Informatics Publishing Limited

H. S. Sudhakar ¹, M. S. Indira ², Gujjala B. Balaraju ³, M. Siddhartha Bhatt ⁴

Affiliations
1 Junior Research Fellow, EATD, Central Power Research Institute, Bangalore - 560080, IN
2 Principal, Sir M Visvesvaraya Institute of Technology, Bangalore - 562 157, IN
3 Electrical Appliances Technology Division, Central Power Research Institute, Bangalore - 560080, IN
4 Energy Efficiency and Renewable Energy Division, Central Power Research Institute, Bangalore - 560080, IN

Abstract

Battery is an electrochemical energy storage device that converts chemical energy into electricity, by use of a galvanic cell. The paper presents operation of lead acid battery, its chemical reactions and the charging methods to improve its performance and life span. The constant current charging mode results in overcharging of the battery as it is being pushed at full current. The constant voltage charging mode takes more time to charge the battery fully due to float charge, but the battery will not overcharge improving the life span. If the lead acid battery is undergoing deep discharge repeatedly then the life span of the battery will be less than its rated value. The operating temperature also has bearing on the life span. The paper is also presents the introduction to battery management system (BMS,) which is the heart of the battery system. The BMS involves a sophisticated supervisory control and data acquisition system (SCADA) with data management, control, protection and prediction.

Keywords

Valve regulated Lead Acid (VRLA), Ampere hour (Ah), constant current charging, constant voltage charging

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H. S. Sudhakar ¹, Gujjala B. Balaraju ¹, K. Pradeep ², M. Siddhartha Bhatt ²

Affiliations
1 Electrical Appliances Technology Division, Central Power Research Institute, Bangalore-560080, IN
2 Energy Efficiency and Renewable Energy Division, Central Power Research Institute, Bangalore-560080, IN

Abstract

Performance of a SPV system is dependent on temperature, array configuration, solar insolation, and shading across it. Shading can occur when the PV arrays/modules get covered by shadows of passing clouds, buildings, etc., or even by shadows cast by other modules/arrays. As a result the ideal operation of the PV systems is severely affected the P-V and I-V characteristics. The modeling of nonlinear current-voltage characteristics of solar cells for performance prediction becomes difficult under the influence of shading. Non-uniform solar radiation due to shadows casted by the other panels/ modules, buildings, clouds, etc. can cause maximum power to change drastically. Partial shading of PV installations has an impact on its power production. For the simulated results it has been observed that 74.66% loss in I-V characteristics and 85.41% loss in P-V characteristics respectively. The power losses in the individual shaded cells would result in local heating and create thermal stress on the entire module/array resulting in hot-spot formation.

Keywords

Maximum power point tracking (MPPT), Partial shading, Solar photovoltaic (SPV) characteristics.

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H. S. Sudhakar ¹, Gujjala B. Balaraju ¹, Pradeep K. ², Siddhartha Bhatt M. ²

Affiliations
1 Electrical Appliances Technology Division, Central Power Research Institute, Bangalore-560080, IN
2 Energy Efficiency and Renewable Energy Division, Central Power Research Institute, Bangalore-560080, IN

Abstract

In large PV hybrid power systems, battery management is critical due to the continuous operation of the power system, the limited power available for temperature control in the battery room, and the high cost of maintenance.Charge controllers are required in solar or wind power generating systems where electrical energy storage is required in these systems. Optimal charging is required in order to improve the performance and life of the batteries. The charge controllers are used for optimal charging of the entire system. The different types of charge controllers, terminologies, set points and importance of hybrid system are explained in this paper. The shunt and series type charge controller’s current and voltage regulations are shown and battery current and voltage characteristics according to the source availability and load applied are also shown for the understanding.The studies of a system of the three sources (Solar, wind and diesel generator) includes than it in practice to optimize performance by 35% by optimal charging of battery using charge controller

Keywords

Charge controller, Shunt type controller, Series type controller

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H. S. Sudhakar ¹, Gujjala B. Balaraju ¹, K Pradeep ², M. Siddhartha v ²

Affiliations
1 Electrical Appliances Technology Division, Central Power Research Institute, Bangalore - 560 080, IN
2 Energy Efficiency and Renewable Energy Division, Central Power Research Institute, Bangalore-560 080, IN

Abstract

MPPT algorithms are necessary in PV applications because the MPP of a solar panel varies with the irradiation and temperature, so the use of MPPT algorithms is required in order to obtain the maximum power from a solar array.Over the past decades many methods to find the MPP have been developed and published. These techniques differ in many aspects such as required sensors, complexity, cost, range of effectiveness, convergence speed, correct tracking when irradiation and/or temperature change, hardware needed for the implementation or popularity, among others. Among these techniques, the P&O and the In Cond algorithms are the most common. These techniques have the advantage of an easy implementation but they also have drawbacks, as will be shown later. Other techniques based on different principles are fuzzy logic control, neural network, fractional open circuit voltage or short circuit current, current sweep, etc. Most of these methods yield a local maximum and some, like the fractional open circuit voltage or short circuit current, give an approximated MPP, not the exact one. In normal conditions the V-P curve has only one maximum, so it is not a problem. However, if the PV array is partially shaded, there are multiple maxima in these curves.

Keywords

Battery Energy Storage System, Maximum Power Point, Optimal Charging

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