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.

Sln..

The vehicle industry is experiencing technological revolution in the power train of vehicles A hybrid electric vehicle is an effective choice to solve the problems of the low enegry density of a power battery and the short driving distance of an electric vehicle (EV)

Different congiguration of HEV's have different control strategies production costs and applicable conditions

However for any configuration the ultimate goal is to achieve the comprehensive optimization of the efficiency of the engine and the motor as to improve the vehicles performance parameters such as economy, emissionsm and durability

The procedure of realizing the goal is commonly calles an EMS

The act of load sharing is mainly implemented through the EMS system according to the power demand of vehicle the power request from sources distributed among the different enegry giving

Process Flow of EMS:

Before creating the simulink model of EMS the process flow of power sharing mechanism was implemented in a flow chart

Power sharing :

The fuel cells having range of operating condition to produce the power needed for propulsion

Here we are taking fuel with have capability to produce power in the range of min 23KW to max 72KW but for better efficiency of fuel cell power usage it is derived that fuel cells will operate at max efficiency in moderate power generation area as seen from polarization curve

Thus we are considering lesser power production level for max fuel cell power generation as 55 KW

MODEL:

Here from the model we see that

Inpur of the model is power demand KW which can be provided by the power train of the vehicle as loas power demand to move vehicle

The output of the model is the power request to fuel cell, ultracapacitor and battery to get powerdrain and charge during regeneration

Construction and Working

Above mentioned flowchart we can start to build model

Initially power demand values from power train was given as input for simplicity we had given using a signal builder block. The values are uploaded from an excel file as power with respect to time

The uploaded power demand signal is shown as below.

From this power demand signal we can see that there is positive power demand as proplusion power demand and negative power demand as power generated during regeneration to charge battery or ultracapacitor

The fuell cell doesn't accept the regenerated power as fuel cell are operate only in proplusion mode

The condition of state fo charge at a particular time of ultracapacitor and battery are given in a constant block as shown in model and given to goto blocks using it subsystem

The maximum and min values of SOC of battery and ultracapacitor are given in workspace as shown below.

The max SOC values of UC and Battery are given as 90%

The min SOC values of UC and Battery are given as 30%

STEP-2

The power demand values are sorted into positive power demand as shown below.

The positive power is given as input for proplusion power subsystem and negative power is given to regenration subsystem.

STEP-3

Propulsion power subsystem:

In propulsion subsystem the power demand is tested for three components UC Fuel cell and Battery based on thier operating range using interval test block as shown below

For fuel cell test operating range set as from above 23KW to 55 KW

If the condition is true when the output of this block is 1 This output is checked with swith block as input where if the input if 1 then this positive poer id considred as fuel cell power request

For ultracapacitor test operating range set as from above 55KW

If the condition is true then the output of this block is 1 This output is checked with switch block as input where if the input is 1 then this positive power is again checked for UC_Soc condition

if the SOC of UC is >=its minimum value then this positive power is considered as ultracapacitor power request

For battery test operating range set as from 0 to 23KW

If the condition is true then the output of this block is 1 This ouput is checked with a switch block as input where if the input is 1 then this positive power is again checked for battery SOC condition

if the SOC of battery is>= its min values then this positive power is considered as battery power request

STEP-4

But during ultracapacitor and battery fail conditions as less than thier min SOC values we have to shift its power request to primary source of fuel cell

These Operations are modelled as below.

Ultracapacitor fall subsystem:

This subsystem consisit of logic conditions as shown below.

In this subsystem the SOC of UC is checked as a Fail condition using switch block to give as output 1 and 0 for true condition

the UC test result is again checked with a switch block as it is true for set on only both signals are true

final output from AND is checked in a switch block if output is 1 this positive power input is consider as battery backup source when Bat_SOC> Min, values as shown above as from outport 1.

UC and Battery fall condition:

if both the SOC of UC and battery are less than thier min values in this stage the power drawn source is shifted to fuel cell

This operation is implemented in this subsystem as shown below.

Intially the SOC's of UC battery are checked for FAIL Conditions using switch block to give as output 1 and 0 for true condition.

These two signals are given to an AND block as both the values should get failed to get output as 1 from this AND block

Then the battery test result and UC test results are again checked with switch blockd for their TRUE stated as for 0-23KW and above 55KW operating conditions

These signals are given to OR block to get output 1 as even any one condition is true output is TRUE

The signals form AND block and OR block are given to another AND1 block. The result is 1if both the signals are true

Final output from AND1 is checked for true condition if output is 1 then the Positive power is considered as fuel cell backup power as shown in model

Addition of Powers:

The Power output From FC test and backup FC Power are added to get final propulsion FC Power

* The power output from UC_test as final propulsion UC Power

Step 5:

Regenration Power subsystem:

It was checked for UC_SOC>UC_Battery with the swicth block if the condition is False (O) then the negative power demand is passes as output from the switch 4.

Then if UC_SOC== Bat_SOC was checked, a half of the negative power is given as UC a charge power and if fails the ouput form switch 4 is given as UC charge power.

This battery charge power was checked in a switch 3 as if Bat_SOC>90% charging will not occur and if condition fails this battery charge power from switch 2 is considered as final battery charging power.

it was checked for UC_SOC>UC_battery with this switch block if the condition if False (0) then the negative power demand is passes as output from the switch 4.

This UC charge power was checked in a switch 6 as if UC_SOC>90% Charging will not occur and if condition fails this UC charge power from switch 5 is considered as final UC charging power.

Step6:

Addition of Powers:-

The regenerative UC_Power and final UC Propulsion power are added to get final output UC Power request

the regenerative Battery power and final battery proplusiom power are added to get final output battery power request

The final proplusion power as final output FC Power request

Results:

Running the simulation fo 598 Sec and results are as follow.

Case 1: UC_Soc> Bat_SOC condition-

From the above plots we can understand that according to the power demand Values the power request shared to different sources as UC Power, Battery power and FC Power based of thier.

Operating Regions:

The Power demand above 23KW is achieved by Fuel cell above 55Kw is acheived by Ultracapacitor and 0-23KW from battery Source as seen from plots.

And also as UC_SOC is greater than Bat_Soc the charging power is shifted to battery to charge first rather than Ultracapacitor This can be verified as Charging is occuring in Battery Power plot alone and not in UC Power Plot.

Case 5: UC_SOC<Min Values and Bat_SOC

In this situation both UC and Battery power required are satisfied by Fuel cell alone as seen from plots.

The load is fully delivered to fuel cell alone due to this the efficiency of vehicle gets gradually decrease

Both UC and Battery are fails to operate and gets charge equally as both having eual SOC of 25%

CONCLUSION: Assignment Successfully Submitted.

Thank you..