Study On The Adhesion Control Of Parallel Connected Induction Motors In High Speed Train

For the advantage of lightness, lower cost and compact structure, the multiple induction motors connected in parallel fed by a single inverter has been generally applied in high speed train’s traction system. It is necessary to study on the control method of parallel connected induction motors to achieve higher adhesion coefficient and decrease the torque difference of each motor, which is caused by the difference of wheel radiuses, motor parameters and adhesion states. In this paper, a control method including motor control and adhesion control is proposed. First, the CRH2A EMU dynamics model of single axle and single EMU are built based on the analysis of force interaction between traction motor and transmission gear, and the wheel-rail contact theory. Second, steady-state model of parallel connected motors is built, the influence of wheel radius and parameter difference is analyzed, the variation rule between torque difference and operating state if train is obtained. Third, the mathematic model of weighted vector control is built, and the relationship of the torque’s summation, torque’s difference and weighted value is achieved. The control method of parallel connected motors under wheel radius is adopted. The torque difference can be controlled by adjusting the weighted value. Fourth, the optimum adhesion control for parallel connected motors which combined with the weighted vector control is proposed. The purpose of control method is to guarantee the axle which has the smallest adhesion coefficient from slipping or skidding, and increase the torque difference of each motor as much as possible to achieve higher average torque. Finally, based on the inertia simulation and power scale strategy, a5.5kW hardware-in-the-loop platform for the parallel connected motors is built. The weighted vector control method and optimum adhesion control method are verified.