top of page
Search

Grid-Connected PV System With SEPIC Converter in MATLAB

100.2 kW PV System | Incremental Conductance MPPT | SEPIC-Based Grid Integration

Grid-connected solar PV systems are increasingly becoming a key component of modern renewable power generation. In this article, we explore the modeling, design, and simulation of a 100.2 kW grid-connected PV system integrated with a SEPIC converter and a Voltage Source Inverter (VSI) in MATLAB. The system also implements the Incremental Conductance (INC) MPPT algorithm to maximize power extraction under varying environmental conditions.

Grid Connected PV System With SEPIC Converter in MATLAB
Buy Now

🌞 1. Introduction

Solar photovoltaic (PV) technology has witnessed significant growth due to its scalability, reliability, and cost-effectiveness. When integrated with the electrical grid, PV systems must regulate their output efficiently while maintaining power quality and voltage stability.A SEPIC (Single-Ended Primary Inductance Converter) offers flexible voltage regulation and improved control, making it ideal for grid-connected PV applications. This blog explains how a SEPIC converter-based PV system is modeled in MATLAB and how it performs under different irradiation conditions.

⚡ 2. Overview of Grid-Connected PV Systems

A grid-connected PV system typically consists of:

  • PV array generating DC power

  • DC-DC converter (here, SEPIC) regulating voltage

  • Grid-tie inverter converting DC to AC

  • Control algorithms ensuring power quality and MPPT

  • Grid interface filter reducing harmonics

In this system:

  • A 100.2 kW PV array is the primary energy source

  • The SEPIC converter boosts/conditions DC voltage

  • The voltage source inverter synchronizes with the grid for AC power delivery

🔋 3. SEPIC Converter in PV Systems

The SEPIC converter is widely used for PV systems because:

  • It can boost or buck the input voltage

  • Provides non-inverted output, compatible with inverter DC-link

  • Maintains stable output despite environmental variations

Why SEPIC for Grid-Tied PV?

  • Offers flexible voltage regulation

  • Minimizes switching losses

  • Smooth DC output for grid integration

  • Enhances the lifespan of PV modules by reducing voltage stress

🔧 4. Operating Principle of SEPIC Converter

A SEPIC converter operates in two key modes:

✔ Charging Mode (Switch ON)

  • Current flows from the PV array through the switch

  • Energy is stored in the primary inductor

  • Output capacitor receives part of the energy

✔ Discharging Mode (Switch OFF)

  • Stored energy in inductors is released

  • Output capacitor delivers power to the DC-link or load

  • Voltage remains regulated under varying PV conditions

This dual-mode operation enables precise control of PV output voltage before feeding the inverter.

🧠 5. Incremental Conductance MPPT for Optimal Power Extraction

The Incremental Conductance (INC) MPPT algorithm ensures the PV system extracts maximum power by continuously comparing:

  • ΔI/ΔV (incremental conductance)

  • –I/V (instantaneous conductance)

Benefits of INC MPPT

  • Highly accurate tracking

  • Reduces oscillation around MPP

  • Superior performance during fast irradiance changes

  • Suitable for large PV systems like 100 kW plants

🖥️ 6. MATLAB Modeling and Simulation Approach

MATLAB/Simulink provides a robust environment for designing and testing PV systems. The simulation includes:

Step 1: Modeling the PV Array

  • Input parameters:

    • Irradiance

    • Temperature

    • Module characteristics

  • Output: Voltage-current-power curves under real-time conditions

Step 2: Modeling the SEPIC Converter

Key elements modeled:

  • Inductors

  • Switch (MOSFET/IGBT)

  • Diode

  • Capacitors

  • Duty cycle control

The equation-based model accurately captures charging/discharging dynamics.

Step 3: Modeling the Grid Inverter

The VSI block ensures:

  • Sinusoidal AC output

  • Grid synchronization

  • Voltage/current regulation

  • Harmonic minimization

Step 4: System Simulation

The complete system is simulated to observe:

  • DC‐link voltage stability

  • Output power variation with irradiance

  • MPPT efficiency

  • Grid voltage and current quality

  • Response during fast irradiance changes

📈 7. Simulation Results

Under varying irradiance conditions:

  • PV output adjusts dynamically

  • SEPIC converter maintains stable DC-link

  • Inverter supplies clean AC power to the grid

  • The system smoothly transitions as irradiation changes

The combination of SEPIC converter + INC MPPT ensures maximum energy transfer and high system efficiency.

✅ 8. Conclusion

The Grid-Connected PV System using a SEPIC converter in MATLAB illustrates a reliable and efficient approach to solar integration. The SEPIC converter’s flexible regulation, combined with the Incremental Conductance MPPT algorithm, ensures optimal power extraction and stable grid delivery.Such designs form the backbone of modern large-scale solar power plants, enabling clean, sustainable, and efficient energy generation.

Comments

bottom of page