Phase Photovoltaic Research Articles

An experimental simulation testing of single-diode PV integrated mppt grid-tied optimized control using grey wolf algorithm

In the context of this paper a three phase grid connected Photo-Voltaic (PV) system that is used to design with MPPT and developed Grey Wolf optimization (GWO) algorithm for analyzing the power quality issues in the grid system. The proposed Grey Wolf optimization (GWO) algorithm is incorporated in the prototype model and compared with other related optimization algorithms namely Particle Swarm Optimization (PSO) and Genetic Algorithm (GA). The various loading conditions as well as solar irradiances are modeled by using MATLAB simulation and experimentally validated by a DSPIC (DS 1104) based prototype model. A three phase PV grid connected non-linear load is observed in different operating environmental conditions. The optimization control algorithms was developed and implemented in Super-Lift Inverter (SLI) grid connected system. The findings of this work are, grid reactive power demand is compensated using DSTATCOM, and also from the real power of renewable energy system. But, majority of the active power is provided or absorbed by DSTATCOM component. The objective of this proposed work is that the three optimization control algorithms are examined, and the PV integrated grid tied system maintains a compensation power at Unity Power Factor (UPF). The proposed optimization methods produce load output power factor values such as 0.89 (GWO), 0.88, (PSO) and 0.86 (GA).

Single phase PV system operating under Partially Shaded Conditions with ABC-PO as MPPT algorithm for grid connected applications

Single phase transformerless grid connected Photovoltaic (PV) systems have become prevalent in recent years because of the reduced size & volume and enhanced working efficacy. A single phase two stage grid connected PV system is successfully implemented under Partially Shaded Condition (PSC), Standard Test Conditions (STC) and load variations in this work. The first stage includes the use of a MPPT controller-based DC–DC boost converter. Artificial Bee Colony integrated Perturb & Observe (ABC-PO) MPPT algorithm is used to obtain maximum power from the photovoltaic module. ABC-PO is capable of tracking Global Maximum Power Peak (GMPP) even under PSC. A DC–AC inverter along with LC filter and Phase Locked Loop (PLL) is used in the second stage to synchronize with the grid. A small scale grid connected solar power generation system with a maximum capacity of 1kW power output has been considered for analysis. The simulation results validate the efficient maximum power point tracking characteristics of ABC-PO algorithm over ABC algorithm for a grid connected network. Moreover, the successful synchronization of grid current with grid voltage under variations in irradiance as well as load has been carried out. The result shows the satisfactory performance of the entire system.

Research on FPGA controlled three phase PV inverter using multi carrier PWM control schemes

Research on FPGA controlled three phase Photovoltaic (PV) inverter using Multi-Carrier Pulse Width Modulation (MC-PWM) is presented in this article. In this proposed work, reduced active switching count, transformers, Single DC input (SDC), modular topologies and redundancy are key advantages. The proposed three-phase five level Multilevel Inverter (MLI) with SDC source using three-phase transformer is controlled by MC-PWM schemes. To evaluate the performance of the inverter, a Phase Disposition (PD), Phase Opposite Disposition (POD) and Alternate Phase Opposite Disposition (APOD) have been proposed. The effectiveness of the inverter is analyzed in terms of Total Harmonic Distortion (THD) by varying the Modulation Index(MI). Field Programmable Gate Array (FPGA) can realized for generation gating pulses to the inverter. The results were analyzed through MATLAB/Simulink and validated by FPGA based experimental setup.

AFLL-Based Control Technique for Grid Interfaced Three Phase PV System

This work deals with an advanced frequency locked loop (AFLL)-based control algorithm for a three phase double stage grid interfaced solar photovoltaic (PV) system. This AFLL-based algorithm extracts fundamental component of the load current and eliminates harmonics, performs grid currents balancing, improves the system performance during distorted grid conditions, and isolates the system during the occurrence of a grid fault. In a long radial network, the far away ends have the problem of voltage quality but this controller maintains the grid power quality by providing required reactive and active powers to the grid. The voltage source converter (VSC) of the PV system supplies the PV energy to the grid even under the worst situations of dc offset, solar insolation variation, load unbalancing, grid faults, voltage distortion, voltage unbalance, and voltage swell/sag. The VSC switching losses are reduced using an adaptive dc link voltage. This system is modeled and simulated in MATLAB and tests are conducted on a prototype built in the research laboratory under various odd states as stated earlier. Even during the disturbance, the harmonics level in the grid currents is seen in limits as suggested in the IEEE Standard-519.

GaN‐based split phase transformer‐less PV inverter with auxiliary ZVT circuit

This paper explores performance enhancement of the common ground dynamic dc-link (CGDL) inverter for single phase photovoltaic (PV) applications by a combination of gallium nitride (GaN) devices, split phase topology, coupled inductors, and zero voltage transition (ZVT) scheme. The CGDL inverter has the inherent advantage of minimised dc-link capacitance and negligible leakage current due to the common ground configuration, but its reported efficiency was usually lower because of the higher dc-link voltage used for the reduction of decoupling capacitance to a great extent. To solve the efficiency problem, in this study, a soft switching circuit is proposed for the first stage, while a coupled inductor integrated magnetics is incorporated in the second stage to reduce inductor loss, volume, and cost. Both of these topological improvements combined with the use of GaN devices facilitate in achieving high efficiency without compromising converter power density. Extensive experimental results are provided from a GaN based 1 kVA hardware prototype to demonstrate the superior performance of the CGDL inverter attaining a peak efficiency of 98.7% and a California Energy Commission efficiency of 98.5% at 75/50 kHz switching frequency.

Performance Enhancement of a Single-Stage CUK Based Three Phase Photovoltaic Inverter using Anfis Controller

A modular structured and high efficient photovoltaic (PV) system is essential in today’s scenario. The single stage Cuk based inverter has continuous input and output current, and hence, makes it suitable for applying MPPT techniques when used for PV applications. The PI, PID, and fuzzy controllers could be applied for PV inverter. The PI controller decreases the error in steady state, and at the same time, it also decreases the stability of the system. The PID controller involves large time delay process. The random nature in fuzzy controller may not lead to optimum results. Hence, this paper proposes a controller based on Adaptive Neuro-Fuzzy Inference System (ANFIS) for a three phase PV inverter based on Cuk converter. The effectiveness of proposed system is verified using MATLAB/SIMULINK, and the results are presented. The performance of proposed ANFIS controller for Cuk based three phase inverter is compared with conventional PI controller. The proposed system has several merits like increased performance, accuracy, and efficiency.

Design and development of new control technique for standalone PV system

A Sub-Maximum Power Point Tracking (S-MPPT) algorithm improves the performance of Photo Voltaic (PV) systems. This S-MPPT is used in single-phase PV system to test the tracking accuracy and its impact on the consistency of the whole system. Single phase PV Deadbeat Scheduler is proposed in this paper. The Deadbeat scheduler is a linear system. It initializes each initial state of the system to zero in shortest time possible. A single phase PV structure configuration is proposed to decrease the partial shading effect by changing the parameters of S-MPPT control algorithm. Thus, voltage sensor based S-MPPT algorithm through voltage reference control technique with the help of controller is developed for minimizing the tracking time and steady state oscillations. Selection of the objective function to mitigate the drawbacks associated with voltage sensor based algorithm for a decrease in solar irradiance are also demonstrated. The proposed MPPT algorithm with the designed controller is tested for a step change in irradiance from 270 to 480 W/m2 with a perturbation time of 20 ms and ∆V = 0.5 V (perturbation of voltage). From the simulation results, the proposed method with S-MPPT plus deadbeat control algorithm is compared with other existing algorithms.

Analytical approach to assess the loadability of unbalanced distribution grid with rooftop PV units

Photovoltaic (PV) power is a promising source of renewable energy, which is expected to provide a significant share of electrical energy in the near future. However, a stable voltage condition of the system must be always insured even with a high level of PV penetration. It should be noted that a large portion of PV systems are single-phase and they are being integrated into distribution network (DN). In addition, the DNs are unbalanced due to their loads and line characteristics. As a result, it is necessary to investigate the impact of power from both single and three phase PV units on the voltage stability of unbalanced DN. This paper has proposed an analytical methodology to investigate the static voltage stability of unbalanced DN with high PV penetration considering both single and three phase connections. For this purpose, the loadability of general unbalanced distribution system and how it is affected by PV power is analytically investigated for both single and three phase PV integration scenarios. In addition, the impact of reactive power capability of PV systems on the loadability has been assessed. Analytical outcomes are further studied and justified using results from IEEE 37-bus DN. Presented results conclude that both unbalanced system, and single and three phase PV penetrations must be taken into account to accurately assess the static voltage stability of practical DN.

A Novel Current Control Technique for Photo Voltaic Integrated Single Phase Shunt Active Power Filter

In this paper, a Model Predictive Current Control (MPCC) of single phase Photo Voltaic (PV) integrated Shunt Active Power Filter (SAPF) is proposed. A PV integrated single phase Voltage Source Inverter (VSI) is used to generate a part of the real power and compensate harmonics, reactive power of a Non-Linear Load (NLL). In this paper, a DC link voltage regulation based PI control algorithm is adopted for determining the reference current at the filter side. The performance of SAPF with PV and associated control methods like switch on response and change of nonlinear load were carried out. Also, the performance of the controller has been examined with variation in irradiance, filter inductance value and variation in controller sampling time through a simulation in MATLAB software.

Improved ADALINE Harmonics Extraction Algorithm for Boosting Performance of Photovoltaic Shunt Active Power Filter under Dynamic Operations

This paper presents improved harmonics extraction based on Adaptive Linear Neuron (ADALINE) algorithm for single phase photovoltaic (PV) shunt active power filter (SAPF). The proposed algorithm, named later as Improved ADALINE, contributes to better performance by removing cosine factor and sum of element that are considered as unnecessary features inside the existing algorithm, known as Modified Widrow-Hoff (W-H) ADALINE. A new updating technique, named as Fundamental Active Current, is introduced to replace the role of the weight factor inside the previous updating technique. For evaluation and comparison purposes, both proposed and existing algorithms have been developed. The PV SAPF with both algorithms was simulated in MATLAB-Simulink respectively, with and without operation or connection of PV. For hardware implementation, laboratory prototype has been developed and the proposed algorithm was programmed in TMS320F28335 DSP board. Steady state operation and three critical dynamic operations, which involve change of nonlinear loads, off-on operation between PV and SAPF, and change of irradiances, were carried out for performance evaluation. From the results and analysis, the Improved ADALINE algorithm shows the best performances with low total harmonic distortion, fast response time and high source power reduction. It performs well in both steady state and dynamic operations as compared to the Modified W-H ADALINE algorithm.

MULTI UNITS OF SINGLE PHASE DISTRIBUTED GENERATION COMBINED WITH BATTERY ENERGY STORAGE FOR PHASE POWER BALANCING IN DISTRIBUTION NETWORK

Randomly installed distributed generators (DGs) in households may cause unbalanced line current in a distribution network. This research presents a battery energy system for balancing of line current in a distribution network involving multi units of single phase photovoltaic (PV) distributed generators (DGs). In this paper, the PV generators were simulated consisting of a buck-boost DC/DC converter and single phase DC/AC inverter. It was connected to the distribution line through the low voltage 220 volt 50 Hz. The proposed phase balancing system uses battery energy storage and three single phase bidirectional inverters. The inverter is capable of injecting current or absorbing power from the line to the battery. This inverter operation is arranged to balance each distribution line separately, as well as to improve other power quality parameters, such as voltage and current harmonics. Simulation results show that the system was capable of improving the unbalanced line current from 15.59 % to 11, 48 % and unbalanced line voltage from 1.76 % to 0.58 %. The system was able for increasing current harmonics from 0.98 % to 1.03% and voltage harmonics from 38.96% to 39.08%.

Fault contribution from large photovoltaic systems in building power supply networks

This paper presents a detailed analysis for determining the impact of adding large three phase photovoltaic (PV) systems in secondary (building) power distribution networks. The analysis highlights the protection relay coordination problems arising due to the increase in network fault levels caused due to the contribution from PV generators. A typical distribution network for power supply to large buildings with multiple apartments in a housing complex has been modeled and used as a test network. Simulation result shows that the magnitude of fault current contribution from PV system depends on a number of different factors, not only on the size of the PV system. The analysis emphasizes the requirement to review protection settings of similar installations prior to connection of PV generators to the network and suggests a method of protection coordination to minimize the requirement of reviewing the protection setting every time a new PV system is connected to the distribution network. It is found that fault current contribution from PV systems, depending on the size, can cause significant relay coordination problems in terms of discrimination and thereby reduce system reliability.

Power Quality Analysis for Photovoltaic System Considering Unbalanced Voltage

Background/Objectives: Voltage unbalance is one of the most important power quality problems in distribution network. In this way, three phase Photo Voltaic (PV) system can increase voltage unbalance. Methods/Statistical Analysis: In this paper a three phase photovoltaic system with Maximum Power Point Tracking (MPPT) has been installed in an unbalance distribution network due to reduce Voltage Unbalance Factor (VUF). Also, a Dynamic Voltage Regulator (DVR) has been used to get better outcomes. Results: Results show that in the case in which load is balance and only network is unbalance, the system comprised of PV, MPPT and DVR can diminish VUF by 10%. Moreover, THD analysis is done and is obtained around 2.27%. This system is modeled in MATLAB/ SIMULINK. Conclusion/Application: Considering the benefits of using PV system for sustainable energy, utilizing MPPT and DVR can lessen voltage unbalance in distribution networks inclusive photovoltaic systems. First, output voltage waveform of three-phase photovoltaic system simulated in this paper with regard to existing controlling structure in PV system is balanced to radiation change (500 –1000W/m2) in a good approximation and acts like a balanced three-phase source. Second, when this photovoltaic system approaches an unbalanced load which is located in an unbalanced network, the voltage imbalance decreases in that bus. Also when PV system gets further from the considered load, the impact of voltage imbalance reduction decreases in that load and also whatever the used photovoltaic system in the network is nearer to a special load, the imbalance compensating effect becomes more sensible. Also according to the performed simulations if there is a load which is sensible to the imposed voltage imbalance from network, PV-DVR system can be used for modify the observed voltage imbalance from network. It is worth noting that the PV-DVR system hasn’t the ability to modify observed imbalance from network due to imbalance load. PV-DVR system in this paper has the ability to compensate voltage imbalance up to 10% and for more, the capabilities of both photovoltaic system and DVR must be added. In addition, or proposed network, FFT analysis is done. Therefore harmonic load flow illustrates the suggested photovoltaic system using PV-DVR is acceptable from harmonic distortion point of view. THD is obtained around 2.27% that is good value for PV-DVR system in comparison with 5% allowable standard value.

Power System Harmonics Study for Unbalanced Microgrid System with PV Sources and Nonlinear Loads

Harmonics distortion is a crucial problem in microgrid. Harmonic sources can be categorized as two main factors: renewable energy integration and nonlinear loads. Both factors are investigated in this paper. For renewbale energy, photovoltaic (PV) power is one of the most effective solutions for energy crisis and it is showing great potential for serving customers in microgrid. A three- phase PV source model is establised and integrated at different locations in order to observe the impact of harmonics on a microgrid and power quality (PQ). A composite load is modeled using Crossed Frequency Admittance Matrix theory. A practicdal microgrid loacated at GA, USA is used as a study system. The microgrid, PV model and nonlinear load model are simulated in MATLAB/ Simulink environment. The results show the impact of installing PV sources at two types of locations considering linear and composite nonlinear loads. In addition, three PQ indices are discussed to show the numerical impacts with various perspectives.

Three Level Single Phase Photovoltaic and Wind Power Hybrid Inverter

This paper presents a new topology of three-level single phase photovoltaic (PV) and wind power hybrid inverter. It consists of three main circuits; they are a hybrid controller circuit, a charger circuit, a pulse driver and full bridge circuit. The inverter is installed in front of Electrical Energy and Industrial Electronic Systems (EEIES) Cluster, Universiti Malaysia Perlis, Northern Malaysia. Its main energy source is a PV array and wind power generation. In this research, AC three-level waveform and square wave single phase PV and wind power hybrid inverter are developed and created by a microcontroller PIC16F627A-I/P and analyzed their performance comparisons. The result shows that the AC waveform which is formed by the PV and wind power hybrid inverter will effect on AC load rms voltage, AC current and current total harmonic distortion (CTHD), for a load of 20W 220V 50Hz AC water pump, its AC load rms voltage and current are higher when the single phase PV and wind power hybrid inverter is formed as AC square wave than as AC three-level waveform, but the CTHD is lower when the single phase PV and wind power hybrid inverter is formed as AC three-level waveform than as AC square wave.

Research on Combined Control Strategy of Three-Phase Photovoltaic Grid-Connected Inverter Based on Fuzzy PI Controller

The control objective of three-phase photovoltaic (PV) grid-connected inverter is to generate high quality and stable AC sinusoidal output power with the same phase angle, frequency and amplitude compatible with the grid-connected voltage. To overcome the shortcoming of the normal current PWM control method and traditional PI algorithm, this paper researches a combined control strategy of three phase PV grid-connected inverter based on fuzzy PI controller. The combined control strategy switches different PWM current control method among the hysteretic PWM, SVPWM, hysteretic current SVPWM according to the error between command current and feedback current，and the d-axis command current is output of fuzzy PI controller of DC bus voltage. The simulation model of the combined control strategy for three phase PV grid-connected inverter based on normal PI controller is built with Matlab, simulation results verified the combination control strategy based on fuzzy PI controller has excellent performances.