Effect of MOSFET lifetime on reliability of low-side MOSFET current sensing technique

This paper deals with evaluation of reliability and quality of low-side MOSFET current sensing technique which has already been published recently. This current sensing technique utilizes low-side MOSFETs in three phase low voltage power inverters in order to estimate the phase current. The MOSFET parameters are highly temperature dependent, hence the realization challenges are made up. The proposed algorithm is based on mathematical model, in which temperature dependent characteristics of MOSFET like on-state resistance and body diode forward voltage as a function of temperature are utilized. All MOSFET parameters and characteristics can be changed, while the MOSFET is exposed extreme operation conditions. This effect is called the aging effect of MOSFETs. The MOSFET aging effect can influence the proposed mathematical model of current sensing technique, hence this effect is investigated and simulated in order to evaluate the reliability of proposed technique. The evaluation is carried out by means of simulation approach in the LTspice.