct torque control (DTC) control stator flux and electromagnetic torque of asynchronous motor directly. Since it does not need complicated calculation, its control method is getting simple.At first, this article introduces basic theory of the AC adjustable-speed technology, then the simulation model of the DTC speed control system was established based on MATLAB, the result is presented and analyzed. The advantage and disadvantage are pointed out. The author has done the experiments of the adjustable-speed control system using the DSP test-bed, and some waves in experiment are captured and has analyzed the results of experiments. At last the author analyse the disadvantage of the DTC, and give a new method with vector subdivision, the simulation results suggests that the model is correct and the control system is effective.