Power electronics plays a vital role in the control of PMSM which has emerged as favourite for small electric formula race car. With the limited space in these cars, need for compact power electronic solutions is key, hence the motivation to design and develop a compact power electronic box for Chalmers Formula Student electric car. This work is based on the 2- wheel drive formula car with a DC source of 400 volts. Using the benching test results performed by AROS on the PMSM, data and results collected from the 2014 formula student competition rules and the endurance speed prole of the 2013 CFS car, The peak phase voltage and current drawn by PMSM at different operating points are obtained. The dimensioning of the switches is dependent on the peak phase current and voltage values and the source voltage. Power losses of the selected power modules are calculated using data-sheet parameters of IGBTs and MOSFETs. Evaluation of the power losses, weight, size and cost of the power modules is done using stacked bus bars and a heat sink is designed for the power module selected as the most suitable. Also capacitors, IGBT/MOSFET drivers, bus bars, current and voltage sensors are selected.