Research On Virtual Space Vector Pulse Width Modulation And Related Problems For Three-Level Converters

In the field of power electronics,two-level topology has always been the main topology of the inverter.However,However,with the continuous improvement of voltage level in application,and because of the voltage stress of power electronic devices,two-level topology has been difficult to meet the needs of the current application,so the multi-level topological inverter homeopathy,and quickly become an effective solution to this problem.In addition to this advantage,the multilevel topological inverter has the characteristics of good output characteristics and high efficiency at the same time.The Neutral Point Clamped(NPC)type three-level topological inverter is the most widely used type of multi-level topological inverter,but its topology has the problem of neutral-point potential balance,which becomes a limitation of its application development.Therefore,the research on the topological inverter has become one of the hot spots in current multi-level inverters.Firstly,the working principle of diode NPC type three-level topology is analyzed and the mathematical model is built in the two-phase static coordinate system.Then in detail this paper analyzes the Carrier-based pulse width modulation(CBPWM)and Space Vector pulse width modulation(SVPWM)and the traditional Virtual Space Vector pulse width modulation(VSVPWM)in three level inverter in the implementation process and their respective characteristics,in view of the traditional VSVPWM Based on Space Vector synthesis way to realize more complex problems,combining with the characteristics of unity CBPWM and SVPWM,A new VSVPWM algorithm is proposed to simplify the implementation process of VSVPWM.In addition,aiming at the problem of high common mode voltage output by traditional VSVPWM algorithm,a VSVPWM algorithm is proposed to reduce common mode voltage.The implementation process is extended to the multi-level topological inverter and multiphase system.Finally,a three-level experimental platform is set up in the laboratory to verify the above algorithm through experiments.Finally,the experimental results verify the validity of the above theoretical derivation.