Power optimizer

About: Power optimizer is a research topic. Over the lifetime, 10525 publications have been published within this topic receiving 199245 citations.

Analysis of high efficiency DC/DC converter processing partial input/output power

Abstract: This paper presents the analysis of two types of DC/DC converter structures processing partial input/output power and feeding directly a considerable amount of input power to the output. We compare the performance of partial power converters to traditional full power converter in terms of power ratings, regulation ability, switch stresses, and efficiency. The design trade-offs are considered as well. It concludes that partial power converters are a high-efficiency and low-power-rating solution for DC/DC power supplies. The power loss and power rating of partial power converters could be reduced up to 80% compared to these of full power converters. Simulation and experimental results are presented to validate the analysis.

Compensating for wind variability using co-located natural gas generation and energy storage

Abstract: Wind generation presents variability on every time scale, which must be accommodated by the electric grid. Limited quantities of wind power can be successfully integrated by the current generation and demand-side response mix but, as deployment of variable resources increases, the resulting variability becomes increasingly difficult and costly to mitigate. We model a co-located power generation/energy storage block which contains wind generation, a gas turbine, and fast-ramping energy storage. Conceptually, the system is designed with the goal of producing near-constant “baseload” power at a reasonable cost while still delivering a significant and environmentally meaningful fraction of that power from wind. The model is executed in 10 second time increments in order to correctly reflect the operational limitations of the natural gas turbine. A scenario analysis identifies system configurations that can generate power with 30% of energy from wind, a variability of less than 0.5% of the desired power level, and an average cost around $70/MWh. The systems described have the most utility for isolated grids, such as Hawaii or Ireland, but the study has implications for all electrical systems seeking to integrate wind energy and informs potential incentive policies.

Hybrid clean-energy power-supply framework

Abstract: A hybrid clean-energy power-supply framework integrates a fuel cell, solar cell, and wind energy, applies a max power tracking rule, raises the output power of a solar cell and wind energy to supply a power load and transfer the surplus electrical energy to a water-electrolyzing apparatus for producing hydrogen and oxygen, and provides a fuel for a fuel cell power generating system. Furthermore, the present invention utilizes features of each clean-energy power generating system, depends on the powerful calculation capacity of a central processing unit to monitor and dispatch each power generation and supply system, and thus ensures the reliability of supply power and reduces the power generation cost. Such a framework can selectively grid-connect with the utility power or run as a stand-alone power supply system and has a mechanism for preventing the island effect.

Capacitor-Less Photovoltaic Cell-Level Power Balancing using Diffusion Charge Redistribution

Abstract: This paper presents a new strategy, diffusion charge redistribution (DCR), for balancing power among photovoltaic cells to increase energy extraction and to improve maximum power-point tracking (MPPT) efficiency under partial shading conditions. With DCR, testing and binning during cell manufacturing can be eliminated and significant cost savings can be achieved during production. The proposed technique performs power balancing by taking advantage of the intrinsic diffusion capacitance of the solar cells and requires no external passive components for energy storage, thereby minimizing power electronics cost and complexity. Strings balanced by this technique exhibit power versus current curves that are convex, which also greatly reduces the cost and complexity of the required MPPT algorithm.

A Simple Energy Recovery Scheme to Harvest the Energy from Shaded Photovoltaic Modules During Partial Shading

Abstract: This paper proposes a simple circuit to recover the energy that otherwise would be lost due to the partial shadings on photovoltaic (PV) modules. Since the circuit can be readily retrofitted to an existing PV system, no modification on the central inverter is required. The main idea of the scheme is that, during partial shading, parts of the current from the nonshaded modules are harvested by an energy recovery circuit using power electronic switches and storage components. In doing so, the current of the PV string is maintained at the level generated by the shaded module. There is no need for the shaded module to be short-circuited; as a result, it can still actively produce output power (despite being partially shaded). To investigate the idea, the proposed circuit is retrofitted to a prototype PV system using eight modules. The partial shading conditions are emulated using a solar simulator with a controllable irradiance capability. The results are validated by a good agreement between the experimental and simulation works.