Step Size Incremental Conductance Research Articles

Modeling and Simulation of Modified MPPT Techniques under Varying Operating Climatic Conditions

Enhancing the performance of photovoltaic (PV) systems has recently become a key concern because of the market demand for green energy. To obtain the most possible power from the solar module, it is imperative to allow the PV system to operate at its maximum power point (MPP) regardless of the climatic conditions. In this study, a comparison of distinctive Maximum Power-Point Tracking (MPPT) techniques is provided, which are Perturb and Observe (P&O) and Modified Variable Step-Size P&O, as well as Incremental Conductance (INC) and Modified Variable Step-Size INC, using a boost converter for two types of solar panels. Using MATLAB software, simulations have been performed to assess the efficiency of the solar module under several environmental conditions, standard test conditions (STCs), and sudden and ramp variations in both solar irradiance and temperature. The output power efficiency, time response, and steady-state power oscillations have all been taken into account in this study. The simulation results of the improved algorithms demonstrate an enhancement in the PV module performance over conventional algorithms in many factors including steady-state conditions, tracking time, and converter efficiency. Furthermore, a boost in the dynamic response in monitoring the MPP is observed in a variety of climatical circumstances. Moreover, the proposed P&O MPPT algorithm is implemented in a hardware system and the experimental results verified the effectiveness, regarding both fast-tracking speed and lower oscillations, of the proposed Variable Step-Size P&O algorithm and its superiority over the conventional P&O technique.

A Novel Approach Based Incremental Conductance Method for MPPT Strategy of PV Systems Considering Partial Shading Conditions

The main advantages in terms of a simple algorithm, easy to use, fast maximum power point tracking (MPPT) speed of the incremental conductance (InC) and perturbation and observation (P&O) algorithms have been adopted in the literature. Besides, the oscillation phenomenon around the maximum power point (MPP) is a major drawback of these typical algorithms. More specifically, these traditional algorithms failed to find the global maximum power peak when the PV system was operating under partial shading conditions where multiple peaks appeared on the PV curve characteristic. Therefore, a new approach based on the conventional InC algorithm is proposed in this paper. By evenly dividing the search area at the early stage, this proposed method avoids the regional traps encountered by the traditional InC algorithm. Then select the regions where there is a high probability of finding the global MPP to implement the conventional InC approach. After finishing this process, the location with the best power is selected and the MPP search is further performed using the various step-size InC algorithm for the final stage. With this improvement, the steady-state oscillation amplitude of the proposed method is significantly reduced. The implementation process and simulation results show that the proposed method has key advantages in terms of simplicity, fast convergence speed, and reduced steady-state oscillation amplitude. Simulation and experimental results are also compared with the conventional P&O and PSO methods to demonstrate the effectiveness of the proposed method in both uniform illuminance and partial shading conditions.

Modified Variable Step-Size Incremental Conductance MPPT Technique for Photovoltaic Systems

A highly efficient photovoltaic (PV) system requires a maximum power point tracker to extract peak power from PV modules. The conventional variable step-size incremental conductance (INC) maximum power point tracking (MPPT) technique has two main drawbacks. First, it uses a pre-set scaling factor, which requires manual tuning under different irradiance levels. Second, it adapts the slope of the PV characteristics curve to vary the step-size, which means any small changes in PV module voltage will significantly increase the overall step-size. Subsequently, it deviates the operating point away from the actual reference. In this paper, a new modified variable step-size INC algorithm is proposed to address the aforementioned problems. The proposed algorithm consists of two parts, namely autonomous scaling factor and slope angle variation algorithm. The autonomous scaling factor continuously adjusts the step-size without using a pre-set constant to control the trade-off between convergence speed and tracking precision. The slope angle variation algorithm mitigates the impact of PV voltage change, especially during variable irradiance conditions to improve the MPPT efficiency. The theoretical investigations of the new technique are carried out while its practicability is confirmed by simulation and experimental results.

Maximum Power Point Tracking of PV Systems Based On a Novel Adaptive Variable Step Size INC MPPT Method

In the future solar energy will become a very important green energy. Maximum power point (MPP) tracking (MPPT) technology is widely used in solar photovoltaic (PV) systems to generate peak power for PV arrays that depend on solar irradiation and ambient temperature. Literature[1] shows that the maximum power point tracking (MPPT) technology can improve the efficiency of photoelectric conversion by more than 20% and the economic cost is relatively low. Based on PROTUES, the output characteristics of PV arrays under different shadow conditions are simulated and the rule between local maximum power point and open circuit voltage is obtained. Among all the MPPT strategies, the incremental conductance (INC) algorithm and perturb and observe (P&O) algorithm are widely used due to the high tracking accuracy at steady state and easy implementation.In this paper, a novel adaptive variable step size INC MPPT method is proposed according to the above rule. This algorithm not only has the advantage of INC, but also can automatically adjust the step size to track the maximum power point of PV arrays. Compared with the adaptive perturb and observe (P&O) algorithm, the proposed approach can effectively improve the MPPT steady-state response speed and accuracy simultaneously. The theoretical analysis and design principle of the proposed algorithm are presented in this paper. The simulation results show that the algorithm can accurately track the maximum power point (MPP) with shadow. The average tracking time is only 0.13 seconds, and the power tracking efficiency reaches 98%.

How fuzzy logic can improve PEM fuel cell MPPT performances?

This paper addresses the development of new variable step size fuzzy based MPPT controller. In this study, the fuzzy logic approach is firstly used to auto-scale the variable step size of the Incremental Conductance (IC) MPPT controller. Secondly, the proposed variable step size fuzzy based MPPT controller is used to track the output power of the PEM fuel cell system composed of 7 kW fuel cell supplying a 50Ω resistive load via a DC-DC boost converter controlled using the proposed MPPT. The proposed variable step size fuzzy-based MPPT controller is compared to the conventional fixed step size IC, the variable step size IC and the fuzzy scaled variable step size IC MPPTs using the implemented Matlab/Simulink PEM Fuel Cell power system model. Comparative simulation results between the four studied MPPTs show better performances for the proposed fuzzy based variable step size MPPT in term of: response time reduction between 3.6% and 82.35%; overshoot reduction between 34.55% and 100%; and ripple reduction between 70.93% and 100%, improving as consequence the fuel cell lifetime affected by high current ripple.

Comparative study of the reliability of MPPT algorithms for the crystalline silicon photovoltaic modules in variable weather conditions

The crystalline silicon photovoltaic modules are widely used as power supply sources in the tropical areas where the weather conditions change abruptly. Fortunately, many MPPT algorithms are implemented to improve their performance. In the other hand, it is well known that these power supply sources are nonlinear dipoles and so, their intrinsic parameters may vary with the irradiance and the temperature. In this paper, the MPPT algorithms widely used, i.e. Perturb and Observe (P&O), Incremental Conductance (INC), Hill-Climbing (HC), are implemented using Matlab®/Simulink® model of a crystalline silicon photovoltaic module whose intrinsic parameters were extracted by fitting the I(V) characteristic to experimental points. Comparing the simulation results, it is obvious that the variable step size INC algorithm has the best reliability than both HC and P&O algorithms for the near to real Simulink® model of photovoltaic modules. With a 60Wp photovoltaic module, the daily maximum power reaches 50.76W against 34.40W when the photovoltaic parameters are fixed. Meanwhile, the daily average energy is 263Wh/day against 195Wh/day.

An Improved Variable Step Size MPPT Algorithm Based on INC

In order to ensure that photovoltaic (PV) systems work at the maximum power point (MPP) and maximize the economic benefits, maximum power point tracking (MPPT) techniques are normally applied to these systems. One of the most widely applied MPPT methods is the incremental conductance (INC) method. However, the choice of the step size still remains controversial. This paper presents an improved variable step size INC MPPT algorithm that uses four different step sizes. This method has the advantages of INC but with the ability to validly adjust the step size to adapt to changes of the PV’s power curve. The presented algorithm also simultaneously achieves increased rapidity and accuracy when compared with the conventional fixed step size INC MPPT algorithm. In addition, the theoretical derivation and specific applications of the proposed algorithm are presented here. This method is validated by simulation and experimental results.

FPGA‐based real time incremental conductance maximum power point tracking controller for photovoltaic systems

Maximum power point tracking (MPPT) is an important issue in photovoltaic (PV) systems. Hence, we need to design an efficient and cost-effective system which is able to transfer the maximum power received from PV cell to the load. This study describes the hardware implementation of a real time incremental conductance (INC) MPPT algorithm for a PV module. According to the PV dynamic model, a criterion is presented that by modifying the original algorithm, an adaptive variable step size INC algorithm is realised and efficiently is implemented on XILINX XC3S400 field programmable gate array (FPGA). At first, the PV model characteristics and the proposed algorithm with the mathematical equations are modelled and simulated using ‘MATLAB/Simulink-system generator’ environment; then the system performance is examined. It is worth that some solutions are proposed to simplify the system based on the design constraints for hardware implementation of digital controller on FPGA. The optimised design of hardware architecture and the high processing speed of FPGA have enhanced the performance of digital controller in designed MPPT system. The experimental results show the proposed method provides a good tracking speed and also mitigation of fluctuation output power.

Modified Asymmetrical Variable Step Size Incremental Conductance Maximum Power Point Tracking Method for Photovoltaic Systems

The power?voltage (P?V) characteristic of a photovoltaic (PV) array is nonlinear and time varying with the change in atmospheric conditions. As a result, the maximum power point tracking (MPPT) technique must be applied in PV systems to maximize the generated energy. The incremental conductance (INC) algorithm, one of the MPPT strategies, is widely used for its high tracking accuracy, good adaptability to rapidly changing atmospheric conditions, and easy implementation. This paper presents a modified asymmetrical variable step size INC MPPT method that is based on the asymmetrical feature of the P?V curve. Compared with conventional fixed or variable step size method, the proposed method can effectively improve tracking accuracy and speed. The theoretical foundation and design principle of the proposed approach are validated by the simulation and experimental results.

A Variable Step Size Incremental Conductance Direct MPPT Method for Stand-Alone PV Systems

This paper presents a variable step size incrementalconductance direct Maximum Power Point Tracking (MPPT) method using fuzzy membership for a standalone photovoltaic (PV) system under rapidly changing irradiation. MPPT techniques have been widely applied in PV systems to make a PV array generate maximum power, which depends on solar irradiation. In most applications of MPPT technologies, MPPT algorithm design methods are performed and tested under slowly changing atmospheric conditions such as irradiation and temperature. The short-term effect under rapidly changing irradiation should be considered, however, to improve the dynamic performance of PV system. Our proposed MPPT method is based on an incremental conductance algorithm with a direct control scheme that can directly adjust the duty cycle for the PI controller. A fuzzy membership function is adopted to determine the variable step size according to rapidly changing irradiation. The proposed methods thus has not only faster dynamic performance but also high tracking accuracy. In order to show the effect of the proposed method, the simulation model and proposed MPPT is designed with MATLAB/Simpower and simulated with MATLAB/Stateflow.

An Intelligent Incremental Conductance MPPT Method for a Photovoltaic System

In this paper, a novel incremental conductance (INC) maximum power point tracking (MPPT) method based on extension theory is developed to make full use of photovoltaic (PV) array output power. The proposed method can adjust the step size to track the PV array’s maximum power point (MPP) automatically. Compared with the conventional fixed step size INC method, the presented approach is able to effectively improve the dynamic response and steady state performance of a PV system simultaneously. A theoretical analysis and the design principle of the proposed method are described in detail. Some simulation results are performed to verify the effectiveness of the proposed MPPT method.

A Novel Improved Variable Step-Size Incremental-Resistance MPPT Method for PV Systems

Maximum power point (MPP) tracking (MPPT) techniques are widely applied in photovoltaic (PV) systems to make PV array generate peak power which depends on solar irradiation. Among all the MPPT strategies, the incremental-conductance (INC) algorithm is widely employed due to easy implementation and high tracking accuracy. In this paper, a novel variable step-size incremental-resistance MPPT algorithm is introduced, which not only has the merits of INC but also automatically adjusts the step size to track the PV array MPP. Compared with the variable step-size INC method, the proposed scheme can greatly improve the MPPT response speed and accuracy at steady state simultaneously. Moreover, it is more suitable for practical operating conditions due to a wider operating range. This paper provides the theoretical analysis and the design principle of the proposed MPPT strategy. Simulation and experimental results verify its feasibility.

A Variable Step Size INC MPPT Method for PV Systems

Maximum power point tracking (MPPT) techniques are employed in photovoltaic (PV) systems to make full utilization of PV array output power which depends on solar irradiation and ambient temperature. Among all the MPPT strategies, the incremental conductance (INC) algorithm is widely used due to the high tracking accuracy at steady state and good adaptability to the rapidly changing atmospheric conditions. In this paper, a modified variable step size INC MPPT algorithm is proposed, which automatically adjusts the step size to track the PV array maximum power point. Compared with the conventional fixed step size method, the proposed approach can effectively improve the MPPT speed and accuracy simultaneously. Furthermore, it is simple and can be easily implemented in digital signal processors. A theoretical analysis and the design principle of the proposed method are provided and its feasibility is also verified by simulation and experimental results.