OUR Team Develops High-Performance Power Distribution Module (PDM)

PDM

During the development of Formula Student race cars, achieving a reliable, compact, and safe electrical system is of utmost importance. This season, our team set out to design and develop a new, custom-built Power Distribution Module (PDM), which serves as the central unit for the car’s power distribution.
The project was made possible through the professional support of Eurocircuits, who provided the PCB manufacturing and ensured high-quality implementation. This collaboration not only enabled the creation of a high-performance PDM but also offered the team valuable experience in industrial-level electronic development.

A We designed the PCB using EasyEDA, an online platform that allows all team members to access
and collaborate on the design files easily. The core concept was to create a single input and a single output connector to ensure water resistance. The main requirement was to distribute one input into 11 channels (Figure 1), each equipped with overcurrent protection, while five of these channels are switchable and include current sensors. Additionally, the module is capable of measuring internal temperature and voltage.

The 11 channels have different maximum current ratings — the highest being 20A, and the lowest 5A. For cost efficiency, we could only use copper layers up to 70 microns thick. To safely handle higher currents, two copper layers are required; however, using only two layers would make proper signal routing impossible. Therefore, the PCB was designed as a four-layer board, with 2×35 μm and 2×70 μm copper thickness, built on an FR4 substrate (a flame-retardant material, which was an important requirement). The required copper trace widths were calculated using an online PCB trace width calculator, and a 10% safety margin was added throughout the design.
It is important to note that these thickness values are nominal after consulting with the manufacturer, we learned that the final copper thicknesses will be approximately 45 and 90 microns, providing an additional safety buffer.
The input is provided through a power feedthrough connector, which is connected to the PCB using wires. The output uses a 60-pin connector manufactured by TE Connectivity, a type commonly used in automotive applications. Since
each pin can handle a maximum current of 8A, the higher-current channels use three pins in parallel (Figure 2).

Each channel includes a 3568-type fuse holder, allowing for easy replacement of fuses. Five channels are equipped with relay sockets, compatible with standard 40A automotive relays, which can also be replaced quickly if needed. The relay coil pins are routed to external connectors, allowing them to be controlled freely for example, by a switch or a motor controller.

For current measurement, Hall-effect-based sensors are used, which provide analog output signals. To interpret these signals, a microcontroller (ESP32) is integrated into the system, responsible for signal processing. The ESP32 communicates via SPI with a CAN module, which connects to the vehicle’s CAN bus. Because the sensors have analog outputs, multiple input channels are available, and lowpass filters were designed for signal conditioning to effectively suppress external noise.

Since the microcontroller operates at 5V, we integrated a power supply unit a DC-DC converter that steps down the car’s 12V input to a stable 5V output. We selected the LM2576T-5.0 voltage regulator IC and chose the surrounding components based on the manufacturer’s datasheet to ensure optimal performance. The through-hole version of the regulator was chosen because it allows for easy attachment of a heat sink. Although detailed calculations showed that additional cooling might not be strictly necessary, we decided to include a heat sink anyway. This precaution ensures
greater reliability and prevents potential failures that could arise from thermal underestimation during real-world operation.

Our previous unit was too large (25×35 cm), so one of our main goals for this development was reducing the overall size which was one of the key reasons we opted for a PCB-based solution. The final dimensions are 15×20 cm,
marking a significant improvement in compactness. A 3D model of the final design can be seen in Figure 3.
It is also worth mentioning that after uploading the design files to the Eurocircuits platform, their engineers noticed that some component footprints did not perfectly match the physical part dimensions. Thanks to their careful review, we were able to correct the issue before manufacturing, ensuring a flawless final result.

The new Power Distribution Module has proven its capabilities in the Formula Student race car, providing reliable and efficient power distribution to all vehicle systems. Thanks to careful design, the four-layer PCB structure, and the integrated protection and measurement features, a modern and forward-looking solution was created. Eurocircuits played a key role in enabling this development to be realized at an industrial level, supporting young engineers in gaining practical experience and advancing their professional skills. As a result of this collaboration, a device was produced that not only strengthens the team’s technical capabilities but also supports their ongoing innovation and development efforts.

For more information please visit the OUR Team’s website.