MATLAB Simulation of Photovoltaic Grid-Connection Process in Microgrids

In the design and operation of microgrids, photovoltaic grid-connection represents one of the key technologies. Utilizing MATLAB for simulation can effectively model the switching process between grid-connected and islanded modes in microgrids, helping optimize system stability and control strategies.

### Key Points of Microgrid Photovoltaic Grid-Connection Simulation System Modeling Build models of photovoltaic arrays, inverters, energy storage units, and loads in MATLAB to accurately reflect the dynamic characteristics of actual systems. Simulink's Power Systems Library provides comprehensive components such as photovoltaic cell models and voltage source inverters, which can be used to construct microgrid architectures. Key functions like 'pvArray' and 'inverter' blocks enable precise component representation with configurable parameters.

Grid-Connection Control Strategies Investigate power regulation strategies for microgrids in grid-connected mode to ensure seamless integration of photovoltaic generation with the main grid. Common control methods include PQ control (constant power output) and V/f control (maintaining voltage and frequency stability). During simulation, validate dynamic responses of different control strategies using MATLAB's Control System Toolbox, ensuring smooth transitions through algorithms like phase-locked loops and power calculation modules.

Islanding Detection and Switching When main grid failures occur, microgrids must quickly switch to islanded mode to maintain power supply for critical loads. MATLAB simulations can test the effectiveness of passive detection methods (such as frequency/voltage deviation) or active detection methods (like signal injection), and verify the reliability of switching logic. Implementation typically involves custom MATLAB functions for threshold monitoring and state machine logic.

Transition Process Optimization Analyze transient characteristics during grid-connected to islanded transitions, such as voltage fluctuations and frequency stability. Using MATLAB simulation data, adjust control parameters (like PID tuning and energy storage charging/discharging strategies) to maintain system stability during mode switching. The Optimization Toolbox can be employed to fine-tune parameters through algorithms like gradient descent or genetic optimization.

### Significance of Simulation Analysis Through MATLAB simulation, potential issues in the grid-connection process can be identified early, such as harmonic interference and power imbalance. Simultaneously, simulation results provide basis for hardware design and control algorithm optimization in practical microgrids, reducing on-site debugging risks. Data analysis can be performed using MATLAB's Data Acquisition Toolbox and Signal Processing Toolbox for comprehensive performance evaluation.

Summary: Utilizing MATLAB to simulate the photovoltaic grid-connection process in microgrids facilitates research on smooth transitions between grid-connected and islanded modes, thereby improving system reliability and economic efficiency. The simulation approach enables code-based validation of control algorithms before physical implementation.