ABSTRACT:
This
paper proposes a simple single-phase new pulse-width modulated seven-level
inverter architecture for photovoltaic (PV) systems supporting home-grid with
electric vehicle (EV) charging port. The proposed inverter includes a reduced
number of power components and passive elements size, while showing less
output-voltage total harmonic distortion (THD), and unity power factor operation.
In addition, the proposed inverter requires simple control and switching
strategies compared to recently published topologies. A comparative study was
performed to compare the proposed inverter structure with the recent inverter
topologies based on the number of components in the inverter circuit, number of
components per output-voltage level, average number of active switches, THD,
and operating efficiency as effective parameters for inverter performance
evaluation. For design and validation purposes, numerical and analytical models
for a grid-tied solar PV system driven by the proposed seven-level inverter
were developed in MATLAB/Simulink environment. The inverter performance was
evaluated considering grid-integration and stand-alone home with level-2 AC EV
charger (3–6 kW). Compared with recently published topologies, the proposed
inverter utilizes a reduced number of power components (7 switches) for
seven-level terminal voltage synthesis. An experimental prototype for proposed
inverter with the associated controller was built and tested for a stand-alone
and grid-integrated system. Due to the lower number of ON-switches, the
inverter operating efficiency was enhanced to 92.86% with load current THD of
3.43% that follows the IEEE standards for DER applications.
KEYWORDS:
1. DC-AC
converter
2. Electric
vehicles
3. Home
grid
4. Maximum
power point tracking (MPPT)
5. Multilevel
inverter
6. Photovoltaic
(PV) system
7. Seven-level
inverter
SOFTWARE: MATLAB/SIMULINK
CIRCUIT DIAGRAM:
Figure 1. Circuit configuration
of solar PV system in integrated with the grid and EV loads via the proposed 7level-inverter.
EXPECTED SIMULATION SYSTEM:
(a) Solar irradiation
(b) PV current
(c) PV voltage
Figure 2. Cont
time(s)
(d)PV
power
Figure
3. the pv panel current, voltage, and power.
Figure
4. multi- Level inverter output voltage.
Figure
5. the injected current, voltage, and power variation. (a) Grid voltage and current; (b) Grid injected power.
Figure 6. The reference and actual injected
currents of the seven-level inverter at irradiance variation.
Figure 7. Simulation results of the proposed
7-level inverter as level-2 EV charger (240 V, 3:6 kW); (a) loading profile, (b) multilevel output voltage, and (c) inverter voltage/pulsating current
Figure 8. Simulation results of the proposed
7-level inverter for house loads voltage control (2 kW). (a) Load reference and actual voltages,
(b) Load voltage and current
CONCLUSION:
This
paper has presented a new topology of a single-phase seven-level inverter as an
interface for grid-integrated and stand-alone solar PV systems. The circuit
configuration This paper has presented a new topology of a single-phase
seven-level inverter as an interface for grid-integrated and stand-alone solar
PV systems. The circuit configuration This paper has presented a new topology
of a single-phase seven-level inverter as an interface for grid-integrated and
stand-alone solar PV systems. The circuit configuration and operation principle
of the proposed inverter have been presented in detail a long with the
switching patterns and control strategy. A comparative study between the
proposed inverter structure and the recent MLI topologies is enriched to reveal
the features of the proposed inverter. The proposed MLI structure considers a
reduced number of power switches, NC/L, and NAVG/Pole, which enhances the inverter
operating efficiency and decreases its cost. Only seven switches have been
utilized to synthesis voltage waveform of seven levels at the output terminals.
The performance of the proposed inverter and associated control was investigated
for grid-integrated and stand-alone PV systems based on simulation and
experimental tests. The test platform includes a boost converter with MPPT
control, which feeds the front-end of the proposed MLI. The results show that the
proposed inverter exhibits an improved steady state response, and minimum
settling time (i.e., 5 ms). THD of both voltage and current waveforms during
grid-integration and stand-alone operations is 3.43%, which follows the
IEEE-1547 harmonic standards for DER applications. In addition, the inverter
offers a high operating efficiency of 92.86%, compared to most of the recently
published topologies surveyed in this paper.
REFERENCES:
1. Solangi, K.; Islam, M.; Saidur, R.; Rahim, N.; Fayaz, H. A
review on global solar energy policy. Renew. Sustain. Energy Rev. 2011, 15,
2149–2163. [CrossRef]
2. Ali, A.I.; Sayed, M.A.; Mohamed, E.E. Modified efficient
perturb and observe maximum power point tracking technique for grid-tied PV
system. Int. J. Electr. Power Energy Syst. 2018, 99, 192–202. [CrossRef]
3. Sayed, M.A.; Mohamed, E.; Ali, A. Maximum Power Point Tracking
Technique for Grid tie PV System. In Proceedings of the 7th International
Middle-East Power System Conference, (MEPCON’15), Mansoura University, Dakahlia
Governorate, Egypt, 15–17 December 2015.
4. Ali, A.I.; Mohamed, E.E.; Sayed, M.A.; Saeed, M.S. Novel
single-phase nine-level PWM inverter for grid connected solar PV farms. In
Proceedings of the 2018 International Conference on Innovative Trends in
Computer Eng. (ITCE), Aswan, Egypt, 19–21 February 2018; IEEE: Piscataway, NJ,
USA, 2018; pp. 345–440.
5. Youssef, A.-R.; Ali, A.I.; Saeed, M.S.; Mohamed, E.E. Advanced
multi-sector P&O maximum power point tracking technique for wind energy
conversion system. Int. J. Electr. Power Energy Syst. 2019, 107, 89–97.