Modeling and Analysis of Resonance in LCL-Type Grid-Connected Inverters under Different Control Schemes
نویسندگان
چکیده
As a basic building block in power systems, the three-phase voltage-source inverter (VSI) connects the distributed energy to the grid. For the inductor-capacitor-inductor (LCL)-filter three-phase VSI, according to different current sampling position and different reference frame, there mainly exist four control schemes. Different control schemes present different impedance characteristics in their corresponding determined frequency range. To analyze the existing resonance phenomena due to the variation of grid impedances, the sequence impedance models of LCL-type grid-connected three-phase inverters under different control schemes are presented using the harmonic linearization method. The impedance-based stability analysis approach is then applied to compare the relative stability issues due to the impedance differences at some frequencies and to choose the best control scheme and the better controller parameters regulating method for the LCL-type three-phase VSI. The simulation and experiments both validate the resonance analysis results.
منابع مشابه
The Design of a New Double Loop Controller For Simultaneous Adjustment of Input and Output Voltages of Single-Phase Grid-Connected Inverter
Although LCL filters are used widely in the grid connected inverters to reduce high-orderharmonics, such a system increases system order and therefore sustainable design of closed-loopcontroller system will be complicated. Recently, the single-loop control strategy has beensuggested for L or LC filter based grid-connected inverters. However, the use of single-loopcontrol directly in LCL filter-...
متن کاملStability Improvement of Grid-connected Converter with LCL Filter based on Capacitor Current Active Damping by Computational Delay Reduction
Nowadays, LCL filters utilization to suppress the grid-connected inverter switching harmonics is expanding and various methods such as capacitor current active damping scheme could be investigated to damp out these harmonics. However, the computational delays including control system, and PWM switching delays have significant effect on damping system stability. In most of LCL filter parameter d...
متن کاملCapacitor Current Feedback-Based Active Resonance Damping Strategies for Digitally-Controlled Inductive-Capacitive-Inductive-Filtered Grid-Connected Inverters
Inductive-capacitive-inductive (LCL)-type line filters are widely used in grid-connected voltage source inverters (VSIs), since they can provide substantially improved attenuation of switching harmonics in currents injected into the grid with lower cost, weight and power losses than their L-type counterparts. However, the inclusion of third order LCL network complicates the current control desi...
متن کاملAalborg Universitet Analysis and Design of Improved Weighted Average Current Control Strategy for LCL- Type Grid-Connected Inverters
The LCL grid-connected inverter has the ability to attenuate the high-frequency current harmonics. However, the inherent resonance of the LCL filter affects the system stability significantly. To damp the resonance effect, the dual-loop current control can be used to stabilize the system. The grid current plus capacitor current feedback system is widely used for its better transient response an...
متن کاملSmall-Signal Modeling of Digitally Controlled Grid-Connected Inverters With $LCL$ Filters
When LCL filters are applied to digitally controlled grid-connected inverters, the design of controllers is usually implemented using classic average models. The accuracy of these models in s-domain is only guaranteed in low frequency range. In order to predict the dynamic behaviors, new smallsignal z-domain models are deduced for digitally controlled gridconnected inverters with converter curr...
متن کامل