Control of a Three-Phase Hybrid Converter for a PV Charging Station

ABSTRACT:

Hybrid boost converter (HBC) has been proposed to replace a dc/dc boost converter and a dc/ac converter to reduce conversion stages and switching loss. In this paper, control of a three-phase HBC in a PV charging station is designed and tested. This HBC interfaces a PV system, a dc system with hybrid plugin electrical vehicles (HPEVs) and a three-phase ac grid. The control of the HBC is designed to realize maximum power point tracking (MPPT) for PV, dc bus voltage regulation, and ac voltage or reactive power regulation. A test bed with power electronics switching details is built in MATLAB/SimPowersystems for validation. Simulation results demonstrate the feasibility of the designed control architecture. Finally, lab experimental testing is conducted to demonstrate HBC’s control performance.

 

KEYWORDS:

  1. Plug-in hybrid vehicle (PHEV)
  2. Vector Control
  3. Grid-connected Photovoltaic (PV)
  4. Three-phase Hybrid Boost Converter
  5. Maximum Power Point Tracking (MPPT)
  6. Charging Station.

 

SOFTWARE: MATLAB/SIMULINK

 

BLOCK DIAGRAM:

Fig.1 Architecture configurations of a PV charging station. The conventional topology includes a dc/dc converter and a dc/ac VSC. These two converters will be replaced by a three-phase HBC.

 

EXPECTED SIMULATION RESULTS

 

Fig.2 Performance of CC-CV algorithm

Fig.3. Performance of a modified IC-PI MPPT algorithm when solar irradiance variation is applied.

Fig. 4. Performance of the dc voltage control in the vector control. The solid lines represent the system responses when the dc voltage control is enabled. The dashed lines represent the system responses when the dc voltage control is disabled.

Fig. 5. Performance of a proposed vector control to supply or absorb reactive power independently.

Fig. 6. Power management of PV charging station.

Fig. 7. Dst, Md and Mq for case 4.

Fig. 8.  System performance under 70% grid’s voltage drop.

 

CONCLUSION:

Control of three-phase HBC in a PV charging station is proposed in this paper. The three-phase HBC can save switching loss by integration a dc/dc booster and a dc/ac converter converter into a single converter structure. A new control for the three-phase HBC is designed to achieve MPPT, dc voltage regulation and reactive power tracking. The MPPT control utilizes modified incremental conductance-PI based MPPT method. The dc voltage regulation and reactive power tracking are realized using vector control. Five case studies are conducted in computer simulation to demonstrate the performance of MPPT, dc voltage regulator, reactive power tracking and overall power management of the PV charging station. Experimental results verify the operation of the PHEV charging station using HBC topology. The simulation and experimental results demonstrate the effectiveness and robustness of the proposed control for PV charging station to maintain continuous dc power supply using both PV power and ac grid power.

 

REFERENCES:

  • Ehsani, Y. Gao, and A. Emadi, Modern electric, hybrid electric, and fuel cell vehicles: fundamentals, theory, and design. CRC press, 2009.
  • Sikes, T. Gross, Z. Lin, J. Sullivan, T. Cleary, and J. Ward, “Plugin hybrid electric vehicle market introduction study: final report,” Oak Ridge National Laboratory (ORNL), Tech. Rep., 2010.
  • Khaligh and S. Dusmez, “Comprehensive topological analysis of conductive and inductive charging solutions for plug-in electric vehicles,” IEEE Transactions on Vehicular Technology, vol. 61, no. 8, pp. 3475–3489, 2012.
  • Anegawa, “Development of quick charging system for electric vehicle,” Tokyo Electric Power Company, 2010.
  • Musavi, M. Edington, W. Eberle, and W. G. Dunford, “Evaluation and efficiency comparison of front end ac-dc plug-in hybrid charger topologies,” IEEE Transactions on Smart grid, vol. 3, no. 1, pp. 413–421, 2012.

 

Development and Comparison of an Improved Incremental Conductance Algorithm for Tracking the MPP of a Solar PV Panel

IEEE Transactions on Sustainable Energy, 2015

ABSTRACT: This paper proposes an adaptive and optimal control strategy for a solar photovoltaic (PV) system. The control strategy ensures that the solar PV panel is always perpendicular to sunlight and simultaneously operated at its maximum power point (MPP) for continuously harvesting maximum power. The proposed control strategy is the control combination between the solar tracker (ST) and MPP tracker that can greatly improve the generated electricity from solar PV systems. Regarding the ST system, the paper presents two drive approaches including open- and closed-loop drives. Additionally, the paper also proposes an improved incremental conductance algorithm for enhancing the speed of the MPP tracking of a solar PV panel under various atmospheric conditions as well as guaranteeing that the operating point always moves toward the MPP using this proposed algorithm. The simulation and experimental results obtained validate the effectiveness of the proposal under various atmospheric conditions.

KEYWORDS:

  1. Maximum power point tracker (MPPT)
  2. Solar tracker (ST)
  3. Solar PV panel

 SOFTWARE: MATLAB/SIMULINK

BLOCK DIAGRAM:

Fig. 1. Block diagram of the experimental setup.

EXPECTED SIMULATION RESULTS:

Fig. 2. Description of the variations of the solar irradiation and temperature.

Fig. 3. Obtained maximum output power with the P&O and improved InC algorithms under the variation of the solar irradiation.

Fig. 4. Obtained maximum output power with the InC and improved InC algorithms under the variation of the solar irradiation.

Fig. 5. Obtained maximum output power with the P&O and improved InC algorithms under both the variations of the solar irradiation and temperature.

Fig. 6. Obtained maximum output power with the InC and improved InC algorithms under both the variations of the solar irradiation and temperature.

Fig. 7. MPPs of the solar PV panel under the variation of the solar irradiation

Fig. 8. MPPs of the solar PV panel under both the variations of the solar irradiation and temperature.

Fig. 9. Experimental result of obtained maximum output power with the improved InC algorithm under the variation of the solar irradiation.

CONCLUSION:

It is obvious that the adaptive and optimal control strategy plays an important role in the development of solar PV systems. This strategy is based on the combination between the ST and MPPT in order to ensure that the solar PV panel is capable of harnessing the maximum solar energy following the sun’s trajectory from dawn until dusk and is always operated at the MPPs with the improved InC algorithm. The proposed InC algorithm improves the conventional InC algorithm with an approximation which reduces the computational burden as well as the application of the CV algorithm to limit the search space and increase the convergence speed of the InC algorithm. This improvement overcomes the existing drawbacks of the InC algorithm. The simulation and experimental results confirm the validity of the proposed adaptive and optimal control strategy in the solar PV panel through the comparisons with other strategies.

REFERENCES:

[1] R. Faranda and S. Leva, “Energy comparison of MPPT techniques for PV systems,” WSES Trans. Power Syst., vol. 3, no. 6, pp. 446–455, 2008.

[2] X. Jun-Ming, J. Ling-Yun, Z. Hai-Ming, and Z. Rui, “Design of track control system in PV,” in Proc. IEEE Int. Conf. Softw. Eng. Service Sci., 2010, pp. 547–550.

[3] Z. Bao-Jian, G. Guo-Hong, and Z. Yan-Li, “Designment of automatic tracking system of solar energy system,” in Proc. 2nd Int. Conf. Ind. Mechatronics Autom., 2010, pp. 689–691.

[4] W. Luo, “A solar panels automatic tracking system based on OMRON PLC,” in Proc. 7th Asian Control Conf., 2009, pp. 1611–1614.

[5] W. Chun-Sheng,W. Yi-Bo, L. Si-Yang, P. Yan-Chang, and X. Hong-Hua, “Study on automatic sun-tracking technology in PV generation,” in Proc. 3rd Int. Conf. Elect. Utility Deregulation Restruct. Power Technol., 2008, pp. 2586–2591.