AC solar cells: An embedded "all in one" PV power system

Journal ArticlePower converters constructed from discrete components are difficult to mass produce, and the installation involves a significant labor cost to have the proper interconnection among the panel, inverter and the grid. These facts indicate that the present PV technology may not be able to address the challenges involved in reaching the DOE target of $1/W. Therefore, a paradigm shift in the design of the entire PV power system is needed to reach this goal. In order to increase the converter reliability and watts/$, the active and passive elements of a power converter (especially capacitors and active switches such as MOSFETs, JFETs or IGBTs) could be embedded on the same substrate material used for fabricating the p-n junctions in the photovoltaic panel. To the knowledge of the author, there is no prior work in cell level power conversion, and therefore, this project idea could be considered as an "Out of the box" kind. A novel fabrication process is proposed in this paper demonstrating the integration of PV cells and two major components needed to build a power converter. Because of the cell level power conversion, PV panels constructed from these cells are likely to be immune to partial shading and hot-spot effects. The end goal of this research is to produce 120V/240V ac output directly from the panel. An extremely accurate device simulator (*Silvaco Athena/Atlas) was used to generate reasonably accurate characteristics of the proposed PV system

Fabrication processes and experimental validation of a planar PV power system with monolithically embedded power converters

pre-printThis paper summarizes the research outcome intended to identify the most suitable device architecture and its implementation for cell-level power conversion in a photovoltaic (PV) system. The fabrication process to accommodate the power conditioning unit with the PV cells using the same process run have been presented in this paper. Using this method, the entire converter can be embedded with the PV cells producing AC power directly from the solar cell strings. The initial phase of this project simulated various circuit components in the CMOS process, and the project outcome has been summarized in a previous publication by the authors. This paper presents the experimental results of the proposed process, and a simple chopper circuit has been constructed using the embedded MOSFETs and the PV cells. The circuit has been experimentally characterized, along with components. In addition to the process-related challenges and issues, this paper explains the justification of this integration by achieving higher reliability, portability and complete modular construction for PV-based energy harvesting units. To the knowledge of the authors, no attempt has been made to fabricate power converter components with PV cells in the same process run

Design and simulation of contour mode MEMS resonator on Si for power converters

pre-printMicroelectromechanical systems (MEMS) resonators on Si have the potential to replace the discrete passive components in a power converter. These devices not only can reduce the size and weight of the converter but also can facilitate the implementation of power converter on a chip. In this paper, a contour mode MEMS resonator has been presented that can achieve resonant frequency in the range of several MHz, and the operating principles of the device have been discussed in detail. This device was simulated in COMSOL Multiphysics, and a resonant converter has been simulated in PSIM to harvest energy from a thermo electric generator. The equivalent electrical model of the MEMS resonator was incorporated into that circuit validating the feasibility of using MEMS resonator in power conversion systems. Detailed fabrication process of the device has been presented and implemented at University of Utah's Nanofab. Initial experimental characteristics of the resonator have been included in the paper