MSXII

DC-DC Converter

After looking at the various requirements, the Vicor V150B12C250BL DC-DC converter was chosen for its power rating and packaging. One key benefit of the Vicor Mini series is that it has built in support for parallel operation by connecting the PR pins on the DC-DC to each other via transformers. 

Fuse

As recommended by Vicor's design guide, a Bussmann PC-Tron 5A fuse will be used on each V+ input. 

MSXIV

In the Spring 2019 term, Taiping requested Vicor's new DCM 15V 240W Isolated DC-DC converters with the associated mounting hardware. Vicor supplied the team with the following: 

One thing to note about the new DCM series is that our variant does not support paralleling, so the maximum current drawn by the LV bus must be kept to under 16A. The 15V variant was chosen assuming that we'll likely trim it down to around 13 or 14V, thus guaranteeing that the boards in the front of the car will still receive a minimum of 12V during normal operation of the car. If desired, the DC-DC can have its output dynamically adjustable and we can use this to charge a lead-acid auxiliary battery if needed. 

Fuses and protection should be designed according to Vicor's datasheet. Input and Output filtering should also be added to the board to ensure a clean supply rail to all the boards in the car. 

One thing identified during MSXII's design was that none of our connectors can handle 16A+ continuously without paralleling wires, which can affect the reliability of the car if one crimp was not crimped properly and 1 or 2 wires are required to carry the full current. This means we can either parallel conductors again, switch to a new connector, or use something similar to ring terminals and a PCB mounted lug nut connectors (as seen in the photo below). Care should then be taken to avoid connecting the wires in reverse as most boards do not feature reverse polarity protection. One option will be to ensure the wires are different lengths and cannot be physically connected to the wrong terminal.