Research Projects

The proposed research focuses on developing a permanent magnet (PM) machine with mechanical flux-weakening (MFW) capability for electric vehicles (EVs). PM motors are preferred for EVs due to their high torque density and efficiency. To balance cost and compactness, these motors are typically driven by an inverter with a fixed dc-link voltage. Beyond the rated speed, PM machines require flux-weakening to operate effectively under this constraint. Electrical flux-weakening (EFW) methods achieve this by injecting opposing currents into the motor, but they suffer from drawbacks such as increased copper losses, reduced power factor at high speeds, risks of PM demagnetization, and complex control requirements. MFW, by contrast, manipulates the PM flux-path physically, offering higher efficiency and simpler control by eliminating reliance on the inverter. MFW strategies shunt the PM flux through mechanical means, with an actuator driving this mechanism. However, the actuator must counter restoring forces, raising concerns about its energy consumption. Despite their potential, MFW designs remain largely conceptual, with limited drive-cycle-based evaluations and inadequate comparative frameworks for assessing MFW against EFW techniques. There is an urgent need for focused studies addressing these gaps, especially in India, where awareness and expertise in MFW are limited. This project addresses these challenges through four structured phases: screening/identification, design iteration, detailed analysis, and development/testing. Screening Phase: Promising MFW motor topologies will be identified using a comparative framework integrating motor, inverter, and actuator considerations. Analytical techniques will assess motor performance and actuator energy requirements. Design Iteration Phase: Selected designs will undergo refinement using Finite Element Analysis (FEA) to simulate electromagnetic behaviors and evaluate actuator integration. Variations such as rotor/stator skewing and flux shunt placement will be explored. Detailed Analysis Phase: A script-based simulation model will be developed for drive-cycle evaluations, using data from FEA to simulate real-world motor behavior. The model will be created in an open-source platform to ensure accessibility. Development and Testing Phase: A proof-of-concept prototype will be created, initially through re-purposing existing motors to demonstrate feasibility. Static and dynamic testing will validate the design, refining models iteratively. Expected outcomes include a framework for evaluating MFW and EFW techniques, indigenous motor designs for EVs, and a trained workforce in advanced electric machine design. This project will advance India’s self-reliance in EV technology, foster innovation, and generate intellectual property while contributing to academic curricula.