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This paper introduces the study of a single phase bidirectional high frequency link converter for photovoltaics applications in grid tie systems, based in the Push-Pull topology. The main advantages of high frequency link converters are: the low cost and high power density of the transformers, and the capacity to provide galvanic isolation between the photovoltaic panels and the grid. Furthermore, the capability to manage bidirectional power flow from the electric grid to the dc source allows adding the capability to compensate reactive power in the system using the same circuit. On the other hand, the sizing of the passive elements is explained. Proper operation of the proposed system has been validated through simulation results, showing that the injection of photovoltaic power to the mains and reactive power compensation are being carried out at the same time.Keywords-Bidirectional power flow, high frequency isolation, active power injection, reactive power compensation, power quality, push-pull topology.

Abstract-DC/AC converters with high-frequency isolation and bidirectional power flow are extensively used in photovoltaic power systems and small isolated power converters at low and medium power ranges.The main disadvantages of these circuits are: high freewheeling loss of the primary leakage current, limited ZVS range for the lagging leg switches, the effects of the parasitic elements of the systems and others. To avoid these losses an energy recovery circuit based on an active voltage clamper is presented.The control circuit is designed having a number of soft switching transitions. The system has been verified by simulation and a prototype is being tested. In this paper we present an energy recovery system and a modulation sequence for the cycloconverter. The energy recovery system is based on an active voltage clamper; the voltage peaks energy is returned to the source. Furthermore, the presented modulation sequence is designed to have a maximum number of soft-switching transitions independent of the electric variables; which means minimum losses and independence on measurement systems limitations for modulation.

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Using photovoltaic systems without battery storage is a viable option for water supply in communities isolated from the electricity grid. The system is environmentally friendly, reducing dependence on fossil fuels and reducing the cost of the pumping system and increasing its lifetime. The system consists of the direct interconnection of a photovoltaic array, an H bridge inverter with Mosfet's, an LC low-pass filter and an alternating current (AC) load.