Chawthri Kanagarasa

Waterloop is a student design team at the University of Waterloo, aiming to develop a full-scale Hyperloop prototype by 2025. The team’s vision is to demonstrate the feasibility of intracontinental high-speed ground transportation using the Hyperloop architecture.

Powersim sponsors Waterloop by providing a full PSIM license which is mainly being used to help members understand the functionality of power electronics, specifically, motor controller boards.

“Due to COVID-19 and the team having to work remotely, PSIM has been extremely useful in testing the control theory and motor controller configurations.”

“As we prepare to compete in the 2022 Hyperloop competition which will be hosted by the Canadian Hyperloop Conference in Waterloo, Ontario, PSIM has become a vital tool in the development of our current and even future editions of the motor controller. Waterloop is highly motivated to compete and succeed in this competition as we inch closer to our goal of changing the landscape of transportation starting within Canada and then soon the world over. We strongly believe that having these annual competitions will push us to our limits as we develop the transportation method of the future.”

Chawthri Kanagarasa, who is currently completing his fourth year in Physics and has been the electrical team’s technical advisor since January 2020, believes that PSIM’s code generation tool was incredibly helpful with getting the controller design from simulation onto a microcontroller. PSIM was a useful tool in solidifying his understanding of motor controller design.

Chawthri says, “being able to see the effects of changing designs and component values without any risk of damaging equipment was really beneficial to designing a better pod”.

“The two main use cases for PSIM were to generate code for the TI microcontroller, which was useful because it let us test our motor quickly with minimal previous experience in firmware and electrical design. The software helped us simulate an induction motor with V/f control, giving us a better understanding of how the motor control system works and letting us play around with different parameters before we decided on a design to place into the actual hyperpod.”

Applications of PSIM in Waterloop

As shown in Figure 1, an open-loop motor controller with ramp configuration was created by the Motor Control Subteam. This schematic was to test out the V/f control with ideal components, the open-loop allowed us to test and verify functionality, as well as find improvements that can be corrected before creating a closed-loop configuration. Below are screenshots of the simulation for various aspects of the motor control circuit which we will go into more detail shortly.

Figure 1: Open-loop with Ramp Configuration

The SVPWM signals shown in Figure 2, are the simulated signals prior to being digitized and entering the IGBT gates. The graph shows the SVPWM signals as voltages with respect to time in seconds. The rise of frequency and voltage can be seen here over the 6-second duration. This visualization is extremely useful because it allows us to properly understand what is happening before the IGBT gates receive these SVPWM signals, making debugging and further development easier in the future.

Figure 2: SVPWM Signals Before Digitizing in Open-loop

The speed that the induction motor is rotating at is shown in the graph below (Figure 3). The graph shows the rotations in a continuous direction. The period before ~4s illustrates fluctuations within current signals (refer to Figure 2) causing the speed of the motor to vary.

Figure 3: Speed in RPM in Open-loop

A solution for the issues as described in the previous paragraphs was to create a closed-loop configuration, this was done with the same parameters as used for the open-loop to examine the different designs and compare the graph results.

Figure 4: Closed-loop Simulation

In figure 4, we simulated a three-phase IGBT inverter with a simulated model of a rotary induction motor at the output. PSIM’s extensive modularity in its device parameters allowed us to modify the induction motor model to better characterize our linear induction motor. The conversion of logical signals (green) to power (red) can be seen in the schematic. This closed-loop simulation is very similar to Figure 1, except it measures the output of the motor and feeds it back into the control loop. By closing the loop the controller is able to use the current speed of the motor as well as the desired motor speed to more quickly and efficiently get the motor up to speed.

We have also used PSIM’s auto code generation tools in conjunction with hardware from Texas Instruments to quickly get small-scale motor prototypes running. The code generation features worked like magic and were able to help us get our first few motors up and running with minimal challenges.

Pictured below in Figure 5 is our latest hyperpod, Goose 5. Building the Linear Induction Motor which can be seen on the underside of the pod, would not have been possible without the help of PSIM.

Figure 5: Current status of our Almost Complete Hyperpod, Goose 5.

“PSIM has been and will continue to be extremely useful for getting new members up to speed, faster prototyping, and giving us a better understanding of control theory and motor design. With PSIM, we are able to train new members in a virtual environment and without risking ruined parts. This leads to better-prepared team members who are able to rapidly provide prototypes for future renditions of the motor controller. PSIM will also be a crucial part of understanding control theory and motor design by providing us with meaningful data and visuals which can be used to explain and justify certain design choices we make for our next revision of the motor controller for the G6 Hyperpod.”

To learn more about the Waterloop team, their mission, and their progress in this project, follow them on Instagram or Twitter using the handle @team_waterloop or visit their Facebook page or team website.