A Fixed Zone Perturb and Observe MPPT Technique for A Standalone Distributed PV System
15 Mar 2021-IEEE Journal of Emerging and Selected Topics in Power Electronics (Institute of Electrical and Electronics Engineers (IEEE))-pp 1-1
TL;DR: The FZPO technique requires a PV panel’s information only at the initial design stage but not during real-time tracking, making the implementation possible using only low-cost processors, and the implementation and design of the proposed controller are presented.
Abstract: This paper proposes a fixed zone perturb & observe (FZPO) technique to achieve an improved steady-state efficiency as well as a fast and drift-free maximum power point tracking (MPPT) for photovoltaic (PV) systems without any additional sensors. In this technique, the PV array’s power-voltage curves are divided into multiple zones with unique zone boundary voltages for different irradiance conditions. This technique employs a combination of adaptive and fixed step-sizes to improve the performance, where the adaptive step-size is calculated from simple mathematical equations, resulting in a reduced computational burden. Besides, natural drift-free tracking is achieved without any additional sampling or computation, overcoming existing techniques’ limitations. The FZPO technique requires a PV panel’s information only at the initial design stage but not during real-time tracking, making the implementation possible using only low-cost processors. This paper presents the implementation and design of the proposed controller. The FZPO technique’s performance is validated through a comprehensive set of hardware experiments on a buck-boost full-bridge converter under various irradiance conditions per the EN50530 standard. For a step-change in irradiance, the FZPO technique is experimentally verified to be 42% and 20% more efficient than the conventional and VSS techniques, respectively. During the irradiance varying conditions using the FZPO technique, the peak power loss is one-sixth compared to the conventional and VSS techniques. Practical field-related considerations such as PV panel temperature effects are further investigated through experiments.
Citations
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TL;DR: In this paper, the perturbation step-sizes of hill-climbing MPPT algorithms under a wide range of irradiance conditions were determined and a general expression to determine the optimum digitized step-size for duty-based perturb and observe algorithm under low irradiance condition was defined.
Abstract: Adaptive hill-climbing MPPT algorithms have superior performance as opposed to their conventional counterparts under medium-high irradiance. However, the performance of these hill-climbing algorithms remains mostly unknown under low irradiance condition. The low irradiance conditions are prominent in tropical countries during rainy seasons and niche PV applications. Additionally, several thin-film photovoltaic (PV) technologies have better efficiency under low irradiance conditions. Hence, the optimum operation of MPPT algorithms under low irradiance conditions is vital. In the real-time implementation, MPPT algorithms can fail to detect the incremental changes in voltage and current under low irradiance conditions. Hence, analog to digital converter (ADC) resolution becomes a critical constraint that governs the performance of hill-climbing (HC) MPPT algorithms. This work entails a detailed calculation to determine the perturbation step-sizes of the MPPT algorithms under a wide range of irradiance. Two distinct perturbation step-sizes are determined corresponding to the minimum and optimum change in voltage and current due to perturbation, that is sensed by the ADC. The authors also defined a general expression to determine the optimum digitized step-size for duty-based perturb and observe algorithm under low irradiance condition. This expression is formulated by considering the resolution of the ADC and the desirability of keeping the power oscillations at an acceptable level. Finally, the performance of eight hill-climbing algorithms for two distinct step-sizes is analyzed on a small-scale experimental prototype under both uniform and sudden changes in low values of irradiance. The statistical analysis validates that the adaptive HC drift-free MPPT algorithm outperforms other HC algorithms when implemented with the optimum perturbation step-size under low irradiance conditions.
67 citations
TL;DR: In this article , the design features and operating procedures of six popular conventional MPPT methods are discussed and corresponding modifications of the conventional MPP methods are analyzed and reviewed, and a comprehensive comparative analysis of the twenty-eight adaptive MPPT algorithms is performed based on the tracking time, steady-state oscillations, conversion efficiency, algorithm complexity, implementation cost, capability to perform on the partial shading conditions, etc.
14 citations
TL;DR: In this paper , a novel Parabolic Curve-fitting based Hill Climbing (PCHC) MPPT (Maximum Power Point Tracking) algorithm is developed to extract maximum power from solar photovoltaic (PV) panels under dynamic environmental conditions for household consumers.
Abstract: In this paper, a novel Parabolic Curve-fitting based Hill Climbing (PCHC) MPPT (Maximum Power Point Tracking) algorithm is developed to extract maximum power from solar photovoltaic (PV) panels under dynamic environmental conditions for household consumers. Moreover, this developed PCHC algorithm is integrated with a novel reduced sensor-based approach, where only a single current sensor is used to complete the solar-powered battery charging process. The ease of implementation with a simple controller and reduced sensor approach makes it economical for residential rooftop SPV. In the proposed PCHC methodology, two consecutive points on the Power-Voltage (P-V) characteristic of PV are used to detect the Maximum point region quickly. Moreover, the parabolic nature of the P-V characteristic near the Maximum Power Point (MPP) zone is explored to calculate the approx value of voltage corresponding to the optimum power. Here in every iteration, the size of the perturbation in duty is reduced by fifty percent. It overcomes the trade-off between tracking speed and oscillations near the MPP of conventional MPPT techniques such as perturb and observe, incremental conductance. These oscillations affect the connected consumers’ load working efficiency and lifetime. Moreover, it also improves the dynamic performance by taking different step sizes for sudden and slow changes in irradiation levels. The boost converter has been used to realize the performance of the proposed PCHC MPPT technique. The performance of the PCHC MPPT algorithm has been validated on different types of irradiation patterns and obtained results that fulfill the motive of the work.
12 citations
TL;DR: In this article , an improved salp swarm algorithm based on particle swarm optimization for maximum power point tracking of optimal photovoltaic systems is investigated, where the effect of PV partial shading conditions, uniform and fast-tracking irradiance, duty cycle, frequency, temperature changes, and load types are adequately examined for better performance study of the proposed technique.
Abstract: In this study, an improved salp swarm algorithm based on particle swarm optimization for maximum power point tracking of optimal photovoltaic systems is investigated. The effect of PV partial shading conditions, uniform and fast‐tracking irradiance, duty cycle, frequency, temperature changes, and load types, and besides some comparative studies of different algorithms are adequately examined for better performance study of the proposed technique. The proposed improved salp swarm algorithm based particle swarm optimization utilizes the PV Solarex‐MSX‐60 photovoltaic solar panel, which considers voltage and current as inputs based on the proposed algorithm parameters selection. Besides, it uses a buck‐boost converter as an interface between input and output. The particle swarm optimization monitors the PV voltage and current, and the salp swarm algorithm does for the duty cycle (particles) in various environmental conditions. The proposed algorithm performs efficiencies 99.99%, 99.63%, and 99.24% comparison with other methods, under uniform irradiance and fast‐tracking irradiance respectively. Moreover, the highest power of 316.32 W reached at the duty cycle of 0.6 and 428.6 W at the frequency of 30 kHz under the same partial shading condition with optimal operating temperature values 10°C,15°C,20°C,25°C,30°C,35°C .
10 citations
TL;DR: In this paper , a novel Parabolic Curve-fitting based Hill Climbing (PCHC) MPPT (Maximum Power Point Tracking) algorithm is developed to extract maximum power from solar photovoltaic (PV) panels under dynamic environmental conditions for household consumers.
Abstract: In this paper, a novel Parabolic Curve-fitting based Hill Climbing (PCHC) MPPT (Maximum Power Point Tracking) algorithm is developed to extract maximum power from solar photovoltaic (PV) panels under dynamic environmental conditions for household consumers. Moreover, this developed PCHC algorithm is integrated with a novel reduced sensor-based approach, where only a single current sensor is used to complete the solar-powered battery charging process. The ease of implementation with a simple controller and reduced sensor approach makes it economical for residential rooftop SPV. In the proposed PCHC methodology, two consecutive points on the Power-Voltage (P-V) characteristic of PV are used to detect the Maximum point region quickly. Moreover, the parabolic nature of the P-V characteristic near the Maximum Power Point (MPP) zone is explored to calculate the approx value of voltage corresponding to the optimum power. Here in every iteration, the size of the perturbation in duty is reduced by fifty percent. It overcomes the trade-off between tracking speed and oscillations near the MPP of conventional MPPT techniques such as perturb and observe, incremental conductance. These oscillations affect the connected consumers’ load working efficiency and lifetime. Moreover, it also improves the dynamic performance by taking different step sizes for sudden and slow changes in irradiation levels. The boost converter has been used to realize the performance of the proposed PCHC MPPT technique. The performance of the PCHC MPPT algorithm has been validated on different types of irradiation patterns and obtained results that fulfill the motive of the work.
6 citations
References
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01 Jul 2012
TL;DR: In this paper, a modified current-voltage relationship for the single diode model has been derived from the well-known equivalent circuit for a single photovoltaic cell and the modification presented in this paper accounts for both parallel and series connections in an array.
Abstract: This paper presents a modified current-voltage relationship for the single diode model. The single-diode model has been derived from the well-known equivalent circuit for a single photovoltaic cell. The modification presented in this paper accounts for both parallel and series connections in an array.
14 citations
"A Fixed Zone Perturb and Observe MP..." refers methods in this paper
...For this, the P-V curve slope (in other words, change in power (∆P ) for a given change in voltage (∆V )) is obtained from the solar PV model [23, 25, 39] given in (1) and (2)....
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TL;DR: Comparative analysis between different D-schemes is presented, which indicates that for both loads, the proposed scheme has the superior performance with less complexity.
Abstract: In a photovoltaic (PV) system, the appropriate voltage regulation is essential to guarantee the maximum power operation. In this paper, a direct pulse width modulation controller based on a single gain ( k ) is presented. This controller directly estimates the duty cycle ( D ) through gain k, and simultaneously its mathematical operation contains the properties of integral controller. Initially, a comprehensive study is presented to evaluate the D values according to reference points on I–V curves with contrasted irradiance levels. This study has been carried out for resistive and battery loads. Based on critical observations, separate tuning expressions of k gain have been designed for resistive and battery loads. It is revealed that with regard to varying weather, k gain is dynamic for resistive load, while static for battery load. Moreover, it is also shown that inappropriate setting of load will limit maximum power point tracker controller to reach the MPP point. Therefore, two more expressions have been presented to configure the resistive and battery loads. Comparative analysis between different D-schemes is presented, which indicates that for both loads, the proposed scheme has the superior performance with less complexity. Finally, numerous experimental tests have been conducted to verify the tuning criteria and working principle of the proposed scheme.
8 citations
TL;DR: The operation and analysis of the converter are presented to highlight the DC-current in the transformer and to mitigate this, a hybrid control scheme (HCS) is proposed.
Abstract: A buck-boost full-bridge topology is preferred for low-input voltage, high gain, high-power battery fed front-end converter of an all-electric motor drive system. Variants of this topology feature high direct current (DC)-gain, soft switching, continuous input and output currents with a phase modulation/asymmetrical pulse width modulation (PWM) scheme. These variants exhibit a high-magnitude DC-current in the transformer primary winding for low-input voltage, high-power application leading to poor core utilisation and low-power density of the system. The operation and analysis of the converter are presented to highlight the DC-current in the transformer and to mitigate this, a hybrid control scheme (HCS) is proposed. The proposed HCS consists of a DC-current compensation (DCCC) loop to mitigate the DC-current in the transformer without altering the DC-gain with no additional components and output regulation (REG) loop to regulate the output. The output REG and DCCC loops are independent of each other. Soft switching is retained with this proposed scheme. The necessity to mitigate the DC-current, analysis, and implementation of the HCS is discussed. The verification of the proposed HCS scheme in simulation and the experimental prototype is presented.
8 citations
TL;DR: The Sandia Inverter Model has been taken as a paradigm of methodology and adapted to deal with the available data for an office building’s photovoltaic system over the 2013- 2017 period.
Abstract: Determining the static overall efficiency of inverters is sometimes necessary for control o design purposes. As getting this information from the manufacturers’ datasheets or certified laboratories might not be always viable, this paper addresses its estimation from direct measurements under actual operating conditions. Particularly, the Sandia Inverter Model has been taken as a paradigm of methodology and adapted to deal with the available data for an office building’s photovoltaic system over the 2013- 2017 period. Two unidimensional and two bidimensional models have been selected and compared to assess their goodness of fit on three inverters of the same kind of which the system consists. The best-case scenario corresponds to an exponential curve fitting, in which the R-square value increases over 0.95, outperforming the other models.
7 citations
"A Fixed Zone Perturb and Observe MP..." refers background or methods in this paper
...In general, the MPPT efficiency for any given window is computed based on the energy ratio as [26]...
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...In some test sequences, dwell time between rise and fall of the irradiance is provided for MPPT algorithms to stabilize, as recommended in EN50530 [26]....
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...However, the EA-P&O controller tracks GMPP by comparing multiple samples of perturbation, and therefore, the performance requires further validation for a fast irradiance change of 100 W/m(2)/s, for example, as suggested by the standard EN50530 [26]....
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...The performance is compared with selected other MPPT techniques based on the start-up time, steady-state oscillations, drift occurrence, and all of these at constant, slow, and fast varying irradiances per the EN50530 standard [26]....
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...Additional tests are conducted at various conditions exhibiting the practical scenario, per standard EN50530 [26]....
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01 Jun 2016
TL;DR: A simple zonal based MPPT controller is proposed in this paper which addresses the above limitations without additional requirement of sampling or sensors apart from the basic voltage and current sensors.
Abstract: The limitations of the conventional MPPT technique are oscillations of the system at steady state leading to energy loss, slower response and the occurrence of drift. A simple zonal based MPPT controller is proposed in this paper which addresses the above limitations without additional requirement of sampling or sensors apart from the basic voltage and current sensors. The proposed system is simple, cost effective and easy to implement. Phase shift reference (Duty) for the DC-DC converter is varied dynamically by the proposed MPPT controller depending upon the operating point voltage to have a better dynamic response. The error in the perturbation direction, if any, is corrected by the controller while computing the change in duty reference ΔD). This ensures the drift free operation. The response speed of the proposed controller is improved compared to the conventional controller by having a variable step size. Solar PV fed full bridge series resonance DC-DC converter with resistive load is considered for evaluating the proposed control scheme. The performance of the proposed MPPT control technique is verified by simulations and hardware results.
3 citations
"A Fixed Zone Perturb and Observe MP..." refers background in this paper
...Therefore, these are not suitable for standalone (off-grid) solar applications due to periodic service interruptions [23, 30, 31]....
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