Week 9 Challenge

Complete the energy management strategy model with battery, UC and fuel cell for the positive power and distribute the power demand among these components. Set simulation stop time to 598 sec.

The output of the model should be the power request from UC, fuel cell and battery.

Let us assume some conditions for the UC, Battery, and FC

Power demand	Conditions	Source
0-9999	if UC-SoC > 35% If UC-SoC < 35%	UC FC
10000 - 29999	if Battery-SoC > 35% if Battery-SoC < 35%	Battery FC
23000 - 54999	No condition	FC
55000 and above	if UC-SoC > 35% if UC-SoC < 35%	UC FC

According to these conditions, the Energy Management strategy is designed.

Simulation:

Power demand:

In practical cases, the power demand is given by the driver block, and the powertrain block is designed by using the equation. but here there are no such blocks are there so we need to create a replica of that demand. It is designed by using the Signal block

Note that the simulation is done only for the Positive power demand because, for negative power demand, the Regeneration will take place, in that case, the SoC of UC and Battery will change it will be complicated to design in the same model. If the total vehicle model is done it will change automatically because then we will supply the SoC of Battery and UC from the Battery and UC model so this disadvantage will be eliminated.

Mode-1: Ultra Capacitor Mode

Step - 1:

When the power is between 0 and 9999 and UC_SoC is > 35%

UC_lower_power

It is designed in such a way that when both the conditions i.e, Power and SoC conditions are true, it will use the UC power in output otherwise it will give the 0 as output.

Step - 2:

When the power is between the 55000 and above and UC_SoC is > 35%

It is designed in such a way that when both the conditions i.e, Power and SoC conditions are true, it will show the UC power in output otherwise it will give the 0 as output.

Step-3:

Both step-1 and step-2 should be added to get the resultant UC output. Both conditions never going to be true at a time so Adding will not affect the output.

Step-4:

FC_backup calculation: There is a condition that the power range is in between 0 - 9999 or 55000 and above but the UC_SoC i< 35%. In that case, we need to use the FC power even though it is efficient. For that condition, the logic is designed as shown below

Mode-2: Battery Mode

Step-5:

When the power is between 10000 and 22999 and Battery_SoC is > 35%

It is designed in such a way that when both the conditions i.e, Power and SoC conditions are true, it will use the Battery power in output otherwise it will give the 0 as output.

Step-6:

When the condition power is in battery range but the battery SoC is < 35%, in that case, we need to use the FC power even though it is in efficient. For that, we need FC backup calculation in the battery

Mode-3: FC mode

Step - 7:

When the power is between 23000 to 54999 and not working under any SoC conditions we need to use the FC power for the output. Its design is shown below

Step-8:

For the FC mode, we need to add the step-7, 6, and 4 to get the resultant FC power usage. In practice never all the 3 conditions are not going to be true so adding them will not affect the output. And adding all the Energy sources we can see the resultant output which will match the power demand.

Results:

To test all the conditions we need to try all the contions which will result in 4 conditions based on the UC and battery SoC and the FC has no conditions it is going to act all the time when the condition is met.

The conditions are

	UC_SoC	Battery SoC
Case-1	> 35% (use UC)	>35% (use Battery)
Case-2	>35% (use UC)	<35% (use FC)
Case-3	<35% (use FC)	>35% (use Battery)
Case-4	<35% (use FC)	<35% (use FC)

Case - 1

SOC_UC = 0.5

SOC_Batt = 0.5

UC_power sharing:

Battery Power sharing:

FC power sharing:

Battery and UC backup power by FC is zero because the SoC of both the UC and Battery are above its min value i.e., < 35% which is 50%

Resultant total output power:

Case-2:

SOC_UC = 0.5

SOC_Batt = 0.2

UC power-sharing

Battery power sharing: it shows zero as the soc < 35% which is 20%

FC power sharing:

Battery backup power by FC

Toatl FC Power:

Conclusion:

Here we have simulated the energy management system for an electric vehicle. As per the power demand, the vehicle will shift the requirement which will be the most efficient ( battery, FC, or UC). In the results shown above we can observe that when the power demand is upto 23000w the vehicle will run on battery when the power demand is in between 23000w to 55000w, it will run on FC and when it is beyond 55000w it will run on ultracapacitor. We can observe that the Energy management is working according to the conditions we assumed.