Motion control in open environment will be more and more important. The recent machines are required to have an ability to contact unknown environment. The environmental information is a key to be compliant to unknown environment. It is obtained from the modal decomposition. The environment may have infinite modes. On the contrary, motion control systems have finite number of degree-of-freedom (DOF) for their motion. It is necessary for motion controller to quarry information from the environment at least to the extents of DOF.
This paper develops a novel viewpoint of motion control based on quarry of environmental information. A quarry process of information from the environment using Hadamard matrix has been proposed. An extension method of the Hadamard matrix is proposed and quarry matrix is generalized in this paper. This paper shows a quarry of the planar environmental modes using the third-order quarry matrix. The motion of a robot with three supporting points has three modes, which are heaving, rolling and pitching modes. As a result, compliant motion control to unknown environment is attained in each mode. The modal system design method based on the quarry matrix will be a fundamental technique of design of decentralized system.

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The losses of induction motors driven by PWM inverters are analyzed using the finite element method considering the carrier harmonics. The calculated results are compared with the experimental ones. To consider the effect of the carrier, the theoretical voltage waveform due to the switching pattern of the inverter is given to the analysis by coupling the primary voltage equation and the finite element formulation. The method to decompose the electromagnetic field distribution into time-harmonic components is introduced in order to investigate the effects of the harmonic fields separately and to specify the main loss factors. It is clarified that the rotor surface loss especially increases due to the carrier and that the accuracy of the calculated characteristics of the motor is improved by considering the carrier.

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A novel segment type switched reluctance motor (SRM) is proposed, in which the segment core is embedded in aluminum (conductive metal) rotor block in order to increase the mechanical strength and easy manufacturing as well as to improve the performance characteristics and reduce the vibration and acoustic noise. The effect of design parameters on the average torque is investigated using the finite element method. Comparison with conventional VR type SRMs and segment type SRMs without conductive metal construction rotor show the proposed segment type SRM has advantages in the torque performances and the vibration and noise characteristics. The performance is also investigated by experiment.

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Silicon Carbide (SiC) power devices offer significant benefits of improved efficiency, dynamic performance and reliability of electronic and electric systems. The challenges and prospects of SiC power device development are reviewed considering different device types. A close correlation between an exponential increase of current handling capability during the last ten years and improvement in substrate quality is demonstrated. The voltage range of silicon and SiC unipolar and bipolar power devices with respect to the on-state voltage is determined based on device simulations. 4H-SiC unipolar devices are potentially superior to all silicon devices up to 5kV design voltage and to all SiC bipolar devices up to 5-6kV design voltage for temperatures up to 150°C. The low end of SiC unipolar devices is determined to be around 200V design voltage provided substrate resistance is reduced by reducing the thickness of the substrate down to 100μm. The influence of reduced channel mobility on the specific on-resistance of 4H-SiC and 3C-SiC DMOSFETs is shown. It has been demonstrated that 3C-SiC DMOSFETs could be a better choice compared to 4H-SiC DMOSFETs in the voltage range below 1.2kV utilising better channel mobility and larger substrate size obtainable in the near future in 3C-SiC polytype. An impact of the super junction (SJ) concept on silicon and SiC MOSFET specific on-resistance limits is demonstrated.

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This paper proposes a novel control method for synchronous motors without the use of current sensors. The proposed method is based on optimal placement of pole of the closed loop system that includes the motor controller. The voltage commands necessary are directly calculated based on the velocity error without any inner current loop. The main compensator consists of a notch filter and a PI regulator. The notch filter is designed such that its zeros cancel the poles of the plant, the transfer function of which, is the ratio of the output rotational velocity to the input q-axis voltage command. The poles of the notch filter and the parameters of the PI regulator are selected such that the resulting poles of the entire plant are located in the stable region. Based on the model of the synchronous motor, the currents of d and q axes are estimated using the reference voltage commands of d and q axes. The decoupled compensating voltages and the dead-time compensating voltages are calculated using the estimated currents in the d and q-axes, which in turn are used to generate the reference voltage commands. The proposed control technique was implemented on a practical system. Experimental results are given to show the effectiveness of the proposed technique for velocity and position control in a permanent magnet synchronous motor.

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A high-speed analysis method for 3-phase high frequency voltage input sensorless control of interior permanent magnet synchronous motors (IPMSM) driven by pulse width modulation (PWM) inverters taking magnetic saturation into consideration is proposed. By using finite element method (FEM) analysis, partial differential values of flux-linkage can be calculated directly and precisely in a short time. High-speed analysis of motor voltage equations is realized by interpolating table data of calculated partial differential values and using simplified power device models. The geometric relation of motor magnetic circuit and redundancy of motor current help reduce the number of points in table data. Analyzed results are well fit in with experimental results and the validity of proposed methods is confirmed.

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A Direct Torque Control (DTC) strategy for dual-three phase induction motor drives is discussed in this paper. The induction machine has two sets of stator three-phase windings spatially shifted by 30 electrical degrees with isolated neutral points. The proposed control strategy is based on Proportional Integral (PI) regulators implemented in the stator flux synchronous reference frame. To improve the flux estimation, an Adaptive Stator Flux Observer (ASFO) has been used. Doing so, besides a better flux estimation in contrast to open-loop flux estimators, it is possible to use the observed currents to compensate the inverter non-linear behavior (such as dead-time effects), improving the drive performance at low speed. This is particularly important for low voltage/high current applications, as the drive considered in this paper.
The advantages of the discussed control strategy are: constant inverter switching frequency, good transient and steady-state performance and less distorted machine currents in contrast to DTC schemes with variable switching frequency. Experimental results are presented for a 10kW dual three-phase induction motor drive prototype.

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The paper aims to perform an overview on the state-of-the-art in the control of multi-phase drives employing dual-three phase induction machines. In particular, the paper is focused on modeling aspects, Pulse-Width Modulation (PWM) techniques for Voltage Source Inverters (VSI), Field Oriented Control (FOC) and Direct Torque Control (DTC) strategies for dual-three phase induction machines. Furthermore, the paper briefly presents the advantages of dual-three phase induction motor drives over the conventional three-phase drives and the different applications reported in the literature.

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The paper presents a speed sensorless vector control method for an induction motor that is supplied by a PWM inverter through an output LC filter. The system states are estimated by an adaptive full-order observer, and no additional voltage, current or speed measurements are needed. The rotor speed adaptation is based on the estimation error of the inverter output current. Quasi-steady-state analysis is used to illustrate the speed adaptation, and the stability is analyzed using a linearized model. Simulation and experimental results show that it is possible to achieve performance comparable to that of a drive without the LC filter.

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In recent years, various types of fault current limiter (FCL) have been developed, because installation of the FCL will bring a lot of benefits to power system operation. Power system controllers based on a concept of Flexible AC Transmission Systems (FACTS) can also be applicable as the FCL with growing power ratings of them. Such FCLs are expected to contribute power system stabilization or power quality enhancement in addition to fault current limitation. Authors have developed a new type of FCL, which consists of a series reactor and a self-commutated voltage source inverter connected in series with a power distribution line by a coupling transformer. In case of a system fault, the FCL will insert a sufficiently large inductance in series with the distribution line by both the series reactor and the inverter, then it will reduce the fault current. On the other hand, the inverter compensates a voltage drop across the series reactor in a standby mode. As a result, the FCL behaves like a negligible impedance in the standby mode. One of the distinctive features of the FCL is a simple configuration because its control strategy does not require an active power source. In addition, inverter voltage rating of the proposed FCL can be reduced by installing the series reactor as compared with other converter-based FCLs. The aim of this paper is to evaluate the operating characteristics of the FCL with both simulation and experimental studies.

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This paper proposes an autonomous control for parallel-connected uninterruptible power supply (UPS) systems based on electrical power system interrelations. The controllable variables are the output voltage phase angle and magnitude. Relation between active current and output voltage phase angle is derived from a synchronous machine model. Electrical power systems suggest that voltage regulation and reactive current can be proportionally related to yield another control equation. The resulted control scheme is very simple and only requires an output current measurement to provide a voltage reference signal locally in synchronism with other UPSs without communication signal exchange. A small-signal model represents the entire system and constitutes proof of its stability. Feasibility is confirmed by an experimental setup with three UPSs connected in parallel with different output power ratings. In the experiments, voltage limiters (1%) are employed and three cases are verified. Under all conditions, the results show excellent performance in terms of stability, and active and reactive load sharing.

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An online real time simulator for a RTLinux based speed control system of SPMSM (Surface Permanent Magnet Synchronous Motors) is proposed. For realization of the online real time simulator, a motor mathematical model based on the three phase stationary coordinate is solved using a fourth order Runge-Kutta algorithm in real time. The Runge-Kutta algorithm is required since the model includes non-linear operation, such as, trigonometric functions, square waves generated by a PWM inverter and limiter circuits, so on. The experimental system based on the RTLinux accomplishes both the motor control and the real time simulation at the same time in 200μs control period. The online simulation results show considerable coincidence with the experimental results.

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The Large Helical Device (LHD) is an experimental facility for fusion plasma using a large scale mutually coupled superconducting coil system and it is now operating at the National Institute for Fusion Science. This paper introduces the design and the operation results of the dc power systems to drive these coils. First, the outline of the LHD and the power supplies are described. Next, a control system and the current controller for the power supplies are introduced. Finally, some experimental results are introduced.

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The stable operating power limits of a small scale HVDC system composed of voltage source converters (VSC-HVDC system) are analyzed with a simple model. The VSC-HVDC system could operate where the AC system must be somewhat larger in capacity than the VSC-HVDC system capacity. The stable operating power limits were between one and two times the SCR (short circuit ratio). When the inverter of the VSC-HVDC system was operated with lead reactive (capacitive) power control conditions, the stable operating limits were increased through AC voltage stabilization. When the inverter was a STATCOM operation, it could operate regardless of the SCR but regions within allowable AC voltage variations.

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Toyota Motor Corporation developed in 2005 a new hybrid system for a large SUV. This system included the new development of a high-speed traction drive motor achieving a significant increase in power weight ratio. This paper provides an overview of the hybrid system, discusses the characteristics required of a traction drive motor, and presents the technologies employed in the developed motor.

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The objective of this paper is to indicate the advantages of Silicon Carbide (SiC) devices and to introduce the instruction which type of devices should be developed. For recent years, several-kV-class high voltage SiC devices have been manufactured, and it is expected that converters for medium voltage distribution networks can be realized using these devices. In this paper, some kinds of converters have been designed and compared with each other in respect of total losses and size. As a result, it has been confirmed that carrier frequency doubles and total loss reduces by half approximately when SiC devices replace Silicon devices, SiC-FET + SiC-SBD is better than SiC-IGBT + SiC-PND, and the series connection of more devices with lower design voltage is better in the case of SiC-FET.

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The distribution system with the rectangular voltage waveform is useful for the electrical equipment with the dc voltage source because the high input power factor is obtained by using the diode rectifier circuits. This paper presents a single-phase type AC/DC converter using a novel power factor correction (PFC) technique to realize the unity effective power factor and stable output dc voltage for both the distribution systems with sinusoidal or rectangular voltage waveform. Also, this paper presents the estimation and judgment of the input voltage waveform and its stability and the design of the estimation gains. The new control strategy has a notable advantage that it is flexible for both sinusoidal and rectangular waveforms to realize the good characteristics. The effectiveness of the proposed control scheme has been verified by experiments.

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This paper presents the analysis and design of a shunt hybrid active filter for harmonic damping in a 6.6-kV power distribution system. This hybrid filter has been proposed and tested experimentally with a 200-V, 20-kW laboratory system, showing good damping performance. Another possible solution for harmonic damping is to install a shunt pure active filter at the end of a feeder. However, the pure filter is too costly and bulky to be installed in a 6.6-kV system. This paper discusses the design criteria for a hybrid filter intended for installation on a 6.6-kV power distribution system. Detailed comparisons between the pure filter and the hybrid filter are also included as a foundation for the design of the hybrid filter. The performed design confirms the feasibility of installation of the hybrid filter on a 6.6-kV power distribution system.

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A photovoltaic AC module system has been expected to be installed on the private residences. The AC module inverter needs an active power decoupling circuit in order to enlarge the lifetimes of the inverter by eliminating a large electrolytic capacitor on the DC input bus. This paper proposes a novel modulation method, which we call Time-shared Magnetizing Modulation (TMM) method, realizing the power decoupling in the AC module flyback inverter as well as improving the efficiency conversion. The Sequential Magnetizing Modulation (SMM) method, which the authors have proposed earlier, are compared with the proposed method in operation principle and conversion efficiency point of view. It is verified that the TMM method has advantage with respect to the conversion efficiency. This paper concludes that the flyback inverter with the TMM method for the power decoupling is one of the suitable method for a single-phase grid interactive inverter used in the AC module system.

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In this paper, a few techniques of the efficiency improvement of SRM drive are described. One of these improvements is the optimization of applied voltage waveform. In addition, application of recent low iron loss material such as super E-core is also effective. To improve the efficiency, optimization of iron and copper parts is executed by PC-SRD. As a result, the highest efficiency of 94.3% is achieved.

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Cylindrical linear synchronous motors with permanent magnets have merits of compactness, high efficiency and easy to support because of no end-windings and negligible radial force. A propulsive force simulation method of the cylindrical linear synchronous motors was developed using FEM analysis code ANSYS, and the simulation results were well agreed with the test results of an experimental machine, which shows the effectiveness of the simulation method. Two kinds of countermeasures for decreasing propulsive force fluctuations were proposed and the effects of their countermeasures were cleared using the simulation method. One of them are the novel countermeasure, in which the separated two armatures are used and excited from phase shifted currents by the electrical phase angle difference corresponding to the separated position, and it is found that the novel countermeasure was very useful.

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Three-phase buck rectifier using snubber energy recovery bridge legs is studied. The snubber capacitors assembled into the bridge legs are mainly charged and discharged under the resonance and the energy stored in them is transferred to the load circuit. Also, the currents flowing through power semiconductor devices are always limited to the dc current. The experimental prototype employing insulated-gate bipolar transistors is implemented to investigate the operation under the pulse-width modulation. The experimental results confirm that the input current can be waveshaped sinusoidally with a near-unity power factor.

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This paper presents a filter design method for harmonics extraction of positive- and negative-phase sequence in a three-phase system. Using the complex transformation of the three-phase voltage, the filter can be designed in the frequency domain. The design example and the experimental results have been shown.

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A bidirectional DC-DC converter for supercapacitor-based energy storage systems in advanced electric vehicles is proposed in this letter. This converter consists of a half-bridge and current-fed push-pull circuit linked with a high frequency transformer, which is well applicable to the low voltage/high current charge and discharge of the supercapacitor. The experimental results of the prototype system prove the effective properties of the proposed topology in terms of a low device-conduction loss and a low switching surge.

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Soft-switched single-phase voltage-doubler rectifier using pump circuits is presented. The active power devices in the full-bridge resonant switch are allowed to turn on and off under zero-current switching (ZCS) and zero-voltage switching (ZVS) conditions, respectively. The switching transition is mainly governed by a series resonance. The experimental prototype employing two dual-switch power modules with insulated-gate bipolar transistors is implemented to investigate the operation under the pulse-width modulation. The experimental results confirm that the input current can be waveshaped sinusoidally with a near-unity power factor.

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