Research on Control Strategy of Double-stage Three-phase LCL PV Grid-connected Inverter
The resonant peak of LCL filter seriously endangers the stability of PV grid-connected system.To overcome the problem,the double-stage three-phase LCL-type PV grid-connected inverter is researched,and active damping method is used to suppress the resonant peak.The maximum power point tracking control of the PV array is realized by controlling the duty of the pre-stage Boost circuit.The voltage outer loop control of back-stage direct current to alternating current(DC-AC)inverter is used to stabilize the DC side voltage.And the current inner loop control uses double current loop control.In order to realize unit power factor grid-connected control,the proportional resonant(PR)control is used in the grid-connected current outer loop control,and the capacitor current inner loop is applied to increase system damping and realize the resonant peak suppres-sion.A simulation model of the system is built in MATLAB/Simulink,and the effectiveness of the control strategy is proved by analyzing the simulation results.
LCL filterdouble-stage three-phase PV grid-connectedinverterdouble current loop control
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