Description
ECE 438/538 Project 3
Due Friday 3/4, 11:59 PM
Recycle the BEV of your assignment from the last project and complete the following:
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1) Size the battery pack (i.e., number of series and number of parallel) for your vehicle using all 2.2 Ah Li- ion cells. Assume the nominal DC bus voltage about 400 V, the nominal battery cell voltage about 3.8 V, and the BOL range of 200 km.
2) Simulate the battery cell terminal voltage vs. SOC under 0.5C, 1C, 2C, 5C, for the given battery. This part has nothing to do with your particular vehicle choice.
3) Construct the efficiency map of the given battery at 0.8 SOC, with x-axis as motor RPM and y-axis as motor torque, using the same motor from Project 2. Assume power electronics at a constant 95% efficiency.
4) Now including all the losses from the battery, power electronics, and motor, what is the new range this designed battery pack from 1) can drive up to?
5) Suppose the battery pack from 1) starts from 0.9 SOC. What is the final SOC after one FTP drive cycle? How does the battery pack terminal voltage change over this drive cycle?
This project is total 40 points. Each calendar day late is 10% off the project grade.
For 1), you need to find the average vehicle power consumption rate in Wh/km. To do this, take the total motor energy consumption over the FTP drive cycle divided by the total distance watch for units. The distance is an integration of speed over time. For this step, assume ideal batteries and power electronics so that all the battery energy goes into the motor, which was already calculated from Project 2.
For 2), a baseline battery model is provided, see below Base Codes. The given battery Voc (open circuit voltage) and Rstat (series resistance) both depend on SOCs. You may use the command interp1() to interpolate the values based on the actual SOC. Note SOC is 1-DOD.
For 3), each motor RPM and torque combination requires a specific power from the battery pack. This battery power includes the motor power losses, so it is not simply torque times speed but should consider the motor efficiency calculated from Project 2. Then assume a 95% efficiency for the power electronics between the battery pack and the motor. Given the designed battery pack from 1) and the required power, you should be able to solve for the required current using the quadratic equation from class. Subsequently you can find the battery loss and efficiency at each of motors RPM/torque combinations.
For 4), you should be able to plot the required battery power and energy over the drive cycle. From there you can find the new Wh/km value.
For 5), the SOC should track the energy consumption already calculated in part 4), just to be normalized (0-100%). At each time stamp, the required battery power and the SOC will calculate the battery current and terminal voltage.
Base Codes
Base codes are available in Proj3.m. In this relatively more practical battery model, the internal resistance also depends on SOC instead of being constant. If you have a question about how the codes are written (e.g., syntax or special functions), use MATLAB help command or find answers on related Q&A forums online.
Submission Requirement
For question 1) in the Description above, plot the motors cumulative input energy consumption (Wh) vs. driving distance (km) over the FTP drive cycle. In the report, show basic math leading to the design of the battery pack, i.e., number of series and parallel cells.
For question 2), plot all four traces (0.5C, 1C, 2C, 5C) on one figure.
For question 3), plot the battery efficiency map. The battery efficiency map should be in similar format as the motor efficiency map (i.e., color bar, contour line, etc.). This time be sure to add the embedded numbers (90, 91, etc.) inside the contour lines so that it is obvious to tell the efficiency boundaries.
For question 4), plot the required battery power vs. time, and the required battery energy vs. distance. Show basic math leading to the new vehicle range.
For question 5), plot the SOC vs. time over the drive cycle, and the battery pack terminal voltage vs. time.
All of the above plots and math are to be pasted into one single document for submission. MATLAB figures are to be exported in .jpg or .png format before pasting into the document, i.e., no screenshots of the MATLAB scopes. For each plot, write a brief paragraph to describe what information you can extract from the figure. Does everything make sense? If there is discrepancy, what could be the possible causes?
On Canvas under Assignments Project 3, submit:
i) All plots and written paragraphs in a single .pdf document;
ii) All source codes .m individually.
Upload each file separately, NOT in a .zip folder. All files should be named in the format of LASTNAME_Firstname_xxx. xxx stands for a specific file name of your choice. If there is a main .m file, please clearly mark that in the file name. All models must be able to run by clicking the run button. Files are subject to plagiarism check against other students submissions, including this years and all previous years.
CS: assignmentchef QQ: 1823890830 Email: [email protected]
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