Week 4 Session 5

DC-DC Converter :

1. Horn:

As mentioned, the horn typically requires a DC power supply with a voltage of less than 10V.

A DC-DC converter can be used to step down the high-voltage DC supply from the vehicle's battery (typically 200- 400V) or from the auxillary battery (12V-24V) to the lower voltage required by the horn

2. Lighting and Sound Systems :

Electric vehicles require various lighting systems, including headlights, taillights, and interior lights.

Power converters are used to convert the auxillary battery's DC power (12V-24V) to the appropriate voltage and current levels (either step up or step down) for powering these lighting systems (13-14V).

AC-DC Converter :

1. On-Board Charger :

Electric vehicles require a means to recharge their batteries from an external power source.

An on-board charger, also known as a battery charger, is responsible for converting AC power (200-230V) from the charging station or power grid to DC power (200-400V) suitable for charging the vehicle's battery.

It incorporates AC-DC conversion and power factor correction (PFC) techniques to efficiently convert the AC power into the required DC voltage and current.

2. Main and auxillary battery charging:

When braking is applied, through regenertive operation kinetic energy of vehicle is converted into electrical energy.

Thus this AC power (200-230V) from the generator is converted into DC power with the help of power converter to recharge the battery (200-400V) or auxillary battery (12-24V).

DC - AC Converter :

1. HVAC System:

The heating, ventilation, and air conditioning (HVAC) system in an electric vehicle requires power for its operation.

Power converters are used to convert the DC power (12V) from the auxillary battery to AC power (230V) for driving the HVAC compressor and fans.

2. Motor Drive Inverter:

The motor drive inverter is a critical component in an electric vehicle's propulsion system.

It converts DC power (200-400V) from the battery into AC power (230V) to drive the electric motor.

By controlling the frequency, voltage, and current of the output, the inverter enables precise control of the motor's speed, torque, and direction.

3. Power Steering Converter:

Electric power steering (EPS) systems assist the driver in steering the vehicle.

A power converter is employed to provide the required power to the EPS motor, which adjusts the steering assistance based on driver input and vehicle conditions.

It converts DC power (12V) from the auxillary battery into AC/DC power (230V/12V) to drive the electric motor in the power steering.

List of the main electric vehicle auxiliaries :

Subsystem	Operation mode	Power (W)
Air-conditioner	Continuous	500
Audio	Continuous	35
Driving control	Continuous	150
Energy management system	Continuous	150
Head and tail lamps	Continuous	120
Parking, turn and interior lamps	Intermittent	50
Horn	Intermittent	10
Power steering	Continuous	400
Power windows	Intermittent	80
Window defroster	Continuous	250
Wipers	Continuous	40