A Decentralized Control Strategy for Series-Connected Single-Phase Two-Stage Photovoltaic Grid-Connected Inverters

Abstract

Currently, most of the series inverter control methods rely on communication, which greatly reduces the reliability of the system and increases the cost. To address the above problems, this paper proposes a decentralized control strategy for series-connected single-phase two-stage grid-connected photovoltaic (PV) inverters. By improving the traditional droop control, the frequency and phase of the output voltage of each inverter unit are consistent and self-synchronized with the power grid while relying only on local independent control, and each unit realizes maximum power point tracking (MPPT). At different light intensities, each series-connected unit can quickly track the new maximum power point while still maintaining self-synchronization between the units. The system stability is analyzed via the small signal method, and sufficient conditions for system stability are obtained. Finally, the simulation results verify the correctness and effectiveness of the proposed control strategy.

Investigation of novel control strategies for grid-connected photovoltaic inverters

“…This is in line with the composite control strategy advocated by Li et al, which meticulously regulates the output current of LCL photovoltaic grid-connected inverters, further stabilizing the system against fluctuations [4]. Luo et al emphasized the need for a decentralized approach in controlling series-connected single-phase two-stage photovoltaic grid-connected inverters, highlighting the trend towards more modular and adaptable control systems [5]. The sophistication of these control strategies brings to the fore the critical issue of cybersecurity.…”

“…Equation 5: Total Harmonic Distortion (THD) conditions. (5) Where; Vn is the RMS voltage of the nth harmonic, V1 is the RMS voltage of the fundamental frequency.…”

“…The landscape of grid-connected photovoltaic inverters is also witnessing a paradigm shift with the introduction of decentralized control strategies. These strategies, tailored for single-phase two-stage photovoltaic grid-connected inverters, not only streamline the control architecture but also enhance the system's adaptability to varying operational conditions [5].…”

Current Sensorless Pole-Zero Cancellation Output Voltage Control for Uninterruptible Power Supply Systems with a Three-Phase Inverter

“…These applications require of the power converters to secure the high performance in both transient and steady state operations. In particular, the uninterruptible power supply (UPS) systems composed of the three-phase inverter and output LC-filter must be carefully designed to meet the specified high-level closed-loop performance under the abrupt power failure scenario (i.e., DC to AC power conversion) [1][2][3][4][5].…”