Modified Direct Torque Control of Solar Fed Sensorless Switched Reluctance Motor Drive for Electric Vehicle With Regenerative Braking

In this article, a Photovoltaic (PV) fed Zeta converter based Switched Reluctance Motor (SRM) drive is demonstrated for light electric vehicle (LEV) application. An improved direct torque control (DTC) scheme is implemented on a 12/8 SRM. The flux loop is eliminated, and switching sectors are formed, based on rotor position. Turn-off angle control makes sectors' span adjustable. By carefully choosing switching vectors, innate restriction on creation of negative torque is removed. Implemented algorithm provides a reduced torque ripple with phase current profiling at turn-on instants. With a use of discrete rotor position estimates, rotor position is determined. Through a comparison between phase flux and stored flux, discrete rotor position is computed. A flux polynomial is formed to store magnetic data of SRM. A lead acid battery is connected to DC-link directly. To enhance range and reliability, a PV panel is connected to the system. A zeta DC-DC converter is employed with a variable step size P&O MPPT (maximum power point tracking) control algorithm to extract maximum power from PV panel. A regenerative braking strategy is also integrated with the system to extract kinetic energy stored in inertial system. This energy is fed-back to source and enhances range of vehicle with a same battery pack. Validation of algorithm is demonstrated on a prototype.