Challenge

Week 2 Session 7

Q. Compare the different architectures of HEV. Discuss the pro's and con's.

----> HEV stands for Hybrid Electric Vehicle. Different architectures of HEV are Series, Parallel & Sereis-Parallel.

1. Sereis HEV

It has 2 energy source components in sereis to drive the transmission i.e. Motor and ICE.
In Battery Mode : Energy flow is from Battery --> Power Converter --> Motor --> Transmission.
In ICE Mode : Energy flow is from Fuel tank --> ICE --> Generator --> Power Converter --> Motor --> Transmission.
Only Electric Motor is connected with the transmission.

Advantages :

- ICE can be operated in optimal narrow region, hence better efficiency.

- As motor directly drives the transmission, no need of multi-gear transmission box.

Disadvantages :

- Involves dual energy conversion i.e. from mechanical to electrical and from electrical to mechanical again, thus offers low overall efficiency .

- Space and weight constraints as a extra generator is required, thus increases cost as well.

2. Parallel HEV

It has 2 energy source components in parallel to each other i.e. Motor and ICE.
Motor and ICE are coupled to transmission via a coupler like DCT (Dual Clutch Transmission).
In Battery mode : Energy flow is from Battery --> Power Converter --> Electric Motor --> Coupler --> Transmission.
In ICE mode : Energy flow is from Fuel Tank --> ICE engine --> Coupler --> Transmission.
In Hybrid mode : Energy is balanced between ICE and Motor.
Advantages :

- No energy conversion involved, hence more overall efficiency.

- Compact design due to absence of generator.

- Reduction in size of traction motor due to less vehicle weight.
Disadvantages :

- ICE cannot be just operated in narrow optimal range.

- Complex operation due to DCT and coupler.

3. Series - Parallel HEV

It is a combination of both Series HEV and Parallel HEV architecture.
Both Motor and ICE are connected individually to the transmission.
The engine can both drive the vehicle directly (as in parallel HEV) and be effectively disconnected, with only the motor providing power (as in series HEV).
Battery can also be charged from the ICE extra power via a generator.

Advantages :

- With fuel-only and electric-only options, the engine operates at near optimum efficiency.

- At lower speed it operates with motor and at high speed it operates with ICE, thus minimising the loss at high speed in series HEV.

Disadvantages : - High cost as it requires a generator and a larger battery pack.

Ship work like this
in your own course.