Final Post - End of Research

      It's hard to believe my REU is nearly over! I have a few more meetings today, and then a poster show tomorrow (see my poster at the end of this post!). My research has gone pretty well though, and I'm excited to present it.

      My project this summer was modelling a new pressure-controlled, hydro-mechanical transmission (PCHMT) for mid-size wind turbines in Simulink. I optimized and configured the transmission, and then examined its operation over several different wind speeds. I found that the best configuration using commercially available components looked like this:

     The planetary gears were sized to have a ratio of 1:16, the variable pump was sized to 110 cc/rev, and the pressure-controlled transmission (PCT) -- the motor-like component on the right -- was sized to 63 cc/rev. The PCHMT's core component is this PCT, which is basically a more efficient compact hydrostatic transmission (pump connected to motor) based on a vane pump with a floating ring at the output shaft.
     The PCT makes the system highly efficient - the transmission's efficiency was about 80% for wind speeds of 5 m/s to 11 m/s. This means that the PCHMT is a pretty good alternative to traditional mechanical gearboxes for wind turbines: it is efficient, as well as compact, reliable, less expensive to maintain, and commercially available (like all hydraulic transmissions for mid-size turbines).

      While I met my goal of  having efficiency data from an optimized system, I had hoped to compare it to similar data from other hydraulic transmissions (hydrostatic, a different hydro-mechanical). However, I did not have time to complete a dynamic simulation (one where the wind speed changes during simulation, to model real-life wind turbulence), so I could not compare my data to the other transmissions that were previously modeled with turbulence included. However, I hope that other researchers on my team will be able to use my Simulink model to complete a dynamic simulation with little trouble and empirically compare the PCHMT to other transmission options.

     Aside from my simulation's results, I gained both knowledge and experience this summer that I believe will help me as I start my career. My new knowledge about wind turbines should be very helpful, since I'm considering renewable energy (specifically wind turbines or solar panels) as a career focus. Also, I'm sure that my new skills and familiarity with Matlab and Simulink will come in handy in both my future schooling and career. Modelling and simulations are important in a lot of engineering, so I think I can apply the skills from this summer to a variety of projects.

     If there was one thing I wished I had done differently during my REU, I would have to say I wish I had made more effort to be in contact with my post-doc mentor. While working out problems on my own improved my understanding of the system and familiarity with Matlab, I feel like I could have worked more efficiently if I had asked my post-doc for help sooner. I guess this would be my advice to future REU's: your grad student mentor is there to help you learn - while you shouldn't be utterly dependent on them for problem-solving, they usually have great advice and knowledge that will move your project along more quickly.

      Overall, I had a great time this summer while learning about renewable energy, gaining simulation skills, and generally enjoying the Twin Cities in the summer. I hope everyone's research went as well as mine, and I'm looking forward to reading about your projects!

Best wishes everyone,
Hannah