Control By Design

Overview

A motorcycle voltage regulator takes the output of a permanent magnet AC generator (ACG) and converts it to a constant DC voltage to supply the vehicle's electrical system and charge its battery.

In 2013, we designed a 'Series Type' regulator that saves fuel and reduces the vehicle's emissions. It went into production in 2014, has been installed on over 250k scooters in TW and is still in production today (2026).

Shunt (Closed) Type Regulator

The most common type of motorcycle regulator is a 'Shunt Type'. This type of regulator is cheap and easy to produce, but suffers from inefficiency.

The shunt (or closed) type regulator is based on switches placed in parallel to the generator. It regulates by shorting (shunting) the generator terminals to limit power transfer to the load. This is wasteful regulation because, during the shorting, high current flows in the generator and switches, causing power to be dissipated in the regulator switches and generator windings and an undesired braking effect on the engine. In short, with a shunt regulator the engine is always loaded by the generator, regardless of the electrical load.

This energy waste causes higher fuel consumption, higher emissions, and decreased performance. The rider's cost of ownership is higher over the life time of the motorbike.

Series (Open) Type Regulator

The series (or open) type regulator has switches placed in series between the generator and load. It regulates by disconnecting the generator from the load. This off loads the generator and avoids the power loss. In short, with a series regulator the engine load is proportional to the electrical load. If the electrical load is low, the engine load is low, and the regulator runs cool.

Smart Series Regulator; SSR

The SSR features a microprocessor control system to achieve the series regulation technique. This allowed us to implement features that are unique to our regulator from all the different regulators we have seen. Smart temperature monitoring systems ensure that the regulator will never overheat and burn up. Starting is improved because the SSR detects and waits for stable idle before applying load to the engine. The processor is constantly monitoring the status of the bike and keeping a precise control on the voltage levels and charge.

Development photos