Power losses analysis in MOSFET 3-phase high current power inverter for automotive application area

Abstract

Abstract This paper deals with analyzing losses of three-phase high current and low voltage inverter, which is intended for automotive applications. High current inverters are becoming more popular in automotive area due to increasing the number of high power electrical drives in cars and trucks. The less reliable and less efficient, usually mechanical drive systems are replaced for more effective and more reliable electrical drive systems. There are liquid pumps, HVAC blowers, turbochargers, etc. Total losses of the common inverters are divided into three main parts, conductive and joule losses, switching losses and additional losses. The highest part of losses usually generates power switches, in this case MOSFETs. The size of other part of losses is determined by parameters of used components, i.e. DC-link capacitors, shunt resistor sensors, etc. The power losses and efficiency of inverter are analyzed by using the simulation model in LTspice. The model of inverter contains spice models of MOSEFTs and DC-link capacitors. The parasitic components of high current and excitation traces are also included into model. The analyzed inverter contains only DC-link shunt resistor for current sensing purpose in order to minimize joule losses of shunt resistors. Joule losses of shunt resistor, DC-link capacitor losses, reverse polarity battery protection MOSFET and three-phase half-bridge inverter are analyzed from power losses and efficiency point of view. The final result of this paper describes the size of losses of power circuit and the value of efficiency of inverter, which the high current inverter is able to reach.