Swissloop – PCB Design and Testing Journey

Advancements in Full Contactless Levitation System: The PCBs of Swissloop have arrived!

As engineers, we at Swissloop want to push the boundaries of transportation technology. For the past seven years, we have built a Hyperloop prototype every year. Our long-term goal is to build passenger capsules which by full levitation, contactless propulsion through electromagnetic linear motors, and low air resistance in low-pressure tubes enable carbon-neutral, efficient transportation at extremely high speeds.

This year, we took to redesign most of our PCBs. Here, a special focus on put on developing a new contactless levitation system. This levitation system keeps the vehicle at a controlled distance both laterally and vertically from its guidance rails. By eliminating rolling resistance and vibrations, much higher speeds can be reached. The levitation systems rely on electromagnets which attract the vehicle to the rails vertically and laterally. By actively controlling the current in these electromagnets based on proximity sensing, the vehicle can be stabilised. To facilitate this new levitation system, four PCBs were developed from the ground up:

1. Laser Sensor Unit (LSU): The LSU plays a critical role in reading laser sensor data laterally and vertically, providing precise information on the proximity to the rails.
2. Levitation Control Unit (LCU): Responsible for data processing and six individual position feedback control loops using an STM microcontroller. It also manages current control with a hysteresis control strategy on an FPGA.
3. Levitation Driver Unit (LDU) and Levitation Power Unit (LPU): These power electronics units work in tandem with a piggyback configuration to drive the electromagnets.

Additionally, we recognised the need for improved performance in various aspects of our project, leading to the redesign of several PCBs:

1. Vehicle Controls: Our Vehicle Control Unit (VCU) received some minor enhancements to implement new functionalities, including an IMU, new sensors for the pneumatic systems, and pump controls for a new cooling system.
2. Battery Management: The battery management PCB underwent a complete redesign, focusing on power distribution and safety.
3. Propulsion Power Electronics and Control Boards: Major modifications were made to these boards to accommodate higher voltages and currents, resulting in increased motor power. Additionally, we incorporated additional input capabilities for position sensor data. The precise control this enabled improved motor efficiency.

Currently, we are in the testing phase, evaluating the motor and levitation power PCBs. During isolation testing, we detected a minor issue with the propulsion power electronics, leading to slight redesign and reordering. Rigorous testing and continuous refinement are crucial to ensure the safety and reliability of our system. In parallel, the control boards have been soldered and are being tested with software. Thanks to careful preparations during PCB design, many things have been going to plan this far.