Comparison of Scalar and Vector Control of Induction Motors Used in Electric Vehicle Applications

Abstract

It is widely recognized that induction motor drives are well-suited for propulsion purposes of electric vehicles (EVs) due to their features such as being efficient, economical and reliable. In this paper, two control methods of an induction motor (IM) for Electric Vehicles (EVs) are compared; scalar control (constant V/f) and vector control. The scalar control, which is a simple to implement method, is based on the magnitude variation of chosen control quantities. The purpose of the technique also known as constant V/f control is to maintain a constant flux value. It is cheap and does not require IM parameter identification, but it is not as sufficient in controlling drives with dynamic behavior such as EVs. On the other hand, vector control is a more advanced control method that is costly, difficult to implement, and require the identification of IM parameters. Its capability to control phase currents independently allows better transient operation, making it more appropriate for dynamic drives that is of great importance for EV applications. By means of vector-based control, higher starting torque, higher low-speed torque, and better speed control can be obtained. As a conclusion, a vector controlled IM motor has excellent speed-regulation performance and is very well competent for working as an EVs driver. Therefore, vector control can be a viable option to be used in EVs drive control.