关键词: T型, 三电平逆变器, 三次谐波注入PWM, 损耗模型, 中点钳位

Abstract: The loss of power devices in two inverter topologies was studied. Through the device's characteristic parameters, a simple curve fitting method was established which considered the influence of operating voltage, driving resistance and junction temperature. The loss calculation model of the three-level T-type and two-level inverter was derived under the third harmonic injection PWM(THIPWM) strategy. It is found that the power loss is related to the modulation factor, switching frequency, power factor angle and the output current. Under the same inverter operating conditions, when the switching frequency is more than 6.8 kHz, the loss of T-type topology can be smaller than two-level topology within all current extent, reflecting the three-level superiority. The study of power loss can be extended to other topologies, lay the foundation of design and increase the efficiency of the grid-connected inverter.