A novel multilevel DC chopper supplying DC motor

This paper deals with controlling DC motor speed and/or torque through the multilevel Chopper circuit. The proposed switching circuit consists of four cascaded switching elements with three clamping diodes and four equal or different voltage sources connected in series. The configuration provides a constant five levels of voltage and has the ability to generate and track any reference input voltage within the source voltage range. The generated voltage has relatively very small harmonic and ripples compared to the traditional step down chopper. The profile of the generated voltage positively affects the performance of the motor armature current, the generated dynamic torque and the rotor. The simulation results show adequate voltage reference tracking, smooth speed response and reduced current and torque ripples, which normally reflect in smaller mechanical vibration and acoustic noise.