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This article proposes a single-stage, seven-level (7L), switched-capacitor-based grid-connected inverter architecture with a common ground feature. This topology has the ability to boost the output voltage up to three times the input voltage. The proposed topology can diminish the leakage current in grid-connected photovoltaic (GC-PV) applications, and its capacitor voltages are self-balanced without any additional control strategies. The different operating modes are described in detail with their related mathematical expressions. The design of passive components and a detailed power loss analysis are presented. The merits of the proposed structure are demonstrated using a detailed comparative assessment. The grid-connected operation of the proposed inverter structure is simulated in the MATLAB/Simulink environment, and the results are presented. The laboratory prototype of 935 W is built and analyzed to validate the performance of the proposed structure.

The article discusses a nine-level switching capacitor-based common ground-type boost inverter for grid-connected photovoltaic applications. The proposed structure’s direct connection between the negative terminal of the input source and the grid neutral eliminates leakage current. The proposed topology uses eleven switches, two diodes, and three switching capacitors to produce a double voltage boost with nine different voltage levels. Self-balancing switching capacitors eliminate the need for sophisticated independent control algorithms. The maximum voltage stress on one of the three capacitors equals the input voltage, while it is equal to half of the input voltage on the other two switched capacitors. The various modes of operation and capacitance calculation are discussed in depth. A comprehensive comparison with various nine-level topologies has been conducted in terms of total component count, total standing voltage, capacitor voltage, and approximate cost to demonstrate the proposed topology’s benefits. A 400-W inverter prototype is constructed, and the experimental findings under various operating situations are reviewed.

Human motion is a vital parameter signaling indoor occupancy in occupant-centric building energy management systems. In this letter, a WiFi-based device-free sensing model employing ESP32—a low-cost embedded Internet of Things device, is proposed as a suitable retrofit for human motion sensing in new and existing buildings. A low complexity feature set derived from WiFi received signal strength indicator and channel state information samples collected by ESP32 is utilized for training ensemble machine learning models. The proposed model shows an accuracy of up to 99.4% in classifying human motion in three different rooms of a residential building, with a single WiFi access point. The proposed model can be employed for motion-driven smart load control and for a typical residential occupancy scenario, this approach exhibits a potential monthly electricity savings of up to 66.26% and a three times reduction in CO2 emissions. [ABSTRACT FROM AUTHOR]

Prolific integration of renewable energy sources (RESs) such as solar photovoltaic systems into the distribution network will result in various issues associated with their intermittent nature. Energy storage is a vital component for overcoming issues associated with the intermittent nature of such RES. Though stationary battery systems are used as energy storage for such applications, smart energy storage (SES) systems are also becoming popular owing to various advantages and advent of smart grid systems. SES can be achieved by aggregating electric vehicles (EVs) or by using demand response management for loads with large time constants. Aggregated residential refrigerators are potential candidates for creating SES which has virtual storage capacity, unlike EVs. In this study, residential refrigerators are modelled analogously to energy capacity and self-discharge of electro-chemical batteries using the artificial neural network based kWh modelling. The model is further extended to estimate the virtual energy storage (VES) capacity with aggregated residential refrigerators; particularly in high-rise residential buildings. Simulation results are presented for scenarios covering the complete range of thermal capacity of typical refrigerators applicable in Singapore's climatic condition. Furthermore, a brief description of the possible applications for the estimated VES, pertaining to smart grid architecture and cyber-attack is also presented

In recent years, common ground (CG)‐type transformerless (TL) inverters have been paid more attention. However, the existing topologies have more voltage stress on either switch or on capacitor voltage or in both. This article proposes a novel five‐level TL inverter topology with a CG type and a voltage stress reduction on power components. The proposed topology offers less component count and a simple structure. Here, the quasi‐soft charging (QSC) technique is proposed to minimize the high charging current during the capacitor charge. Since the proposed topology is the family of switched capacitors (SC), the determination of SC and QSC is presented. A detailed comparison of the proposed topology with other recent five‐level topologies is presented, and the proposed topology's advantage is highlighted. Further, the performance of the proposed topology is verified in simulation software and verified in a scale‐down hardware setup developed for 400 W. The various experimental results are presented to ensure the feasibility of the proposed topology. [ABSTRACT FROM AUTHOR]

This paper proposes a hybrid method for an accurate parameter estimation of the solar photovoltaic (PV) module. The proposed method combines the features of analytical as well as the optimization technique to ensure the speed and accuracy in computation. Two‐diode model consist of seven unknown parameters namely the photocurrent (IPV$$ {I}_{\mathrm{PV}} $$), reverse saturation current of diode D1$$ {D}_1 $$ and D2$$ {D}_2 $$ (I01$$ {I}_{01} $$ and I02$$ {I}_{02} $$), series resistance (Rs$$ {R}_s $$), shunt resistance (Rsh$$ {R}_{\mathrm{sh}} $$), diode ideality factor for diode D1$$ {D}_1 $$ and D2$$ {D}_2 $$ (A1$$ {A}_1 $$ and A2$$ {A}_2 $$). First five parameters are analytically determined with the help of area under the curve, while the remaining two are optimally calculated by using the Grey Wolf Optimization technique. The results obtained by simulation are verified with the experimental data of different PV module and the error is calculated. The superiority of the proposed estimation approach is compared with the recent literature and the results are presented. The proposed model is very useful for the solar PV module designers and simulators to realize its physical characteristics. [ABSTRACT FROM AUTHOR]

In this article, a single-switch continuous input current (CIC) buck–boost converter with noninverted output voltage is proposed. The proposed converter utilizes capacitor and inductor along with three diodes in conjunction with a quadratic boost converter to adopt its CIC feature. The features of high voltage gain, single active power switch, less ripple CIC, and noninverted output voltage make the proposed converter suitable for renewable and industrial applications. In addition, it provides a wide operating voltage gain with optimum component count, which is higher than the conventional buck–boost converter. Furthermore, it has low voltage stress across the power switch with comparable converters. To elevate the importance of the proposed converter, a detailed comparison analysis has been carried out considering voltage stress, voltage gain, effectiveness index, and component count. The operating principle and steady-state analysis in continuous conduction mode and discontinuous conduction mode of the proposed converter are discussed in detail. To validate the theoretical analysis and performance of the proposed converter, a prototype has been developed and tested in laboratory. [ABSTRACT FROM AUTHOR]

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