This paper presents a simple and direct power control approach to control a single-phase Grid-Connected boost Inverter (GCBI) for renewable energy applications. A DC voltage source and a single-phase single-stage boost Inverter that is Connected to the Grid by an L filter form the power injection system (PIS). Unlike the conventional voltage source Inverters (VSIs), the boost Inverter can generate an AC output voltage with amplitude larger than the DC input one, only in a single stage. In comparison with multi-stage power c0. onversion systems, the aforementioned Inverter has less number of devices and components which results in low cost and higher efficiency. Nevertheless, the boost Inverter suffers from undesirable dynamic behavior and extreme fluctuation response that makes it difficult to control. Thus, the proposed power injection control system consists of two parts. First, a proper state-feedback control scheme is designed to increase damping and also improve the stability of the closed-loop system. Then, the direct power control strategy is employed to control and track the desired powers that should be injected into the Grid. Simulation results are presented to validate the effectiveness of the proposed control strategy.

A new single-phase transformerless Grid-Connected PV Inverter is presented in this paper. Investigations in transformerless Grid-Connected PV Inverters indicate the existence of the leakage current is directly related to the variable common-mode voltage (CMV), which is presented in detail. On the other hand, in recent years it has become mandatory for the transformerless Grid-Connected PV Inverters to satisfy new Grid-codes such as low-voltage ride-through (LVRT) capability via injecting reactive power during Grid faults. Therefore, in this paper, the design of the proposed topology is based on retaining the constant CMV to suppress the leakage current and also to provide reactive power injection capability during Grid faults. The control strategies for injecting reactive power in the LVRT condition are also examined. To validate the presented theoretical concepts, the performance and dynamic response of the proposed transformerless PV Inverter are investigated by MATLAB/Simulink and the simulation results are presented and discussed.

In this paper, a new control method for quasi-Z-source cascaded multilevel Inverter based Grid-Connected photovoltaic (PV) system, using evolutionary algorithm and Artificial Neural Network (ANN), is proposed. The proposed method is capable of boosting the PV array voltage to a higher level and it solves the imbalanced problem of DC-link voltage in traditional cascaded H-bridge Inverters using ANN. The proposed control system adjusts the Grid injected current in phase with the Grid voltage and achieves independent Maximum Power Point Tracking (MPPT) for the separate PV arrays by Proportional- Integral (PI) controllers. For achieving the best performance, this paper presents an optimum approach to design the controller parameters using Particle Swarm Optimization (PSO). The primary design goal is to obtain good response by minimizing the integral absolute error. Also, the transient response is guaranteed by minimizing the overshoot, settling time, and rise time of the system response. Effectiveness of the new proposed control method has been verified through simulation studies in a seven-level quasi-Z-source cascaded multilevel Inverter.

In this paper, optimization of the backstepping controller parameters in a Grid-Connected single-phase Inverter is studied using Imperialist competitive algorithm (ICA), Genetic Algorithm (GA) and Particle swarm optimization (PSO) algorithm. The controller is developed for the system based on state-space averaged model. By selection of a suitable Lyapunov function, stability of the proposed controller is proved in a wide range of operation. Considering different optimization algorithms, steady-state and dynamic responses of the developed system are studied. In addition, THD values for different test are compared. Finally, to verify accuracy of the proposed method, designed controller is simulated using MATLAB/Simulink software.

Grid-tied voltage source Inverters, used to convert DC power generated by photovoltaic (PV) sources into AC power for injection into the Grid, inherently generate voltage and current harmonics at the Point of Common Coupling (PCC). Although inductor-capacitor-inductor (LCL) filters effectively attenuate the harmonics generated by the Inverter, they can also create resonance, potentially compromising the stability of Grid-Connected systems. Various methods, including active damping through filter capacitor current feedback, have been employed to mitigate these issues. Thorough feedforward control of Grid voltage is considered an effective method for improving the quality of injected current in Grid-Connected Inverters. In this paper, a novel control strategy for Grid-Connected solar array power conditioning systems is proposed, utilizing a weighted thorough feedforward scheme of Grid voltage based on multiple resonant components. The proposed method significantly enhances the system's ability to suppress PCC voltage harmonics by incorporating a set of quasi-resonance sections into the feedforward path of the network voltage. With proper design of these quasi-resonance components, the phase delay created by digital control is resolved, PCC voltage harmonic attenuation is further enhanced, and the stable operation of the Grid-tied solar array power conditioning system is improved under harmonic-polluted Grid conditions.

This paper proposes a two-stage three-phase Grid-Connected Inverter for photovoltaic applications. The proposed Inverter topology consists of a DC-DC boost converter and a three-phase Grid-Connected Inverter. The DC-DC boost converter is used to boost the low voltage DC output of the PV array to a high voltage DC level that is suitable for feeding into the Grid-Connected Inverter. The three-phase Grid-Connected Inverter is used to convert the high voltage DC output of the boost converter into a three-phase AC output that is synchronized with the Grid voltage. The proposed Inverter topology offers several advantages over traditional single-stage Inverters. Firstly, the DC-DC boost converter allows for the use of a smaller, more efficient Inverter in the second stage, reducing the overall cost of the system. Secondly, the use of a boost converter allows for the maximum power point tracking of the PV array, which can increase the overall efficiency of the system. The proposed Inverter topology offers improved control of the Grid current, reducing the impact of the PV system on the Grid. The proposed topology has been simulated using MATLAB/Simulink and the results show that the system is capable of delivering a high-quality three-phase AC output with low harmonic distortion.