Study On Cascaded High Voltage Inverter

High voltage inverter as a high-efficient saving energy equipment has become a hotspot in frequency converter field. At present, high-voltage inverter topology structure basically has three-level and cascade type. Their work principle is introduced, and I chose cascade topology structure as the researching object.Several SPWM modulation strategy is analyzed, including space vector control, carrier phase-shifting, synchronization modulation.By comparison, The carrier phase-shifting modulation is chosen as high voltage inverter modulation scheme. Because V/F as const control is a kind of the traditional control mode, and it is also one of control strategy mainly in the high voltage inverter field. V/F strategy is adopted in this dissertation.High voltage inverter topology structure of single phase power unit is proposed with the horizontal phase-shifting technology as the core of the whole system.Using the software MATLAB built the high voltage inverter modes in order to the simulation analysis.Through single-phase two cascaded power units, six cascaded power units, nine cascaded power units, and three-phase six cascaded power units simulation, the characteristics of N cascade is mastered. The control signal rule is found in cascade high voltage inverter. By comparing, the topology structure of six power units is chosen as the physical topology structure system.Finally, the whole system is designed, including hardware circuit design and the compilation and debugging of the software program. Moreover, six cascaded power units is built to the test system,and the results indicate that the voltage waveform of cascade high voltage inverter is almost sine wave of output and the harmonic pollution is small, without using output filter.The prototype is run for long time. It is showed that the designed system is reasonable, and has good practical value.