Abstract: A failure identification part identifies a switching element pair having off-failure, in which a FET of the switching element pair in a first inverter part is disabled to turn on. A failure-time control part controls other switching element pairs and of the first inverter part based on failure-time phase current command values calculated as a function of a rotation position and a q-axis current command value. The failure-time control part controls a second inverter part normally. A motor is persistently driven with the minimum reduction in motor torque, even when the FET fails.

Abstract: An autonomous controller allows an AC induction motor to operate over a broad range of AC power supply frequencies by reducing the amount of current supplied to the motor at lower frequencies. The controller detects the frequency of the power supply and switches the supply current on and off during each AC cycle to limit the RMS current to a value that is related to the detected frequency. Alternatively, the controller switches capacitive reactance into the power supply circuit which reduces the current supplied to the motor at lower AC frequencies.

Abstract: Piezoelectric vibrating pieces are disclosed having selectively roughened surfaces. An exemplary piece is made of a piezoelectric material configured as a piezoelectric substrate. The piece also includes at least one excitation electrode and at least one extraction electrode. The substrate has opposing main surfaces initially having low surface roughness. At least one main surface is formed in a mesa or reverse mesa manner, wherein the central region has a different thickness than the peripheral region. The central region has relatively low surface roughness (irregular unevenness), while the peripheral region has relatively high surface roughness. The excitation electrode is formed on the central region (mesa or reverse mesa) while the extraction electrode (connected to the excitation electrode) is formed on the peripheral region.

Abstract: A control circuit generates a driving signal indicating an actuator torque. A first operation unit generates position, speed, and acceleration signals, based upon a detection signal indicating the actuator mover state. A second operation unit generates a first difference signal indicating the difference between a target signal and the position signal. A third operation unit generates a second difference signal indicating the difference between signals based on the first difference signal and the speed signal. A fourth operation unit generates a position control signal such that the second difference signal becomes zero. A fifth operation unit generates a third difference signal indicating the difference between signals based on a driving signal and the acceleration signal. A sixth operation unit generates a driving signal by summing a signal based on the position control signal and a disturbance estimation signal based on the third difference signal.

Abstract: A door closer with an automated calibration mode is disclosed. The door closer that can be self powered and includes a control unit to intelligently control a valve within the door closer to vary the operating characteristics of the door closer as needed. The control unit includes a calibration mode that can be invoked to match the control unit to the mechanical door closer assembly. A plurality of positional values being output encoders coupled to an arm of the door closer and the motor for the valve can be determined. The positional values from the encoders and the positions that they indicate can then be stored in a memory within the controller for use during normal operation of the door closer.

Abstract: An electric machine including a housing and a stator arranged within the housing. The stator includes a plurality of stator windings that define a number of phases. A switch module is mounted at the housing. The switch module includes a plurality of switch members that are operatively connected to the plurality of stator windings. The plurality of switch members are configured and disposed to selectively establish one of a first electrical connection configuration and a second electrical connection configuration of the plurality of stator windings.

Abstract: A power tool comprises a housing, a direct current motor arranged in the housing, a speed reduction mechanism coupled to a shaft of the motor, a tool head driven by the speed reduction mechanism, a first direct current power source, and a switching device. The motor comprises a common brush, a high speed brush and a low speed brush which are in sliding contact with a commutator. The switching device is configured to selectively connect the common brush and the high speed brush with the power source to operate the motor in a high speed mode and to connect the common brush and the low speed brush with the power source to operate the motor in a low speed mode.

Abstract: A pulse generating device includes a rotatable disc having a plurality of patterns that are formed on a surface of the rotatable disc in a circumferential direction of the rotatable disc, and three pulse generators to each detect the plurality of patterns formed on the rotatable disc and to respectively generate three pulse signals each corresponding to a rotational speed of the rotatable disc based on the detected patterns. The three pulse generators are evenly spaced at intervals of 120 degrees of angle with respect to a rotational axis of the rotatable disc in the circumferential direction of the rotatable disc.

Abstract: A method of generating electrical energy in an integrated circuit that may include setting into motion a (3D) three-dimensional enclosed space in the integrated circuit. The 3D enclosed space may include a piezoelectric element and a free moving object therein. The method may also include producing the electrical energy from impact between the free moving object and the piezoelectric element during the motion.

Abstract: A method of operating a synchronous motor having a stator that includes a set of electromagnets and a permanent magnet rotor. The synchronous motor is controlled by calculating in a flux controller a measure of a flux magnitude, which is the magnitude of the stator flux of the motor and by calculating in a load angle controller a measure of a load angle. Information about a desired motor torque or a reduced motor torque, which is smaller than the desired motor torque, is input to the load angle controller and the load angle controller calculates the measure of the load angle depending on the input motor torque. The measure of the flux magnitude is combined with the measure of the load angle to obtain commands for controlling electric currents of electromagnets of the stator, thereby directly controlling the stator flux.

Abstract: The method of changing ultrasound wave frequency by using the acoustic matching layer presents a replaceable acoustic matching layer to offer an effective means of filtering the original broadband frequency of an ultrasonic transducer into certain composite discontinuous frequencies. The filtering effect could be improved by connecting the electrodes of the acoustic matching layer when it is made of a poled piezoelectric material. This method may provide novel applications for commercial ultrasonic transducers.

Abstract: A piezoceramic transducer (PZT transducer) and a method for manufacturing the same are provided. The PZT transducer includes a piezoceramic substrate and an electrode unit. The piezoceramic substrate has a first surface and a second surface opposite the first surface, and has a mechanical quality factor (Qm) greater than 1400. The electrode unit has a first electrode and a second electrode. The first electrode is disposed on the first surface and has a first diameter. The second electrode covers the second surface and extends to cover a part of the surface at a periphery of the first surface, and the part of the second electrode covering the second surface has a second diameter. The ratio of the first diameter to the second diameter is 0.498 to 0.502. The PZT transducer has a large mist amount and a long service life.

Abstract: A torque ripple suppression control device for a permanent magnet motor includes a current command conversion unit that outputs a current command value, a position detector that detects a rotational position of the permanent magnet motor, a current detection unit that detects a current at the permanent magnet motor, an induced voltage coefficient setting unit that outputs an information signal related to an induced voltage coefficient for an induced voltage at the permanent magnet motor, a torque ripple suppression operation unit that outputs a current correction command value for the permanent magnet motor, a current control operation unit that outputs a voltage command value based upon addition results obtained by adding together the current command value and the current correction command value and the current detection value, and a power converter that outputs a voltage with which the permanent magnet motor is to be driven.

Abstract: In a motor control device, a control calculation unit obtains a phase voltage instruction value. A current detecting unit detects an electric current which flows into the brushless motor. A rotational position detecting unit detects the rotational position of a rotor in the brushless motor. A correction unit corrects the phase voltage instruction value based on the detection results of the current detecting unit and the rotational position detecting unit so that a dependency of a ratio on an electric angle shown by a secondary harmonic component of the ratio concerning the electric angle of the brushless motor. The ratio is a ratio of a q-axis or d-axis component of the electric current, which flows into the brushless motor, to a q-axis or d-axis instruction value. A driving unit drives the brushless motor based on the phase voltage instruction value after the correction by the correction unit.

Abstract: A door position control including an electric door actuator having a motor and a motor controller in communication with a system controller. A motor actuation operation is selected from a plurality of predetermined motor actuation operations to provide control signals to the motor controller for controlling actuation of the motor for control of door movement. Control of door movement is effected with reference to parameters specific to an installation location including an angular sweep of the door between open and closed positions and with reference to an available bus voltage for supplying power to the motor.

Abstract: Systems, methods and computer program products for reducing or removing current spikes generated during a current recirculation period associated with phase switching in a spindle motor are described. In some implementations, the duty cycle of the drive signals applied to the windings of the spindle motor can be adjusted to reduce or eliminate the current surge resulting from current recirculation. In some implementations, the duty cycle of the drive signals during spin-up can be reduced based on a current limit, and the reduced duty cycle can then be used to drive the spindle motor taking into account of current surges in the supply current.

Abstract: A motor drive controller includes a position detector that detects and outputs positional signals representing rotational positions of the magnetic rotor at first resolution, a position change detector that detects and outputs position change signals representing rotational positions of the magnetic rotor at second resolution higher than the first resolution, a phase synchronizing circuit that generates and outputs low resolution absolute phase information based on the positional and position change signals. The phase synchronizing circuit generates and outputs high-resolution absolute phase information based on the position change signals. A drive voltage signal outputting device outputs a drive voltage signal causing the current to flow through the coils in accordance with the absolute phase information.

Abstract: A coupling structure for coupling piezoelectric material generated stresses to an actuated device of an integrated circuit includes a rigid stiffener structure formed around a piezoelectric (PE) material and the actuated device, the actuated device comprising a piezoresistive (PR) material that has an electrical resistance dependent upon an applied pressure thereto; and a soft buffer structure formed around the PE material and PR material, the buffer structure disposed between the PE and PR materials and the stiffener structure, wherein the stiffener structure clamps both the PE and PR materials to a substrate over which the PE and PR materials are formed, and wherein the soft buffer structure permits the PE material freedom to move relative to the PR material, thereby coupling stress generated by an applied voltage to the PE material to the PR material so as change the electrical resistance of the PR material.

Abstract: A miniaturizable, low-cost highly reliable inverter unit. A control circuit section for controlling operating timing of high breakdown voltage semiconductor elements included in an inverter circuit section and first and second drive and abnormality detection circuit sections for outputting drive signals for driving the high breakdown voltage semiconductor elements according to the operating timing and for feeding back an abnormality of the inverter circuit section to the control circuit section are formed on an SOI substrate as one integrated circuit chip. On the integrated circuit chip, circuit formation areas which differ in reference potential are separated from one another by dielectrics. A plurality of level shifters for transmitting signals exchanged between circuit formation areas separated by the dielectrics are formed.

Abstract: A system and method for detecting a rotor fault condition in an AC induction machine is disclosed. The system includes a processor programmed to receive voltage and current data from an AC induction machine, generate a current frequency spectrum from the current data, and identify rotor-fault related harmonics in the current frequency spectrum. The processor is also programmed to calculate a fault severity indicator using the voltage and current data, identified rotor-fault related harmonics, and motor specifications, analyze the fault severity indicator to determine a possibility of rotor fault. The processor generates an alert based on the possibility of rotor fault.