45 research outputs found
Design of a Highly Efficient Microinverter
This paper proposes a grid-tied single-phase photovoltaic (PV) microinverter consisting of five-level four-switch (5L-4S) DC-AC converter fed by an isolated fly-back DC-DC converter. The microinverter utilizes a split-coil inductor to produce five levels of pulse width modulation (PWM) compared to the three levels of PWM using conventional four-switch topologies. These implementations reduce losses by up to 39% compared to a conventional topology. The results show that the proposed design improves performance throughout the switching frequency spectra with various loads. The theoretical expectations are validated with simulation and experimental results
Analysis and Design of Solar Photo voltaic Grid Connected Inverter
This paper presents common mode voltage analysis of single phase grid connected photovoltaic inverter. Many researchers proposed different grid tie inverters for applications like domestic powering, street lighting, water pumping, cooling and heating applications, however traditional grid tie PV inverter uses either a line frequency or a high frequency transformer between the inverter and grid but losses will increase in the network leading to reduced efficiency of the system. In order to increase the efficiency, with reduced size and cost of the system, the effective solution is to remove the isolation transformer. But common mode (CM) ground leakage current due to parasitic capacitance between the PV panels and the ground making the system unreliable. The common mode current reduces the efficiency of power conversion stage, affects the quality of grid current, deteriorate the electric magnetic compatibility and give rise to the safety threats. In order to eliminate the common mode leakage current in Transformerless PV systm two control algorithms of multi-carrier pwm are implemented and compared for performance analysis.The shoot-through issue that is encountered by traditional voltage source inverter is analyzed for enhanced system reliability. These control algorithms are compared for common mode voltage and THD comparisons. The proposed system is designed using MATLAB/SIMULINK software for analysis
Eliminating ground current in a transformerless photovoltaic application
For low-power grid-connected applications, a single-phase converter can be used. In photovoltaic (PV) applications, it is possible to remove the transformer in the inverter to reduce losses, costs, and size. Galvanic connection of the grid and the dc sources in transformerless systems can introduce additional ground currents due to the ground parasitic capacitance. These currents increase conducted and radiated electromagnetic emissions, harmonics injected in the utility grid, and losses. Amplitude and spectrum of the ground current depend on the converter topology, the switching strategy, and the resonant circuit formed by the ground capacitance, the converter, the ac filter, and the grid. In this paper, the ground current in a 1.5-kW PV installation is measured under different conditions and used to build a simulation model. The installation includes a string of 16 PV panel, a full-bridge inverter, and an LCL filter. This model allows the study of the influence of the harmonics injected by the inverter on the ground current.Ministerio de Ciencia e Innovación | Ref. DPI2009-0700
Nuevo inversor fotovoltaico integrado sin transformador
Los inversores sin transformador son ampliamente utilizados en sistemas fotovoltaicos conectados a la red eléctrica, debido a los beneficios de lograr alta eficiencia y bajo costo.El inversor fotovoltaico sin transformador puede generar una corriente de fuga entre el inversor y la red eléctrica, a través de la capacitancia parásita del módulo fotovoltaico y la tierra física. Esta corriente de fuga provoca una disminución de la eficiencia, reduce el tiempo de vida del módulo fotovoltaico y pone en riesgo al personal que esté en contacto con el sistema. Se han propuesto varias topologías de inversores sin transformador para reducir esta corriente de fuga; este trabajo propone una topología diferente que consiste en la integración de dos etapas, un inversor puente completo y un convertidor CD/CD elevador. Una terminal de salida del inversor está conectada directamente a tierra y el convertidor es controlado por modos deslizantes.Palabra(s) Clave(s): control por modos deslizantes, corriente de fuga, inversor fotovoltaico
Analysis and Implementation of Transformerless LCL Resonant Power Supply for Ozone Generation
This paper describes the analysis and design of an
LCL resonant power supply for ozone generation. The main advantage
of the proposed topology is the absence of high-voltage transformer;
the high voltage gain is achievable by means of doubleresonance
phenomena. Furthermore, the bandwidth is wider than
the ordinary LC and its phase difference is constant over specific
frequency range; as a result, an open-loop operation can be implemented.
The complete analysis and design procedure of the power
supply is presented. The design procedure is verified by implementing
the power supply to drive a dielectric barrier discharge
prototype ozone chamber. The hardware results are found to be
in close agreement with simulation and thus justify the validity of
the design procedures. The proposed circuit is suitable for portable
ozone power supply fed by low-voltage source such as battery or
photovoltaic module