Week 4 Session 5

The converters are devices used to convert the type of current (Alternating Current [AC] or Direct Current [DC]) or to step up or step down voltage from a high voltage device for a low voltage device used for a specific application. The major types of converters used in electric vehicles are -

1. AC to DC - Helps to convert AC to DC.
2. DC to AC - Helps to convert DC to AC.
3. DC to DC - Helps to step up or step down DC voltage from one system to another.

Electric vehicle is mostly made of low voltage equipments for example the infotainment systems, wipers, air conditioning circuits etc., and in order to use these devices a converter is needed to step up or step down or convert from AC to DC, DC to AC or DC to DC.

• For a Horn that requires less than 10V from high voltage requires a DC-DC converter called buck converter or buck-booster converter that helps to step down the voltage from High Voltage system to give 10V.
• Similarly, entertainment devices such as radio, indicator, wiper, tail lights, head lights, the HVAC (Heating, Ventilation and Air Conditioning) systems are all low-voltage devices that need a buck converter or buck booster converters to step down from high to low voltage values.
• The charging infrastucture in EVs need an AC to DC coverter. This because the current produced in the source to charge the vehicle is an Alternating Current (AC) and the energy stored in battery produces Direct Current (DC) which is why the current coming from the grid needs to be converted from AC to DC.
• The voltage coming from battery needs to be stepped up for the motor. Hence a booster or buck booster converter must be used to step up the voltage as they are high voltage devices.
• The motor works on AC, so the DC to AC convertor also known as the inverter must be implemented to provide an AC to the motor.

Reference - Overview of Power Electronic Converters in Electric Vehicle Applications | IEEE Conference Publication | IEEE Xplore