Design of A Proportional–Integral (Pi) Speed Controller Scheme

Abstract

Electric vehicles (EVs) are one of the best possible solutions for reducing carbon emissions and reduction in greenhouse gas emissions owing to their high efficiency thus promoting green transportation. Among different motors used for power drive train or propulsion system of an electric vehicle, brushless direct current (BLDC) motors are most advantages as they are highly efficient, have high power and torque density and reduced weight and size for same power output due to permanent magnet rotor structure. There are no maintenance motors and produce better response due to low inertia. However, these motors require electronic commutation for their operation as they work with specific switching pattern. To achieve an optimal level of efficiency, BLDC motors require appropriate and robust speed controllers. Proportional – integral (PI) controllers are widely used for speed control applications of BLDC motors to adjust its speed. They are simple and have a very straightforward approach for execution of the speed control loop. However, when it is difficult to control the speed of the motor using PI controller when it is faced with nonlinearities of the motor and drive mechanism. They also find it difficult to execute the control loop properly during any sudden load disturbances and due to the effect of parametric variations during running of the motor. Hence, researchers sought for a better controller as compared to PI controller.