design of single-phase grid-connected based on …ieomsociety.org/ieom_2016/pdfs/100.pdfa novel mppt...

Proceedings of the 2016 International Conference on Industrial Engineering and Operations Management Kuala Lumpur, Malaysia, March 8-10, 2016

Design of Single-Phase Grid-Connected Based on Dual-MPPT for Photovoltaic Generation Systems

Slamet Malaysia – Japan International Institute of Technology (MJIIT)

University Teknologi Malaysia Kuala Lumpur Jalan Semarak, 54100 Kuala Lumpur, MALAYSIA

[email protected]

Rasli bin Abd Ghani Malaysia – Japan International Institute of Technology (MJIIT)


[email protected]

Fuminori Kobayashi Malaysia – Japan International Institute of Technology (MJIIT)


[email protected]

Abstract—A new development of Dual-MPPT algorithm for single-phase grid-connected photovoltaic generation systems under variation of irradiance is presented in this research. This method is extract the maximum available power from PV module by making them operates at the most efficient output and fastest transient response. In order to accelerate the tracking speed, an incremental conductance based integral proportional (IP) controller and integrated with a new maximum power point tracking (MPPT) based on control region for operating the dc–dc converter is also proposed, which uses the reference voltage information from the tracking algorithm to shift the operation toward the maximum power point(MPP). For synchronizing to grid voltage is used a synchronization algorithm by using two phase locked loop (PLL) as a reference and feedback for the synchronization controller. Simulation and experiment results show that the Grid-Connected controller functions well in regulating the output voltage and current under variation of irradiance. The developed controller can regulate the output voltage and current in the same phase under irradiance variation from 1000 W/m2 to sudden irradiance of 600 W/m2, and from 600 W/m2 to sudden irradiance of 1200 W/m2. The tracking time with this controller is about one-sixth as compared to an incremental conductance. When the system connected to the grid at the time of 3.5s the output voltage experiences small drop before it is recovered to stable condition. It can be concluded that the developed control system works well satisfying the design specification.

Keywords— grid-connected; dual-MPPT; integral- proportional; phase locked loop; controller; synchronization

I. INTRODUCTION

Energy is currently one of the human needs in daily life. Although the energy crisis and environmental pollution that happened makes a lot of people begin to look to renewable energy sources and environmentally friendly. Therefore, research in the field of renewable energy has now become a very interesting topic to be studied in depth. Solar power plant (SPP) became one of the alternatives being chosen topic to be developed for several reasons, namely pollution-free, energy sources can be obtained for free and widely available in nature. The presence of simultaneous developments in the field of materials technology and electronics, which are useful in increasing efficiency, is also a major reason why research in the field of photovoltaic (PV) energy intensified and rapid growth. The main problem to be able to provide a source of electrical energy which is synchronous with the electrical network power supply is a challenge for the development of renewable energy sources, especially solar cells. The solar cells are required to become an alternative energy source that can provide cheaper power supply, simple (plug and play) and reliable, especially in housing with single-phase power system. A PV array and an electrical power system connected to a dc-dc converter and a dc/ac inverter as energy conversion system. To track the maximum power point of the PV array used the various maximum power-point tracking (MPPT) methods in the dc-dc converter [1]. The rectifier-arm based on the MPPT control algorithm was used to control the maximum power point tracking (MPPT) of the PV modules and a variable dc-link voltage is used for balancing the power among utility, PV, and the load [2]. A controller was designed on the basis of customizing perturb and observe (P&O) to optimize one cycle controlled single-phase inverter in order to perform a real MPPT in presence of varying irradiance conditions[3]. A single-phase three-level

3210© IEOM Society International


diode clamped inverter was used to improve the efficiency and reduce the current ripple has been proposed [4]-[5]. To implement a digital proportional–integral current control algorithm was used a DSP TMS320F2812 to keep the current injected into the grid sinusoidal and to have high dynamic performance with rapidly changing atmospheric conditions [6]. To overcome this drawback of maximum power point tracking (MPPT) method in dc-dc converter was presented a buck–boost principle [7]. To reduce the system complexity and cost with a high performance was applied a simple maximum-power-point-tracking method based on power balance in the PV system [8]. A novel Maximum Power Point tracking algorithm based on Differential Evolution (DE) was used in conjunction with a Boost (step up) DC-DC converter to track the global peak [9]. A novel MPPT method capable of RMPPT under PSCs was proposed to overcome under solar irradiance mismatching conditions [10]. The incremental conductance (IncCond) algorithm is identified as the best method, primarily because it is easy to implement in DSP [11]. A current control strategy is developed to overcome instability problems associated with the series compensated transmission connecting the photovoltaic system to the grid [12]. An OCC-based grid-connected single-stage PV system was proposed to overcome the aforementioned limitation [13]. The total efficiency of the single-stage system has been improved around 10% over the range of the power rating [14]. The dynamics of the system due to the interaction between the proportional-resonant-integral (PRI) controller and the adaptive compensation scheme was also analyzed [15]-[16]. The inner loop stability is analyzed, and the proper parameters were selected. In the outer loop, proportional–integrator (PI) controller was applied to stabilize the dc-link voltage, and power feed-forward is introduced to speed up system response [17]-[18]. High efficiency and fast transient response time are essential features of any PV source simulator. The simulator efficiency, including the active-front-end rectifier and the converter stages, peaks at 96.7% [19]. The design of the model reference adaptive control (MRAC) algorithm was implemented to eliminate the underdamped modes in power conversion [20]. The discontinuous current mode (DCM) converter was applied to a grid-connected converter for domestic renewable energy and energy storage, including Photovoltaic and battery energy storage devices [21]. A multiple-integrated converter module sharing an unfolding full-bridge inverter with a pseudo dc link (MIPs) was used for grid-connected photovoltaic systems that can improve the power conversion, the control circuit complexity, and the cost competitiveness [22]-[23]. A new nonlinear current control scheme for a single-phase grid-connected photovoltaic (PV) system was designed using partial feedback linearization [24]-[25]. The overall peak efficiency of the Module integrated converters (MICs) in single phase was measured and found to be 96% with 98.2% in the first stage and 98.3% in the second stage. On the other hand, have improved energy harvest, improved system efficiency, lower installation costs, plug-and-play operation, enhanced flexibility, and modularity [26]-[27]. A simple notch filtering control algorithm was designed to facilitate extraction of the real component of load current, exempting the services of a phase locked loop (PLL). The absence of a PLL reduces the system dependence on the proportional-integral (PI) controller tuning, which in turn improves the dynamic response and makes the system quite robust [28]. A constant peak current switching scheme was implemented by a cycle-by-cycle predictive controller that uses a fast integrator to control the switching period, achieving high bandwidth and stability. The prototype uses standard silicon devices and a small inductor to achieve a weighted efficiency of 99.15% [29]. The proposed paper mainly concentrates on the dual MPPT method algorithm for single-phase grid-connected. This study will be done the modeling, simulation and analysis of the system that can be used to provide power supply in synchronizing with the power supply of electrical network without being connected to the battery.

II. PROPOSED DESIGN OF DUAL MPPT METHOD FOR SINGLE-PHASE GRID-CONNECTED

A. Dual MPPT method Dual MPPT method is connected between a new MPPT (NMPPT) algorithm and incremental conductance Method

(IncCond) preexisting. NMPPT controller is designed to make solar cells working at the gradient point on the P-V curve is zero. Therefore, the set point for controlling the constant NMPPT is zero, while the feedback is the gradient of the PV characteristic curve. Positive gradient means that the working point is located on the left side maximum power point (MPP), then Vref must be added, while the negative gradient opposite. The error as a controller input of NMPPT upside down, set point as a negative input, while the feedback as positive feedbacks. Calculation error of controller input determines the quality NMPPT shown in equation (1).

. .

( ).

dV I dI Verror

dVI Iprev V

error IV Vprev

+=

−= +

Δ −

(1)

where,

Vprev = previous voltage



Iprev = previous current V = output voltage of PV

MPPT algorithm is designed to provide reference voltage (Vref) with two different objectives. The First, a large Vref with constant change that is used to calculate the error as an input controller of NMPPT. Secondly, Vref with varies changes that come from NMPPT controller to find the point of maximum work quickly and keep the system working at that point. The proposed of NMPPT algorithm is used to separate the control region, the current source region, and voltage source region by utilizing a controlled gradient value. Controller parameter values for each region are shown in Table 1.

TABLE I. PARAMETERS OF NMPPT CONTROLLER

Controller Parameters of NMPPT Controller

Current Source Region Control Region Voltage Source Region

Kc 0.03 0.1 0.2

τi 0.3×10-3 0,2×10-3 0,3×10-3

Dual MPPT algorithm is expressed through the flow chart diagram shown in Fig. 1.

1_ 1 1

0

( ) ( )t

pPV ref p

i

KV K e t e t dt

T= + ∫

2_ 2 2

0

( ) ( )t

pPV ref p

i

KV K e t e t dt

T= + ∫

__ _ _

0

( ) ( )t

p mppPV ref mpp p mpp

i

KV K e t e t dt

T= + ∫

I Ip r evV V p r e v

Ie r ro r I VV

==

Δ= + •Δ

Ierror I VV

Δ= + •Δ

Fig. 1. The control flow chart of Dual MPPT method

B. All combination circuits with Dual MPPT method All combination circuits model consisting of irradiance, ambient temperature, number of solar cell panels arranged 15

series (NS) and the switch signal 1 to the switch signal 7 is written in the programming language C ++. Switch 1 through 7 has a value of ‘1’ means the switch closed or ‘0’ means the switch opened. Dual MPPT block requires the input current (IPV) and input voltage (VPV) of solar cell flowing in the grid-connected inverter system. With these input parameters, then the Dual MPPT algorithm searches the point value of the working voltage of solar cells are optimized to produce maximum output power. The reference voltage value of Dual MPPT is compared with the voltage value measured of the solar cell system. The difference between the reference voltage value and the value of the measurement results is controlled by an Integral-Proportional (IP) controller with a value of Kp = 0.001 and Ki = 1, which is determined by trial and error. The output of the

Ministry of Energy and Mineral Resources Republic Indonesia



controller is a duty cycle value that forms the pulse width modulation (PWM) signal. Furthermore, PWM signal becomes the input for the signal switch ‘1’. Test of verification for Dual MPPT method is done by changing the value of irradiance varied so that the output voltage variation of the Dual MPPT method can provide a reference voltage value of the solar cell, so it can also operate at the working point voltage the most optimal and produce maximum output power. In the simulations, the temperature of the solar cell is given the value of 298 K (25 ° C) while the irradiance value varied based on the following conditions at t <2s and λ = 1000 Watt / m2; at 2s <t <3s and λ = 600 Watt / m2; and at t> 3s, λ = 1200 Watt/m2. The diagram block of single-phase grid-connected PV generation based on dual-MPPT method is shown in Fig. 2.

Fig. 2. Block Diagram of Single-Phase Grid-Connected with Dual MPPT method

III. SIMULATION RESULTS AND DISCUSSION

Fig.3. shows the output voltage of the solar cell (VPV) with a reference voltage (V*PV) which is the output of the MPPT

algorithm. From this picture it appears that VPV generated by the solar cells can follow the reference voltage value. Initially the output value of VPV system volatile and continue to increase following the V*

PV values and eventually reach at a point where the MPPT algorithm has found the optimum working point of the solar cell. The VPV value continues to follow V*

PV value due to the IP controller uses, so that the working point voltage of the solar cell can reach a value of around 260 Volt approaching the point value of the working voltage of solar cells that achieve the reference value around 260 Volt. In the t=3.5s, The voltage of solar cells experiences a voltage drop of 152.26 Volt, this happens due to the signal switch 7 is in an active state, which means the state of grid-connected, thus making the value of the grid voltage influence into the solar cell voltage value. Finally, the solar cell voltage can be returned following the reference voltage value with better transient response in accordance with the design IP controller implemented.



Fig. 3. Output voltage of solar cells versus reference voltage with varies methods

Ideally, the value of current and voltage are in phase that resulting the supply of power to the maximum load.

Fig. 4. Load voltage versus Inductor current (IL2)



Fig. 5. Load voltage versus Inductor current (IL2): (enlargement)

Fig.4. shows the magnitude of the current and voltage supplied to the load (R2, RY and L3). Before the t=2.5s, there is no current or voltage supplied to the load, and due to the switch 6 and 7 are still in the OFF state. In Fig. 5 (magnification of Fig. 4) it appears that after the t=2.5s, the switch 6 in the ON state, then came the current and voltage supplied to the load, Thecurrent and voltage appears in the same phase condition..

ACKNOWLEDGMENT The authors would like to thank the Malaysia – Japan International Institute of Technology (MJIIT), University Technology Malaysia Kuala Lumpur, and the Ministry of Energy and Mineral Resources of the Republic of Indonesia for providing the facilities to carry out this research activity.

REFERENCES [1] Y. Kuo, T. Liang, and J. Chen, “A High-Efficiency Single-Phase Three-Wire,” vol. 50, no. 1, pp. 116–122, 2003.[2] I. Nomenclature, “Single-Phase Grid-Connected PV System using Three-Arm,” vol. 42, no. 1, pp. 211–219, 2006.[3] I. Introduction, “Optimized One-Cycle Control in Photovoltaic Grid Connected Applications,” vol. 42, no. 3, 2006.[4] R. González, E. Gubía, J. López, and L. Marroyo, “Transformerless Single-Phase Multilevel-Based,” vol. 55, no. 7, pp. 2694–2702,

2008.[5] S. G. P. V. C. Inverters, C. Meza, J. J. Negroni, D. Biel, and F. Guinjoan, “Energy-Balance Modeling and Discrete Control for,” vol.

55, no. 7, pp. 2734–2743, 2008.[6] H. Patel, V. Agarwal, and S. Member, “A Single-Stage Single-Phase Transformer-Less,” vol. 24, no. 1, pp. 93–101, 2009.[7] J. Selvaraj and N. a. Rahim, “Multilevel Inverter For Grid-Connected PV System Employing Digital PI Controller,” IEEE Trans. Ind.

Electron., vol. 56, no. 1, pp. 149–158, Jan. 2009.[8] B. Yang, W. Li, “Design and Analysis of a Grid-Connected Photovoltaic Power System,” vol. 25, no. 4, pp. 992–1000, 2010.[9] H. Taheri, Z. Salam, and K. Ishaque, “and Rapidly Fluctuating Shadow Conditions,” no. Isiea, pp. 82–87, 2010.[10] Y.-H. Ji, D.-Y. Jung, J.-G. Kim, J.-H. Kim, T.-W. Lee, and C.-Y. Won, “A Real Maximum Power Point Tracking Method for

Mismatching Compensation in PV Array Under Partially Shaded Conditions,” IEEE Trans. Power Electron., vol. 26, no. 4, pp. 1001–1009, Apr. 2011.

[11] S. Balathandayuthapani, C. S. Edrington, S. Member, S. D. Henry, J. Cao, and S. Member, “Analysis and Control of a PhotovoltaicSystem : Application to a High-Penetration Case Study,” vol. 6, no. 2, pp. 213–219, 2012.

[12] D. Dong, S. Member, T. Thacker, I. Cvetkovic, S. Member, R. Burgos, D. Boroyevich, F. Wang, and G. Skutt, “Modes of Operationand System-Level Control of Single-Phase Bidirectional PWM Converter for Microgrid Systems,” vol. 3, no. 1, pp. 93–104, 2012.

[13] S. E. S., K. Chatterjee, and S. Bandyopadhyay, “One-Cycle-Controlled Single-Stage Single-Phase Voltage-Sensorless Grid-Connected PV System,” IEEE Trans. Ind. Electron., vol. 60, no. 3, pp. 1216–1224, Mar. 2013.

[14] G. Hsieh, S. Member, H. Hsieh, C. Tsai, and C. Wang, “Photovoltaic Power-Increment-Aided With Two-Phased Tracking,” vol. 28,no. 6, pp. 2895–2911, 2013.



[15] G. D. G. System, A. Luo, S. Member, Y. Chen, Z. Shuai, and C. Tu, “An Improved Reactive Current Detection and Power ControlMethod for Single-Phase Photovoltaic,” vol. 28, no. 4, pp. 823–831, 2013.

[16] G. P. V System, B. N. Alajmi, K. H. Ahmed, S. Member, G. P. Adam, and B. W. Williams, “Single-Phase Single-Stage Transformerless,” vol. 28, no. 6, pp. 2664–2676, 2013.

[17] G. S. P. V Inverter, “Mitigation of Lower Order Harmonics in a,” vol. 28, no. 11, pp. 5024–5037, 2013.[18] M. Jang, S. Member, and M. Ciobotaru, “A Single-Phase Grid-Connected Fuel Cell System Based on a Boost-Inverter,” vol. 28, no.

1, pp. 279–288, 2013.[19] R. Khanna, Q. Zhang, W. E. Stanchina, and G. F. Reed, “Reference Adaptive Control,” vol. 29, no. 3, pp. 1490–1499, 2014.[20] A. Koran and T. LaBella, “High Efficiency Photovoltaic Source Simulator with Fast Response Time for Solar Power Conditioning

Systems Evaluation,” IEEE Trans. Power Electron., vol. 29, no. 3, pp. 1285–1297, Mar. 2014.[21] T. Isobe, K. Kato, N. Kojima, and R. Shimada, “Soft-Switching Single-Phase Grid-Connecting Converter Using DCM Operation and

a Turn-Off Snubber Capacitor,” IEEE Trans. Power Electron., vol. 29, no. 6, pp. 2922–2930, Jun. 2014.[22] M. A. Mahmud, H. R. Pota, M. J. Hossain, and S. Member, “Nonlinear Current Control Scheme for a Single-Phase Grid-Connected

Photovoltaic System,” vol. 5, no. 1, pp. 218–227, 2014.[23] T. G. Module, “Design and Implementation of Three-Phase Integrated Converter,” vol. 29, no. 8, pp. 3881–3892, 2014.[24] S. Silvestre, S. Member, A. Chouder, and E. Karatepe, “Global MPPT Scheme for Photovoltaic String Inverters Based on Restricted

Voltage Window Search Algorithm,” vol. 61, no. 7, pp. 3302–3312, 2014.[25] B. Singh, C. Jain, S. Goel, and S. Member, “ILST Control Algorithm of Single-Stage Dual Purpose Grid Connected Solar PV

System,” vol. 29, no. 10, pp. 5347–5357, 2014.[26] T. V Thang, N. M. Thao, J. Jang, J. Park, and S. Member, “Analysis and Design of Grid-Connected Photovoltaic Systems With

Multiple-Integrated Converters and a Pseudo-DC-Link Inverter,” vol. 61, no. 7, pp. 3377–3386, 2014.[27] A. El Khateb, N. A. Rahim, J. Selvaraj, and M. N. Uddin, “Fuzzy-Logic-Controller-Based SEPIC Converter for Maximum Power

Point Tracking,” IEEE Trans. Ind. Appl., vol. 50, no. 4, pp. 2349–2358, Jul. 2014.[28] S. Deo, C. Jain, and B. Singh, “A PLL-Less Scheme for Single-Phase Grid Interfaced Load Compensating Solar PV Generation

System,” IEEE Trans. Ind. Informatics, vol. 11, no. 3, pp. 692–699, Jun. 2015.[29] Y. Levron and R. W. Erickson, “High Weighted Efficiency in Single-Phase Solar Inverters by a Variable-Frequency Peak Current

Controller,” IEEE Trans. Power Electron., vol. 31, no. 1, pp. 248–257, Jan. 2016.

BIOGRAPHY

Rasli bin Abd Ghani is a senior lecture in the department of Electronic System Engineering from Malaysia-Japan International Institute of Technology (MJIIT), Universiti Teknologi Malaysia (UTM). He is teaching in Power System, Power Electronic and Drives, Automation and Electronic System courses. A graduate of UTM, Kuala Lumpur, he received his MEE (Hons) and PhD from UTM and Universiti Kebangsaan Malaysia (UKM), Bangi respectively. He has published several papers in renowned journals. His areas of current interest include Power Fault Analysis, Power Electronic Conversion, Harvester Energy, High Voltage Technology and Lightning Phenomena.

Fuminori Kobayashi received Ph.D degree in control engineering from Tokyo Institute of Technology in 1980, when he became a research associate in Nagaoka University of Technology. In 1989, he moved to Kyushu Institute of Technology, where he had worked as an associate professor, professor, dean and vice president. Since 2012, he has been with Universiti Teknologi Malaysia as a professor and deputy dean. He is interested in circuits and systems and is a member of IEEE.

Slamet received the M.Eng degree in control engineering from the University of Indonesia. He is currently working toward the Ph.D. degree in electronic systems engineering at the University Technology Malaysia, Malaysia. His dissertation research concerns the analysis and control of grid-connected PV systems. He is currently a Researcher at the ministry of energy and mineral resources, Indonesia. His research interests include nonlinear control and renewable energy control systems.


design of single-phase grid-connected based on …ieomsociety.org/ieom_2016/pdfs/100.pdfa novel mppt...

Documents