Research On Neutral-Point Balance Of Three-Level Inverter

NPC three-level inverter has been one of the focus areas of the current large-capacity power conversion in hypertension,through different combinations of the partial pressure and the switching state of the DC side,multi-level step wave output voltage inverter can effectively improve system capacity and pressure levels,reducing output voltage harmonics and switching losses.Paper introduces the diode clamped(NPC)three-level inverter works as well as the traditional three-level SVPWM control algorithm,and then study some typical three-level PWM modulation methods,including saddle-wave modulation,croissants and DPWM modulation wave modulation.Focus on the midpoint voltage balance.Midpoint potential imbalance is a problem inherent in the three-level converter.Papers from the impact angle vector and the midpoint of the current in-depth analysis of the midpoint potential balance control law,the use of a simplified algorithm adapted SVPWM point Balancing Control Method balance factor,it can precisely control the midpoint of the balance by adjusting the control factor potential balance.Study of a midpoint algorithm is then balanced unity,from the perspective of the carrier superimposed zero-sequence component on the basis of the modulated wave,so as to effectively control the midpoint potential.Based on the theoretical analysis of simplified SVPWM algorithm and several typical PWM modulation strategy,the mid-point potential balance control strategy using Matlab/Simulink simulation analysis.The results demonstrate the feasibility of the midpoint of balance control method of design.Midpoint voltage control effect is also evident,meet the design requirements.After the theoretical analysis and simulation,set up a task-based TMS320LF28335 as the control center of the three-level inverter 10KW experimental platform,will theory into practice.Three-level modulation method,point Balancing Control Strategy for experimental research,experimental results demonstrate the feasibility of the overall algorithm and modulation strategy.