Novi gen algoritam za detekciju propada i poskoka napona na jednofaznom izmjenjivaču u mikromreži

In this manuscript, a novel sag and peak detector by means of a delta square operation for a single-phase is suggested. The established sag detector is from a single phase digital phase-locked loop (DPLL) that is founded on a d-q transformation employing an all-pass filter (APF). The d-q transformation is typically employed in the three-phase coordinate system. The APF produces a virtual phase with a 90 deg phase delay, but the virtual phase can not reproduce an abrupt variation of the grid voltage, at the moment in which the voltage sag transpires. As a consequence, the peak value is severely garbled, and settles down gradually. A modified APF produces the virtual q-axis voltage factor from the difference between the current and the former value of the d-axis voltage component in the stationary reference frame. Nevertheless, the amended APF cannot sense the voltage sag and peak value when the sag transpires around the zero crossing points such as 0 deg and 180 deg since the difference voltage is not adequate to sense the voltage sag. The suggested algorithm is proficient to sense the sag voltage through all regions as well as the zero crossing voltage. Furthermore, the precise voltage drop can be obtained by computing the q-axis component, which is relational to the d-axis component. To authenticate the legitimacy of the suggested scheme, the orthodox and suggested approaches are contrasted by means of the simulations and investigational results.U ovom radu je predložen novi detektor propada i poskoka napona korištenjem delta kvadratične operacije za jednu fazu. Predloženi detektor propada napona je u digitalnoj fazno-zatvorenoj petlji (DPLL) zasnovanoj na d-q transformaciji koja koristi svepropusni filtar (APF). D-q transformacija se tipično koristi u trofaznim koordinatnim sustavima. APF generira virtualnu fazu s 90 deg faznog kašnjenja, ali virtualna faza ne može reproducirati skokovitu promjenu napona mreže u trenutku u kojem se događa propad napona. Kao posljedica, detektirana vršna vrijednost se značajno izmijeni i smiruje se postepeno. Modificirani APF generira faktor napona virtualne q osi iz razlike između struje i prošle vrijednosti komponente napona na d osi u stacionarnom koordinatnom sustavu. Međutim, izmijenjeni APF ne može detektirati propad i poskok napona kada se propad događa u okolini točaka presijecanja nule, kao što je 0 deg i 180 deg s obzirom da diferencijski napon nije prikladan za detekciju propada napona. Predloženi algoritam je prilagođen detekciji propada napona u cijelom radnom području, uključujući i napon prelaska nule. Nadalje, precizni propad napona može se dobiti izračunom komponente napona na q osi, koja je u odnosu s obzirom na komponentu d osi. Za validaciju predloženih metoda provedena je njihova usporedba s konvencionalnim metodama u simulacijskom i eksperimentalnom okruženju

Modeling and Analysis of PV System with Fuzzy Logic MPPT Technique for a DC Microgrid under Variable Atmospheric Conditions

Due to the easiness of setup and great energy efficiency, direct current (DC) microgrids (MGs) have become more common. Solar photovoltaic (PV) and fuel cell (FC) systems drive the DC MG. Under varying irradiance and temperature, this work proposes a fuzzy logic controller (FLC) based maximum power point tracking (MPPT) approach deployed to PV panel and FC generated boost converter. PV panels must be operated at their maximum power point (MPP) to enhance efficiency and shorten the system’s payback period. There are different kinds of MPPT approaches for using PV panels at that moment. Still, the FLC-based MPPT approach was chosen in this study because it responds instantaneously to environmental changes and is unaffected by circuit parameter changes. Similarly, this research proposes a better design strategy for FLC systems. It will improve the system reliability and stability of the response of the system. An FLC evaluates PV and FC via DC–DC boost converters to obtain this enhanced response time and accuracy

Real Time Sustainable Power Quality Analysis of Non-Linear Load under Symmetrical Conditions

Voltage sag is one of the most significant power quality problems in the industry and has a significant impact on induction motor safety and stability. This paper analyzes the characteristics of voltage dips in power systems and induction motors with a special emphasis on balanced dips with the help of virtual grids (regenerative grid simulator), as per IEC 61000-4-11. Three phase induction motors with 3.3 kW, 16 A coupled to a DC generator with 3.7 kW, and 7.8 A rated are considered for the test analysis. This paper aids in the development of an induction motor to achieve improved precision by taking different voltage sags into account. The experimental results benefit the design modifications of induction motors at industrial and other commercial levels of consumers regarding major power quality issues and the behavior of the induction motors. A proposed modification employing ANSYS is provided to further examine the precise performance of induction motors during sag events

An Enhanced Emulated Inertia Control for Grid-Connected PV Systems with HESS in a Weak Grid

The role of renewable energy sources in the power grid is increasing tremendously. However, power electronic converters are used to incorporate RES into the grid without inertia. This article recommends an improved emulated inertia control approach focused on the frequency deviation and rate of change of frequency to enhance the inertia of a power system. The required inertial power calculated from emulated inertia control is delivered through hybrid energy storage systems equipped with a proper hybrid energy storage system control. The fast-varying power calculated from emulated inertia control is linked to super-capacitor. Simultaneously, the battery handles the slow varying power by regulating the DC bus voltage proportionate to the frequency variations. Further, the stability of the emulated inertia control and hybrid energy storage system controller is validated by Bode plots. The simulation results verified the correctness of the proposed emulated inertia control and hybrid energy storage system control. The real-time simulation results with the help of OPAL-RT are presented to validate the proposed method’s feasibility

Current Compensation in Grid-Connected VSCs using Advanced Fuzzy Logic-based Fluffy-Built SVPWM Switching

A main focus in microgrids is the power quality issue. The used renewable sources fluctuate and this fluctuation has to be suppressed by designing a control variable to nullify the circulating current caused by voltage fluctuations and deviations. The switching losses across power electronic switches, harmonics, and circulating current are the issues that we discuss in this article. The proposed intelligent controller is an interface between a voltage-sourced converter and a utility grid that affords default switching patterns with less switching loss, less current harmonic content, and overcurrent protection, and is capable of handling the nonlinearities and uncertainties in the grid system. The interfaced controller needs to be synchronized to a utility grid to ensure that the grid–lattice network can be fine-tuned in order to inject/absorb the prominent complex reactive energy to/from the utility grid so as to maintain the variable power factor at unity, which, in turn, will improve the system’s overall efficiency for all connected nonlinear loads. The intelligent controller for stabilizing a smart grid is developed by implementing a fuzzy-built advance control configuration to achieve a faster dynamic response and a more suitable direct current link performance. The innovation in this study is the design of fuzzy-based space vector pulse width modulation controller that exploits the hysteresis current control and current compensation in a grid-connected voltage source converter. By using the proposed scheme, a current compensation strategy is proposed along with an advanced modulation controller to utilize the DC link voltage of a voltage source converter. To demonstrate the effectiveness of the proposed control scheme, offline digital time-domain simulations were carried out in MATLAB/Simulink, and the simulated results were verified using the experimental setup to prove the effectiveness, authenticity, and accuracy of the proposed method