System Overview

Changes for MD26

The main power for the car will still come from a 12V battery, running to a power distribution module. A power distribution module  currently the PDM selected is the Blackbox PDM. Other PDMs do have more outputs and features, however these modules are also more expensive. The modules go from around $2k. This is quite expensive and the goal is to spend around $1.5k for a module as our current plan is to get a minimum viable product, where we don't have too much power output requirements. This PDM is also used by other teams and they have had good experiences with it. 

The new system will run a regulated 12v from a buck boost module throughout the car. The selected module is the DFR... . It is a adjustable buck boost converter, up to 5A output. This should be enough for the GLV system of the car as the high power devices will be directly powered by the GLV battery, where noise and voltage matters less. This separate module will supply regulated 12v to get more stable power for things such as sensors. Running 12v over 5v throughout the car also has other benefits. This means that we can add devices and sensors that draw more power. This hopefully should mean better stability in general. This does add some additional complications for example if a sensor needs 5v, it would mean that there needs to be a regulator of sort to step down the voltage, however a LDO will surfice for most devices. 

Reflection on MD25

The GLV power system for MD26 has been designed with the issues found in MD25 in mind. In MD25, we found that during testing the 5V rail from the SCUM that ran throughout the car had transients. Because there were many analogue sensors, this meant that for APPs and BSPD, the transients would cause unexpected values. In addition to this the main high power distribution was a relay board. This board wasn't designed for this task and was retrofitted to function, resulting in inconsistent behaviour. This highlights a need to change the power distribution for MD26. This highlighted the need for a dedicated power distribution module to power high current demanding devices.