Industrial Electronics
Amir M. Mohamadi; Navid R. Abjadi; Gholam Reza Arab Markadeh
Abstract
The Siwakoti-H inverter (SHI) with a flying capacitor is a recent addition to the transformerless inverter family, suitable for grid-connected single-phase photovoltaic systems. It offers a promising alternative to traditional topologies without the need for transformers, due to its minimal power electronic ...
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The Siwakoti-H inverter (SHI) with a flying capacitor is a recent addition to the transformerless inverter family, suitable for grid-connected single-phase photovoltaic systems. It offers a promising alternative to traditional topologies without the need for transformers, due to its minimal power electronic components. However, one of the key challenges in managing flying capacitor (FC) inverters is ensuring that the voltage of the FC remains within the desired range. Materials and Methods: To tackle this issue, first, a novel nonlinear model of the SHI is obtained defining two control inputs and two control outputs, and then a nonlinear feedback linearization (FBL) control design is proposed for the SHI when connected to a single-phase grid. This article introduces a novel approach to the modeling and control of the SHI enabling simultaneous control of both the injected current to the grid and the flying capacitor voltage. The proposed modeling and the designed control method play a crucial role in maintaining the capacitor voltage within the specified range and in tracking a sinusoidal reference for the injected current into the single-phase network. A PWM implementation of the proposed control is also suggested which is useful in the practical setup. The obtained model can be extended for the SHI with other line filters and it can be used to design more sophisticated controllers for SHI. The simulation and practical results presented in this study demonstrate the effectiveness of the proposed modeling and control approach.
Power systems
Navid Reza Abjadi
Abstract
Due to the growth of renewable energies and the need for sustainable electrical energy, AC microgrids (MGs) have been the subject of intense research. Medium voltage MGs will soon have a special place in the power industry. This paper uses a new and effective control scheme for islanded inverter-based ...
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Due to the growth of renewable energies and the need for sustainable electrical energy, AC microgrids (MGs) have been the subject of intense research. Medium voltage MGs will soon have a special place in the power industry. This paper uses a new and effective control scheme for islanded inverter-based medium voltage MGs using the master-slave (MS) technique. The controllers only need local measurements. The designed controls are based on adaptive input-output feedback linearization control (AIOFLC). These controls have a high-performance response; and are robust against some uncertainties and disturbances. The use of the designed control scheme makes the output voltage of distributed generation (DG) sources have negligible harmonics. Besides, the generated voltage and active/reactive powers track their references effectively. The model of the inverter-based DGs is considered in a stationary reference frame, and there is no need for any coordinate frame transformation. The control method presented in this paper can be used for MGs with any number of inverter-based DGs and parallel inverters. The effectiveness of the proposed control scheme is evaluated by simulation in SIMULINK/MATLAB environment and compared with that of feedback linearization control (FLC) and conventional sliding mode control (CSMC).
Power systems
Seyed Mohammad Hoseini; Nastaran Vasegh; Ali Zangeneh
Abstract
In this paper, a new robust hybrid controller (RHC) is proposed to regulate current, voltage and, as a result, power output of a three-phase grid connected PV system. The creative process of the proposed controller consists of two steps. First, an input-output linearization method is used to eliminate ...
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In this paper, a new robust hybrid controller (RHC) is proposed to regulate current, voltage and, as a result, power output of a three-phase grid connected PV system. The creative process of the proposed controller consists of two steps. First, an input-output linearization method is used to eliminate system nonlinearities. Then, a robust PI controller is designed to reach the desired control objective. The robustness of PI is guaranteed by Lyapunov stability theory. Also, a maximum power point tracking (MPPT) algorithm is provided to adjust the PV output voltage for extracting MPP under various atmospheric conditions. To evaluate the performance of the proposed controller, different system conditions such as standard, considering uncertainties and three-phase short-circuit fault, are simulated and the results are compared with a feedback linearization controller (FLC). The results show superiority of the performance and robustness of the designed RHC versus various uncertainties such as solar irradiation and ambient temperature.
