The Research Of Three-phase Current Source Inverter

Inverters are the core equipment in renewable energy power generation system such as photovoltaic and wind power,so their research is very necessary.At present,inverters that are used more often are voltage source inverters(VSI),but VSI can only realize step-down,and the circuit needs to incorporate over-current protection,and the electrolytic capacitors in the circuit also have a problem of short lifetime.However,the current source inverter(CSI)essentially belongs to the Boost circuit,which can realize boosting,the DC-side energy storage element is a large inductor,so the bridge arm can pass through,and the longer life of the large inductor compared to the electrolytic capacitor.Therefore,the three-phase current source inverters are studied in this paper.This paper firstly analyzes the working principles of the three modulation technologies of SPWM technology,SVPWM technology and 1DM technology in three-phase CSI system.By comparing and analyzing the output results of these three modulation technology,the output waveform quality of 1DM technology is optimized,and the technology also has the smallest amount of calculations in the implementation process.Then for the hard switch will cause the system switching losses large defects,this paper added a soft-switching technology in the three-phase CSI system,and the switch tubes achieve a zero current shutdowm.Then,a mathematical model was established for the three-phase CSI system,and a double-loop structure of the DC-side current loop and the AC-side voltage loop was designed so that the system can quickly recover stable operation after being disturbed.Aiming at the resonance problem of the structure of the CLC filter itself in the three-phase CSI system of this paper,a passive damping control scheme is added to the filter structure of the system to suppress the resonance peak of the filter,and verified by simulation software.Finally,an experimental platform for three-phase CSI is set-up.The three-phase CSI modulation technology is verified by open-loop experiments,and the passive damping closed-loop control of three-phase CSI is verified by closed-loop experiments,and the experimental results verify the correctness of the proposed theoretical scheme.