1. Energy Management of a Series
Hybrid Electric Powertrain System
(EMoSHEPS)
By: Saifuddin Abdul Halim (Mech Eng MEng)
Project Supervisor: Dr Saber Fallah

2. Introduction
 Why Hybrid?
• Due to the increasing vehicle emissions, researchers and vehicle manufacturers
resorted to develop electric vehicle as an alternative.
• Disadvantages of EV results in the introduction of hybrid vehicle.

3.  Why series HEV?
• Equivalent Consumption Minimization Strategy (ECMS) was originally
introduced by Paganelli et al., in 2002 for parallel configuration.
• Series HEV has a huge potential due to the downsizing of the engine as well
other factors such as the removal of gearbox, simplifying the configuration
reducing vehicle mass.
• Beneficial for urban-driving cycle.

4.  What is ECMS?
• The basis of ECMS is that discharging of power from the battery at any instant
will results in equivalent fuel being consumed by the ICE to recharge the
in the future and vice versa.
• ECMS reduces the overall fuel consumption by minimizing the total equivalent
fuel consumption.
• The total fuel consumption is the sum of fuel consumed by the ICE to drive
motor via generator and the fuel consumed to recharge the battery.
𝐺𝑡 = ṁ𝐼𝐶𝐸 𝑃𝐼𝐶𝐸,𝑑𝑒𝑚 𝑡 + ṁ 𝐵𝑎𝑡𝑡,𝑒𝑞 𝑃𝐵𝑎𝑡𝑡 𝑡
𝑃𝐼𝐶𝐸,𝑑𝑒𝑚 𝑡 =
𝑃𝐼𝐶𝐸,𝑑𝑟𝑖𝑣𝑒(𝑡)
𝜂 𝑔𝑒𝑛
+ 𝑆𝑐ℎ𝑔 𝜂 𝑔𝑒𝑛 𝜂 𝐵𝑎𝑡𝑡 𝑃𝐼𝐶𝐸,𝑟𝑒𝑐ℎ𝑔(𝑡)
ṁ 𝐵𝑎𝑡𝑡,𝑒𝑞(𝑡) =
𝑆 𝑑𝑖𝑠 𝑃𝐵𝑎𝑡𝑡
𝜂 𝐵𝑎𝑡𝑡 𝐻𝐿𝐻𝑉

5.  Disadvantages
• Tendency of significant power source variation that leads to dramatic wheel-torque
oscillation.
• Possibility of delayed and hesitation of torque response / poor throttle response.
• In series HEV, these problems can be reduced due to having only one type of energy,
electrical energy, supplied to the EM and since the ICE is decoupled from the driving the
wheels.

6. Objectives
 Modelling a conventional and a series hybrid powertrain.
 Identifying and applying basic operating conditions.
 To simulate the Equivalent Consumption Minimization Strategy (ECMS) control strategy.
 Carrying out forward simulations for both models under two different driving conditions.
 Comparing fuel economy as well as the velocity performance of both vehicles.
 Optimizing the ECMS parameters to achieve a minimum of 15% reduction in fuel
consumption.

7. Modelling
 Model of Series HEV

8.  Model of Conventional vehicle

9.  ECMS controller & power distribution
Driver
determines current
angular speed
Accelerate
Decelerate
Increase in Angular Speed
Decrease in Angular Speed
Determine corresponding
torque demand at EM via
characteristic curves;
+ve for driving or -ve for RBS
Calculation of Power
demand, P(dem);
+ve for driving or
-ve for RBS
Negative Power
(RBS)
Positive Power
(Driving)
SoC
P(ICE,opt)=P(maxICE)
P(Battery,opt)=0
P(ICE,rchg)=0
P(ICE,opt)=P(dem)
P(Battery,opt)=0
P(ICE,rchg)=P(maxICE)-P(dem)
P(demand,EM)=P(ICE)+P(Battery) P(demand,EM) = P(Battery)
P(ICE,opt)=0
P(Battery,opt)=0
P(ICE,rchg)=0
P(EM,rchg)=P(dem)
SoC ≥ SoC (max)SoC ≤ SoC (min) SoC (min) < SoC < SoC (max)
P(dem)>P(maxICE) P(dem)<P(maxICE)
Fuel
consumption
Determination of Fuel
Consumption using ICE fuel
flow map
Calculation of
torque
supplied to
drivetrain
Drivetrain
Transmission
system
Vehicle
velocity
Wheels

11. Simulation
 Driving conditions

12.  Change in equivalency factor
 The performance evaluated
• Overall fuel consumption at the end of the drive.
• Velocity trend of the vehicle.
Equivalency Factor, 𝑺 𝒅𝒊𝒔
1.125 (-10%)
1.250
1.375 (+10%)

13. Results
 Cruising mode
Series HEV Conventional
Fuel consumption 0.989 1.199
Max Velocity 92.5 79.0
Improvement in fuel
consumption (%)
17.5 N/A

14.  Random driving mode
Series HEV Conventional
Fuel consumption 0.699 0.975
Max Velocity 113.5 159.7
Improvement in fuel
consumption (%)
28.3 N/A

15.  Change in equivalency factor, Sdis
Equivalency Factor, 𝑺 𝒅𝒊𝒔
Total Fuel Consumption (L)
Cruising mode Random Driving mode
1.125 (-10%) 0.985 0.685
1.250 0.989 0.699
1.375 (+10%) 0.991 0.711
N/A 1.199 0.975

16. Conclusion
 The implementation of ECMS in series HEV managed to reduce fuel consumption up to
17.5% than the conventional vehicle under cruising mode and up to 28.3% under
cruising mode.
 Although fuel consumption is reduced, but the downsizing of engine in series HEV
means that the benefit is achieved at the expense of vehicle velocity.
 ECMS controller also able to adapt to change in its own parameter.
 In addition, the benefits of the ECMS are also transferable between configurations and
also driving conditions.