High-voltage Multi-level Inverter Control Strategy And Its Modeling

With the development of electric-driver technology, high voltage frequency conversation timing technology of large capacity driving has been applied widely in the field alterating current motor driving. Multi-levels inverter has become a researchful hotspot in this field due to the peculiarity that it has multi output levels and its output wave is more close in upon sine wave, etc, compared with two-levels inverter.The principle and characteristc of diode-clamping multi-levels inverter, capacity-clamping multi-levels inverter, cascaded multi-levels inverter are analyzed in this dissertation. Several control-strategies of multi-levels inverter are discussed. These control-strategies are Sub-harmonics PWM, Special harmonic elimination PWM, Phase chifted carrier PWM, Multi-carrier PWM, Selected harmonic elimination, Based on Control Degrees of Freedom PWM, a Phase Shifting space vector modify. The arithmetic of Space Vector Pulse Width Modify applying in diode-clamping inverter is studied particularly in the third chapter, the controlling of midspot voltage is embedded in the arithmetic which makes the midspot voltage in blanace. A new topology structure of cascaded multi-levels inverter is given, and the arithmetic of Space Vector control is researched in detail in the fourth chapter. At the same time, the models of these two inverters system are founded and simulated in the condition of MATLAB/Simulink. According to the simulation output wave of these two inverters, the conclusion that the wave of output line-voltage and line-current are comparatively close to the sine-wave is made, which proves the effectivety of these two control arithmetics.