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EV Powertrain EVPT

The development and realization of the advanced electric drive system for an electric vehicle requires a well-optimized geometry of electric machine, proper power electronic circuitry, advanced control system, and sensing mechanism, which will result in the enhanced efficiency of energy conversion of an electric vehicle. In literature, different studies are performed regarding the advanced electric drive system [4-10]. A detailed review of energy efficiency measures is carried out in the motor system [4]. The dynamic behavior analysis of a torque-controlled strategy is provided in a decoupling-controlled permanent magnet synchronous motor drive [7].

 

A variable speed drive (VSD) system is designed to measure the rotor speed and control the torque [10]. Although a considerable amount of research has been carried out regarding EVPT, little work is available about the integration of complete EVPT with basic components for EV applications. Moreover, developing speed and torque control according to the practical driver actions is quite crucial for the performance of EVs. To address these research challenges for EVs, advanced power electronics and control technologies will be used to design and implement EVPT according to the specifications of the already developed EV prototype at the School of Mechanical and Manufacturing Engineering (SMME), NUST. The following are the main components of EVPT.

 

1) Design of Electric Motor

The motor will be designed according to the requirements of an electric vehicle. The finite element method (FEM) based model will be built to properly design the motor according to the given ratings. By using FEM, an optimized geometry of the motor will be achieved that will efficiently perform in the electric vehicle at the desired operating conditions. Besides this, mathematical modeling will be carried out to compare its results with FEM model-based results. The optimized design parameters of the motor will be used to design the CAD model of the motor. Furthermore, the CNC machine will be utilized to manufacture the motor for EVPT according to the desired ratings

2) Advanced Drive Control System & Power Converter

A traction drive will be designed and developed which consists of inverters (DC/AC power converter), a pulse-width modulator (SVPWM), and a motor. The inverter will be driven at high switching frequencies up to 20 kHz by using the gate driver. A gate driver is a power amplifier that accepts a low-power input from a controller IC and produces a high-power drive input to the gate of a high-power transistor such as an IGBT. It provides isolation so that logic signal is not connected to a high voltage in the power. The traction drive will be supplied by the battery pack which is the main component of the battery management system. Besides this, the sensing mechanism will be established by using current, position, and voltage sensors. The current measurements are performed by means of Hall-effect current transducers. The current transducers are used for the measurement of currents with isolation between the primary circuit (high power) and the secondary circuit (low power). In addition to this, the incremental encoder will be utilized to measure the position in EVPT. As far as the controller implementation is concerned, a motor controller will be designed to implement flux vector control. The controller will be dynamically configured to drive the motor according to different parameters during the trips. The control algorithm will be digitally implemented using DSP controller boards to evaluate its performance for EVs. The proposed EVPT will effectively tackle various issues such as low-speed range, low acceleration rates, low traveled distance, low energy capacity, and low charging/discharging rates. The EVPT will provide fast torque and speed performance while also considering the flux saturation problem.