Research On Arbitrary Level Output Topology And Control Strategy

Multilevel inverters will generate current backflow and harmonics due to their different inverter topologies in the inverter process. According to a large number of literatures, currently the topology that is able to control current backfilling while reducing both low and high harmonics and total harmonics is yet available. Therefore, in order to address these issues, there should be as many switching devices in the multilevel inverter as possible and the inverter waveform should be closer to the sine waveform. In this context, this paper presents a topology of an inverter circuit with arbitrary level output that adopts binary coded power input and is capable to output a total of up to 45 levels. The proposed inverter can achieve a large voltage span thanks to its combined advantages of both hybrid multilevel and modular multilevel, thus requiring a smaller number of switching devices. It is also able to achieve 0 ~ 45 level control by employing the nearest level control strategy and the output loop of any level through varying level states. The simulation results show that the presented topology can effectively suppress current inversion while reducing total harmonic distortion rate, with the total harmonic content of less than 2% after output filtering.