Intelligent Control Based Effective

International Journal of Applied Engineering Research, ISSN 0973-4562 Vol. 10 No.4 (2015) pp.3952-3957 © Research India Publications; http://www.ripublication.com/ijaer.htm

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Intelligent Control Based Effective Utilization of Renewable Energy Sources

A.Dhanam G.Anandha Kumar1, M.Venkatesh Kumar2, Dr.P.Shankar3

UG students, Saveetha School of Engineering Associate Professor -Department of EnEE, Saveetha School of Engineering, Saveetha University

Assistant Professor(SG) -Department of EnEE, Saveetha School of Engineering, Saveetha University Principal, Saveetha School of Engineering, Saveetha University

[email protected], [email protected], [email protected]

Abstract - In this paper we focus on the load optimization and management of battery storage for improving the utilization of Renewable energy sources. Intelligent Controller based system continuously monitors the charge available in the Battery and indicates the amount of charge remaining in the Battery Level indicator. Based on the amount of charge remaining the charging and discharging of the battery is controlled by Fuzzy Logic controller. Distribution of power among the loads and priority to the load is decided by the Fuzzy Logic controller based on the amount of charge remaining in the battery. Comparing to conventional BMS it is a more suitable solution for Renewable Energy due to its high flexibility and scalability.

Keywords - Renewable Energy Source,

I. INTRODUCTION

The Renewable Energy Power System has been put into operation, requires long charge time and a smallest of charge equipment to limit the cost requirement of the entire system. To solve the problem that it must take long time for battery to charge and to wait for charge, a new quickly swapping battery package mode is brought out. That is, we can charge the battery packages in early time and exchange the battery packages on the source with the full-charged packages when it is required. Thus it is easier for a battery charge. Compared with the old-style charging mode, this new charge mode has relatively a large difference. In this paper we analyze the features of this mode, and do some research on it. After that we give out some ideas applicable. At last we apply the ideas to monitor the state of the battery online, charge battery packages and battery unit under the control of BMS (battery management system), identify parameter, estimate and calibrate SOC (State of charge).

Problems in the charge mode: 1. Communication network 2. Parametric recognition

3. Battery packages recombination 4. Battery package charge 5. SOC estimate and calibration

II. METHODS AND OPERATION A. Measure Function Battery Management System uses MC9S12 Series Chip as Center Microchip Unit to complete the measure of the battery voltage, temperature, current and the remaining battery capacity (AH). a) Voltage Measure We use the multi-channel MOSFET and resistor to get the voltage signal. After that, the signal must be filtered so as to get rid of the 50HZ ripple from electric net during charging. In the end we use A/D converter to get the value of the battery voltage.

Fig 1. Battery voltage Measurement

b) Temperature Measure We use temperature A/D converter to get the value of temperature. All A/D converters are tie in a bus. So it is easy for us to lay the temperature A/D. c) Current Measure (Ah counting) We use current sensor to get the battery current as precise quickly as possible. At the same time, the


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current sample A/D can also calculate the current integral for energy and SOC. B. The Package Mode When battery union is broken into packages, slavers can also send messages to portable equipment for monitor by slaver CAN, and also send messages to charger for control. Once battery packages are placed for use in the renewable energy source, we can also measure voltage, temperature, battery package message, charge message thought slaver CAN, etc. In this mode, for traditional BMS used in renewable energy source [4], because of losing the brain of master, it cannot deliver the battery messages and control the process of the charge and discharge. C. Battery Packages Charge For traditional battery charging, the series connected battery union in an renewable energy source is usually charged as a whole. So the process of charge is completed under the control of BMS master[8]. But once the battery union is broken to packages, without the "brain" --- the BMS master, the process of charge can only rely on professional people to complete. But in the new communication system above, we know that battery package has RS485 and CAN interfaces[3]. As the Figure , when the capacity of battery is little, we can make the charger voltage output connected to the battery package, and also we tie the communication line (RS485) to BMS slaver RS485 interface. Before the charger gives out current, it must confirm that a well data link between BMS and charger is establishment. Then, BMS slaver must send some battery messages and charge messages to the charger. After the charger sends commend to BMS slaver, the process begins. In the charging process, BMS slaver detects the state of battery in the package on-line. It also needs to analyze how to charge the battery package according to voltage, temperature, the health of any battery. At the same time, BMS slaver also can send the messages to the charger by RS485 bus. The charger can change its charge voltage or charge current to adapt to the battery package. When BMS detected appeared over-charged battery, charger will be informed to reduce the charge current. At last the charger will complete the charging process of CC and CV.

Fig 2. Packages Charge Mode

III. BATTERY MANAGEMENT SYSTEM

The BMS normally provides inputs to protection devices which generate alarms or disconnect the battery from the load or charger when any of the parameters become out of limits. The major objectives of BMS are [10]: (1) to protect the cells or the battery from damage; (2) to prolong the life of the battery; and (3) to maintain the battery in a state in which it can fulfill the functional requirements of the application for which it was specified. Thus, the BMS may incorporate one or more of the following functions: cell protection, charge control, demand management, state of charge (SOC) determination, state of health (SOH) determination, cell balancing, communication, and etc. Fig shows the BMS which was developed in the previous study. The SOC of each cell can be monitored by a BIM (Battery Interconnect Manager), as shown in Fig. and each BIM is instructed by the BWM (Battery Module Manager), as shown in Fig, to communicate with its next neighbor BIM through a communication bus. Once overcharging or over- discharging of a cell occurs, the BIM reports to its supervised BWM and self-purge to maintain the safety of the system. The BIM configuration provides very easy interface with its neighbors and offer the salient feature of plug-and-play[5,9].

A. Charging State The charging module contains one or more smart battery chargers. The charging module charges one or more battery units connected in series or in parallel. For simplicity of discussion, only the configurations for the smart BMS with only one CDM-PPA module are demonstrated. Fig. shows that the battery unit U1 is charged.


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Fig 3. Battery Management System

Switches SUP1 and SUM1 are turned on forming a battery path which includes U1, and switches SP1 and SM1 are turned on to connect the battery path to the smart battery charger. Similarly, it can easily to generate a path that causes the smart charger to charge more than one battery units[2]. For example, the path may include both units U1 and U2 connected in series, or include both units U1 and U3 connected in series with bypassing unit U2. If it is desired to charge the smart battery units U1 and U3 connected in parallel, one can turn on corresponding switches to form two paths, Path #1 and Path #2, containing U1 and U3, respectively. Both paths are then connected to the smart battery charger, as shown in Fig 4. B. Discharging State When any of the smart battery units has its power almost used up during discharge, the control circuitry will control the corresponding switches to isolate the unit and timely add one or more smart battery units according to the power requirements of the discharging module. Consequently, the discharging capacity[6] of the smart battery module can be maintained in a desired and usable range while allowing the rest of smart battery units smoothly discharge without interruption[1]. In Fig.4 the smart battery module is in its discharging state. The load requires the power supplied by three smart battery units U1, U2, and U3. The corresponding switches are turned on and off to make these units connected in series before making the serially connected to the

load. Suppose that the load needs the power supplied by four units U1, U2, U5, and U6.

Fig 4. Smart Battery Module

Fig. 5(b) illustrates the configuration, where both units U3 and U4 are bypassed and isolated. Serially-connected battery units provide higher supplied voltage, while parallel-connected battery units deliver more currents. Similar to Fig. 4(b), one can generate parallel-connected battery units to connect to the load for delivering more currents. Fig. 6 shows that the proposed BMS provides various output voltages so that the smart battery module is used more flexibly and enhances the utilization rate of the discharge energy, improving the overall power efficiency of the smart battery module. Load1, Load2, and Load3 are respectively discharged by the supplied voltages from one, two, and three battery units.

IV. BENEFITS

Safety: Improves safety of high-voltage batteries and decreases the occurrence of thermal runaway and catastrophic failures

Reliability: Utilizes a low pin count, causing reduced complexity and increased reliability

Dual-purpose: Detects the individual bad cells within series and parallel cells

Extended battery life: Manages battery cells within a string, which increases the life of battery systems


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Decreased battery damage: Prevents damage from too much or too little voltage

Limited charge current: Balances cells by adding charge to individual cells after main charge is complete

Low cost: Provides a less expensive alternative to existing, commercially available solutions

V. FUZZY LOGIC

In contrast to conventional control techniques, fuzzy logic control (FLC) is best utilized in complex ill-defined processes that can be controlled by a skilled human operator without much knowledge of their underlying dynamics[7]. The basic idea behind FLC is to incorporate the "expert experience" of a human operator in the design of the controller in controlling a process whose input – output relationship is described by collection of fuzzy control rules (e.g., IF-THEN rules) involving linguistic variables rather than a complicated dynamic model. The utilization of linguistic variables, fuzzy control rules, and approximate reasoning provides a means to incorporate human expert experience in designing the controller. FLC is strongly based on the concepts of fuzzy sets, linguistic variables an approximate reasoning introduced in the previous chapters. This chapter will introduce the basic architecture and functions of fuzzy logic controller, and some practical application examples. A typical architecture of FLC is shown below, which comprises of four principal comprises: a fuzzifier, a fuzzy rule base, inference engine, and a defuzzifier. If the output from the defuzzifier is not a control action for a plant, then the system is fuzzy logic decision system. The fuzzifier has the effect of transforming crisp measured data (e.g. speed is 10 mph) into suitable linguistic values (i.e. fuzzy sets, for example, speed is too slow). The fuzzy rule base stores the empirical knowledge of the operation of the process of the domain experts.~ The inference engine is the kernel of a FLC, and it has the capability of simulating human decision making by performing approximate reasoning to achieve a desired control strategy.The defuzzifier is utilized to yield a non-fuzzy decision or control action from an inferred fuzzy control action by the inference engine

Fig 5. Operation of a Fuzzy Logic

Controller

Fig 6. Block Diagram

VI. EXPLANATION

This block diagram illustrates the photovoltaic power system and wind energy is the input source. From photovoltaic power system the output is given to DC-DC converter. DC-DC converters convert only DC voltage to constant 12V DC. From the wind energy the output will be AC supply. To convert AC –DC rectifiers are used. This both converter and rectifiers are connected to the battery through bus bar. From the battery DC-AC inverter is connected. Inverter is connected because it is AC load. From the battery other side battery level indicator is used. This indicator will help to show the battery level in LED display. Battery is important in this project because according to the battery level the load will be in ON or OFF condition. This load is controlled by an intelligent controller. According to the battery level the controller will control the load.


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Fig 7. Simulation Model

Fig 8. Battery Voltage Waveform Fig 9. Battery Capacity in Percentage

Fig 10. Load Current Waveform


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VII. CONCLUSION

Thus a Battery Management system for effective utilization of the Renewable energy source by increasing the efficiency of the battery storage has been implemented. ARM Processor based embedded system acts as battery level indicator which continuously monitors the status of the battery and displays the available amount of Battery Capacity in terms of percentage. Fuzzy logic controller monitors the available amount of battery Capacity and distributes to the load accordingly, thereby flexible and efficient utilization of the Renewable energy Source has been achieved.

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Intelligent Control Based Effective