MATLAB Code Implementation for Photovoltaic Inverter Simulation

Photovoltaic inverter simulation plays a vital role in renewable energy system research, focusing on converting DC power generated by photovoltaic arrays into grid-compatible AC power. MATLAB provides efficient tools for building such simulation models, with key emphasis on precise grid-connected voltage/current control and harmonic interference suppression. Core Simulation Objectives DC-AC Conversion: Utilizes PWM modulation techniques to generate grid-frequency sinusoidal waves, requiring careful design of inverter bridge switching logic. Implementation typically involves configuring carrier wave frequency and modulation index parameters in Simulink's PWM generator blocks. Grid Synchronization Control: Employs Phase-Locked Loop (PLL) algorithms to track grid voltage phase in real-time, ensuring output current synchronizes with grid voltage frequency and phase. Code implementation often includes discrete PLL designs with proportional-integral controllers for phase error correction. Harmonic Suppression: Incorporates LCL filters to reduce high-frequency switching harmonics, complemented by advanced control algorithms like Proportional-Resonant (PR) controllers for active residual harmonic compensation. The PR controller implementation requires resonant term tuning at specific harmonic frequencies. MATLAB Implementation Key Points Simulink Modeling: Utilizes Simscape Power Systems library to construct main inverter circuits, including IGBT modules and filtering components. The system configuration involves proper parameter setting for semiconductor devices and passive components. Control Algorithm Design: Implements dual-loop control structure (outer voltage loop + inner current loop) as a standard solution, requiring PI parameter tuning through methods like Ziegler-Nichols to optimize dynamic response. The code typically implements discrete PI controllers with anti-windup protection. Harmonic Analysis Tools: Employs FFT analysis modules or Powergui's harmonic analysis functionality to quantify THD (Total Harmonic Distortion), validating filter performance through spectral analysis of output waveforms. Extended Directions Can integrate with MPPT (Maximum Power Point Tracking) algorithms as a preliminary simulation stage to form complete photovoltaic power generation system models. For advanced research, explores modern control strategies like Model Predictive Control (MPC) applications in harmonic suppression, requiring implementation of prediction models and optimization solvers in MATLAB code.