A hybrid car combines an internal combustion engine with an electric motor and batteries. There are three main hybrid drivetrain designs: series, parallel, and series-parallel. A series hybrid is powered solely by the electric motor, while a parallel hybrid uses both the engine and motor. A series-parallel hybrid can switch between the two. The car's electrical system has a high-voltage system for propulsion and a low-voltage system for safety and controls. The high-voltage system includes the motor, controller, and lithium-ion battery packs. The low-voltage system operates safety devices like the shutdown buttons and brake sensors that cut power if issues arise. The shutdown circuit uses relays and switches to isolate the high-

1. PRESENTED BY :-
DIVYA KUMAR GUPTA

2. What does hybrid car mean ???
• It means that the vehicle combines a conventional internal
combustion engine (ICE) propulsion system with an electric
propulsion system.
• 3 possible drivetrains are possible in hybrid system :
 Series hybrid
 Parallel hybrid
 Series/Parallel hybrid

3. SERIES HYBRID
• In it, the electric motor is the only means of providing power
to get your wheels turning. The motor receives electric power
from either the battery pack or from a generator run by a
gasoline engine.

4. PARALLEL HYBRID
• With it both the engine and the electric motor generate the
power that drives the wheels.
• Parallel hybrids can use a smaller battery pack and therefore
rely mainly on regenerative braking to keep it recharged.

5. SERIES/PARALLEL HYBRID
• By combining both series and parallel designs, the engine can
both drive the wheels directly (as in the parallel drivetrain)
and be effectively disconnected from the wheels so that only
the electric motor powers the wheels (as in the series
drivetrain).

6. CAR’S ELECTRICAL SYSTEM
• The car's electrical system can be broken up into two major
parts :-
1. High Voltage System
2. Low Voltage System
--- LV System consist of shutdown circuit of car which
includes safety systems that help keep the driver and those
around the car free from harm.

7. HV SYSTEM
• The high voltage system includes the primary propulsion components of
the car, which consists mainly of the Motor, Controller and their
connection to the batteries.
• The motor is an Axial Flux permanent-magnet DC motor.
• For batteries two Lithium-ion "Z-force" packs are used. The
benefits of Lithium ion batteries include a low self-discharge
rate, high energy density, high power density, and a high level of safety.
• To give the driver control of the motor beyond “Off” and “Full Blast”, we
made use of a standard motor controller. The controller’s output is
manipulated by changing the resistance of an adjustable 0-5kOhm
resistor called the “Throttle Potentiometer”.
• The primary relays disable and enable current flow from the batteries to
the motor controller.

9. LV SYSTEM
• The low voltage system operates and controls many of the devices that
can shut down the car, as well as the indicator lights, brake light, and the
battery charger ventilation fan.
• To prevent damage to our Low Voltage system in case of a short circuit, we
used a standard 5A automotive blade fuse in a fuse holder.
• The next major part of the LV system is a chain of safety devices
connected in series, there safety devices are collectively referred
to as the “Safety Latch System”. This chain includes the Big Red
Buttons, the Brake Over-travel Switch, and the Dashboard Switch.
• The brake over-travel switch is triggered in case the brakes fail.
• For the sake of basic safety, our vehicle requires a generic LED brake light
to alert the drivers behind us that our vehicle is slowing down or stopping.

11. SHUTDOWN CIRCUIT
• The shutdown circuit consists of series of switches/relays in series with
the 24V supply which powers the HV contactors. When any of the
switches/relays is open along the 24V line the power supply to the
contactors is cut off and the discharge circuit is activated. Thus the HV
Battery is isolated and the tractive system is de-energized.

13. 1. INSULATION MONITORING DEVICE (IMD) :
It monitors the insulation resistance between the insulated and active HV-
conductors of the electrical drive system and the reference earth (vehicle
mass/chassis ground).
2. INERTIA SWITCH :
It shuts down the power to HV contactors upon vehicle
impact, reducing the risk of fire and electrical shock in
post-crash situations.
3. BRAKE SYSTEM PLAUSIBILITY DEVICE :
Brake plausibility device opens the power
supply to the contactors in case of
detection.

14. 4. MAIN MASTER SWITCH (TSMS) :
The Main Master Switch activates the BMS, and when all other switches are in
their normal positions it activates the pre - charge circuit and thus the HV system
is connected to the accumulator.
5. SHUTDOWN BUTTONS :
When any of the shutdown buttons is open the safety circuit is activated. The
switch is a push pull switch which opens when pushed.
6. BOT :
The brake over - travel switch is activated in the event of brake failure. The
switch is a push pull switch which opens when pushed.
7. HV DISCONNECT (HVD) :
It ensures the opening of the main contactors if the auxiliary contact is
opened. It disconnects both positive and negative wire between the accumulator
and motor controller.