Power losses of switch devices restrict the performance of inverters. Specific Harmonic Elimination PWM (SHEPWM) strategy has several advantages and great research significance for controlling three-level inverters. This paper analyzes and compares the conduction losses and switching losses of NPC (neural-point-clamped) and T-type inverters with SHEPWM strategy. Improving power device reliability is also described in this paper. Some interesting conclusions can be obtained according to simulation and analysis results.