Research on Improved D-NPC Three Phase Three Level Converter and Its Control Strategy

Abstract

Diode Neutral Point Clamped (D-NPC) three-level topology with simple structure and low withstand voltage of single power device is suitable for medium voltage applications. Due to the long working time and high temperature of the inner tube in the main bridge arm of the d-npc structure, the design of the radiator is difficult, and the output current and switching frequency are limited. In order to solve this problem, this paper proposes an improved d-npc three-phase three-level topology, optimizes the traditional seven segment SVPWM modulation strategy, builds a simulation model based on PMSM control device, and proves the correctness and feasibility of the improved structure.