Dynamic Load Emulation for Evaluating EVs Machines Based on Sliding Mode Control

Dynamometers are widely used for electric machines and their drive systems assessment, reducing prototyping time for many applications, such as Electric Vehicles machines. Having the same mechanical topology allows changing the control algorithm of the dynamometer to significantly improve the overall functionality and precision of mechanical load emulation imposed on motor under test. Hence, this paper proposes dynamic load emulation (DLE) by utilizing sliding mode control in the dynamometer. The proposed method is characterized by its simplicity, robustness, and low computational effort that meets industry requirements. First a proper sliding manifold is designed in which the sliding manifold contains the desired dynamic. The control signal is derived from that, which consists of two parts; the first part is based on the dynamics of the system, and the second part is a switching function, responsible for the rejection of disturbances. Thus, dynamic load emulation can be attained with a fast and precise response to various linear and nonlinear loads based on the mathematical model of the desired load. The desired model of mechanical load provides the speed reference to achieve the desired dynamic by forcing the shaft to rotate at a specific speed. The approach has been validated using a linear and a nonlinear load models simulated in MATLAB/Simulink. The perfect tracking of the reference has shown that emulation can still be carried out despite uncertainty in the model and disturbances.