IEEE TRANSACTIONS ON SUSTAINABLE ENERGY, 2015
ABSTRACT:
This paper presents a new
system configuration for integrating a grid-connected photovoltaic (PV) system
together with a self-supported dynamic voltage restorer (DVR). The proposed system
termed as a “six-port converter,” consists of nine semiconductor switches in
total. The proposed configuration retains all the essential features of normal
PV and DVR systems while reducing the overall switch count from twelve to nine.
In addition, the dual functionality feature significantly enhances the system
robustness against severe symmetrical/asymmetrical grid faults and voltage
dips. A detailed study on all the possible operational modes of six-port
converter is presented. An appropriate control algorithm is developed and the
validity of the proposed configuration is verified through extensive simulation
studies under different operating conditions.
KEYWORDS:
1.
Bidirectional power flow
2.
Distributed power generation
3.
Photovoltaic (PV) systems
4.
Power quality
5.
Voltage control
SOFTWARE: MATLAB/SIMULINK
BLOCK DIAGRAM:
Fig.
1. Proposed integrated PV and DVR system configuration.
Fig.
2. Simulation results: operation of proposed system during health grid mode
(PV-VSI: active and DVR-VSI: inactive). (a) Vpcc; (b) PQload; (c)
PQgrid; (d) PQpv-VSI; and (e) PQdvr-VSI.
Fig.
3. Simulation results: operation of proposed system during fault mode (PV-VSI:
inactive and DVR-VSI: active). (a) Vpcc; (b) Vdvr; (c) Vload;
(d) PQload; (e) PQgrid; (f) PQpv-VSI; and (g) PQdvr-VSI.
Fig.
4. Simulation results: operation of proposed system during balance three phase
sag mode (PV-VSI: active and DVR-VSI: active). (a) Vpcc; (b) Vdvr-VSI;
(c) Vload; (d) PQgrid; (e) PQpv-VSI; and (f) PQdvr-VSI.
Fig.
5. Simulation results: operation of proposed system during unbalanced sag mode
(PV-VSI: active and DVR-VSI: active). (a) Vpcc; (b) Vdvr-vsi; (c)
Vload; (d) PQgrid; (e) PQpv-VSI; and (f) PQdvr-VSI.
Fig.
6. Simulation results: operation of proposed system during inactive PV plant mode
(PV-VSI: active and DVR-VSI: active). (a) Vpcc; (b) Vload; (c) Vdc;
(d) PQload; (e) PQdvr-VSI; and (f) PQpv-VSI.
CONCLUSION:
In this paper, a new system configuration for
integrating a conventional grid-connected PV system and self supported DVR is proposed.
The proposed configuration not only exhibits all the functionalities of
existing PV and DVR system, but also enhances the DVR operating range. It
allows DVR to utilize active power of PV plant and thus improves the system
robustness against sever grid faults. The proposed configuration can operate in
different modes based on the grid condition and PV power generation. The
discussed modes are healthy grid mode, fault mode, sag mode, and PV inactive
mode. The comprehensive simulation study and experimental validation
demonstrate the effectiveness of the proposed configuration and its practical feasibility
to perform under different operating conditions. The proposed configuration
could be very useful for modern load centers where on-site PV generation and
strict voltage regulation are required.
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