Determination of the power loss in inverters which supplies a BLDC motor

This paper presents a methodology for estimating the losses occurring inside an inverter with full controlled bridge supply for supplying a BLDC motor. The motor drives a small vehicle. The PWM inverter supply voltages on the three phases starting from an accumulator battery and is made with MOSFET transistors. The proposed method presents a method of determining the losses of a transistor located on top of the three-phase bridge and a transistor located on the bottom of the bridge. It is based on the use of data from the catalog sheet specified by the manufacturer of the power transistor. To facilitate the understanding and application of the calculation of losses in various types of MOSFET we choose to complete the equations with numerical values determined based on the catalog sheet of the transistor which fits the analyzed inverter. Note that the precision of the results provided by the methodology proposed in the paper can be improved if one takes into account changing some transistor parameters due to its heating. The methodology was designed in order to allow the implementation of a MATLAB-SIMULINK system integrated with modeling and simulation systems of the inverters for motor supplying.