One-cycle control of brushless DC motor

Abstract

This work applies one cycle control algorithm to reduce the torque ripple of brushless dc motor drives having non-ideal back emf. The main principle involved here is to ensure that the average torque follows the reference command in each switching cycle. The average torque is obtained indirectly via dc bus voltage and current, which gives the energy flowing into the system in each control cycle. The method proposed here is cost effective, since expensive sensors are not required. Back emf information is not required as there is no online or offline estimation. Accurate position of rotor is not necessary. No current sensor is required to measure the phase current. Only two sensors are used: one sensor is used to obtain the dc bus voltage and the other to obtain phase current information to calculate the input energy supplied to the motor. The feasibility of the proposed control algorithm is validated through simulation and experimental studies.