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In this paper, we propose the control method of a peak shaving system for an electric injection molding machine (EIMM). The peak power shaver consists of a multiphase bidirectional dc–dc converter and supercapacitors (SCs), and is connected to a dc link of the inverter fed injection motor drive system of the EIMM. In the proposed control method, electric power is stored in the SCs through the multiphase bidirectional dc–dc converter with a pulsewidth-modulation rectifier while the injection motor is at rest. When the injection motor is accelerating, the stored power in the SCs together with the power from the distribution feeders is supplied to the injection motor. Thus, the peak power can be shaved. The basic principle of the proposed control method is discussed in detail, then confirmed by digital computer simulation and experimental setup. The simulation and experimental results demonstrate that the peak power is shaved by 70% using the peak power shaving system. [ABSTRACT FROM PUBLISHER]

This paper proposes a novel active power quality compensator (APQC) topology with a DC voltage balancer for electrified railways. The APQC is composed of a three-leg structure with two common DC capacitors. Two legs perform as two half-bridge inverters, which compensate the unbalanced active, reactive, and harmonic currents on the source side in the traction substation. The third leg controls two common DC capacitor voltages with a small amount of the output currents. Therefore, the current rating of the third leg can be reduced as compared to that of the already proposed three-leg structured APQC. In the control algorithm of the two half-bridge inverters, a strategy based on constant DC capacitor voltage control is used, which does not need any calculation blocks of the unbalanced active, reactive, and harmonic components of the load current to perform the APQC operation. Thus we offer the simplest algorithm for the proposed APQC. The basic principle of the proposed APQC topology with the DC voltage balancer is discussed in detail, and then confirmed by digital computer simulation using the PSIM software. A prototype experimental model is constructed and tested. Experimental results demonstrate that the proposed APQC can achieve balanced and sinusoidal source currents on the primary side of the Scott transformer in traction substations for electrified railways. © 2013 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc. [ABSTRACT FROM AUTHOR]

This paper proposes a starting method of the harmonic current compensator using a hybrid active filter for wind power generation systems. The active filter (AF) in the proposed method of the hybrid power filter behaves as a resistor and reactive power compensator to suppress the inrush current and leading currents for the passive filter (PF) under the starting condition. The basic principle of the proposed starting method is discussed, and then confirmed by digital computer simulation using PSCAD/EMTDC. Simulation results demonstrate that the proposed starting method can overcome the inrush and leading currents for the PF, building up the DC capacitor voltage of the AF. IEEJ Trans 2011 DOI: 10.1002/tee.21815 [ABSTRACT FROM AUTHOR]

This paper proposes a novel method of detecting the active and reactive currents in single-phase circuits using the correlation and cross-correlation coefficients in the time domain. The active current is detected using the correlation coefficient between the source voltage and load current waveforms, and the reactive current is detected using the cross-correlation coefficient. The basic principle of the proposed detection method is discussed, and the proposed method is applied to a previously proposed single-phase shunt active filter for consumer electronic equipment. Simulation and experimental results demonstrate the excellent practicability of the proposed detection method. [ABSTRACT FROM AUTHOR]

This paper presents the newly proposed hybrid resonant commutation bridge-leg link (HRCB) snubber circuit which can achieve zero voltage and zero current soft-switching commutation for single-phase and three-phase voltage source-type inverter, along with its unique features and operation principle. The circuit parameter design approach for the HRCB snubber circuit and the determination estimating scheme of the gate pulse timing processing which is more suitable and acceptable for single-phase and space voltage vector modulated three-phase voltage source inverter using the HRCB snubber circuit are described in this paper. In particular, the three-phase voltage source soft-switching inverter associated with the proposed HRCB circuits are evaluated and discussed from simulation and experimental viewpoints. The practical effectiveness of the HRCB snubber-assisted three-phase voltage source soft-switching inverter using IGBT power modules which is based on the instantaneous space voltage vector modulation is clarified on the output voltage waveform, actual efficiency of electromagnetic noise in comparison with three-phase voltage source-type conventional hard-switching inverter. [ABSTRACT FROM AUTHOR]

In this paper, we propose a single inductor type resonant AC link snubber as a technique for introducing soft-switching PWM technology into three-phase voltage source inverters and explain its circuit operation. We then explain the suitability of instantaneous space voltage vector sinewave modulation compared to sinewave-triangle wave relative modulation as the sinewave modulation technique of the soft-switching inverter introducing this resonant AC link snubber, and propose a time sharing pulse pattern based on the operating principle of this resonant AC link snubber. Furthermore, we discuss the limits on the widths of the pulses that can be output when the time sharing pulse output method is used and the soft-switching inverter performs sinewave modulation, and the need to correct narrow output pulse widths; describe in detail the relationship between the generation principle of the correction pulse pattern and the waveform distortion; and illustrate the simulation results when the minimum pulse width is corrected. Finally, we propose a new time sharing pulse pattern that does not need the minimum pulse width correction by using the time sharing pulse pattern feature for the resonant AC link inverter and demonstrate its effectiveness from the simulation results for this output pulse pattern. © 2004 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 88(2): 34–40, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.20144 [ABSTRACT FROM AUTHOR]

Series–series (SS) and series–parallel (SP) topologies are widely used in resonant inductive coupling wireless power transfer systems for various applications. However, the selection of an appropriate topology to achieve higher output power or higher efficiency is typically difficult because design optimization of the circuit parameters (e.g., characteristic impedance, load resistance, and mutual inductance) for each topology is generally separately discussed using different equivalent circuits with multiple resonance modes. Therefore, the purpose of this study involves proposing a simple strategy to select an appropriate topology. The proposed strategy is based on quasi-duality between the SS and SP topologies that are elucidated from the novel equivalent circuits derived using Lagrangian dynamics. Based on the quasi-duality, the output power and efficiency of the SP topology are calculated via the equivalent circuit of SS topology. Thus, the quasi-duality offers a simple comparison between the SS and SP topologies. The proposed strategy selects an appropriate topology by comparing only the equivalent ac load resistance, which is the ac resistance including the rectifying circuit and the load resistance, the characteristic impedance, and the ac load resistance that achieves the maximum efficiency or maximum output power of the SS topology. Experiments verify the appropriateness and effectiveness of the proposed strategy. [ABSTRACT FROM AUTHOR]

Gallium-nitride-field-effect transistors (GaN-FETs) are promising switching devices with fast switching capability. However, they commonly have low gate threshold voltage, suffering from susceptibility to the false triggering. Particularly, the oscillatory false triggering, i.e., a self-sustaining repetitive false triggering, can occur after a fast switching, which is a severe obstacle for industrial applications. The purpose of this paper is to elucidate the design instruction for preventing this phenomenon. The oscillatory false triggering is known to be caused by the parasitic oscillator circuit formed of a GaN-FET, its parasitic capacitance and the parasitic inductance of the wiring. This paper analyzed the nonoscillatory condition of this oscillator. The result revealed an appropriate ratio between the gate-drain capacitance and the common-source inductance is a key to prevent the oscillatory false triggering. Experiment successfully verified this analysis result, supporting the effectiveness of the appropriate design of this ratio for preventing the oscillatory false triggering. [ABSTRACT FROM AUTHOR]

Recent progress of widebandgap semiconductor switching devices enabled extremely high-frequency operation of power converters owing to their ultrafast switching capability. Fast switching may cause large switching noise at the common source inductance, which may increase the switching loss and lead to false triggering. Therefore, measurement of the common source inductance is often intensely required in practical design of fast switching power converters. However, measurement of the common source inductance is difficult, because 1) the wiring path hidden beneath the molded package significantly contributes to this inductance, 2) the mutual inductance between the gating circuit and the power circuit also contributes to this inductance, and 3) this inductance cannot be defined as the stray inductance of a loop wiring path. These difficulties are addressed in this paper by proposing a novel measurement method of the common source inductance. The proposed method is applicable to already-mounted power circuits. In addition, the proposed method offers a straightforward measurement procedure with common instruments, such as a signal generator, an oscilloscope, and voltage and current probes. Along with the measurement principle, this paper also presents an experiment to evaluate the proposed method. [ABSTRACT FROM PUBLISHER]

Gallium nitride field-effect transistors (GaN-FETs) are attractive devices because of its low on-state resistance and fast switching capability. However, they can suffer from false triggering caused by fast switching. Particularly, a disastrous oscillation of repetitive false triggering can occur after a turn-off, which may deteriorate the reliability of power converters. To address this issue, we give a design guideline to prevent this phenomenon. We analyze a simple circuit model to derive the condition of occurrence of this phenomenon, which is then verified experimentally. Results show that the parasitic inductance of the gating circuit, L g, and that of the decoupling circuit, L d, should be designed so that the LC resonance frequency of L g and the gate-source capacitance of the GaN-FET does not coincide with that of L d and the drain-source capacitance, respectively. © 2016 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc. [ABSTRACT FROM AUTHOR]

Switched reluctance motors (SRMs) have recently attracted researchers’ attention owing to their robust mechanical construction, high thermal tolerance, and strong cost-effectiveness, which are promising for vehicle propulsion. However, they tend to generate large ripples in the torque and input currents to the inverter; this deteriorates the driving comfort, and damages the battery lifetime. Preceding articles have investigated using the phase currents of SRMs to eliminate these ripples. However, these articles had difficulties in sufficiently eliminating these ripples in operations under magnetic saturation. This article further evolves one of these preceding articles, and proposes a derivation method for the phase-current waveform for improving the elimination of the torque and input-current ripples in operation under magnetic saturation. The proposed method analytically determines the phase-current waveform based on a nonlinear behavior model of the SRM while considering the magnetic saturation. A finite-element-method-based simulation and experiment are performed to evaluate the proposed method. These results reveal the successful reduction of the torque and input-current ripples under the magnetic saturation relative to a preceding study, supporting the appropriateness of the proposed method. [ABSTRACT FROM AUTHOR]

Wide-bandgap semiconductors such as silicon carbide (SiC) and gallium nitride (GaN) are promising materials for next-generation power devices. We have fabricated a normally on GaN-based high-electron-mobility transistor (GaN HEMT) for power electronic converters. In this paper, the current collapse phenomena, which are distinctive characteristics of GaN devices, are evaluated in detail for several voltages with two switching frequencies. We also evaluate a gate drive circuit that we previously proposed for the normally on GaN HEMT with a single positive voltage source. We construct and test prototype circuits for a boost-type dc–dc converter and a single-phase full-bridge inverter with a gate drive circuit. The problems to be solved for the normally on GaN HEMT, which has a (static) voltage rating of over 600 V, are clarified on the basis of the experimental results. [ABSTRACT FROM AUTHOR]

This paper proposes a new current control strategy that is based on the internal model principle for a current balancer in single-phase three-wire distribution systems. The proposed current control strategy includes a sinusoidal reference input model to achieve the zero steady-state error tracking. The appropriate control gains of this control strategy can be systematically determined by using a state-feedback controller design method via linear matrix inequalities. The basic principle of the proposed control strategy is discussed in detail, and then confirmed by digital computer simulation using the PSIM software. A prototype experimental model is constructed and tested. Experimental results demonstrate that zero steady-state error tracking is achieved by the proposed control strategy. Also, balanced source currents are obtained on the secondary side of a pole-mounted distribution transformer while the load conditions are unbalanced. © 2013 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc. [ABSTRACT FROM AUTHOR]

This paper proposes a new current balancer in single-phase three-wire secondary distribution systems using the correlation coefficients. The components of the load currents correlative to the primary side voltage waveform, which correspond to the active currents, are detected in each feeder, then the nonactive and unbalanced-active components are compensated on the source side. The balanced currents with unity power factor are obtained in each feeder. The basic principle of the proposed method is discussed in detail, and then confirmed by digital computer simulation. A prototype experimental system is constructed and tested. Experimental results demonstrate that the balanced source currents with unity power factor are obtained in spite of unbalanced load currents. © 2009 Wiley Periodicals, Inc. Electr Eng Jpn, 169(1): 50–58, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20843 [ABSTRACT FROM AUTHOR]

In this paper, the practical impedance approach steady-state analysis in the frequency domain for the three-phase self-excited induction generator (SEIG) with squirrel-cage rotor is presented along with its operating performance evaluations. The three-phase SEIG is driven by a variable-speed prime mover(VSPM) in addition to a constant-speed prime mover (CSPM) such as a wind turbine and a micro gas turbine for clean alternative renewable energy in rural areas. The basic steady-state characteristics of the VSPM are considered in the three-phase SEIG approximate equivalent circuit and the operating performance of the three-phase SEIG coupled with a VSPM and/or a CSPM are evaluated and discussed online under the conditions related to the speed changes of the prime mover and the electrical inductive load power variations with simple computation processing procedures. A three-phase SEIG prototype setup with a VSPM is implemented for small-scale clean renewable and alter- native energy utilizations. The experimental performance results give good agreement with those obtained from the simulation results. Furthermore, a proportional-integral (P1) closed-loop feedback voltage regulation of the three-phase SEIG driven by the VSPM on the basis of the static var compensator (SVC) composed of the thyristor phase-controlled reactor in parallel with the thyristor switched capacitor and the fixed-excitation capacitor bank is designed and considered for the wind generation as a renewable power conditioner. The simulation analysis and experimental results obtained from the three-phase SEIG with SVC for its voltage regulation prove the practical effectiveness of the additional SVC with the P1-controller-based feedback loop in steady-state operation in terms of high performance with low cost. [ABSTRACT FROM AUTHOR]

Litz wire has been widely utilized in power transformers and inductors as a wire with low copper loss at high-frequency operation. The Litz wire is commonly made of many thin isolated strands twisted in multiple levels. Due to its complicated structure, the copper loss prediction of the Litz wire has been difficult, hindering the design optimization of the Litz wire structure. To overcome this difficulty, preceding studies have investigated the analytical copper loss models of the constituting elements of the Litz wire, i.e., the strands and the bundles of strands. The purpose of this article is to propose an analytical copper loss model of the Litz wire by utilizing these preceding knowledge. The proposed model is formulated only with parameters that can be measured by basic testing instruments. Besides, the proposed model considers the bundle structure of the Litz wire, which affects the local ac current distribution, and the twisting pitch, which causes the inclination of the Litz wire strands. The proposed model was tested by comparing the analytical prediction and experimental measurements of the ac resistance of commercially available Litz wires. As a result, the predicted ac resistance showed good agreement with the measured ac resistance, suggesting the appropriateness of the proposed model. [ABSTRACT FROM AUTHOR]

Switched reluctance motor (SRM) is recently emerging as a cost-effective but mechanically and thermally robust motor for vehicle propulsion. However, the conventional driving method of the SRM causes a large input current and torque ripples, both of which are scarcely acceptable for vehicle application. Recently, a promising driving method has been proposed that tunes the phase current to eliminate the input current and torque ripples simultaneously, although this method suffers from large copper loss when applied to the normal SRMs. To solve this problem, this article proposes simultaneous tuning of the rotor shape in combination with the recently proposed driving method, which includes only tuning of the phase current. Tuning of the rotor shape is targeted at minimizing the copper loss. Meanwhile, the stator structure is the same as the normal SRM design. The proposed approach was revealed to reduce the effective value of the phase current by 18% in simulation and by 23% in experiment compared with the recently proposed driving method, without increasing the input current and torque ripples. This result suggests the effectiveness of tuning both the rotor shape and the phase current for applying SRMs to vehicle propulsion. [ABSTRACT FROM AUTHOR]

It is quite often to utilize the transformer leakage inductance in the resonant tank of the LLC resonant converter to allow for a drastic reduction in the converter cost, weight, size, and volume. The effects of the secondary leakage inductance on the operation of the LLC resonant converter are not well discussed in the relevant literature, and it is the purpose of this paper to give an insight into these effects. The contribution of this paper lies in the following: first, highlighting that it is not always an accurate assumption to consider that the values of the primary and secondary leakage inductance are identical, specifically in asymmetric magnetic core structures. Second, it has been disclosed that the well-known coupling factor (k12) cannot properly express the unequalized leakage inductance distribution in the proposed asymmetric transformer. Therefore, the authors bring the primary coupling factor (k1) and secondary coupling factor (k2) into practice to appropriately express the unequalized leakage distribution on the primary and secondary windings, which can be controlled by the allocation of the relevant winding with respect to the air gap, utilizing the noise absorber, and changing the distance between the winding. Several transformer prototypes had been built and experimentally tested to validate these hypotheses. Third, it has been observed that the transformer voltage gain and efficiency can be improved when the transformer leakage inductance is concentrated on the secondary side to avoid the voltage drop inflicted by the relatively large value of the magnetizing current $(i_{m})$ , especially at the light load condition. Fourth, it has been reported that in a transformer structure with a concentrated value of leakage on the secondary side would decrease the resonant tank input impedance, vertically widen the voltage–gain curve of the converter, and eventually increase the frequency control bandwidth with respect to the load variation. Transformer prototypes had been constructed and tested in a 390 V/12 V–220 W LLC resonant converter to evaluate the proposed analysis. [ABSTRACT FROM AUTHOR]

This paper proposes a novel simple reactive power control strategy for the active load balancer (ALB) in three-phase four-wire distribution systems. The proposed reactive power control strategy may be applicable for adjustment of the source-side power factor under the balanced load condition. Only dc capacitor voltage control is used in the proposed control strategy. Therefore, the calculation blocks of the active and reactive components of the load currents are not necessary. The authors, thus, offer the simplest control strategy to control reactive power under the balanced load condition on three-phase four-wire distribution feeders. The basic principle of dc-capacitor-voltage-control-based reactive power control strategy is discussed in detail and then confirmed by digital computer simulation. A prototype experimental system was constructed and tested. Experimental results demonstrate that balanced source currents with reactive power control are achieved on three-phase four-wire distribution feeders. These experimental results also demonstrate that controlling the reactive power reduces the required power rating of the ALB compared with that of the conventional unity power factor control strategy. [ABSTRACT FROM PUBLISHER]

In this paper, we propose a new control algorithm to reduce the capacity of a previously proposed smart charger for electric vehicles (EVs) on single-phase three-wire distribution feeders with reactive power control. The basic principle of the proposed control algorithm is discussed in detail. It is shown that controlling the reactive power on the source side reduces the capacity of the previously proposed smart charger. A digital computer simulation is implemented to confirm the validity of the proposed control algorithm using PSIM software. A prototype experimental model is also constructed and tested. Experimental results demonstrate that balanced source currents with a power factor of 0.9, which is acceptable for Japanese home appliances, are obtained on the secondary side of the pole-mounted distribution transformer during both the battery charging and discharging operations in EVs. The capacity of dc capacitor CDC is also reduced by 37% with the proposed reactive power control algorithm. [ABSTRACT FROM AUTHOR]

In this paper, we propose a smart charger for electric vehicles with a power-quality compensator. The proposed smart charger consists of four-leg insulated-gate bipolar transistors (IGBTs). Three legs are used for a single-phase full-bridge-based pulsewidth-modulated (PWM) rectifier, which converts power from ac to dc during the battery-charging operation or from dc to ac during the battery-discharging operation. This PWM rectifier can compensate reactive and unbalanced active currents on single-phase three-wire distribution systems because the third leg is connected to the neutral line of single-phase three-wire distribution feeders. The fourth leg is used as a bidirectional dc–dc converter for battery-charging and battery-discharging operations. The three-leg PWM rectifier uses only constant dc-capacitor voltage control, which is commonly used in active power line conditioners. Thus, the authors have developed the simplest possible control method for a single-phase power-quality compensator. The basic principle of the proposed smart charger is discussed in detail and then confirmed by digital computer simulation using PSIM software. A prototype experimental model is constructed and tested. Experimental results demonstrate that balanced source currents are obtained on the secondary side of the pole-mounted distribution transformer for battery-charging and battery-discharging operations. [ABSTRACT FROM PUBLISHER]

This paper proposes a new topology for a current balancer with half-bridge inverters in single-phase three-wire distribution systems. Two half-bridge inverters are connected to the sources. The midpoint of the two capacitors on the DC-side is connected to a neutral line. The two half-bridge inverters function as a current balancer for single-phase three-wire distribution systems by exchanging the active and reactive power on each feeder through the two DC capacitors. The third leg functions as a DC-capacitor-voltage balancer for two DC capacitors connected to the half-bridge inverters. Thus, balanced source voltages and currents are obtained on the secondary side on the pole- mounted distribution transformer with balanced DC-capacitor voltages. The basic principle of the proposed current balancer is discussed in detail, and then confirmed by digital computer simulation using PSIM software. A prototype experimental model is constructed and tested. Experimental results show that balanced source voltages and currents are obtained on the secondary side on the pole-mounted distribution transformer with balanced DC-capacitor voltages. © 2012 Wiley Periodicals, Inc. Electr Eng Jpn, 180(4): 38-46, 2012; Published online in Wiley Online Library (). DOI 10.1002/eej.22277 [ABSTRACT FROM AUTHOR]

Electric-field coupling wireless power transfer has been commonly analyzed using the circuit model. However, the circuit behavior of this model is not necessarily apparent because their resonant modes can be far complicated than the basic LC oscillation. This issue is addressed in this paper by proposing a novel equivalent circuit for a basic wireless power transfer system. This equivalent circuit has a simpler topology than the conventional circuit model. Furthermore, the equivalent circuit allows intuitive understanding of three types of the resonant modes. Along with theoretical derivation of the proposed equivalent circuit, this paper also presents simulation results, which verified the appropriateness of the equivalent circuit. © 2015 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc. [ABSTRACT FROM AUTHOR]

This paper presents a single lossless inductive snubber-assisted ZCS-PFM series resonant DC-DC power converter with a high-frequency high-voltage transformer link for industrial-use high-power magnetron drive. The current flowing through the active power switches rises gradually at a turned-on transient state with the aid of a single lossless snubber inductor, and ZCS turn-on commutation based on overlapping current can be achieved via the wide range pulse frequency modulation control scheme. The high-frequency high-voltage transformer primary side resonant current always becomes continuous operation mode, by electromagnetic loose coupling design of the high-frequency high-voltage transformer and the magnetizing inductance of the high-frequency high-voltage transformer. As a result, this high-voltage power converter circuit for the magnetron can achieve a complete zero current soft switching under the condition of broad width gate voltage signals. Furthermore, this high-voltage DC-DC power converter circuit can regulate the output power from zero to full over audible frequency range via the two resonant frequency circuit design. Its operating performances are evaluated and discussed on the basis of the power loss analysis simulation and the experimental results from a practical point of view. © 2005 Wiley Periodicals, Inc. Electr Eng Jpn, 153(3): 79–87, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20126 [ABSTRACT FROM AUTHOR]

A variety of switched-mode high-voltage DC power supplies using voltage-fed-type or current-fed-type high-frequency transformer resonant inverters with MOS gate bipolar power transistors (IGBTs) have been recently developed for medical-use X-ray high power generators. In general, the high-voltage high-power X-ray generator using voltage-fed high-frequency inverter with a high-voltage transformer link has to meet some performances such as (i) short rising period in start transient of X-ray tube voltage, (ii) no overshoot transient response in tube voltage, (iii) minimized voltage ripple in periodic steady-state under extremely wide load variations and filament heater current fluctuation conditions of the X-ray tube. This paper presents two lossless inductor snubber-assisted series resonant zero current soft switching high-frequency inverters using a diode-capacitor ladder-type voltage multiplier called Cockcroft-Walton circuit, which is effectively implemented for a high DC voltage X-ray power generator. This DC high-voltage generator which incorporates a pulse frequency modulated series resonant inverter using IGBT power module packages is based on the operation principle of zero current soft switching commutation scheme under discontinuous resonant current and continuous resonant current transition modes. This series capacitor compensated for transformer resonant power converter with a high-frequency transformer-linked voltage boost multiplier can efficiently work a novel selectively changed dual mode PFM control scheme in order to improve the start transient and steady-state response characteristics and can completely achieve stable zero current soft switching commutation tube filament current dependent on wide load parameter setting values with the aid of two lossless inductor snubbers. It is proved on the basis of simulation and experimental results in which a simple and low cost control implementation based on selectively changed dual-mode PFM for high-voltage X-ray DC-DC power converter with a voltage multiplier strategy has some specified voltage pattern tracking voltage response performances under rapid rising time and no overshoot in start transient tube voltage as well as the minimized steady-state voltage ripple in tube voltage. © 2004 Wiley Periodicals, Inc. Electr Eng Jpn, 149(4): 60–72, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.10345 [ABSTRACT FROM AUTHOR]

This paper presents a prototype of a new concept of electromagnetic inductionbased fluid heating appliance using a voltage-source type series capacitorcompensated load-resonant high-frequency inverter using IGBT modules, which incorporates a phase-shifted pulse-width modulation (PWM) power regulation scheme. Proposed are also the load-resonant and quasi-resonant hybrid circuit topology of the voltage-fed soft-switching PWM inverter with inductive and capacitive hybrid lossless snubbers. In addition, some new types of electromagnetic induction heater to produce hot water, hot dry air and hightemperature superheated steam vapour are demonstrated. The feasible appliance employing the inverter mentioned above for electromagnetic induction-based liquid heating or gas heating is implemented from a practical point of view, along with the steady-state operating principle of this inverter system in addition to its remarkable features. The steady-state and dynamic-state operating characteristics of this high-frequency power electronic appliance are illustrated and evaluated on the basis of computer-aided simulation results and experimental results tested by a 10kW breadboard set-up which is actually produced for a low-fluid-pressure induction-heated boiler including an induction-heated hot water supplier and induction-heated high-temperature steamer and gas producer. Furthermore, this promising cost-effective inverter-fed heat exchanger employing electromagnetic induction-based fluid heating in various pipeline systems is introduced as an induction-heated evaporator and an electromagnetic induction superheated steamer in comparison with a conventional heat exchanger using a sheathed heater, together with induction-heated metal catalyst heating for exhaust gas cleaning in a diesel engine-driven system. [ABSTRACT FROM AUTHOR]

This paper presents a novel prototype of three-phase current-fed PWM converter with a switched capacitor type resonant dc link snubber circuit, which can basically operate under a principle of zero current soft switching commutation. The optimum PWM pattern-based control scheme proposed by the authors is effectively applied for this active converter. In this paper, the steady-state operating principle of a new converter circuit treated here is described. The practical design procedure of this converter is discussed from a theoretical point of view. The feasible experiment to confirm zero current soft switching commutation of this converter is concretely implemented and evaluated herein. [ABSTRACT FROM AUTHOR]

Proposes a precise tracking servo control system using the compact traveling-wave-type ultrasonic motor. Problems of the speed servo control system incorporating the ultrasonic motor developed in Japan; Composition of the algorithm of the proposed control scheme; Experiments that demonstrate and evaluate the proposed control system.