Week 4 Session 5

The 4 major types of power electronics converters are.

a)AC to AC

b)AC t DC

c)DC to DC

d)DCto AC

Out of these the most commonly used power electronic controllers are as follows,

AC to DC

These are also called rectifiers, It is widely used to convert the AC voltage to rectified DC voltage to charge the battery from an external power source. Depending on the application different type of AC DC converter is used.

Application

These are most commonly used in charging circuits where the power from the AC source is converted into equivalent DC.

DC to DC

It converts an unregulated DC voltage to a regulated and controlled DC voltage. It is most commonly used as voltage regulators and voltage translators in the charger setup in auxiliary loads connected to the system.

In an EV there is a large number of components and many of them will be working at different voltage levels. The battery is only able to provide a fixed voltage across its terminals, Therefor to provide a regulated power supply to the connected components a DC-DC converter is employed between the battery and the component.

Application

These types of converters are used to power horns and other auxiliary equipment that operates at different voltages. They are also used in the charging circuit.

DC-DC converters can be classified into 2

i) Isolated: In applications where the output needs to be completely isolated from the input, an isolated converter is necessary.

Eg-Half-Bridge, Full-Bridge, Fly-back, Forward, and Push-Pull DC/DC converters.

ii) Non- Isolated: It is used where the voltage needs to be stepped up or down by a relatively small ratio (less than 4:1). And where it is safe to have the input linked to the output.

Eg- Buck, boost, buck-boost, Cuk, and charge-pump converters.

DC to AC

These are commonly known as inverters. It is commonly used to power the ac motor of an electric vehicle. It also acts as a motor controller.

Application

This type of converter is used in EVs that run on induction motors. Here the DC power from the battery is converted to AC by the inverter and is supplied to the induction motor.