T-type 3-level Inverter
  The 3-level diode clamped inverter has the following advantages. The NPC inverters structure is simple, dv/dt and THD in its AC output voltages are smaller in comparison to those in conventional two-level inverters. Many kinds of topologies derived from NPC have been proposed to improve the efficiency. In these proposed topologies, interests about the T-type inverter have increased recently. The T-type inverter uses the same IGBT as a main switch as those in a conventional 2-level inverters. A bidirectional switch is connected between the neutral point and each output. It can reduce the witching loss and the switching noise compared to the conventional 2-level inverter. It also a conduction loss lowers than the NPC inverter in medium switching frequency (5~20 kHz).


Block Diagram of the T-type 3-level inverter



T-type 3-level experiment set