The Waterloop team from the University of Waterloo is aiming to build the technologies to prove that supersonic vacuum tube transportation is possible. They will be competing in the next SpaceEx Hyperloop competition and are planning to demonstrate a full-scale Hyperloop by 2025. Powersim is a proud sponsor of the team and provides a full PSIM license to them for the development of a high-speed linear induction motor as well as the motor controller board. Jason Wu is the motor control lead of the team and summarizes their work progress so far and how PSIM helped them to get there.
For students at the University of Waterloo, the most valuable learning opportunities are not just found in the classroom. To Jason Wu, joining Team Waterloop introduced him to the vast world of power electronics engineering.
“I joined Waterloop because I wanted to grow my abilities in power electronics specifically, and in motor control,” Jason notes. “The school doesn’t teach you these things until the fourth year, and sometimes exclusively to Master’s students. Being at Waterloop, I was able to expose myself to high-level topics very early.”
Jason, who is currently completing his third year of Electrical Engineering at Waterloo, first joined Waterloop during his second year as a member of the motor control team. Today, he is the motor control lead, taking a hands-on role in the team’s progress of their latest Hyperloop pod: Goose 5. Yet within months of taking the helm as team lead, an unexpected complication arose. As buildings and labs on the Waterloo campus shut down due to COVID-19, the team had to rely on other tools to ensure progress was being made.
“The only way for the motor control team to make progress on the project was to simulate our designs in the software,” Jason explains. “PSIM allowed us to do that.”
PSIM is a software application that simulates electrical circuits. Through a graphical user interface, users can set up their system to simulate various parameters, then analyze their behavior through the Simview application. The software’s uses span fields such as control theory, motor design, and photovoltaics. Using PSIM’s simulation functionalities, the team was able to test various configurations and designs of their motor controller.
A proof-of-concept motor controller was designed from the ground up, and a second version featuring isolation will soon begin manufacturing. During the pandemic lockdown period, PSIM simulations allowed the team to continue the research and development of the controller, despite a lack of access to testing equipment.
“PSIM has a dedicated induction motor module. We are able to just fill in the values from the mechanical team and simulate the circuit,” says Jason. “PSIM had a lot of amazing example circuits in their software. By following the examples, we learned how to properly design a motor controller.”
PSIM excels in performance speed, features a large library of components, and provides excellent customer service, allowing the software to easily outperform other options. As remote working continues, the team knows that they can rely on PSIM to bring Goose 5 closer to completion.
See Jason’s notes on his use of PSIM below:
This is one of many circuit simulations we have done for the motor controller
Our goal during the Spring term was to find out the component ratings, such as voltage, current, and power ratings, so we could source the appropriate components.
In figure 1, I built a simple full-bridge IGBT inverter with inductive load at the output. The components are ideal, so we could find out the absolute maximum requirements of the components.
Figure 2 shows the simulation result of the circuit. With a 500V input DC rating, we need the IGBTs to handle at least 80A peak to peak given the load. We added an extra 25% margin on the ratings to adjust for errors.
We got the required induction motor specifications from the mechanical team, with PSIM’s included induction motor module, we were able to simulate the controller in open-loop design in figure 3.
Figure 4 shows the open-loop simulation result. The main issues here are the large current overshoot and the high negative slip value. We realized we needed a closed-loop design to overcome these issues.
We have not learned about closed-loop design for 3-phase induction motors. Fortunately, PSIM included many great induction motor controller examples. We used one of the examples as a foundation and improved our design. Figure 5 shows the closed-loop design of our system. The example control circuit introduced us to the abc-dqo transformation, and we were able to adjust the PI controller values to achieve the desired transient and steady-state response. Figure 6 shows the simulation result of the closed-loop design. We were able to suppress the high transient current and a steady slip value.