MATLAB Simulation Model of Grid-Connected Inverter Based on Proportional-Resonant Control

In renewable energy generation systems, grid-connected inverters serve as the core equipment for power conversion and grid feed-in. Proportional-Resonant (PR) controllers, known for their infinite gain characteristics at specific frequencies, are commonly employed to replace traditional PI controllers for AC signal tracking applications.

Control Strategy Features Resonance Principle: The PR controller achieves zero steady-state error tracking of sinusoidal reference signals by setting resonant points at fundamental and harmonic frequencies. Harmonic Suppression Capability: Can be extended to multi-resonant structures to selectively suppress specific grid harmonics (e.g., 3rd, 5th, 7th orders). Disturbance Rejection: Offers better adaptation to grid voltage distortion and frequency fluctuations compared to PI controllers.

Simulation Modeling Key Points Grid Interface: Requires phase-locked loop (PLL) module for grid synchronization to establish phase reference in rotating dq-frame. Implementation typically involves park/clarke transformations and PI-based frequency tracking. Dual-Loop Structure: Outer voltage loop with PR control generates current references, while inner current loop ensures fast tracking response. Code implementation often uses separate PR controllers for d and q axes. Decoupling Control: Feedforward decoupling eliminates cross-coupling effects between dq axes, improving dynamic performance through voltage compensation terms.

Typical Application Scenarios This model can validate grid-connection performance for PV/wind power systems, including low-voltage ride-through and harmonic compensation functions, providing pre-research basis for practical hardware parameter design. Simulation tests may include THD analysis and fault condition scenarios.