Application of a Low-Pass Filter to Reduce the Influence of Measurement Path Errors in the Automatic Speed Control System

Purpose: To select an automatic speed control system of an electric train. To estimate the speed measurement error effects on the traction drive dynamics. To justify the selection and application of the low-pass filter, particularly Butterworth filter. To determine a set of quality criteria for an electric train speed control. To solve the problem of parametric synthesis of automatic speed control system. Methods: Simulation modelling, automatic control theory, optimizations. Results: Negative influence of speed measurement errors on the formation of the traction force control signal and, consequently, on the transient process in the traction drive has been established. As a result of solving the problem of the system parametric synthesis, proportionalintegral rational parameters with mismatch prediction of control law have been determined. The dependence of the value change of the control law parameters on the Butterworth filter order has been established. It has been revealed that with increasing the filter order it is required to increase its cut-off frequency. The inclusion of the Butterworth filter in the structure of the automatic speed control system has been proved to provide smoothing of high-frequency components in the measured speed signal. Practical significance: The structure of the automatic speed control system has been developed taking into account the presence of method error of the measuring device (pulse speed sensor). The simulation results obtained have shown the filters’ efficiency in the control system.