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This paper introduces a new structure of a multi-level inverter (MLI) to generate high-level AC voltages using a low number of switches with a quasi-sine waveform. The small number of driver circuits utilised in bidirectional switches is a salient characteristic of this inverter. Also, the number of conducting switches at each voltage level is low in this structure. This results in lower conduction losses of the switches. The proposed topology can be used as the cascaded structure with different approaches to select the value of voltage sources. Power losses are discussed for the proposed structure. To compare the proposed multi-level inverter and demonstrate its superiority, a comparison has been made with some recently presented topologies. According to the comparison results, the advantage of the proposed structure is producing high voltage levels with a smaller number of switches and driver circuits. To prove the suitable performance of the proposed MLI, a 21-level symmetric and 37-level asymmetric inverter containing 14 switches are designed and simulated in the MATLAB/Simulink program. A laboratory prototype for each of these inverters is implemented. The experimental results finely verify the simulations. Besides, an accurate comparison with recently introduced multilevel inverters has been carried out to confirm the effectiveness and superiority of the proposed structure. [ABSTRACT FROM AUTHOR]

This article proposes an enhanced non-isolated high-gain DC-DC converter for interfacing renewable energy sources (RESs). This converter utilizes active switched-inductor (ASL) and switched-capacitor (SC) networks in which the ASL network increases the voltage gain. Furthermore, using the SC network as a multiplier cell helps to reach a high voltage conversion ratio with a proper duty cycle. The main advantages of the proposed converter are the high voltage gain, continuous input current, and low voltage stress on the semiconductor switch and the passive component. Since the voltage stress of the semiconductor element is low, a low ON-state resistance switch is used, which leads to reduced conduction losses. Comprehensive analysis of the steady-state operation in continuous conduction mode (CCM), inductor and capacitor design, and a comparison considering other similar topologies are presented in this article. Also, the parasitic elements are assumed to calculate the DC-Voltage gain and the efficiency of the converter. Finally, simulation results are presented in the PSIM environment to validate the feasibility of the proposed converter. [ABSTRACT FROM AUTHOR]

Solar energy as a limitless, clean, and cost-effective energy source could be converted to electrical power by photovoltaic cells. In this paper, a photovoltaic power conditioner, which is connected to the low voltage grid via an LCL filter, is presented. This power conditioning system supplies high-quality current and has high stability against disturbances. Since the generated PV voltage is lower than the grid voltage, a DC-DC converter is utilized. Also, DC voltage is also converted to AC by an LCL-type inverter. To ensure the resonance elimination yielded from the LCL filter, inverter and grid side currents, a double feedback strategy is employed. By considering resonance damping, stability margin, and the grid-connected requirements, a systematic design procedure for the suggested strategy is investigated to ensure the system stability in the low-voltage network. In comparison with the conventional strategies, the suggested strategy gives suitable resonance damping capability, higher marginal stability, and better grid-connected properties. Simulation results of the PV power conditioning system illustrate the accurate performance of the control system, suitable tracking of the PV array maximum power point, and high-quality current injection into the grid. [ABSTRACT FROM AUTHOR]

The 2/3-level hybrid inverters are a combination of three-level Neutral Point Clamped (NPC) inverter and conventional two-level inverter, which has the advantage of both two-level and three-level structures with fewer switches than the NPC inverter. In this paper, a new structure of 2/3 hybrid inverter based on dual-Z-‏source network is proposed. The proposed structure improves the performance of the 2/3-level inverter and increases its independent DC input voltages. The output voltage gain can be obtained by selecting the shoot-through interval appropriately in dual Z-source networks. In addition, shoot-through intervals in Z-source networks allow the inverter to run without dead time, thus increasing the output voltage quality. A modified switching method is presented for the proposed inverter, and the necessary calculations are performed. The proposed structure can be used to connect different distributed generation sources to the load separately from the grid or to the low-pressure network. The performed simulations show the accuracy of the proposed structure. [ABSTRACT FROM AUTHOR]

Aleuroclava jasmini (Hemiptera: Aleyrodidae) is a major insect pest of paper mulberry (Broussonetia papyrifera) in Iran, negatively affecting its production. Considering the importance of oils in the integrated management programs of such pests, the present study examined the possibility of whitefly control on paper mulberry plant to assess mortality rate (MR), synergistic rate (SR), resistance rate (RR), and lethal concentration for 50% of the population (LC50) of oils and common insecticide in populations from four areas of Tehran, Iran (one susceptible and three non-susceptible). The best chemical treatments against A. jasmini adults and nymphs in paper mulberry plants were neem oil (1 ml L−1) mixed with deltamethrin (0.5 ml L−1) or with buprofezin (1 ml L−1). The neem, akylarylpolyglyglycol ether and volk oils mixed with deltamethrin or buprofezin also had synergistic effects on adults and nymphs of A. jasmini, respectively, in Azadi, Shahrake Gharb, and Vanak areas (non-susceptible populations), but with higher concentrations (> LC50) and lower SR than in Garm Dareh area (susceptible population). We observed that A. jasmini adults showed the greatest resistance to deltamethrin in Vanak area and nymphs of this pest to buprofezin in Shahrake Gharb area. [ABSTRACT FROM AUTHOR]