T. Sonoda

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For an induction motor driven by a sinusoidal voltage source of adjustable amplitude and frequency, such as a pulse-width-modulation (PWM) inverter, the occurrence of sustained oscillations has often been observed when the drive is underloaded. In order to solve this problem, a linearized model is considered. The conditions under which the oscillations(More)
In order to extend the applicability of a voltage/frequency (V/f) controlled induction motor drive system, the problem of reducing to zero the steady-state speed error caused by load changes without using a rotor speed sensor is treated. The theoretical basis for this is given, and a scheme for constituting the control system is presented. The frequency of(More)
A linear-type switched-reluctance motor (SRM) of simple structure is presented. It is quite useful for investigations on force characteristics, magnetic flux, and force distributions. It is shown that (1) the SRM is quite effective as a generating force; (2) each external shape of the stator and rotor poles has to be specified based on the flux(More)
Stability problems associated with the interactions between electric transients and rotor dynamics are examined. The concept of an inherently stable idealized induction motor is introduced. It is shown that the destabilizing factors are stator winding resistance and leakage inductance in both stator and rotor windings. The importance of stator voltage and(More)
An induction motor control idea derived on the basis of the concept of the idealized induction motor, which is defined as a motor having neither stator resistance nor leakage inductance, is presented. The proposed control is to compensate for the effects of these parameters and to try to keep the magnetic flux which interlinks with the rotor circuit at a(More)
We show the dynamics computation employing Jacobian that relates the center of gravity (COG) to joints of link mechanisms, in this paper. COG Jacobian is used for the behavior planning and the control of humanoids. And, it usually expresses the relationship between the joints and COG of a robotpsilas whole body. However, in this scheme, itpsilas calculated(More)
A current sensor of high-accuracy fit for precise and exact motion control, particularly appropriate for the control of an AC-servo drive system, is presented. The proposed sensor, named for the sensing principle it uses, is called the magnetic-field-controlled type and has the ability to fulfil the following specifications: (i) the sensor is a(More)
Partial Discharge (PD) measurement is well known as powerful method to identify the condition of high-voltage insulation. This paper investigates the properties of the ultra-high frequency (UHF) electromagnetic (EM) wave emanating from the air discharge (corona) under high voltage DC source. By applying both positive and negative high voltage DC ranging up(More)