High Power Range Research Articles

Hybrid resonant inverter-based induction heating converter with CFPDM

This article proposes a 50 kHz hybrid (series–parallel) resonant inverter-based induction heating (IH) converter which is controlled with commercial frequency pulse density modulation (CFPDM). Since the hybrid resonant inverter enhances the series resonant inverter performance due to short-circuit handling capability and current gain, it has been successfully employed in IH. High power conversion efficiency and wide output power range can be obtained using CFPDM. In addition, some harmonic current problems occurred in conventional pulse density modulation because of the resonant frequency of non-smoothing filter are eliminated via CFPDM. There is no need for the application of any additional switches or passive components in CFPDM. In this article, CFPDM hybrid resonant inverter-based IH converter is modelled and the analysis of the converter is presented in detail. The operation principle of CFPDM controller is shown. In addition, the advantages of hybrid resonant inverter and CFPDM are stated. The theoretical analysis is verified via simulation and experimental studies, which are in very good agreement.

Modeling of Core Loss Resistance for $d\hbox{-}q$ Equivalent Circuit Analysis of IPMSM considering Harmonic Linkage Flux

This paper presents modeling of core loss resistance for d-q equivalent circuit analysis of IPMSM considering harmonic linkage flux. High efficiency is one of the major advantages of IPMSM, therefore precise loss analysis is required for high efficiency design. However, there is practical limitation of d-q equivalent circuit analysis in the calculation of core loss due to harmonic components of flux especially in high speed region where field weakening is generally applied. Harmonic components of linkage flux leads to the underestimation of core loss. Especially operation with high constant speed power range results in severe underestimate of core loss. Harmonic components of linkage flux are added to the general d-q axis equivalent circuits in this paper, therefore core losses due to harmonic components are considered by increased voltage drop across core loss resistance. From the presented modeling of core loss resistance, precise core loss can be obtained. Verification with FEA and experiments are presented.

Multidimensional Modulation Technique for Cascaded Multilevel Converters

Multilevel cascaded H-bridge converters have found industrial application in the medium-voltage high-power range. In this paper, a generalized modulation technique for this type of converter based on a multidimensional control region is presented. Using the multidimensional control region, it is shown that all previous modulation techniques are particularized versions of the proposed method. Several possible solutions to develop a specific implementation of the modulation method are addressed in order to show the potential possibilities and the flexibility of the proposed technique. In addition, a feedforward version of this technique is also introduced to determine the switching sequence and the switching times, avoiding low harmonic distortion with unbalanced dc voltages. Experimental results are shown in order to validate the proposed concepts.

Enhancement of Input Power Dynamic Range for Multiwavelength Amplification and Optical Signal Processing in a Semiconductor Optical Amplifier Using Holding Beam Effect

We demonstrate a considerable enhancement of input power dynamic range (IPDR) for multiwavelength amplification and optical signal processing in a semiconductor optical amplifier (SOA) by using holding beam effect. The effect is used in SOA gain region at power level well below 10 dBm, which is much smaller than the required power as the setting at transparency wavelength. The IPDR is extended not only to high power range due to the reduction of nonlinear crosstalks, but also to low power range due to the compression of amplified spontaneous emission (ASE) noise. The technique is first applied to the amplification of wavelength-division multiplexed (WDM) channels using a continuous wave (CW) holding beam. The holding beam is particularly useful for the amplification of large number of channels thanks to the suppression effect of interactions among WDM channels. It is then carried out for one of extensively-used optical processing schemes, terahertz optical asymmetric demultiplexer (TOAD), for multiwavelength data format conversion without the need of an external CW light. The IPDR of TOAD reaches over 20 dB as control clock behaves simultaneously as the holding beam. We also present that the patterning effect and the impact of ASE noise on the converted signal are strongly dependent on the TOAD's switching window, which is optimized at 40% duty ratio for the largest IPDR.

PRESENTE Y FUTURO DE LA ELECTRONICA POTENCIA (I). APLICACIONES DE GRAN POTENCIA.

Power Electronics has been gaining relevance in countless fields throughout industry, defence, transport, public buildings, communications, computing, home automation and electro-medical equipment. Although usually unnoticed, due to its subsidiary role of supplying energy to electrical equipment and systems, its applications and implantation are continuously growing. The power range is very wide, covering from over five thousand megawatts in High Voltage DC Transmission to a few tenths of a watt in micro-power converters for mobile telephones and personal electro-medical devices. Its multidisciplinary character and universality makes of power electronics a technological synergic vortex where semiconductor physics, electrical engineering, thermal management, control theory, industry communications, transport and most industrial disciplines are brought together. This paper, first of two, covers general aspects of Power Electronics and its applications in the high power range.

PRESENTE Y FUTURO DE LA ELECTRONICA DE POTENCIA ( II PARTE). APLICACIONES DE PEQUEÑA Y MEDIANA POTENCIA.

Power Electronics has been gaining relevance in countless fields throughout industry, defence, transport, public buildings, communications, computing, home automation and electro-medical equipment. Although usually unnoticed, due to its subsidiary role of supplying energy to electrical equipment and systems, its applications and implantation are continuously growing. The power range is very wide, covering from over five thousand megawatts in High Voltage DC Transmission to a few tenths of a watt in micro-power converters for mobile telephones and personal electro-medical devices. Its multidisciplinary character and universality makes of power electronics a technological synergic vortex where semiconductor physics, electrical engineering, thermal management, control theory, industry communications, transport and most industrial disciplines are brought together. This paper, first of two, covers general aspects of Power Electronics and its applications in the high power range.

Power quality improvement in load commutated inverter-fed synchronous motor drives

The load commutated inverter (LCI)-fed synchronous motor (SM) drive, also known as commutatorless motor (CLM) drive, is popular in high power applications. Most promising features of these drives include high efficiency, economic operation, flexibility of operation and variable speed in high power range, which led to their applications in blowers, fans, pumps, mill drives for a range of industries as mining, water treatment plants, chemical, paper, textile, cement, rolling mills and petrochemical plants. However, the power quality (PQ) concerns have resulted in a set-back for such applications of these drives. This study investigates various topologies for the mitigation of PQ problems in LCI-fed SM drives using multi-pulse AC-DC converters. A set of hybrid topologies is proposed to feed CLM, which use a multi-winding transformer and diode rectifiers with a chopper cascaded named as -rectifier-chopper-. These topologies improve PQ at AC mains, that is, reduce total harmonic distortion in the input current and correct the power factor. It also presents a basis for selection of a suitable AC-DC converter for PQ improvement at the input AC mains of the LCI-fed SM drives.

Improvement of photovoltaic pumping systems based on standard frequency converters by means of programmable logic controllers

Photovoltaic pumping systems (PVPS) based on standard frequency converters (SFCs) are currently experiencing a growing interest in pumping programmes implemented in remote areas because of their high performance in terms of component reliability, low cost, high power range and good availability of components virtually anywhere in the world. However, in practical applications there have appeared a number of problems related to the adaptation of the SFCs to the requirements of the photovoltaic pumping systems (PVPS). Another disadvantage of dedicated PVPS is the difficulty in implementing maximum power point tracking (MPPT). This paper shows that these problems can be solved through the addition of a basic industrial programmable logic controller (PLC) to the system. This PLC does not increase the cost and complexity of the system, but improves the adaptation of the SFC to the photovoltaic pumping system, and increases the overall performance of the system.

Closed solution of the transient skin effect in induction machines

The transient skin effect is solved for the rectangular open and semi closed slots containing a massive conductor. The solution is applied to the Joule losses and to the analytical calculation of the air gap torque and the stator currents of the induction machine exposed to the three-phase short circuit. The calculation of the Joule power losses under transient conditions has been accomplished, especially, for induction machines of the middle- and high-power range. This becomes important in dynamically controlled induction machines, especially when torque cycles of approximately 100 ms or less occur. Never before have the copper losses been evaluated completely under these transient conditions. For the calculation of the losses, the direct proportionality of the losses between torque and rotor bar current can be used. Furthermore, the results of the transient skin effect can find application in the operational behavior of the induction machine. The consideration of the transient skin effect of the rotor is necessary for calculating currents and torques. Until now, state of the art has only provided an analytical solving of the skin effect free model. Aiming to apply the given rotor geometry, this paper derives an approach which includes the transient skin effect, applying it on the three-phase short circuit of the idle running induction machine.

High power wavelength linearly swept mode locked fiber laser for OCT imaging

We report a long coherence length, high power, and wide tuning range wavelength linearly swept fiber mode-locked laser based on polygon scanning filters. An output power of 52.6 mW with 112 nm wavelength tuning range at 62.6 kHz sweeping rate has been achieved. The coherence length is long enough to enable imaging over 8.1 mm depth when the sensitivity decreases by 8.7 dB (1/e(2)). The Fourier components are still distinguishable when the ranging depth exceeds 15 mm, which corresponds to 30 mm optical path difference in air. The parameters that are critical to OCT imaging quality such as polygon filter linewidth, the laser coherence length, output power, axial resolution and the Fourier sensitivity have been investigated theoretically and experimentally. Since the wavelength is swept linearly with time, an analytical approach has been developed for transforming the interference signal from equidistant spacing in wavelength to equidistant spacing in frequency. Axial resolution of 7.9 microm in air has been achieved experimentally that approaches the theoretical limit.

Preparation of positive LiCoO 2 films by electron cyclotron resonance (ECR) plasma sputtering method and its application to all-solid-state thin-film lithium batteries

Thin films of LiCoO 2 prepared by the electron cyclotron resonance (ECR) sputtering method are investigated under various deposition conditions. Well-crystallized LiCoO 2 films were obtained without a post-annealing process in a high microwave and RF power range with a low O 2 to Ar ratio. All-solid-state thin-film lithium batteries using the LiCoO 2 films (thickness: 6.2 μm) provided a discharge capacity of about 250 μAh cm −2 with good cyclability.

Exploring adaptive locomotion with YaMoR, a novel autonomous modular robot with Bluetooth interface

PurposeThis paper aims to present a novel modular robot that provides a flexible framework for exploring adaptive locomotion.Design/methodology/approachA new modular robot is presented called YaMoR (for “Yet another Modular Robot”). Each YaMoR module contains an FPGA and a microcontroller supporting a wide range of control strategies and high computational power. The Bluetooth interface included in each YaMoR module allows wireless communication between the modules and controlling the robot from a PC. A control software called Bluemove was developed and implemented that allows easy testing of the capabilities for locomotion of a large variety of robot configurations.FindingsWith the help of the control software called Bluemove, different configurations of the YaMoR modules were tested like a wheel, caterpillar or configurations with limbs and their capabilities for locomotion.Originality/valueThis paper demonstrates that modular robots can act as a powerful framework for exploring locomotion of a large variety of different types of robots. Although present research is limited to exploring locomotion, YaMoR modules are designed to be general purpose and support a variety of applications.

Normalized IMD Spectra of High-T C and Low-T C Superconducting Resonators

Analyzing the results of the two-tone intermodulation distortion (IMD) measurements for the 2.3 GHz YBa2Cu3O7− x and GdBa2Cu3O7− x microstrip resonators we described the IMD spectra by the normalized values of P IMDn/P 0, where P IMDn is the output power of the n-th order IMD product and P 0 is that of the fundamental tone. The circulating power in the resonator was normalized by the power of the third-order intercept: P circ/P TOI. It was found, that the examined resonators exhibited the same dependence of P IMDn/P 0 versus P circ/P TOI and the same dependence of P IMDn/P 0 versus the change of the microwave surface resistance (ΔR S) at any measurement temperature. We reproduced these measurements for the indium microstrip resonators of the same geometry and obtained the same results. We conclude, that the nonlinear response of the superconducting microstrip resonators in the high power range is strongly affected by a geometry-dominated hf loss mechanism (likely the hf hysteretic losses due to magnetic flux penetration), which overshadows other nonlinear mechanisms related to the intrinsic material properties. This conclusion is in agreement with the results of the indium disk resonator measurements.

Effect of third-order intermodulation on radio-over-fiber systems by a dual-electrode Mach-Zehnder modulator with ODSB and OSSB signals

Third-order intermodulation (IM3) is a very important issue as a degradation factor of system performance in the range of high input signal power. In this paper, the effect of IM3 from a dual-electrode Mach-Zehnder modulator (DEMZM) and a photodetector (PD) is analyzed for optical single-sideband (OSSB) and optical double-sideband (ODSB) signals incorporating fiber dispersion. In addition, the optimum input signal power and the signal-to-noise-and-distortion ratio (SNDR) for the two cases are also investigated to optimize the performance of the entire system. In the case of OSSB signals, the fundamental components are robust against fiber dispersion, whereas their IM3 components are still sensitive to fiber dispersion. Subsequently, the SNDR for OSSB signals fluctuated to within 6 dB in the relatively high input power range due to fiber dispersion. In the case of ODSB signals, both powers of the fundamental and IM3 components are attenuated. However, the power attenuation of IM3 due to fiber dispersion is significantly faster than that of the fundamental. Thus, the SNDR for ODSB signals is improved as fiber dispersion increases until the power of IM3 is greater than that of the additive noise level.

Compact ASD Topologies for Single-Phase Integrated Motor Drives with Sinusoidal Input Current

A standard configuration of an Adjustable Speed Drive (ASD) consists of two separate units: an AC motor, which runs with fixed speed when it is supplied from a constant frequency grid voltage and a frequency converter, which is used to provide the motor with variable voltage-variable frequency needed to adjust the speed ofthe motor. The integrated motor drive concept is a result of merging the two units in order to achieve the following benefits [1–3]: reducing the design and the commissioning time in complex industrial equipments, no need for a cabinet to host the frequency converter, no need for shielded cables to reduce EMI (Electro Magnetic Interference), no need for cables for the speed transducers or for other sensors for industrial process control (e.g. pressure). This solution is currently available up to 7.5 kW being not used in the medium and high power range due to a low-density integration ofthe converter caused by the large size of the passive components (electrolytic capacitors and iron chokes) and vibration ofthe converter enclosure.This paper analyzes the implementation aspects for obtaining a compact and cost effective single-phase ASD with sinusoidal input current, investigating the physical removal of power inductors from the converter enclosure in conjunction with reducing the number of semiconductor active devices. There are two ways to do that: to integrate the inductors in the unused area of the stator yoke of the motor or to use the leakage inductance of the induction motor as a boost inductor for a PFC (Power Factor Correction) stage controlled by the inverter zero-sequence voltage component. By determining how much energy is possible to store in a corner inductor, it is proven that integrating the magnetics into the stator yoke is a feasible solution. Topologies of single-phase converters that take advantage ofthe motor leakage inductance are analyzed. The installed power in silicon active devices of these topologies is compared with a standard situation, showing that this will involve higher cost. As the iron core ofthe inductors is not suitable for high frequency operation, higher core losses will occur, but outside the converter enclosure. The advantages are: the reduction of the number of active semiconductor devices, the reduction ofthe ASD size and the better integration potential.

Ecological Validity of the WMS-III Rarely Missed Index in Personal Injury Litigation

The purpose of this study was to evaluate the clinical utility of the Rarely Missed Index (RMI) to detect cognitive exaggeration in 78 nonlitigant patients (i.e., Mixed Clinical group) and 158 personal injury litigants (i.e., 20 Suspected Exaggerators, 12 Borderline Exaggerators, 126 Genuine Responders). The base rate for probable malingered neurocognitive dysfunction in the litigant sample was 12.7%. The false positive error rate of the RMI in the Genuine Responder and Mixed Clinical group ranged from 5.4% to 8.6%. Positive RMI scores were found in 25% and 41.7% of the Suspected Exaggerator and Borderline Exaggerator groups respectively. The clinical utility of the RMI to identify Suspected Exaggerators versus individuals in the Genuine Responder and Mixed Clinical groups revealed low sensitivity (sensitivity = .25), very high specificity (range = .91 to .95), moderate positive predictive power (range = .50 to .71), and moderate to high negative predictive power (range = .68 to .83). These results do not support the use of the RMI as a reliable predictor of cognitive exaggeration. This study was supported in part by a research grant from the Queensland University of Technology, Brisbane, Australia

Integrated fluidic lenses and optic systems

Functionally integrated fluidic lenses and lens systems were demonstrated. Fluidic optic lenses can function as lenses with tunable focal distance, lens doublets with variable and convertible lens type, zoom lenses, and a lens system possessing both telephoto and reverse telephoto functions. High lens power and broad tuning range were achieved in a single 20-mm aperture device that can be tuned to have a convex or concave shape, with the respective tunable focal distance from 14.3 mm to infinity and from -6.1 mm to negative infinity. For fluidic adaptive zoom-lens-on-a-chip, a zoom ratio of 2.14 was achieved for 20-mm lens aperture, and a zoom ratio of 2.83 for 5-mm lens aperture. For the latter device, a tunable field-of-view from 10/spl deg/ to 80/spl deg/ was demonstrated, suggesting that the functions of telephoto and reverse telephoto systems can be achieved in a single zoom lens chip. Finally, the fluidic devices including the microfluidic pumps can be integrated with the lenses. All these integrated fluidic lenses and lens systems were microfabricated using a modified UV-LIGA process.

Constant modulus interference rejection at DSSS/QPSK transmission system

Consideration is given to a possibility of constant modulus (CM) interference rejection at a DSSS/QPSK transmission system. A new structure, called ξCM, is proposed. Compared to a complex two-sided filter, the ξCM structure gives better error probability for at least two orders of magnitude. The appliance of the new structure is especially significant within the range of high CM interference power.

A Novel 3-Phase Hybrid Harmonic and Reactive Power Compensator

The application of shunt active filters for the harmonic and reactive power compensation in the high power range is mainly restricted because of their low efficiency and the high cost of inverters with high switching frequency. Moreover; the compensation effect is completely lost in case of internal fault in active filter. Hybrid active filters as the combination of a low power PWM inverter and passive filters have been researched and developed to overcome the limitations of shunt active filter. However, they do not have control over fundamental reactive power. This paper proposes a new hybrid active compensator for harmonic and fundamental reactive current compensation, which consists of two small-rated active filters and one bank of passive filters. Simulation and experimental results are presented to show the advantages of the proposed compensator topology.

New developments in the Electric Fuel Ltd. zinc/air system

Abstract Electric Fuel Ltd. is engaged in the design, development and commercialization of its proprietary zinc/air battery technology for electric vehicles, consumer electronic products and defence applications. To meet the challenging requirements for propelling an all-electric bus, the Vehicle Division sought a unique solution: an all electric battery–battery hybrid propulsion system. The high energy zinc/air battery is coupled with a high-power auxiliary battery. The combined system offers zero emission, high power and long range in an economically viable package. The consumer battery group has developed a high power primary zinc/air cell aimed at cellular phone users, offering extended use, convenience and low cost.