| The unbalanced load will have a huge impact on the power supply system,making it difficult for the inverter to continuously output high-quality voltage that can meet the demand for amplitude and phase.Low-quality voltage will reduce the working efficiency of power equipment,and even cause the power equipment to fail to work.In severe cases,it may cause damage to the equipment.Therefore,how to ensure that the output voltage can meet the needs of electrical equipment under unbalanced loads has also become one of the hot spots in the domestic and foreign power industry research.This paper compares several three-phase inverters commonly used in unbalanced loads,and selects the split-capacitor three-phase inverter as the main research object,and studies how to suppress the neutral point voltage offset.In order to improve the quality of the output voltage under unbalanced loads,a splitcapacitor three-phase inverter is designed to suppress the neutral point voltage offset based on the principle of flyback capacitor voltage equalization topology.Through detailed analysis of the working mode of the topology,a capacitor voltage equalization control strategy is designed to realize the energy interaction between the split capacitors,which greatly reduces the voltage difference of the split capacitors under unbalanced loads and achieves the suppression of neutral point potential offset.Because the application of SVPWM modulation technology can effectively improve the utilization rate of DC voltage,the control of the inverter bridge part uses SVPWM modulation technology.This article explains the working principle of 3D-SVPWM in detail,and establishes a dual-loop control strategy based on 3D-SVPWM to realize the control of the inverter bridge.The simulation verifies that the split capacitor three-phase inverter with capacitor voltage-sharing topology can effectively suppress the neutral point voltage offset under unbalanced load,making the output voltage symmetrical. |
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