A fault ride through, power management and control strategy for grid integrated photovoltaic (PV) system with supercapacitor energy storage system (SCESS) is presented in this paper. During normal operation the SCESS will be used to minimize the short term fluctuation as it has high power density and during fault at the grid side it will be used to store the generated power from the PV array for later use and for fault ride through. To capture the maximum available solar power, Incremental Conductance (IC) method is used for maximum power point tracking (MPPT). An independent P-Q control is implemented to transfer the generated power to the grid using a Voltage source inverter (VSI). The SCESS is connected to the system using a bi-directional buck boost converter. The system model has been developed that consists of PV module, buck converter for MPPT, buck-boost converter to connect the SCESS to the DC link. Three independent controllers are implemented for each power electronics block. The effectiveness of the proposed controller is examined on Real Time Digital Simulator (RTDS) and the results verify the superiority of the proposed approach.
- Active and reactive power control
- Fault ride through
- Photovoltaic system
- RTDS Supercapacitor
- Energy storage
Fig.1. Grid connected PV system with energy storage
EXPECTED SIMULATION RESULTS:
Fig.2. Grid voltage after three phase fault is applied
Fig.3. PV array power PPV with SCESS and with no energy storage
Fig.4. Grid active power Pg for a three phase fault with and without energy storage
Fig.5.SCESS power PSC for the applied fault on the grid side
Fig.6. Grid reactive power Qg during three phase fault
Fig.7. DC link voltage for the applied fault
Fig.8. PV array voltage VPV during three phase fault
Fig.9. MPPT output voltage Vref for the applied fault
This paper presents grid connected PV system with supercapacitor energy storage system (SCESS) for fault ride through and to minimize the power fluctuation. Incremental conductance based MPPT is implemented to track the maximum power from the PV array. The generated DC power is connected to the grid using a buck converter, VSI, buck-boost converter with SCESS. The SCESS which is connected to the DC link controls the DC link voltage by charging and discharging process. A P-Q controller is implemented to transfer the DC link power to the grid. During normal operation the SCESS minimizes the fluctuation caused by change in irradiation and temperature. During a grid fault the power generated from the PV array will be stored in the SCESS. The SCESS supplies both active and reactive power to ride through the fault. RTDS based results have shown the validity of the proposed controller.
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