Improved design of three-level NPC inverters in comparison to two-level inverters

As voltage source 3-level NPC inverters are suitable for AC drives in average voltage and FACT applications in distribution systems, this report introduces optimized design of 3-level NPC inverter by decreasing inverter losses and costs. At first optimization parameters and application functions of losses are introduced[1], then by using MATLAM6.5 program and IGBT, diodes, switching frequency and load current typical input parameters [1] are considered then by SPWM switching algorithm in program, optimized RGon, RGoff and gate voltage for 3-level NPC inverters are calculated for minimizing switching and conduction losses of inverter among all amounts of calculated RGon, RGoff and gate voltage in comparison to optimized design of 2-level inverters[1]. Then results of NPC optimization are applied for simulation of improved NPC, using SVM switching algorithm as the best method of switching and results are presented.