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 as well as experimental 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
Fig.
1. Proposed integrated PV and DVR system configuration.
EXPECTED SIMULATION RESULTS:
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 plantmode
(PV-VSI: active and DVR-VSI: active). (a) Vpcc; (b) Vload; (c) Vdc;
(d) PQload; (e) PQdvr-VSI; and (f) PQpv-VSI.
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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