A Coordinated Control Method for Leveling PV Output Power Fluctuations of PV–Diesel Hybrid Systems Connected to Isolated Power Utility

A photovoltaic (PV) system's power output is not constant and fluctuates depending on weather conditions. Fluctuating power causes frequency deviations and reduction in reliability of the isolated power utility or microgrid when large output power from several PV systems is penetrated in the utility. In this paper, to overcome these problems, a simple coordinated control method for leveling the fluctuations of combined power output from multiple PV systems is proposed. The conflicting objective of output power leveling and acquisition power increase is achieved by means of the proposed method. Here, output power command is generated in two steps: central and local. Fuzzy reasoning is used to generate the central leveling output power command considering insolation, variance of insolation, and absolute average of frequency deviation. In local step, a simple coordination is maintained between central power command and local power commands by producing a common tuning factor. Power converters are used to achieve the same output power as local command power employing PI control law for each of the PV generation systems. The proposed method is compared with the method where a modified maximum power point tracking control is used for smoothing the short-term change in each of the PV system's output. Simulation results show that the proposed method is effective for leveling output power fluctuations and feasible to reduce the frequency deviations of the isolated power utility to maintain reliability.

[1]  H. Asano,et al.  Influence of photovoltaic power generation on required capacity for load frequency control , 1996 .

[2]  Richard Perez,et al.  Maximizing the value of customer-sited PV systems using storage and controls , 2007 .

[3]  Chuen-Chien Lee.  FUZZY LOGIC CONTROL SYSTEMS: FUZZY LOGIC CONTROLLER - PART I , 1990 .

[4]  Rainer Dr Wagner,et al.  Large lead/acid batteries for frequency regulation, load levelling and solar power applications , 1997 .

[5]  Hong-Sung Kim,et al.  Advanced grid connected PV system with functions to suppress disturbance by PV output variation and customer load change , 2001 .

[6]  R. Belmans,et al.  Voltage fluctuations on distribution level introduced by photovoltaic systems , 2006, IEEE Transactions on Energy Conversion.

[7]  Tomonobu Senjyu,et al.  Output power control for large wind power penetration in small power system , 2009 .

[8]  Yu-Kai Chen,et al.  Robust fuzzy controlled photovoltaic power inverter with Taguchi method , 2002 .

[9]  Kenji Kobayashi,et al.  A study on a two stage maximum power point tracking control of a photovoltaic system under partially shaded insolation conditions , 2003, IEEE Power Engineering Society General Meeting.

[10]  Kosuke Kurokawa,et al.  Peak-power reduction with 100 kW PV and battery combined system at Shonan Institute of Technology , 2001 .

[11]  Tsai-Fu Wu,et al.  Photovoltaic inverter systems with self-tuning fuzzy control based on an experimental planning method , 1999, Conference Record of the 1999 IEEE Industry Applications Conference. Thirty-Forth IAS Annual Meeting (Cat. No.99CH36370).

[12]  Takeyoshi Kato,et al.  Evaluation of LFC capacity for output fluctuation of photovoltaic power generation systems based on multi-point observation of insolation , 2001, 2001 Power Engineering Society Summer Meeting. Conference Proceedings (Cat. No.01CH37262).

[13]  T. Funabashi,et al.  Generating power leveling of renewable energy for small power system in isolated island , 2005, Proceedings of the 13th International Conference on, Intelligent Systems Application to Power Systems.

[14]  Takeyoshi Kato,et al.  Smoothing of PV system output by tuning MPPT control , 2005 .

[15]  Fuzzy Logic in Control Systems : Fuzzy Logic , 2022 .

[16]  Boriana L. Milenova,et al.  Fuzzy and neural approaches in engineering , 1997 .

[17]  Piero P. Bonissone,et al.  Automated fuzzy knowledge base generation and tuning , 1992, [1992 Proceedings] IEEE International Conference on Fuzzy Systems.

[18]  John P. Barton,et al.  A probabilistic method for calculating the usefulness of a store with finite energy capacity for smoothing electricity generation from wind and solar power , 2006 .

[19]  K. Kiefer,et al.  Power characteristics of PV ensembles: experiences from the combined power production of 100 grid connected PV systems distributed over the area of Germany , 2001 .

[20]  Susumu Yamashiro,et al.  Development of an Advanced Grid-Connected PV-ECS System Considering Solar Energy Estimation , 2005 .

[21]  Jongrong Lin,et al.  Implementation of a DSP-controlled photovoltaic system with peak power tracking , 1998, IEEE Trans. Ind. Electron..

[22]  Chuen-Chien Lee,et al.  Fuzzy logic in control systems: fuzzy logic controller. II , 1990, IEEE Trans. Syst. Man Cybern..

[23]  T. Senjyu,et al.  Output levelling of renewable energy by electric double-layer capacitor applied for energy storage system , 2006, IEEE Transactions on Energy Conversion.

[24]  J. R. McDonald,et al.  Model validation and coordinated operation of a photovoltaic array and a diesel power plant for distributed generation , 2001, 2001 Power Engineering Society Summer Meeting. Conference Proceedings (Cat. No.01CH37262).

[25]  M. Vitelli,et al.  Optimization of perturb and observe maximum power point tracking method , 2005, IEEE Transactions on Power Electronics.