Research On Minimum Stator Current Control Of Asynchronous Motor Based On Power-fed AC Drive System

ABSTRACT: AC drive technology has been the evolution direction of railway locomotives in China, the same as the railway traffic developed countries, because of its economical and technical superiorities. AC drive test rigs with equivalent power are needed to provide good test site for the research, development and production of high power AC drive systems. So this dissertation makes some researches on a twin inverter-motor reciprocal power-fed AC drive test system. And the minimum stator current control has been proved that this scheme was effective. All of this is prepared for the big power systerm.First, the methord of improving motor's efficiency and the suggestion of minimum stator current have been simply introduced in the paper. Then,this dissertation expatiates on the work principle and energy conserving principle of the reciprocal power-fed test system, proposes the associated control strategy of twin motors based on vector control. Test results show that twin inverter-motors reciprocal power-fed system using the above control strategy has good steady-state performance, good features of speed and load torque adjustment.Second, in this paper, the vector control is first introduced, and then we thoroughly analyze and prepare the literatures on Max Torque Per Ampere (MTPA) control. Based on them, a minimum stator current control strategy of asynchronous motor on light-load and steady state is put forward, and also the math model.The minimum stator current control scheme designed in the paper is simulated by Matlab. The result indicate that it not only decoupled the magnetic flux and torque but also improved motor's efficiency .And the experiment proved that the MTPA can be used in praxis. Also found that we can achieve the minimum stator current control under light load condition as wished.