Torque Ripples Reduction in BLDC Drive for Electric Automobile Application
This paper presents a reduction of torque ripples in brushless DC (BLDC) drive by using Hysteresis Current
Limiting technique to extend the lifetime of batteries per charge in electric vehicle applications. In the conventional current
control method the current is still drawn from the batteries even when the motor is turned off which results it reduces the life
time of the battery by continuous leakage current from the battery. To avoid that leakage current it is fed to zero crossing
detector here the leakage current is controlled by using Hysteresis comparator but it produces high switching frequency
which produces ripples in torque.In this technique only current control is possible but the ripples are caused by hysteresis
control and inverter switching intervals.BLDC motors are one of the motor type’s fast gaining the interest of the researchers.
This motor attracts to a great extent concern due to its better speed, high dynamic response, high efficiency, long
operating life, noiseless operation and power density, compactness, high torque potential for steep slope or road
conditions, high reliability, robustness for electric vehicle and offers a reasonable cost. The proposed method controls the
inverter switching intervals and high switching frequency by using DC to DC Converter which minimizes the Torque
Ripples. The simulation and control of the BLDC motor is done by using the MATLAB/SIMULINK.
Keywords - Current Source Inverter (CSI), Electric vehicle, Hysteresis controller, Brushless DC (BLDC) motor, Converter
(Buck), Step down converter (Buck) Zero Crossing Detector.