Abstract: A power conversion device include: a power conversion circuitry configured to generate a driving voltage for an electric motor; and control circuitry configured to: control the power conversion circuitry to generate the driving voltage corresponding to a voltage command; acquire information indicating an output current that has flown to the electric motor according to the driving voltage; calculate a phase error based on the voltage command, the output current, and an inductance of the electric motor; calculate an updated voltage command based on a frequency command, the output current, and the inductance, wherein the updated voltage command has a command phase; calculate a phase error based on the voltage command, the output current, and the inductance; correct the command phase based on the phase error; and control the power conversion circuitry to generate the driving voltage corresponding to the updated voltage command having the corrected command phase.

Abstract: A power conversion device include: a power conversion circuitry configured to generate a driving voltage for an electric motor; and control circuitry configured to: control the power conversion circuitry to generate the driving voltage corresponding to a voltage command; acquire information indicating an output current that has flown to the electric motor according to the driving voltage; calculate a phase error based on the voltage command, the output current, and an inductance of the electric motor; calculate an updated voltage command based on a frequency command, the output current, and the inductance, wherein the updated voltage command has a command phase; calculate a phase error based on the voltage command, the output current, and the inductance; correct the command phase based on the phase error; and control the power conversion circuitry to generate the driving voltage corresponding to the updated voltage command having the corrected command phase.

Abstract: A motor control system includes a motor and a motor control circuitry. The motor includes a rotation axis and a bearing rotatably supporting the rotation axis. The motor control circuitry is configured to control the motor. The motor control circuitry includes a driving time adding circuit configured to add up a driving time of the motor to obtain an accumulated driving time of the motor, a remaining lifetime calculation circuit configured to calculate a remaining lifetime of the bearing based on a lifetime of the bearing and the accumulated driving time, and a warning outputting circuit configured to output warning information when the remaining lifetime is equal to or less than a threshold.

Abstract: A power conversion apparatus includes circuitry to: generate a first command to provide a first electrical output to a motor; receive a first electrical response to the first electrical output; estimate a position of a magnetic pole of the motor based on the first electrical response; set a pulse provide condition in accordance with the estimated position of the magnetic pole; generate a second command to provide a positive electrical pulse output and a negative electrical pulse output to the motor in accordance with the pulse provide condition; receive a positive electrical response to the positive electrical pulse output and a negative electrical response to the negative electrical pulse output; calculate a magnitude difference between the positive electrical response and the negative electrical response; change the pulse provide condition to generate a modified second command when the magnitude difference is smaller than a predetermined difference level; and estimate a polarity of the magnetic pole based o

Abstract: A motor control system includes a motor and a motor control circuitry. The motor includes a rotation axis and a bearing rotatably supporting the rotation axis. The motor control circuitry is configured to control the motor. The motor control circuitry includes a driving time adding circuit configured to add up a driving time of the motor to obtain an accumulated driving time of the motor, a remaining lifetime calculation circuit configured to calculate a remaining lifetime of the bearing based on a lifetime of the bearing and the accumulated driving time, and a warning outputting circuit configured to output warning information when the remaining lifetime is equal to or less than a threshold.

Abstract: An alternating-current motor control apparatus includes a stator frequency computing unit configured to compute a stator frequency of a motor magnetic flux; a torque error computing unit configured to compute a torque error by using the motor magnetic flux, an estimated current, and a motor current; and a speed estimator configured to estimate a speed of the alternating-current motor by using the stator frequency and the torque error. The speed estimator includes a proportional controller configured to reduce the torque error to zero, and an adaptive filter configured to eliminate a high-frequency component of the torque error.

Abstract: A control device includes a slip calculator that calculates a first slip frequency of an induction motor, a current detector that detects motor current that passes through the induction motor, an adder that calculates a primary frequency by adding a speed command and a second slip frequency that are given, a command voltage generation unit that generates first command voltage from the primary frequency, a voltage error observer unit that estimates a command voltage error from the first command voltage and the motor current, a slip correction unit that calculates a slip correction amount from the command voltage error, an adder that calculates the second slip frequency by adding the first slip frequency and the slip correction amount, and a voltage error correction unit that corrects the first command voltage using the command voltage error and outputs second command voltage.

Abstract: A control device includes a slip calculator that calculates a first slip frequency of an induction motor, a current detector that detects motor current that passes through the induction motor, an adder that calculates a primary frequency by adding a speed command and a second slip frequency that are given, a command voltage generation unit that generates first command voltage from the primary frequency, a voltage error observer unit that estimates a command voltage error from the first command voltage and the motor current, a slip correction unit that calculates a slip correction amount from the command voltage error, an adder that calculates the second slip frequency by adding the first slip frequency and the slip correction amount, and a voltage error correction unit that corrects the first command voltage using the command voltage error and outputs second command voltage.

Abstract: An alternating-current motor control apparatus includes a stator frequency computing unit configured to compute a stator frequency of a motor magnetic flux; a torque error computing unit configured to compute a torque error by using the motor magnetic flux, an estimated current, and a motor current; and a speed estimator configured to estimate a speed of the alternating-current motor by using the stator frequency and the torque error. The speed estimator includes a proportional controller configured to reduce the torque error to zero, and an adaptive filter configured to eliminate a high-frequency component of the torque error.

Abstract: Provided are a washing machine and a method of calculating the amount of laundry. The washing machine includes a spin basket which has an inner space to put laundry therein and is rotatably mounted about a rotation shaft in a rotational direction by driving a motor and includes: a rotation time calculating unit which calculates a time period when the spin basket rotates once; a pulse torque generating unit which supplies a predetermined current or voltage to the motor during the time period when the spin basket rotates once and generates a pulse torque through an output shaft from the motor; an acceleration measuring unit which measures rotation acceleration of the output shaft of the motor according to the pulse torque generated from the motor; and a weight calculating unit which calculates the weight of the laundry put in the inner space of the spin basket by the rotation acceleration.

Abstract: Disclosed herein are a rotating body control device and a washing machine. The rotating body control device includes: a balancing unit including an annular race which is integrally formed with the rotating body and is concentric with the rotation shaft of the rotating body and a plurality of rolling bodies which are movably seated in the race; a detecting unit detecting a bit signal, which is generated according to a variation in relative position between the rolling bodies seated in the race and the eccentric amount of the rotating body which occurs during the rotation of the rotating body; an analyzing unit which analyzes a variation in amplitude of the bit signal detected by the detecting unit; and a control unit which controls the rotation of the rotating body according to the analyzed result of the analyzing unit.

Abstract: A polycarbonate exhibiting excellent fluidity and moisture resistance and a process for efficiently producing the polycarbonate are provided.The polycarbonate has a main chain comprising a repeating unit represented by general formula (I): ##STR1## wherein R.sup.1 and R.sup.2 each represents hydrogen atom or an alkyl group having 1 to 7 carbon atoms; contains 100 ppm by weight or less of a unit of a phenyl salicylate structure expressed by formula (II): ##STR2## in the main chain; and has a viscosity-average molecular weight of 10,000 or more. The polycarbonate is produced in accordance with a process comprising transesterification in the presence of a catalyst comprising a combination of an organic basic compound containing nitrogen and a quaternary phosphonium salt.