In resent years, the soft switching commutated power converter technologies have attracted special interest in order to minimize semiconductor switching power losses and reduce conductive switching noise. This special issue deals with some schematic descriptions on application-specific quasi-resonant power converter circuits, which make use of soft switching commutation schemes.
Non-Contact Energy Transfer System are used in the various fields in the industry. A high frequency constant current must be supplied to the feeder of Non-Contact Energy Transfer System. This paper proposes a High Frequency Constant Power Supply for a Non-Contact Energy Transfer System using an Immittance Converter. When there are two or more pick-up coils on the feeder, the output of one pick-up coil doesn't affect to other pick-up coils on the feeder if the feeder current is constant. We proposed to use an immittance converter to transform the high frequency constant voltage source into a high frequency constant current source. The immittance converter is the combined word for the impedance-admittance converter. The immittance converter has an input impedance that is proportional to the admittance of the load connected across output terminals. In this converter, the output current is proportional to the input voltage and the input current is proportional to the output voltage. Consequently, it converts a constant voltage source into a constant current source and a constant current source into a constant voltage source. The configuration of High Frequency Constant-Current Power Supply for Non-Contact Energy Transfer System, an excessive reactance and a little frequency deviation characteristics and output characteristics in changing duty factor are described in this paper. The experimental result is also described.
In this paper, a soft-switching discontinuous mode (DCM) power factor corrected (PFC) converter is analyzed by applying the double Fourier series expansion. It is found that the fundamental component and higher-order harmonics included in the input current waveform are obtained by the Fourier series expansion of the mean value of the inductor current. From the theoretical analysis, a new method removing the distortion of the input current waveform is proposed. In spite of an open loop system, the proposed method makes a great improvement of the total harmonic distortion even if the ratio of output voltage to input voltage is very low.
We have proposed a high efficiency and high power chopper based on new soft switching scheme QRAS (Quasi-resonant Regenerating Active Snubber) and we studied the practical effectiveness and the novelty of the QRAS by the simulation and by the experiment. This time we made one-tenth prototype model actually and tested it by rating test, light load test, current discontinuous mode test and test out of resonance stable operation. We report the general evaluation of these test results and the possibility of the realization on the 80kW practical model is demonstrated by these successful test results. In addition, as an approach of the next study the feasibility test of 8kW SiC-QRAS is followed and the preliminary evaluation of efficiency rise using “Silicon Carbide (SiC)" power devices is given with the successful experimental results.
In this paper, high frequency power converter without DC smoothing electrolytic capacitor filter link which convert the 100V/200Vrms and 60Hz single phase utility frequency AC power into a high frequency AC. This proposed high frequency AC power converter without electrolytic capacitor filter can operate under a principle of soft switching PWM based on a lossless capacitor snubber is proposed and demonstrated for consumer high frequency induction heating (IH). In particular, this high frequency power converter capable of producing a high frequency AC more than 20kHz is developed for consumer IH applications as hot water producer and steamer based on the specially designed spiral type IH-Dual Packs Heater (DPH), which includes the dual mode pulse modulation control scheme based on soft switching PWM for high output power setting and commercial frequency AC zero voltage soft switching pulse density modulation (PDM) for low output power settings. This developed high frequency power frequency converter using trench gate IGBTs is clarified on the basis of experimental and simulation results for its circuit operation of the utility frequency AC to high frequency AC frequency PWM power converter without the electrolytic capacitor bank DC filter link for the IH hot water and IH steamer. These IH appliances are based upon an innovative electromagnetic IH-DPH for fluid heating as heat exchanger in consumer pipeline. Finally, its power regulation characteristics, power conversion efficiency and harmonic current components characteristics including power factor in utility AC grid side are evaluated and discussed from an experimental point of view. The practical effectiveness of this utility frequency AC to high frequency AC soft switching high power frequency converter defined conveniently as high frequency soft switching cyclo-inverter is proved as one of the important products effective for next generation IH application all electricity power utilizations.
In this paper, the voltage sag compensation using series type SMES (Superconducting Magnetic Energy Storage) with open-circuit protection is proposed. The voltage sags and momentary interruptions during the fault occurred can be mitigated. For open-circuit protection, the faulted incoming line is disconnected and the new current path is made. The control scheme is proposed for voltage sag compensation and open-circuit protection. Simulations of voltage sag compensation and open-circuit protection demonstrated the validation of the proposed circuit and control sequence of switches.
This paper proposes a new 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 in detail, and then applied to the already proposed shunt active filter for consumer electronic equipment. The validity and practicability of the proposed detection method is confirmed by digital computer simulation. A reduced-scale experimental system is constructed and tested to verify the validity and practicability of the proposed method. Experimental results demonstrate that the proposed method can detect the active-reactive current in single-phase circuits in the time domain.
It is necessary to use the renewable energy, such as photovoltaic, wind power, biomass energy, etc., from a viewpoint of CO2 regulation, environmental protection of the Earth. In recent years, the tendency is toward larger wind power generation system to achieve cheaper electricity price. The generators of 1500kW-2000kW capacity tend to dominate the market. However, a large wind power generation system has limitations on the location and can be installed only at suburbs. At the same time, a city type compact wind power generation system, designed for city needs, has more flexibility and can be installed at the residential areas of city. In this paper, we introduce an original control operation system called “pump-up" operation system, designed to effectively use the city wind, and report the results of its field test.
An adaptive friction compensation method based on notion of H∞ optimality is proposed. It is assumed that the static and dynamic characteristics of friction are captured by the dynamic LuGre model. Neural-Network (NN) is used to parameterize the nonlinear characteristic function of the friction model. An adaptive NN based controller is given, and an approximation error in NN is regarded as exogenous disturbance to the system. Consequently, in the resulting control system, the L2 gains from the disturbance to generalized outputs are made less than prescribed positive constants. For the practical applications, σ-modification method and dead-zone method are applied to the estimation strategies. To illustrate the effectiveness of our proposed method, experimental results are shown.
A permanent magnet synchronous motor (PMSM) with non-sinusoidal electromotive force (EMF) generates torque ripple even if the sinusoidal PWM inverter drives the PMSM. A new modified trapezoidal modulating signal for PWM inverter suitable for PMSM drive with non-sinusoidal EMF is proposed in this paper. A new modulating signal for the PMSM drive is determined by the condition of reducing torque ripple of the motor with various trapezoidal EMF. When the PWM inverter using modified trapezoidal modulating signal drives the PMSM having a non-sinusoidal EMF, the torque ripple of the motor can be reduced, the DC link voltage utilization is improved and reduction of switching loss can be obtained.
To develop a human-friendly driver support system, it is essential to detect the driver's status such as consciousness levels and looking aside. We have developed a driver monitoring system, which detect the driver's consciousness reduction and gaze direction change by image processing techniques. Furthermore, we have proposed a new warning method with this driver monitoring system. The effectiveness in this method has been verified using a driving simulator.
The methods to stabilize power sources, which are the measures against voltage drop, power loading fluctuation, regenerative power lapse and so on, have been important issues in DC railway feeding circuits. Therefore, an energy storage medium that uses power efficiently and reduces above-mentioned problems is much concerned about. Electric double-layer capacitors (EDLC) can be charged and discharged rapidly in a short time with large power. On the other hand, a battery has a high energy density so that it is proper to be charged and discharged for a long time. Therefore, from a viewpoint of load pattern for electric railway, hybrid energy storage system combining both energy storage media may be effective. This paper introduces two methods for hybrid energy system theoretically, and describes the results of the fundamental tests.
In improving the resolution of hybrid type stepping motor, there are a method of increasing the number of rotor teeth and a method of increasing the number of phases. The method of increasing the number of rotor teeth comes for the limit to exist from respect of the machining and the increase in the number of rotor teeth causes the deterioration of high-speed characteristics. On he other hand, the method of increasing the number of phases brings the cost amount from becoming of the drive circuit the complexity. In this paper, aiming at improvement of resolution of HB Type stepping motor, double 3-phase stepping motor are examined which has 2 sets of 3-phase stator windings. It has the half step angle as 3-phase stepping motor with the same number of rotor teeth. It is shown that double 3-phase motor has 2 types of construction which are different in magnetic path (multi-phase magnetic path type and uni-phase magnetic path type). In each type, how to choose the number of rotor teeth and stator magnetic pole intervals to compose double 3-phase stepping motor are examined, and the motor characteristics are compared multi-phase magnetic path type with uni-phase magnetic path type.
This paper introduces a grasping control technique by a simple robot hand. The machine under the experiments is not a robot hand correctly. However alternatively we treat a linear machine driven by a DC servo motor as a simple robot hand. A feature of the hand is tensioned by mechanical springs. We have introduced a position sensor-less control method. It uses an observer to realize observability by using mechanical springs. It has an estimation error if the hand has collision with objects. However we have discoverd that the error caused to realize a kind of compliance control on the hand. So, we present a new force control technique making use of this estimation error. In this paper, we show that the control system realize a compliance control mathematically and the typical application result of grasping control using a boiled egg.
In a next-generation city, it is necessary to minimize energy consumption, and to observe environmental regulation. This report would make clear the extent to which a new environmental/energy management model proposed herein contributes to prevention of global warming.