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A function between output current of LCC resonant converter with capacitive load and normalized switching frequency is established using Fundamental Harmonic Approximation (FHA). A two-stage charging control strategy is proposed using a switch to change the resonant frequency to reduce the switching frequency range in constant charging (CC) mode with wide range load. The accuracy of the proposed technology is verified through a 800V, 1A LCC converter model built in SIMULINK of MATLAB. A prototype is manufactured which verifies that the two-stage charging control can reduce the switching frequency range by 50kHz

In this paper, we propose a novel wireless power transfer (WPT) system with fixed transmitting (Tx) coil and rotating receiving (Rx) coil used in automatic revolving doors. The WPT coils provide a high coupling and achieve a high efficiency against rotation. The coils are wound on coaxial structures similar to a pivot joint. The mutual inductance (M) between the coaxial windings is derived and validated by simulation, calculation, and measurement results. Design procedures of the coils are discussed. Finally, the WPT windings were fabricated. Experiment results are in good agreement with the calculation and simulation results.

The economic dispatch (ED) operation is based on determining the optimal output of all the distributed energy resources (DERs) of a microgrid to meet the load demand at the lowest cost. In this paper, a smart commercial building model is supplied by several distributed generations (DGs), for example, PV power plants, diesel generators, and energy storage system (ESS). In addition, the microgrid is connected to the main grid (grid-connected mode), which allows the system to trade power with the main grid. The aim of this paper is managing DERs that operate over a time horizon and satisfy several key constraints at the lowest possible cost. Therefore, an improved energy management (EM) operation is proposed to achieve better energy efficiency in the building. In the proposed EM operation, the ED problem is investigated according to several aspects, such as the impact of air temperature, thermal resistance (R) of the building envelope, and time horizon (day-ahead ED and five-minute-ahead ED). Finally, the results of the general algebraic modeling system (GAMS) are used to validate the accuracy and feasibility of the proposed EM operation.

The accuracy of the estimate of the calculation of power dissipation of the circuit in the technical evaluation and the application of the appropriate equipment and thus the final cost has a significant impact. In switched-capacitor multilevel inverters (SCMLIs), to build higher levels, the capacitors are series connected to the output and pump the stored energy to the load, which reduces the voltage of the capacitors and creates a spike current when the capacitor is paralleled with the source. Charging and discharging modes by the switching frequency makes small spikes. In the intervals, which the capacitor is continuously connected to the output as the series, thus causes more voltage drop and massive spikes. In this paper, small and massive spikes due to the voltage drop of the capacitor and the energy dissipation caused by that are calculated and formulated individually and accurately. MATLAB-SIMULINK is used to the modelling and simulation.

This paper proposes a novel single-phase transformerless 5-level inverter for grid-connected photovoltaic (PV) system. The main advantages of the proposed inverter are 1) By direct connecting the neutral point of the grid to the negative terminal of the PV, this inverter can eliminate the leakage current; 2) It can boost the input voltage; 3) It does not suffer from the current spike. 4) This inverter has an excellent capacity to conduct the reverse current as well as an acceptable output waveform spectrum. The first stage of the proposed circuit consists of two inductance, which makes a boost or buck-boost converter in each half-cycle. Therefore, the capacitor of the converter circuit can be used as the virtual dc source in the inverter stage, which decreases the size and cost of the proposed inverter. Some simulation results by using MATLAB/SIMULINK software are shown to demonstrate the efficacy of the proposed circuit.

Hybrid renewable energy sources is one of the alternatives solution for increasing the generated renewable energy power either in a standalone farms or grid-tie. This paper presents a single-phase 9-level multilevel inverter (MLI) that used for hybrid renewable energy generation systems, the medium and high power energy conversion systems especially in renewable energy applications. The structure of the proposed topology synthesize a nine power switching devices and two asymmetrical power sources to construct the proposed inverter. Also the proposed system has the ability for cascaded connection to increase the generated power level. The low THD level in the generated output power improving the performance of the system, which represented in a decrement in the size of the grid-side filter component and increases the efficiency of the system. The proposed topology MLI is verified using a computerized implementation using MATLAB Simulink© and real-time simulator (RTS) based on dSPACE (DS1103) hardware.

This paper presents a new switched-capacitor multi-level inverter (SCMLI) for photovoltaic systems which can eliminate the leakage current. The traditional SCMLI suffer from the H-Bridge to obtain negative levels, which create variable common mode voltage (CMV) and so generates the leakage current. Here, by direct connection the negative polarity of the DC source to the neutral point of the grid, it can guaranty giving constant CMV and then eliminating the leakage current. In this topology, without applying any extra circuit, all capacitors can be charged in binary asymmetrical structure, then, by reducing the number of components, it has aimed to increase the output levels with acceptable total harmonic distortion (THD). The other advantages of propose topology are that; it has the capability to boost the voltage as well as conduct the reverse current to the PV. To confirm the validity of the proposed topology, some simulation results for 15-level inverter by using MATLAB/SIMULINK software are given.

This paper presents an optimal design of the moveable ball-shaped transmitting coil used for wireless charging. Firstly, the mathematical model of mutual inductance calculation is established. Based on this model, the rates of changes of 9 kinds of coils windings’ mutual inductance are compared and the optimal design of the coils is selected by using the Maxwell (2D) simulation. Secondly, the topology of the wireless power transfer system is designed and simulated in the Matlab. Finally, an experimental platform is built and the results are compared with those of the theoretical calculation and simulation to verify that the proposed wireless power transfer system is feasible.

The economic dispatch is based on finding the optimal combination of all the energy resources of the microgrid. In this paper, a smart building microgrid model is supplied by diesel generators, PV, energy storage system (ESS), and main grid. The objective of this paper is to manage the generation resources which operate over a time horizon while satisfying many key constraints in low cost. In order to achieve better energy efficiency in the building, this paper proposed an improved energy management operation. In the proposed operation, the economic dispatch operation ED is presented according to such aspects as air temperature impact, the resistance of building shell, time horizon and so on. The accuracy and feasibility of the proposed energy management operation has been validated by GAMS simulation results.

In this paper, a modified structure of windings for Wireless Power Transfer (WPT)system is proposed. Transmitting coil (Tc)and receiving coil (Rc)are wound on a bio-inspired joint structure. The power is transferred across the gap while rotating Rc. Design procedures and winding methods are given. The magnetic field density (B)is discussed regarding the safety issues. Moreover, a mitigation method is presented. Finally, the simulation results are validated by experiments, which confirmed that the proposed joint structure can further improve the WPT performance by reducing the variation of mutual inductance $(M)$ .