Summer 2019

Econtrols, Electrical Engineering Intern

 

Project Summary:

    As an Intern, my task was to design a hardware in loop (HIL) testing platform for upcoming battery management products. The stated major specifications were 1mV output accuracy on voltage outputs, 1mV ripple tolerance, voltage and current measurements, and scalability / flexibility of simulated cell configurations. The basis of the project was the simulated "cell" which was an isolated supply capable of 2-5V output range and up to 500mA current output. It was to be controlled through a hardware feedback loop which would allow for output voltages to be set accurately and controlled digitally from a master microcontroller on a chassis board. Each module board had 4 cells, and the chassis board had the capability to carry 10 modules. Unfortunately given the time of the internship a finished product was not completed. Power distribution and transmission to the isolated cells was achieved, but the output of the cells themselves was unstable and the feedback path needed tuning to be able to work around the response time of the adjustable LDO. digital measurement and control was left untested. Despite not coming to a completion, this project was a great learning experience for me because it taught me a lot about iterative design and reducing unknowns when creating a new product. As a whole the performance demanded of this project was ambitious, but necessary to produce viable test equipment. It would have been wiser to try and test each individual piece as a unit instead of all together in the end. I also learned a lot about PCB design as the cell boards came out as an 8 layer stackup. I was able to create an incredibly compact design with a lot of attention paid to keeping analog and high speed seperate, and creating isolation boundaries for the individual cells. I have carried a lot of what I've learned forward into my future designs, and have tried to focus my mindset more towards simplicity and mathematically backed solutions to ensure quicker success.

Chassis board (left) and module board (right) side by side

Chassis board with one module plugged in for testing

Summer 2020

Fiat Chrysler Automobiles, Propulsion Systems Intern

 

Project Summary:

    As an intern in the systems specifications team, my task was to show how virtual engineering tools could be used to increase the systems teams' autonomy when determining specifications for a powertrain. I was able to leverage my knowledge from previous experience and my course work to create a simulation tool which allowed the team to input system specifications for an electric drive and be able to make decisions about electrical system component sizing. The user is able to specify arbitrary loads such as HVAC or DCDC on the HV battery as well as a drive cycle schedule for the motor model to simulate realistic power draw conditions. The original motivation for this simulation was to help in specifying cable size by identifying power loss metrics in the cables over typical drive cycles. It was found that simple metrics such as nominal voltage drop over the cable were not representative of the performance and without more specific information could lead to excessive power loss and cable temperatures that melted insulation. The simulation was implemented in MATLAB and the system model was implemented as a system of ODEs. This setup allowed the simulation to be easily expanded by changing out or adding equations to the system. I also wrote a guide for adjusting to common system architectures like those with multiple motors or auxiliary loads and how arbitrary configuration could be achieved. Some other auxiliary functions of the simulation were a basic charge sustaining algorithm, a pre execution script which emulated a transmission controller to generate drive cycles, and adjacent scripts for determining best, worst, and average case system efficiencies.