Small-signal analysis and control implementation of boost converter fed PMDC motor for electric vehicle applications

Abstract

Small-signal analysis of boost converter fed permanent magnet DC (PMDC) motor for electric vehicle applications is performed, and hardware implementation is realized in this paper. Extensive analysis is performed to identify the relevant steady-state and dynamic features of the proposed system with small-signal linearization, and relevant transfer functions are formulated. The nonlinear equations of the system are derived and then linearized around a stable operating point to construct a small-signal model. Transfer functions relating the control of the converter to the motor speed and control to input current are derived symbolically using computerized symbolic algebra in MathCAD. The control-to-output transfer functions are obtained by introducing perturbation in state variables, equating AC and DC quantities and proceeding with AC quantities. The principle of operation, operation modes, small-signal analysis, experimental verification, and the effectiveness of the speed control are discussed and presented. An experimental prototype is implemented using dSPACE DS1103-based digital signal processor, and the proposed model is used for online parameter tuning of the speed controller. The speed control dynamics and transient response are investigated under sudden load changes. The overall system performance is evaluated and verified experimentally based on a speed feedback control scheme for validation purposes.