Power optimizer

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

Nonlinear Model Predictive Control for DFIG-Based Wind Power Generation

Abstract: Reliable control and optimal operation of the doubly fed induction generator (DFIG) is necessary to ensure high efficiency and high load-following capability in modern wind power plants. This is often difficult to achieve using conventional linear controllers, as wind power plants are nonlinear and contain many uncertainties. Furthermore, unbalanced conditions often exist on the power network, which can degrade DFIG system performance. Considering the nonlinear DFIG dynamics, this paper proposes a nonlinear modeling technique for DFIG, meanwhile taking into account unbalanced grid conditions. Then, a nonlinear model predictive controller is derived for power control of DFIG. The prediction is calculated based on the input-output feedback linearization (IOFL) scheme. The control is derived by optimization of an objective function that considers both economic and tracking factors under realistic constraints. The simulation results show that the proposed controller can effectively reduce wear and tear of generating units under normal grid conditions, and reduce the rotor over-current under unbalanced grid conditions, thereby improving the ability of grid-connected wind turbines to withstand grid voltage faults.

On lossless switched-capacitor power converters

Abstract: This paper addresses the design of efficient switched-capacitor power converters. The discussion starts with a review of the fundamental limitation of switched-capacitor circuits which shows that the topology of such circuits and the "forced" step changes of capacitor voltages are the inherent attributes of power loss. Although the argument follows from a rather trivial result from basic circuit theory, it addresses an important issue on the maximum efficiency achievable in a switched-capacitor power converter circuit. Based on the observed topological constraint of switched-capacitor power converter circuits, the simplest lossless topology for AC/DC power conversion is deduced. Also discussed is a simple version of lossless topology that achieves isolation between the source and the load. Finally, an experimental AC/DC switched-capacitor power converter, based on the proposed idea, is presented which demonstrates an improved efficiency over other existing switched-capacitor power converters. The proposed AC/DC power converter contains no inductors and thus is suitable for custom IC implementation for very low power applications. >

Safety mechanisms, wake up and shutdown methods in distributed power installations

Abstract: A distributed power system including multiple DC power sources and multiple power modules. The power modules include inputs coupled respectively to the DC power sources and outputs coupled in series to form a serial string. An inverter is coupled to the serial string. The inverter converts power input from the serial string to output power. A signaling mechanism between the inverter and the power module is adapted for controlling operation of the power modules.

Generators and power electronics technology for wind turbines

Abstract: Due to the very fast development of power electronics, offering both higher capability and lower price/kW the applicability of power electronics in wind turbines increases rapidly. Moreover, new types of generators which may change the configuration of direct driven generators are being developed. This paper summarises the state of art regarding generator and power electronic concepts for wind turbines. The state of the art on wind turbine technology is established by a market oriented approach and the applied topologies are reviewed. Furthermore, trends for generators and power electronics are reviewed through technical and economical identifiers in terms of weight and price versus nominal power. New wind turbine designs are expected in the near future, exploiting the improved capabilities of generators and power electronics. Some of these new concepts are further discussed. Wind turbines are further being planned in big wind farms. These are subjected to quite high demands concerning power quality, controllability and safety. The paper also reviews potential concepts/technologies that can satisfy the defined restrictions.

Photovoltaic DC-to-AC power converter and control method

Abstract: An apparatus and method of control for converting DC (direct current) power from a solar photovoltaic source to AC (alternating current) power. A novel DC-to-AC power converter topology and a novel control method are disclosed. This combination of topology and control are very well suited for photovoltaic microinverter applications. Also, a novel variant of this control method is illustrated with a number of known photovoltaic DC-to-AC power converter topologies. The primary function of both control methods is to seek the maximum power point (MPP) of the photovoltaic source with novel, iterative, perturb and observe control algorithms. The control portion of this invention discloses two related control methods, both an improvement over prior art by having greatly improved stability, dynamic response and accuracy.