An Improved Control Strategy for Single-Phase Single-Stage Grid-Tied PV System Based on Incremental Conductance MPPT, Modified PQ Theory, and Hysteresis Current Control

Abstract

In this paper, a modified variable step Incremental Conductance (VS-InCond) algorithm integrated with modified pq theory and double-band hysteresis current control (PQ-DBHCC) is proposed for the implementation on a single-stage single-phase grid-tied photovoltaic (PV) inverter system. As the single-phase inverter in a grid-tied PV system receives varying DC voltage from PV modules, the PQ-DBHCC strategy is deployed to regulate the ac output voltage along with its capability to deliver the maximum power during onload conditions. VS-InCond algorithm and DC-link capacitor are used as the interface between the PV modules and the inverter for tracking maximum power point. Furthermore, the PQ-DBHCC strategy also controls active and reactive power between inverter, load, and grid. The simulation results obtained from MATLAB Simulink software show that PQ-DBHCC strategy is capable of achieving the desired fixed DC voltage at inverter input and maintaining the maximum power point tracking, even under varying environmental conditions and load variations. The inverter ac output has a steady 230 Vrms at 50 Hz frequency. The total harmonic distortions (THDs) of output ac current and ac voltage are observed to be less than 5%, as recommended in IEEE 519 standard. Additionally, during full load conditions, the proposed system successfully delivers 95% of the theoretical maximum power from PV modules.

Conjunto de controle finito para o inversor conectado à rede aplicado na suavização de distorção

“…Neste caso o sistema de controle visa a potência suavizada, isto é, o sistema é projetado para forçar a injeção de potência ativa e reativa constante na rede [22]. A busca por uma potência constante pode introduzir variações na forma de onda da corrente, resultando em distorções devido às componentes harmônicas presentes na rede elétrica.…”

Nine-level Cascaded H-Bridge Multilevel Inverter for Photovoltaic Sources Based on Hybrid Active Filter

“…PV modules are rated at a set of conditions known as Standard Test Conditions (STC), which specifies a cell temperature of 25 °C and an irradiance of 1000 W/m 2 with an AM 1.5 spectrum. The peak point at which maximum energy is generated from the PV panel is called Maximum Power Point (MMP) [16]. The amount of solar radiation received by the panels is known to affect the amount of energy produced by the PV cells [17].…”

Research on Grid-Connected Control Strategy of Photovoltaic (PV) Energy Storage Based on Constant Power Operation

“…To address the issue of integrating energy storage systems and photovoltaic systems in order to mitigate the output fluctuations of the latter, the crucial aspect is the design of a three-phase voltage pulse width modulation (PWM) converter, a bidirectional DC/DC converter, and an appropriate control strategy [21][22][23][24]. The T-type three-level converter, as proposed in the literature [25], employs a PID control strategy to maintain a constant shoot-through duty cycle.…”