Dual-Loop Control of Photovoltaic Inverters: Current Loop Phase-Frequency Tracking with Voltage Feedforward Compensation

This paper discusses the core components of dual-loop control for photovoltaic inverters, including current loop regulation, phase-frequency tracking, and voltage feedforward compensation. The implementation of these control strategies significantly enhances inverter performance and efficiency. The current loop mechanism employs PID controllers to track and regulate inverter output current, ensuring waveform stability and precision through real-time error correction algorithms. Phase-frequency tracking utilizes phase-locked loop (PLL) algorithms to maintain synchronization between inverter output voltage and grid voltage, typically implemented through coordinate transformation and filtering operations. Voltage feedforward compensation incorporates disturbance prediction mechanisms that pre-adjust control signals using feedforward gain coefficients, thereby improving dynamic response speed and system stability. Through the application of these control strategies—often programmed using embedded C or MATLAB/Simulink with PWM modulation techniques—we achieve superior photovoltaic inverter performance, contributing to more effective utilization of renewable energy resources. The control architecture typically involves ADC sampling routines, Clarke/Park transformations for current decomposition, and space vector modulation for precise switching signal generation.