This work aims to develop a solar- battery energy storage (BES) based system, which ensures an uninterruptable supply to loads irrespective of availability of the grid. This system comprises of a solar photovoltaic (PV) array, a BES, the grid and local residential loads. A new control is implemented such that the active power demand of residential loads, is fed from the PV array, a BES unit and the utility grid. In this system, the power control operates in different power modes, which delivers the benefits to the end users with an integration of BES and an excess of PV array power, which is sold back to the grid.
For this, an effective control logic is developed for the grid tied voltage source converter (VSC). Moreover, this system deals with the issue of an integrating power quality enhancement along with the power generation from the solar PV source. The cascaded delayed signal cancellation (CDSC) based phase locked loop (PLL) is implemented for grid synchronization during the grid voltage distortion. The developed control is easily implemented in a real time controller (dSPACE-1202). Test results validate the performance of the implemented control in different operating conditions such as varying solar power generation, load variations and unavailability of the grid.
- Energy Storage
- Power Quality
- Quadrature Signal Generation
- Solar PV Generation
- Voltage Control Mode
Fig. 1 System configuration
EXPECTED SIMULATION RESULTS:
Fig.2 Dynamic performance at different operating modes during PV hour
Fig. 3 Dynamic performance of the grid interfaced PV-BES system during SVPM
Fig. 4 Performance of PV-BES system under SVPM (a) IPV and VPV (b) ig and vg (c) iL and vg(d) ivsc and vvsc (e) load power (PL), (f) grid power Pg (g) Ibat and Vbat, (h) Pbat, (i) harmonic spectral of iL (j) harmonic spectral of ig (k) harmonic spectral of vg and (l) grid voltage and grid current phasors diagram
Fig 5 Dynamic response of the system under CGPM (a) vg, VDC, ig, IPV (b)VPV, iL, Ibat, iVSC and (c) Pg, PL, PPV and IPV
Fig. 6 Dynamic performance of the system during non-PV hours (a) vg, VDC, ig, iVSC (b) ig, IPV, iL, Pg and (c) IPVFF, ID, ILoss and isα
The main contributions of this work are on the robustness of the system operating in different operating modes. The performance of a grid interfaced PV-BES system is validated through experimental results where the worst case of PV array insolation, load variation and grid unavailability are used for transition between modes.
In addition, the system is operating in constant and variable power modes to provide power smoothening and a decrease the burden on the distribution grid during peak demand. This system is also found capable to work in an islanding mode to deliver the uninterruptable power to the load. The CDSC-PLL provides synchronization to the grid and MNSOGI-QSG-DQ control uses for current harmonics elimination and power quality improvement. The THD of ig and vL are achieved within limits of an IEEE-519-2014 standard.
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