Power optimizer

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

Integrated voltaic energy system

Abstract: An integrated voltaic energy system incorporates a bio-friendly DC power generator with a photovoltaic (PV) system connected to feed a main service panel and a utility grid. A plurality of inverters are connected one each, to a respective output of one of a plurality of photovoltaic (PV) solar arrays. The outputs of each of the inverters are connected to a main service panel and a utility grid. A further inverter is connected to the DC power generator and in parallel with the other inverters. The DC power generator is also connected to each of the PV solar panel inverters through a switch operated at a specific time manually or automatically. When switched the DC power generator feeds all of the inverters. A resistor/capacitor structure is connected between the DC power generator and each inverter. A self-powered timer may control the output level of the DC power generator.

A Transformer-Less High-Power Converter for Large Permanent Magnet Wind Generator Systems

Abstract: The power conversion systems for large wind turbines are facing a great challenge as today's wind turbine power outputs approach 5 MW and above. The conventional low voltage power conversion system will suffer from a high transmission current, which significantly increases losses and cost of the cables as well as voltage drop. This paper proposes a modular, medium voltage, high-power converter topology for the large permanent magnet wind generator system, eliminating the grid-side step-up transformer, which is desirable for both onshore and offshore wind turbines. The converter modules are cascaded to achieve medium voltage output. Each converter module is fed by a pair of generator coils with 90 phase shift to get the stable dc-link power. The power factor correction (PFC) circuit enables the generator to achieve unity power factor operation and the generator armature inductance is used as ac-side PFC boost inductance. At the grid-side, H-bridge inverters are connected in series to generate multilevel medium voltage output and the voltage-oriented vector control scheme is adopted to regulate the converter active and reactive power transferred to the grid. Simulation results with a 2-MW wind turbine system and experimental results with a down-scaled 3-kW system validate the proposed topology and control methods. The proposed system can successfully deliver power from the wind generator to the grid.

A Fuel Cell Power Conditioning System With Low-Frequency Ripple-Free Input Current Using a Control-Oriented Power Pulsation Decoupling Strategy

Abstract: This paper proposes a fuel cell power conditioning system based on the current-fed dual-half-bridge (CF-DHB) dc-dc converter that can achieve low-frequency ripple-free input current using a control-oriented power pulsation decoupling strategy when an inverter load is connected to the fuel cell system. Without adding any extra circuit components, the proposed power pulsation decoupling strategy can realize a smaller dc bus capacitor; a film capacitor, therefore, can be applied in this fuel cell power conditioning system to replace the bulky electrolytic capacitor. In order to eliminate the double-frequency ripple current disturbance introduced by the inverter load to the fuel cell stack, a proportional-resonant controller is developed to achieve an extra high control gain at a designed resonant frequency. The operation principles of the CF-DHB converter with a proposed power pulsation decoupling strategy are analyzed. In addition, the controller design guidelines are derived based on the system small-signal model. The experimental results of a 1-kW fuel cell power conditioning system are presented to validate the proposed technology.

High-Voltage Gain Boost Converter Based on Three-State Commutation Cell for Battery Charging Using PV Panels in a Single Conversion Stage

Abstract: This paper presents a novel high-voltage gain boost converter topology based on the three-state commutation cell for battery charging using PV panels and a reduced number of conversion stages. The presented converter operates in zero-voltage switching (ZVS) mode for all switches. By using the new concept of single-stage approaches, the converter can generate a dc bus with a battery bank or a photovoltaic panel array, allowing the simultaneous charge of the batteries according to the radiation level. The operation principle, design specifications, and experimental results from a 500-W prototype are presented in order to validate the proposed structure.

Development of a 500-kW Modular Multilevel Cascade Converter for Battery Energy Storage Systems

Abstract: Renewable energy sources such as wind turbine and photovoltaic power generators may make the power grid unstable due to their output fluctuations. Battery energy storage systems (BESSs) are being considered as a countermeasure for this issue. A modular multilevel cascade converter (MMCC) is expected as a power conversion circuit for BESSs because each bridge cell can control the state of charge of a battery unit, independent of that of another one, and the harmonic current generated is low enough to eliminate the ac filter, normally installed on conventional two-level converters, from the MMCC. This paper describes the development of a real-scale (500 kW) single-star-bridge-cell-based MMCC for BESSs and reports successful test results obtained from a downscaled grid model and a 6.6-kV real-scale distribution line.