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Conductive metal organic frameworks (MOFs) are a promising class of porous crystalline materials for photocatalytic applications. We report direct evidence of a charge transport (CT) mechanism in 2D Cu-THQ MOFs using a combination of terahertz (THz) and transient absorption spectroscopies. Zn2+ ions were added to this MOF in order to understand their impact on CT, ultimately causing a decrease in conductivity. This work provides insight into the rational design of 2D MOFs for photoelectronic and photocatalytic applications.

This paper proposes the auxiliary magnetic repeater-aided dual-output wireless charging with coupling analysis and power transfer capability considerations, in which the coupling resonance under different gap distances are concerned as well. This study analyzes the circuit architecture based on the simplification of equivalent models, by which parameters of resonant circuit are determined. Through the proposed design of a dual-output system, the balanced output power is seen to be achieved with higher flexibility. Experimental outcomes indicate that this proposed approach exhibits a satisfactory efficiency under various test scenarios. Test results concluded from comparisons between the proposed system and conventional system further supports the effectiveness of the auxiliary magnetic repeater for the increment of power transfer efficiency and system stability. The outcomes gained from practical tests are anticipated to serve as useful references for automated guided vehicles applications.

This paper proposes the placement of coaxial symmetrical coils for inductive power transfer that is suitable for rail charging applications. It was known that the third rail of mass rapid transit (MRT) is often connected to voltage source so as to supply power to the surface-current collector of subway trains. However, considering that the third rail is directly connected to voltage source that needs to be insulated in order to avoid any unexpected consequence, the study of inductive power transfer hence becomes one of alternatives to improve the safety of power delivery. Therefore, by adding the merit of inductive power transfer for rail charging applications with realization assessment, this paper starts with the design of induction coils based on the analysis of mutual coupling characteristics. It is followed by the two-to-one inductive power transfer along with the appropriate completion of resonance circuit in order to ensure a high-efficiency and stable power transmission. To assess the practical value of the proposed method, both hardware realization and software simulation are made and investigated under different test scenarios. Test results are anticipated to be useful for transportation electrification development.

This paper proposes the design of dual-output wireless power transmission including backup mode operation for electric scooter applications. The study considers two modes of power transmission, where the power is delivered either from the adjacent battery or from the main power source to charge the scooter battery. Three inductive coils and three sets of full-bridges inverters are implemented in the circuit. The study first evaluates the geometrical structures of three inductive coils that include one transmitting coil and two receiving ones. The system is designed to operate at two frequencies to achieve different modes of operation using the same compensated capacitors. To validate the effectiveness of the propose configuration, the hardware realization is made with an achievement of efficiency of 92.7 % at the power delivery mode and 85.2%, at the backup mode. Test results support the practical value of the method for dual-output wireless charging, benefiting the development of transportation electrification.

In this paper, a magnetron-driven system with simple preheat method and power modulation is presented. Since the resonance microwave transmission of the magnetron requires a stable DC high-voltage and an AC preheating voltage, this paper is devoted to simplifying the system architecture while a sufficient resonant gain to drive the magnetron is ensured. In this design, a simple preheating method using the filament coil of the magnetron is also adopted to achieve the preheating requirement of magnetron, which is followed by the utilization of a frequency modulation approach to stabilize the output voltage. To confirm the feasibility of this proposed system, the hardware realization of a 1.3 kW prototype is completed. Experimental results have demonstrated the effectiveness of this magnetron-driven system for microwave industry applications.

This paper proposes a contactless power supply system for automated guided vehicles (AGVs) with a topology of two receiving coils. The study features balanced dual output capability for charging motors of the front and the back wheel of AGVs simultaneously, and they can be charged while moving along the rail. The equivalent resonance circuit configuration is established and characteristics of mutual inductances are analyzed as well in order to determine the system parameters with a higher efficiency. The output voltages can be easily adjusted based on the resonance analysis of the proposed system, where the coupling effect as well as output voltages are stabilized during moving operations. Experimental results reveal that the voltages at dual outputs are suitable for charging motor batteries, confirming the practicality of the proposed method for the application that is considered.

In this paper, a wireless power transmission with foreign-object detection (FOD) consideration is proposed. In the foreign-object detecting technique, a closed-loop feedback control is proposed by tracking the voltage and current of transmitting coil in order to signal the occurrence of a significant phase difference, anticipating preventing the system from potential risks. To validate the effectiveness of this method, three scenarios of foreign intrusions are taken into considerations. Experimental results obtained from these test cases consolidate the feasibility of maintaining a better secured power-transmitting system.

This paper aims to apply the bio-inspired intelligent techniques to optimize the maintenance scheduling of transformers. The study is enhanced with the aid of forest optimization algorithm to reach a schedule of reduced failure rate and decreased insulation life loss of transformers. To verify the effectivity of this approach, the method is tested on a real distribution system consisting of 48 distribution transformers. Test results confirm that the proposed scheduling method is feasible and effective.

This paper presents an ozone-generation system with modular expansion and two-terminal driving mechanism to improve the ozone-generating performance. This study is concerned because the high AC voltage is often utilized to excite the ozone ceramic chip and a high withstand voltage are required for components, possibly causing a larger complexity of circuit design. This paper, therefore, suggests a half-bridge inverter integrated with dual-terminal driving method. The design helps to balance the current flow through the ozone ceramic chip and reduce the output voltage of transformer, while the amount of generated ozone becomes more uniform and stable. In the study, the circuit takes the leakage inductance of transformer and equivalent impedance of ozone ceramic chip as the resonant tank so as to enhance the system performance. A prototype of modular ozone-generation system is realized with four ozone ceramic chips. Test results made on this prototype help confirm the feasibility of the proposed approach for ozone system applications.

This paper presents a converter design for fuel cell operations enhanced with a cooperation of supercapacitors and lithium batteries. The study is motivated because the properties of connected sources of fuel cell, lithium battery and super-capacitor are mutually different. An integrated converter with the energy control to regulate the power flow hence becomes crucially important. In the study, through the utilization of an improved step-down circuit along with the isolated circuit design, the completed converter is proved effective to supply power from fuel cells along with a backup support of supercapacitors and lithium batteries. By validating this proposed circuit under different load scenarios, test results help confirm the practical values of this design for green energy applications.

This paper proposes to install an additional distribution transformer to convert the open-wye/open-delta connection to wye/delta connection, anticipating mitigating the impact of a larger amount of PV systems connected to the distribution network. To validate the proposed scheme, various amounts and connections of PV systems are analyzed along with the examination of different scenarios. Simulation results confirm the benefits of this scheme to endure a higher impact of PV penetration. The outcomes gained from these tests are practically useful for utility engineers to make planning decisions.

This paper proposes a circuit that combines the class E inverter with DC-DC converter so as to provide dual controllable outputs. This study is motivated because the industrial equipment often needs different voltage sources to operate, yet with an inadvertent choice of parameters in the isolated converters, the voltage quality is often highly affected. Therefore, by connecting an auxiliary power switch and a diode in series between class E inverter and DC-DC converter, a circuit with dual controllable outputs is suggested. Moreover, the input inductor and a power switch in the class E inverter are shared with DC-DC converter for the energy storage, hence reducing the number of elements when compared to published techniques. This proposed circuit is completed with hardware experiments performed under different load conditions. Test results support the practical values of this proposed circuit for supplying source applications.

This paper presents an application of flower pollination algorithm for the decision support of distribution transformer placement in a low-voltage grid. The study starts with the model formulation by taking the level of customer satisfaction, transformer installation cost, and energy loss into consideration. It is followed by the application of flower pollination algorithm such that the site decision can be well guided through this optimization technique. To validate the effectiveness of the approach, the method has been tested through an example system with comparisons to other published methods. The test outcome demonstrates the satisfactory computation performance, supporting the feasibility of the method for the application to a grid system that is considered.

The open-wye/open-delta transformers are being adopted in Taiwan to supply either three-phase or single-phase loads, yet it has caused a phase unbalance problem. In this study, a bird-mating optimization (BMO) is hence motivated to assist in the coordinated switching of phase connection in open-wye/open-delta transformers such that the voltage unbalance and power loss can be better ameliorated. By mimicking the bird-mating behaviors, this algorithm excels at the optimal search with a reduced computation effort and a higher efficiency, hence suitable for a better arrangement of phase connection in open-wye/open-delta transformers. To confirm the effectiveness of such an intelligent method, two practical distribution systems of Taiwan Power Company were tested, by which the proposed one was further compared with other published techniques. From the test results, they have demonstrated the feasibility of the method as the decision support to enhance the coordination of phase connection of open-wye/open-delta transformers in a power grid.

This paper presents a wireless power transfer design with pick-up device position detection for dynamic power transmission. Since the fixed-point inductive charging is short of providing the power to the moving equipment, the paper is hence motivated to sense the pick-up device, by which the power and flux can be better regulated, meanwhile benefiting the efficiency and maintaining the voltage profile. As for the control strategy made in this study, the voltage of transmission coil is served as the feedback signal, with which the dynamic protection is reached while the modular platform organized by inductive coils are well accomplished. To validate the effectiveness of this method, the prototype is tested to dynamically deliver the power at 5 cm gap. Test results indicate that the power of each transmission coil can be effectively adjusted, where an 82.55% efficiency of the system can be expected. This method owns a high potential of extending to industrial applications when the dynamic power delivery is considered.

A hybrid-loop control approach applied to inverter circuit design with piezoelectric transducers is proposed in this paper. This approach was motivated because the transducer is easily affected by the temperature effect and damping pressure, causing the mechanical frequency drift and unstable current variation. In view of these demerits, a hybrid-loop control mechanism is suggested to achieve both phase-tracking and constant-current control such that both operation frequency and vibration strength can be well controlled while maintaining a stable mechanical frequency. Moreover, by embedding this hybrid control concept into microprocessor controller units without adding any further sensors devices, the design cost is found to be meanwhile reduced. To validate the feasibility of this approach, the method has been validated through mathematical analysis and hardware realization. Test results confirm the performance improvement of the approach for piezoelectric transducer applications.

This paper is aimed to develop a voltage equalization circuit for lithium iron phosphate batteries cooperating with supercapacitors. In this proposed equalizer, a bi-directional dc-dc converter circuit is utilized to deliver the redundant energy to supercapacitors such that the unequal battery voltage problem can be solved, while the energy loss can be minimized simultaneously. The study begins with the charging and discharging of batteries of interest. Then, the cell balancing circuit is constructed with the designated control procedure. This prototype has been extensively validated in the laboratory. Experimental results confirm the feasibility of the proposed approach for battery voltage balancing applications.

This paper proposes a feedback signal detection method and frequency-tracking control approach for inductive power transfer (IPT) systems. The power delivery efficiency is increased by utilizing a resonance compensation circuit and frequency-tracking control. Yet, it was observed that the resonance characteristics of IPT systems are easily influenced by load impedance and coil gap, hence frequency-tracking control is integrated into the microprocessor control unit (MCU) controller such that the operation frequency can be closely locked with the primary current phase. In the circuit design, a voltage across RDS(on) of the power MOSFET is utilized to compensate the resonance features of IPT system, by which the system delivery efficiency and zero-voltage switching can be both achieved. This proposed system has been tested under several scenarios. Test results help confirm the feasibility of IPT module for the application that is investigated.

This paper proposes a contactless energy-transfer system (CETS) for lithium iron phosphate battery-charging circuits. In the study, the design flow of contactless transformers and compensated circuit are investigated through the analysis of their impedance-matching and resonant features, by which the appropriate inductive coils can be optimally determined such that power transmission efficiency can be increased. Moreover, an algorithm of charging strategy is integrated into the microcontroller chip to facilitate the charging process. From theoretical analysis and hardware realization, they help support the proposed approach applied for the performance improvement of lithium iron phosphate battery-charging applications.

This paper proposes a piezoelectric transformer based on a resonant inverter that allows varying-capacity for ozone generation. The drawback of a piezoelectric transformer (PT) lies in its limited ability to transfer power, rendering it unable to provide sufficient current. Therefore, this study proposes a resonance topology with multiple modular parallel PTs using a PT-equivalent circuit derivation, and analyzes the resulting resonance curve characteristics. The proposed resonance topology can flexibly expand the output capacity, and stabilize the resonance characteristics and mechanical frequency. These results show that the proposed device is better suited to controller design. In addition, the study embeds an asymmetrical pulse width modulation (APWM) control concept into the microprocessor control unit such that the operating power of the ozone generator can be well regulated. This method has been realized with hardware circuit verification. Results demonstrate that the proposed inverter effectively drives the ozone generator system, regulates the operation power, and achieves the zero-voltage switching. The proposed design also ensures that the output current of each PT is evenly balanced, thereby facilitating the flexible capacity operations of the approach for industrial applications.

This paper proposes a charging control strategy for lithium-ion batteries. The method applies the post-charged steady-state battery voltage to justify the characteristics of durability for the lithium-ion battery, while the possibility of over-charging and under-charging conditions can be better avoided. In the method, the charging capacity, the charging security, and battery durability are all taken into consideration. Moreover, a wolf pack algorithm is applied to the charging process and searching for the optimal charging current. With the aid of this bio-inspired algorithm, the redundant energy in the charging can be saved, while the charge process can be more effectively controlled to reduce the time and cost. The method has been implemented on the laboratory prototype. Test results are compared with published techniques.

A wireless power transfer (WPT) platform optimization design for a contact less charging system is proposed. Drawbacks of WPT include low power transfer, low operation efficiency, and unstable output voltage, which are caused by various air gaps between the coils. A shuffled frog-leaping algorithm (SFLA) is hence applied to obtain the optimal frequency, meanwhile anticipating reaching the maximum output power and highest efficiency. Through the assistance of this bio-inspired algorithm, circuit simulations indicate that noises interfere can be restricted along with a maximum transfer power of 27 W and a conversion efficiency of 81%. This test outcome helps confirm the feasibility of bio-inspired algorithm for wireless power transfer design and its applications.

This paper proposes a new resonant circuit enhanced with a new tracking control approach for a piezoelectric transformer-based LED lighting system. In this method, the LED driver architecture features full bridge phase shift converter with C-L-C series-resonant circuit along with the piezoelectric transformer. Then, the concept of tracking control is well designated into the FPGA controller such that a higher efficiency of operation can be better reached. Besides, since only the secondary current of resonant transformer is needed for the controller, it helps facilitate the circuit implementation. From experimental results, they solidify the feasibility of this method for modular LED lighting applications.

This paper is aimed to develop a Li-ion battery charger with the intelligent decisions based on OCV information of the battery. In this method, the OCV function can be formulated through the measurement of output voltage with respect to a certain SOC value. Then using the obtained dynamics of battery intrinsic, a fast charging method can be developed to reach speedy and full charge without entering over-charging area. The method proposed in this paper is examined under various scenarios. The results help consolidate the feasibility and practicability of the approach for the applications considered.

A method of classifying home appliance electricity consumption is proposed in this paper. With the information retrieved from power signatures and harmonic features, the method excels at its systematic grouping capability of home appliances. It is also beneficial for residents to comprehend their home electricity variations. This proposed approach has been prototyped with hardware realization. Experimental results based on the tested appliance shows its potential of development for the application considered.

An enhanced immune algorithm (EIA) is proposed to solve the fault section estimation problem in this paper. By simulating the relationships between antibody and antigen in the immune system, the proposed method has added the vaccine inoculation process in anticipation of further improving the computation performance to solve the fault section estimation problems. In order to validate the effectiveness of such an approach, the method has been tested through a sample systems and a real system with comparisons to other published techniques. From the test results, they reveal the feasibility of the method, meanwhile confirming the method as a forewarning aid to distribution maintenance work.

This paper proposes an identification scheme of capacitor switching transients using Approximate Entropy (ApEn) approach. Detailed procedures of the proposed scheme are presented. Simulation and real results indicated that the scheme is feasible for classification of power event signals.

In this paper, a signal-processing approach is applied to enhance the inspection of wind turbine blades. This method starts with a time-frequency representation of signals, where a generalized time-bandwidth product method integrated with short-time Fourier transform is developed and applied. It is followed by the utilization of convex set to help justify the contour map such that the blade-condition monitoring can be better realized. Through test signals received from the sensors, it was found that the proposed approach would discriminate the damaged structure from the healthy one under several scenarios, thereby ensuring a higher efficiency of wind power generation.

The alternative energy power generator has emerged to be an important research topic in the modern energy study, among which the expansion of generation capacity has a crucially high importance. Therefore, this paper has configured a modular inverter system, where the flexible capacity design was realized within this configuration in anticipation of improving the system operation reliability of the power generations. In order to verify this proposed approach, the simulation tests have been performed. Through these test results, they have supported the feasibility of the method for capacity expansion of distributed generation systems, thus further consolidating the reference value of the overall developed system.

This paper presents a robust method for power system state estimation along with a statistical technique of data debugging. In the estimation process, an exponential function is utilized to modify the variances of measurements in anticipation of enhancing the estimation performance and improving the convergence characteristics. Besides, with the aid of Monte Carlo method (MCM)-based clustering analysis, those bad data can be effectively identified from the set of raw measurements. To validate the effectiveness of the proposed approach, this method has been tested under different scenarios. Test results help confirm the feasibility of the method for the applications considered.

In this paper, a robust algorithm involving a changeable weighting matrix is proposed for static state estimation of electric power. In the estimation process, the exponential function is utilized to modify the variances of measurements so that the estimation performance can be improved when the power system encounters the bad data scenario. This proposed approach has been tested through the data collected from the operation of a power system. Test results show the feasibility of the method for the applications considered.

A novel design of line-interactive uninterruptible power supplies is proposed in this paper. In the designated circuit, by utilizing single-stage power converter, the system can be operated either in the active power filter mode or in the voltage-stabilizing mode based on the operating state of mains power. When the system is operated at the active power filter mode, both the harmonic reduction and reactive power compensation can be achieved via a set of current feedback signals. When the system is operated at the voltage-stabilizing mode, by deeming the capacitor current as the control variable, the first-order current control method can be formulated such that the system stability is maintained while the speed response is significantly improved, With the aid of the FPGA in the digital design, it is found that the hardware circuit can be realized within a shorter time and the design cost can be also lowered down. This proposed system has been validated by theoretical analysis and experimental realization. Test results support the feasibility of the proposed approach for the application considered.

In this paper, an algorithm based on the usage of the exponential function along with the sliding surface-enhanced fuzzy control is proposed to solve prediction-based state estimation in power systems. In the proposed method, the merit of exponential function lies in its immunity to the cases of bad measurement and network configuration error, while that of the fuzzy control is its adaptive capability of preventing from the false estimation under abrupt load variation conditions. This proposed method has been applied to the IEEE 30-bus test system. Test results help support the feasibility of the method for state estimation applications.

In this paper, the box counting method-based fractal geometry technique is proposed to detect the power quality disturbances in power systems. In the proposed approach, the fractional dimension computation is embedded into the detection procedure. Thanks to its quantization capability of disordered dynamics, the proposed method becomes highly effective to monitor the power quality. This proposed approach has been tested on various disturbances and the test results reveal the feasibility of the method for the detection of power quality.

In this paper, a gap statistic algorithm (GSA) is applied for the bad data analysis. In the method, GSA is employed for the enhancement of neural networks. Because the number of cluster can be determined via GSA more effectively, this integrated approach is beneficial for the localization of the group of bad data. The proposed approach was validated through the data collected from the operation of a power system. Test results pointed to the feasibility of the method for the applications considered.

The burn-in test has been regarded as a feasible approach for quality certification of new UPS products. In this paper, we proposed a new approach of circulating current method for UPS burn-in testing with energy recovery. With the application of this method, the testing power can be recycled for reuse such that the experimental cost can be largely reduced. Besides, the proposed method is useful to restrict the degree of harmonic pollution that may affect the utility grid. Therefore, electric power quality can be also better ensured. This method has been validated through the simulation study. Simulation results help consolidate the feasibility of the approach for the applications considered.

Summary form only given as follows. One of critical concerns in the operation of grid-connected dispersed generating units is the occurrence of islanding. It is known that the islanding may pose hazards to utility personnel and complicate the orderly reconnection of the grid. Hence, in this paper, a new algorithm based on the monitoring of the change in /spl delta/f//spl delta/P/sub L/ to detect the islanding is proposed. By the proposed method, a detection index can be evaluated that serves as a useful reference to activate the protective relays. This approach has been applied to investigate different scenarios, including the loss of grid and the parallel operation. Effects of load change and power-quality disturbances to the detection performance are also examined. From these test results, they help solidify the feasibility and effectiveness of the approach for the applications considered.

A web-based virtual instrument software for electric power measurement with Java enhancement is proposed in this paper. Because of the operating platform independence exhibited by Java, such a programming technique is embedded in virtual instrument software LabVIEW/spl trade/ for the improvement of data communication capability. In this method, web-based measurement software is developed that utilizes Java Servlet to achieve the data exchange of power measurement between server and clients. By the proposed software system, utility engineers can perform the measurement at any time even in the remote side. Once the required measurement are made completely, the acquired data can be immediately transferred back to the server in order to activate LabVIEW such that that data can be analyzed in more detail. To facilitate the measurement process, the graphic user interface is also designed. A user authentication is also added in the software to maintain the software security. It is found that, through the proposed approach, the cost required for the data measurement in a utility can be saved significantly, while the electric power quality can be better monitored. This method has been tested through the utility data of Taiwan Power Company. Test results help support the feasibility and effectiveness of the method for Internet applications.

Electric Arc Furnace (EAF) is productive equipment used to melt scrap, but also injects harmonics into the utility. In this paper, the stochastic characteristics of an EAF over three complete heats were estimated at a basic sampling period. Characteristics including stationarity, normality and correlation are investigated. Besides, several statistic parameters such as mean value, standard deviation and accumulative probability were all assessed by varying sampling period. This estimation work was implemented by a microcomputer-based instrumentation system. Test results of a typical AC EAF were and discussed. They can be useful reference for the improvement of electric power quality.

An enhanced query-based learning neural network is proposed to refine the contour in this paper. The proposed learning approach provides a classifier at a lower computational cost comparing with the other method. The ambiguous regions in the classification process can be thus easier clarified. The proposed approach has been tested on the refinement of security contours in the assessment of power system operations. Results demonstrate the effectiveness and feasibility of the proposed approach for the applications.

This paper proposed a method of supervising power system harmonic trends. The method applies a window function on the transformed signals to control their span intervals. By this approach, it helps monitor the harmonic components of transformer inrush current and arc furnace disturbances. The method has been tested on a transformer under various load conditions and an arc furnace in a steel plant. Testing results present the superiority of the proposed method for the applications.

A Kohonen self-organizing neural network embedded with a genetic algorithm is proposed in this paper. The genetic algorithm is embedded to initiate the Kohonen classifiers. By the proposed approach, the neural network learning performance and accuracy are greatly enhanced. In addition, the genetic algorithm can successfully avoid the neural network from being trapped in a local minimum. The proposed method is developed and tested on an electric utility system to access its dynamic security.

A new approach of using genetic algorithms to improve the learning characteristics of Kohonen's neural networks is proposed in this paper. In the proposed scheme, genetic algorithms are applied to decide initial weights in the Kohonen's classifiers. The competitive learning is then applied to train neural networks. The proposed method was tested on the power system static security assessment and travelling salesperson problems. The results were very promising.

In this paper, an islanding detection circuit designed for dispersed generators with self-commutated static power converters is proposed. This circuit is suggested based on the monitoring of the magnitude and sign change in the ratio of the frequency deviation to the load variation. To facilitate the detection process, an asymmetrical circuit for generating the output power deviation is developed. The proposed method has been tested under various scenarios in order to examine the detection performance. It is found that the proposed method effectively detects the islanding event while different amount of power mismatch is considered. The test results help verify the effectiveness and feasibility of the proposed approach.