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On two wheelers, magneto/alternator generates either single/three phase AC power and Regulator Rectifier Unit (RRU) does regulated rectification to charge the battery. In order to face the requirements of 2-wheeler engine with respect to upcoming stringent regulations like electronic fuel injection (EFI), anti-lock braking system (ABS), automatic headlamp on (AHO) in emerging markets like India; vehicles demand more electrical power from batteries. This demands higher power from alternator and consequently from RRU. Requirement of higher output power presents challenges on regulator rectifier unit in terms of size, power dissipation management and reliability. In this paper, improved performance of MOSFET based RRU is discussed in comparison to Silicon Controlled Rectifier (SCR) based RRU. The motivation/benefits of MOSFET based design is described along with the thermal behavior and temperature coefficient performance of RRU with test results.

Emerging markets like India is very cost sensitive for small engines like motorcycle. Capacitive discharge Ignition (CDI) with carburetor is popular low cost solution with good engine performance. CDI system accumulates charge inside the ignition capacitor, until a point at which a signal allows to release discharge of the stored charge to the spark plug through high tension coil. This paper will focus on single spark digital two teeth DC CDI solution and below design challenges with two sparks. 1 Higher power dissipation in step up fly back converter 2 Need higher CPU speed, flash size and restrictions on engine map profile for advance angles This paper will elaborate above problems and their solutions with test results for optimizing solution cost and achieve performance. Solutions include, exploring 8 bit microcontroller peripherals usage and smart software to boost MCU performance for engine dynamic conditions and to achieve lower losses in flyback converter.