Power optimizer

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

An Effective Control Method for Three-Phase Quasi-Z-Source Cascaded Multilevel Inverter Based Grid-Tie Photovoltaic Power System

Abstract: The quasi-Z-source cascaded multilevel inverter (qZS-CMI) presented many advantages over conventional CMI when applied in photovoltaic (PV) power systems. For example, qZS-CMI provides the balanced dc-link voltage and voltage boost ability, saves one-third modules, etc. However, current research studies only disclosed control of single-phase qZS-CMI-based PV power systems, and there was no literature related to control of three-phase qZS-CMI-based PV power systems. In this paper, for the first time, three-phase qZS-CMI's control is proposed and demonstrated for application to PV power systems. The models of PV-panel-fed qZS H-bridge module and qZS-CMI-based PV power system are built to accurately design control algorithms for each module and the whole system. The proposed control method includes the distributed maximum power point tracking for each module, dc-link peak voltage balance control for all modules, and grid-tie control for the whole system; moreover, a new multilevel space vector modulation method is proposed for the three-phase qZS-CMI. Simulation and experimental results on a test bench with a three-phase seven-level qZS-CMI-based PV power system verify the proposed control and modulation methods.

Security-Constrained Unit Commitment With Flexible Uncertainty Set for Variable Wind Power

Abstract: Power system operation has recently witnessed major challenges, which are often due to large-scale integrations of wind power generation. In this paper, a two-stage robust security-constrained unit commitment (SCUC) model is proposed for managing the wind power uncertainty in the hourly scheduling of power system generation. Different from previous studies on robust SCUC, which considered a predefined uncertainty set, the proposed method applies a flexible uncertainty set for managing the variable wind power generation. The proposed method seeks a feasible and economic dispatch in the flexible uncertainty set, takes into account wind spillage and load curtailment risks, and makes a tradeoff between the optimal wind power absorption and the economic grid operation. Several case studies are applied to the proposed method and the corresponding solutions are analyzed in the paper. The impacts of major factors, including flexible generation resources and power transmission capacity, on the proposed solution are also discussed. The numerical results demonstrate the merits of the proposed method for managing large variations in the hourly wind power generation and lowering the power system operation cost in uncertain conditions.

A DC/DC Boosting Technique and Power Management for Ultralow-Voltage Energy Harvesting Applications

Abstract: With the increasing use of low-voltage portable devices and growing requirements of functionalities embedded into such devices, efficient dc/dc conversion and power management techniques are needed. In this paper, an architecture for boosting extremely low voltages (about 100 mV) to the typical supply voltages of current integrated circuits is presented which is suitable for power harvesting applications too. Starting from a 120-mV supply voltage, the converter reaches an output voltage of 1.2 V, providing an output current of 220 μA and exhibiting a maximum power efficiency of about 30%. Along with the dc/dc converter, a power management circuit is presented, which can regulate the output voltage and improve the overall efficiency. A test chip was fabricated using a United Microelectronics Corporation 180-nm low-threshold CMOS process.

High efficiency power system with plural parallel DC/DC converters

Abstract: A distributed staged power system for use in electric and hybrid electric vehicles, and the like. The system comprises a plurality of parallel DC-to-DC power modules that are controlled by way of input and output control signal interfaces using a smart controller. The distributed staged power system provides higher efficiency because of smart staging of the power modules. The distributed staged power system enables or disables each of the modules as determined by a smart controller to provide the highest possible conversion efficiency.

Stochastic Scheduling of Battery-Based Energy Storage Transportation System With the Penetration of Wind Power

Abstract: Battery-Based Energy Storage Transportation (BEST) is a potential solution for optimizing the power system operations with a high penetration of wind energy. In this paper, we propose a scenario-based stochastic model for the BEST-integrated power system scheduling. In this model, load and wind energy forecasting inaccuracies and random disturbances are modeled in scenario trees using the Monte Carlo simulation method. Random disturbances represent forced outages of both power system and railway system components, including generation units, transmission lines, railway stations, and railway lines. Benders decomposition is adopted to solve the stochastic model. Two BEST-integrated power systems are used to illustrate the proposed model and the performance of the proposed solution algorithm. The first one is a 6-bus power system integrated with a 3-station and 3-line railway network. The second one is the modified IEEE 118-bus power system integrated with a railway network composed of 8 railway stations and 10 rail lines. Simulation results show that the BEST system implementation is a viable option for managing the large-scale integration of wind power which can reduce the curtailment of wind power and accordingly lower the operation cost of power systems.