| Multilevel inverters have the advantages of low total harmonic distortion,small electromagnetic interference,low voltage stress of switches,and high efficiency.Inverters are widely used in motors,uninterruptible power supplies,distributed power generation systems,and electric vehicles.Some traditional multilevel inverters,such as diode clamped inverters and active neutral-point-clamped inverters,are difficult to control the voltage balance of capacitors,and require complex control strategies.For switched capacitor inverters,the capacitor voltage can be self-balanced,but switches of the inverter have to withstand the large voltage stress.This paper studies the multilevel inverter with capacitor voltage self-balancing.The contents are as follows:1.Multilevel inverters with capacitor voltage self-balancing are studied.Three typical multilevel inverters with voltage s self-balancing are analyzed.Based on these inverters,a ninelevel inverter is proposed.The principle of the selective harmonic elimination modulation is analyzed.2.Based on switched capacitor technology,a hybrid seven-level inverter is proposed.The proposed hybrid inverter combines the advantages of the traditional hybrid inverters and switched capacitor inverters.This paper analyzes the working principle of the seven-level inverter and the high-frequency modulation method.The inverter has the advantages of low voltage stress of the switches,output voltage boost,and capacitor voltage self-balance.The waveforms of simulation and experiment verify the feasibility and characteristics of the proposed inverter.3.A seven-level inverter with capacitor self-balancing is proposed.The proposed sevenlevel inverter combines the structural of some switched capacitor inverters and the inverters with capacitor self-balancing.The capacitor voltage of the proposed seven-level inverter can be self-balanced.The inverter has fewer switches to achieve seven-level output,and the voltage stress of the devices is reduced. |
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