Simulation And Research Of Photovoltaic Micro-grid DC Link Voltage Control

With the rapid increasing of energy consumption, ecosystem environmentalpollution becoming worsen and worsen and energy consumption sharply growth, and therapid development of distributed generation technologies, all of this make the form ofmicro-grid as the maximum efficiency of energy using when the micro-power energystorage system, load and control devices combining. It coordinated the contradictionbetween the main grid and distributed generation, changed the single power supplymode of traditional electrical power system, and improved the efficiency of the powergrid. This article study on the DC link voltage control of micro-grid which base on thePV electricity generation and the accumulator cell stored energy system, realizes theenergy to maximum use, the alleviation power supply pressure, the enhancement powersupply reliability, and the stable invertor input voltage goal most greatly.Firstly, according to the micro-grid structure and integrated control strategy, basingon Maximum Power Point Tracking(MPPT) and DC/AC conversion, taking theaccumulator cell as stored energy system, which proposed the DC link voltage controlstrategy in non-communication mode of grid-connected mode stabling it by the PVarray and battery combined working. Theoretical analysis and simulation are carried outto confirm the control policy feasibility which this article proposed.Secondly, based on the design main circuit, the engineering mathematical model isestablished. Adopting Perturb&Observe Algorithms(P&O) method to realize maximumpower point tracking(MPPT), then the bi-directional DC/DC converter was used tomake sure the battery power stabilization, and taking electric current forward feeddecoupling’s Space Vector PWM(SVPWM) method, the AC current components idandiqare decoupled. At last the various parts of the simulation and the DC link voltagecontrolling simulation model were established.Thirdly, a kind of DC bus coordination control strategy make use of its voltagechanged as the judgement criterion, it can realize the function with non-communication.The battery stored energy system doing the charging and discharging of powerstalization. For DC/AC conversion, a system with double-loop control is designed onthe basis of synchronous vector current PI controller. The voltage outer loops are usedto control the DC link voltage and the electric inner loop to make AC currentsrespectively.At last but not least, to make sure system has the high efficiency and the reliablestability, it needs to manage PV array and battery must operation together. This paperproposes a power management scheme. And the main circuit structure and the controlpolicy of the direct-current link voltage control has been proposed. In Matlab/Simulinkenvironment, the simulation model was established, and simulation analyses wereaccomplished on MPPT for PV array, battery charging and discharging of theaccumulator cell stored energy system, the SVPWM control of interface invertor. The simulation result has confirmed its control policy and the energy management strategieswere accuracy and effective.