Research on neutral-point potential balance and current control method of NPC three-level inverters
ZHANG Chenlong
ZHAO Qiangsong
Abstract：The Neutral Point Clamped(NPC)three-level inverter has been widely used because of its advantages of high efficiency,low harmonics and low voltage stress.However,there is an imbalance in the neutral point potential of the upper and lower capacitors of NPC inverters,which will aggravate the distortion of the output current of grid-connected inverters.To solve this problem,an effective method of neutralizing potential and suppressing harmonic of output current is proposed.Firstly,the circuit topology of NPC three-level grid-connected inverter is analyzed and the mathematical model is established.Then the Space Vector Pulse Width Modulation(SVPWM)control algorithm is optimized,and the Feedforward Odd Harmonic Repetitive Control(FORC)method is proposed.Finally,a simulation experiment platform is established and verified by MATLAB/Simulink software.The experimental results show that the FORC strategy based on SVPWM midpoint potential control can effectively suppress the midpoint potential fluctuation and reduce the harmonic content of the output current.
Keywords：three-level inverterneutral-point potential balanceharmonic suppression
Publication Date：2025-10-25
Online Publishing Date：2025-11-24(First online date of this platform, not the publication date of the document)
Pages：8( 31-38 )