Design and Simulation of the PV Solar System and MPPT with PI Controller Based on P&O Algorithm

Mohammed BOUDIAF University of M'Sila The First National Conference on Renewable Energies and Advanced Electrical Engineering NC-REAEE’25 Mai 06-07th, 2025 Design and Simulation of the PV Solar System and MPPT with PI Controller Based on P&O Algorithm Benatallah Yacine Electrical Engineering Department University Centre of EL Bayadh EL Bayadh, Algeria [email protected] Benali Abdelkrim Electrical Engineering Department University Centre of EL Bayadh EL Bayadh, Algeria [email protected] Benouis Bellal Electrical Engineering Department University Centre of EL Bayadh EL Bayadh, Algeria [email protected] Nour Mohamed Electrical Engineering Department University Centre of EL Bayadh EL Bayadh, Algeria [email protected] Kerrouchi Mustapha Electrical Engineering Department University Centre of EL Bayadh EL Bayadh, Algeria [email protected] Himour Kamal Electrical Engineering Department University Centre of EL Bayadh EL Bayadh, Algeria [email protected] Abstract—This paper presents the design and simulation of a photovoltaic (PV) solar system integrated with a Maximum Power Point Tracking (MPPT) controller utilizing a PI controller based on the Perturb and Observe (P&O) algorithm. The research focuses on enhancing the efficiency of PV systems under varying atmospheric conditions by optimizing the power extraction process. A comprehensive simulation model is developed using MATLAB R2023a to evaluate the performance of the proposed system under different irradiance and temperature conditions. Results demonstrate that the PIcontrolled P&O algorithm significantly improves the dynamic response and steady-state performance of the MPPT system compared to conventional methods, achieving a power tracking efficiency. The findings contribute to the advancement of renewable energy technologies by offering an improved control strategy for PV systems. Keywords—Photovoltaic systems, Maximum Power Point Tracking, Perturb and Observe algorithm, PI controller, Power optimization. I. INTRODUCTION The global energy landscape is rapidly shifting toward renewable sources, with solar photovoltaic (PV) technology emerging as a leading sustainable energy solution. As concerns about climate change intensify and the costs of PV technology decrease, solar energy has become increasingly viable for large-scale electricity generation [1]. However, PV systems face inherent challenges related to their nonlinear current-voltage characteristics, which vary with environmental conditions such as solar irradiance and ambient temperature [2]. The power output of PV systems is significantly influenced by these changing environmental conditions, necessitating sophisticated control mechanisms to optimize energy harvesting. Maximum Power Point Tracking (MPPT) techniques have been developed to address this challenge by ensuring that PV systems operate at their maximum power point (MPP) regardless of environmental variations [3]. Among various MPPT algorithms, the Perturb and Observe (P&O) method has gained popularity due to its simplicity and effectiveness [4]. While the conventional P&O algorithm offers satisfactory performance in steady-state conditions, it exhibits limitations in dynamic environments, including oscillations around the MPP and slow response to rapid changes in atmospheric conditions [5]. This research aims to overcome these limitations by integrating a ProportionalIntegral (PI) controller with the P&O algorithm to enhance the system's dynamic performance and stability. This paper presents a comprehensive design and simulation of a PV system with an enhanced MPPT controller utilizing the PI-controlled P&O algorithm. The research contributes to the existing body of knowledge by proposing an improved control strategy that optimizes power extraction efficiency under varying environmental conditions. II. PHOTOVOLTAIC MODELLING A. PV Cell Model The equivalent circuit of the PV cell is shown in Fig. 1: Fig. 1. Equivalent circuit of PV model. The basic equation from the theory of semiconductors that mathematically describes the I-V characteristic of the PV cell is as follows [6]: 𝐼 = 𝐼𝑃𝑉,𝑐𝑒𝑙𝑙 −𝐼0,𝑐𝑒𝑙𝑙 [exp(𝑞𝑉 𝑎𝑘𝑇)−1] (1) 𝐼𝑑= 𝐼0,𝑐𝑒𝑙𝑙 [exp(𝑞𝑉 𝑎𝑘𝑇)−1] (2) Where: 𝐼𝑃𝑉,𝑐𝑒𝑙𝑙 : is the current generated by the incident light (it is directly proportional to the sun irradiation) 𝐼𝑑: is the Shockley diode equation 𝐼0,𝑐𝑒𝑙𝑙 : is the reverse saturation or leakage current of the diode q: is the electron charge (1.60217646 × 10-19 C) k: is the Boltzmann constant (1.3806503 × 10-23 J/K) T: (in Kelvin) is the temperature of the P-N junction a: is the diode ideality constant B. Modeling the PV Array Equations (1) and (2) of the PV cell do not represent the V-I characteristic of a practical PV array. Practical arrays are composed of several connected PV cells and the observation of the characteristics at the terminals of the PV array requires the inclusion of additional parameters to the basic equation [6]: 𝐼 = 𝐼𝑃𝑉 −𝐼0[𝑒𝑥𝑝(𝑉+𝑅𝑠𝐼 𝑉𝑡𝑎)−1]−𝑉+𝑅𝑠𝐼 𝑅𝑃 (3) where 𝐼𝑃𝑉 and 𝐼 are the PV current and saturation currents, respectively, of the array and 𝑉𝑡 = 𝑁𝑠kT/q is the thermal voltage of the array with 𝑁𝑃 cells connected in series. Cells connected in parallel increase the current and cells connected in series provide greater output voltages. If the array is composed of 𝑁𝑃 parallel connections of cells, the PV and saturation currents may be expressed as 𝐼𝑃𝑉 = 𝑁𝑃𝐼𝑃𝑉,𝑐𝑒𝑙𝑙, 𝐼0= 𝑁𝑃𝐼0,𝑐𝑒𝑙𝑙 In (3), 𝑅𝑠 is the equivalent series resistance of the array and 𝑅𝑝 is the equivalent parallel resistance. Equation (3) describes the single-diode model presented in Fig. 1 [7]. All PV array datasheets bring basically the following information: the nominal open circuit voltage (Voc,n), the nominal short circuit current (Isc,n), the voltage at the MPP (Vmpp), the current at the MPP (Impp), the open circuit voltage/temperature coefficient (Kv), the short circuit current/temperature coefficient (K1), and the maximum experimental peak output power (Pmax). This information is always provided with reference to the nominal condition or standard test conditions of temperature and solar irradiation. Some manufacturers provide I-V curves for several irradiation and temperature conditions. These curves make easier the adjustment and the validation of the desired mathematical I-V equation. Basically, this is all the information one can get from datasheet of PV arrays [4]. Fig. 2. characteristics of solar module for different irradiance level With the increment in the temperature short circuit current increases but the open circuit voltage of cell decreases. Fig. 2. show the variation in the characteristics curves at fixed temperature by changing irradiance values from 600w/m² to 1000w/m² and T=25°C. The maximum power is higher if the irradiance is getting higher and for the current, increases. If the irradiance is kept increasing, it also increases. C. Maximum power-point tracking using P&O Algorithm By change of environment temperature and irradiance, the maximum power is variable. Since the maximum available energy of solar arrays continuously changes with the atmospheric conditions, a real-time maximum power-point tracker is the indispensable part of the PV system. The perturb and observe (P&O) algorithm is generally the most commonly applied in the control of MPPT algorithm for the PV generator. It has simple structure, low cost, easy to implement, reduced number of parameters, the possibility to introduce improvements and may result in top-level efficiency [8] [9]. This algorithm is depending on investigating the relation between PV module output power and its voltage. The behavior of solar panel indicating MPP and operating principle is shown in Fig. 3 which indicates that the resulting change of PV power is observed as follows: When the PV module operating point is on the left side of the curve (ΔP/ΔV is positive), which means the PV module output power increases, the perturbation of the PV module voltage should be increased toward the MPP. If the operating point of the module was on the right side of the curve (ΔP/ΔV is negative), then the perturbation of the PV module voltage should be decreased toward the MPP. Fig. 3. Behavior of solar panel indicating MPP and operating principle Fig. 4 depicts the flowchart for implementation of the P&O algorithm; first, the practical voltage and current from PV array are measured. After that, the product of voltage and current gives the actual power of PV module. Then, it will check status what whether dP = 0 or not. If this status is satisfied, then operating point is at the MPP. If it is not satisfying, then it will check another status that dP > 0. If this status is satisfied, then it will check out that dV > 0. If it is satisfied, then it indicates that operating point is at the left side of the MPP. If dV > 0 status is not satisfied, then it indicates that operating point is at the right side of the MPP. This process is continuously repeated until it reached the MPP. So, at all times there is a compromise between the increments and the sampling rate in the P&O algorithm. [10]. Fig. 4. Flowchart of the P&O algorithm III. SIMULATION RESULTS A. PV SYSTEM SIMULATION USING THE P&O ALGORITHM matlab/simulink is used to generate the model of the solar panel with the boost converter, as well as the detailed block diagram of the previously stated P&O algorithm. Fig. 5 depicts the model. Fig. 5. PV system Simulink model using the P&O algorithm B. Experimental Results Cell parameters are shown in Table 1: Parameters Values IPV 7.84 (A) ISC 7.84 (A) Imp 7.35 (A) IL 7.86 (A) VOC 36.3 (V) Vmp 29 (V) L 45e-3 (H) C 470e-6 (F) Rsh 313.1819 (Ω) RS 0.396 (Ω) Rp 20 (Ω) Kp 0.001 Ki 0.01 Table 1: Parameters of the PV solar array The study Integration of PI Controller with P&O Algorithm in MATLAB/Simulink for MPPT in a photovoltaic (PV) system including a PV array, step-up DC-DC boost converter. The simulation framework evaluated the PI Controller with P&O algorithm's performance in maximizing PV output power across different operating conditions. The system's output power performance is depicted in Fig 6, where it attains a peak power of 1200 W under the conditions of 1000 W/m2 irradiance and 25°C temperature. Under STC conditions, the PI Controller with P&O Algorithm demonstrates effective maximum power point tracking. Fig. 6. Output power under STC Conditions. Under the shading scenario we have utilized the irradiance and temperature profiles depicted in Fig 7. The irradiance profile was characterized by oscillations spanning in a range of approximately 400 W/m² to 1000 W/m², while the temperature was maintained at a constant value of 25°C. Fig. 7. The variations of irradiance (W/m²) and fixed temperature at 25°C. Fig. 8. Output power at variable irradiation conditions. The simulation demonstrates the nearly linear relationship between irradiation and power in the PV system. The power output closely follows changes in irradiation, indicating an effective response from the MPPT controller (with PIcontrolled P&O algorithm) to changing environmental conditions. The irradiation variations represent a suitable test for evaluating MPPT performance, maintaining proportional power output across different irradiation levels. CONCLUSION In this paper, PV solar system and MPPT with PI controller based on P&O algorithm has been done. This system is designed and modeled in MATLAB and SIMULINK. The MPPT techniques considered in proposed work are Perturb & Observe method, PI controller. Perturb and observe method is used to achieve improvement in terms of speed and accuracy. The simulation study was made to illustrate the response of the proposed method to rapid temperature & solar irradiance. For this purpose, initially irradiation is 1000𝑊/𝑚2 and is reduced to 400𝑊/𝑚2. The proposed system improves the system power quality and gives the continuous power supply to the load demands. Also, PV solar systems have been recognized as a feasible opportunity for energy supply in rural areas and it is also cost effective to the remote areas. REFERENCES [1] International Energy Agency, "Renewables 2023: Analysis and forecast to 2028," IEA, Paris, 2023. [2] T. Esram and P. L. Chapman, "Comparison of photovoltaic array maximum power point tracking techniques,"IEEE Trans. Energy Convers., vol. 22, no. 2, pp. 439-449, Jun. 2007. 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