Abstract
The objective of this paper is to put forth a method of developing a mild hybrid system in a two wheeler. The Mild hybrid system also known as Integrated Starter Generator (ISG) is a single controlled machine that seeks to replace the starter and magneto in modern day two wheelers. The ISG, mounted directly on the crankshaft is capable of offering four modes of operation, namely, starting, generation, torque assist and regeneration. A three phase Permanent Magnet Synchronous machine is fit directly on the engine shaft in place of the existing flywheel magneto. A three phase MOSFET inverter circuit provides a trapezoidal excitation to operate the machine as a motor. As soon as the engine cranks and reaches its idling speed the machine is made to function as a generator with the inverter circuit also performing the function of a rectifier. A series switch is used to regulate the voltage to the desired setpoint. Torque assist is achieved by providing a boosted voltage input to the machine when the engine is running. Regeneration is achieved in a similar fashion as generation. The controlled BLDC machine also facilitates the employment of Idling stop start functionality that helps bring down idling losses.