The increasing integration of variable wind generation has aggravated the imbalance between electricity supply and demand. Power-to-hydrogen (P2H) is a promising solution to balance supply and demand in a variable power grid, in which excess wind power is converted into hydrogen via electrolysis and stored for later use. In this study, an energy hub (EH) with both a P2H facility (electrolyzer) and a gas-to-power (G2P) facility (hydrogen gas turbine) is proposed to accommodate a high penetration of wind power. The EH is modeled and integrated into a security-constrained unit commitment (SCUC) problem, and this optimization problem is solved by a mixed-integer linear programming (MILP) method with the Benders decomposition technique. Case studies are presented to validate the proposed model and elaborate on the technological potential of integrating P2H into a power system with a high level of wind penetration (HWP).

In this paper, a family of new step-up series-parallel dual resonant switched-capacitor converters (SP-DRSCs) is proposed to extend the conversion ratio for high step-up applications. The converters feature wide gain range, continuously adjustable and enhanced light load voltage regulation. All flying capacitors operate in resonance, eliminating high transient current spikes and charge sharing losses. Thus, ZCS turn-on for all transistors and ZCS turn-off for all diodes are achieved. A comprehensive analysis of operation principle, voltage-gain curves, stable regulation range, voltage and current stress is given. An analytical method to quantify the passive component volume for the group of step-up dual resonance switched-capacitor converters (DRSCs) is presented. Further design considerations to optimize the passive component volume of proposed SP-DRSC and the effect of bulky bypass capacitors on volume are discussed.

In this paper, a step-down switched-capacitor converter and a step-up switched-capacitor converter with an integrated passive regenerative snubber (PRS) are proposed based on the Cuk dual resonance core (DRC). The members of the DRC converter family overcome the barrier for switching capacitor converters to achieve continuous output voltage regulation. One remaining challenge is the turn off spikes and oscillations during the switch turn-off transient that cause voltage stress and power loss to the transistor and diode. The proposed integrated PRS eliminates voltage spikes and oscillations across the transistor and diode during the turn-off process. Moreover, ZVS turn-on for the clamped MOSFET, ZCS turn-on for the other MOSFET and ZCS turn-off for all diodes are achieved. A comprehensive analysis of the operation principle, conversion ratio curve, component stresses, and regenerative power of the proposed converters with regenerative snubbers is given. Furthermore, a performance comparison between the proposed snubber configuration and two conventional methods is given. A 50V/99.25V step-up converter prototype of 125W has demonstrated a peak efficiency of 98.4%. The analysis is verified by both simulation and experiments.

In China, the electricity shortage is a serious problem especially in the east. Inducing the demand side and implementing demand side management (DSM) is an important way to solve the electricity shortage. It is good to development of the Chinese power market. Time of use (TOU) is one of the important DSM methods. Through TOU the demand side will respond to the price, and will change the shape of the demand curve. Thus the load condition will be improved. The key of implementing TOU is reasonable setting TOU price. Based on the analysis on historical load data, a multi-object TOU price decision model based on the demand side price response model is presented, and a fuzzy method is used to deal with this multiple objects model. The linear programming method is used to solve the problem. The data of a practical customer is used to test the feasibility of the proposed model.

The large-scale penetration of wind power might lead to degradation of the power system stability due to its inherent feature of randomness. Hence, proper control designs which can effectively handle various uncertainties become very crucial. This paper designs a novel robust passive control (RPC) scheme of a doubly-fed induction generator (DFIG) for power system stability enhancement. The combinatorial effect of generator nonlinearities and parameter uncertainties, unmodelled dynamics, wind speed randomness, is aggregated into a perturbation, which is rapidly estimated by a nonlinear extended state observer (ESO) in real-time. Then, the perturbation estimate is fully compensated by a robust passive controller to realize a globally consistent control performance, in which the energy of the closed-loop system is carefully reshaped through output feedback passification, such that a considerable system damping can be injected to improve the transient responses of DFIG in various operation conditions of power systems. Six case studies are carried out while simulation results verify that RPC can rapidly stabilize the disturbed DFIG system much faster with less overshoot, as well as supress power oscillations more effectively compared to that of linear proportional-integral-derivative (PID) control and nonlinear feedback linearization control (FLC).

This paper aims to accurately identify parameters of the natural charging behavior characteristic (NCBC) for plug-in electric vehicles (PEVs) without measuring any data regarding charging request information of PEVs. To this end, a data-mining method is first proposed to extract the data of natural aggregated charging load (ACL) from the big data of aggregated residential load. Then, a theoretical model of ACL is derived based on the linear convolution theory. The NCBC-parameters are identified by using the mined ACL data and theoretical ACL model via the derived identification model. The proposed methodology is cost-effective and will not expose the privacy of PEVs as it does not need to install sub-metering systems to gather charging request information of each PEV. It is promising in designing unidirectional smart charging schemes which are attractive to power utilities. Case studies verify the feasibility and effectiveness of the proposed methodology.