Abstract: A rotation detecting device for vehicle speedometers includes a housing, a magnetic induction device, and a magnetized rotor near the magnetic induction device. The rotor is connected through a coupling to a rotation source. A braking device forms a magnetic circuit between one end surface of the rotor and the housing, and brings the rotor into pressure contact with the housing by a magnetic attraction force generated in the magnetic circuit. Accordingly, a stable and proper braking torque can be applied against rotor vibration, to prevent a false output signal while idling. Furthermore, the amount of wear of a bearing for rotatably supporting a rotating shaft of the rotor can be reduced to improve durability of the rotation detecting device by reducing the braking torque during high-speed rotation of the rotor.
October 11, 1990
Date of Patent:
August 6, 1996
Katsuo Nishitani, Masaki Hirota, Takeshi Ai
Abstract: A two-state modulation system includes a hysteretic comparator with variable thresholds, a two-state processor and an integrating element. A summing circuit combines a signal coupled from the output of the two-state processor, the signal output, the signal input and a delay compensating signal feedback input and a feedback input from an integrating element at the output of the two-state processor. The hysteretic comparator receives a hysteresis control signal that varies the threshold. The hysteresis control signal may be provided by analog switches switched by the switching signal to provide the switched two-state levels to a low pass filter. Rectifying circuitry may also be used for supplying the hysteresis control signal. Limiters and compressors may be connected to the input with the limiter limiting levels tracking the two-state levels, and the compression proportional to the switching frequency.
Abstract: A voltage regulator especially adaptable for use with field-programmable gate arrays (FPGA). The voltage regulator is configurable as a true voltage regulator or, alternatively, as a pseudo-voltage regulator. The voltage regulator includes circuitry to rapidly generate an operating voltage for the core or nucleus logic elements. Additional circuitry is provided to reduce the steady-state power consumption once the operating voltage is reached. To compensate for die-to-die variations, additional circuitry is also provided to adjust the compensation delays or switching rates.
Abstract: A standby power supply system is provided for supplying normal AC power to a critical load from an AC power source during normal operating conditions, and for supplying emergency AC power to the load during failure of the AC power source. During normal operation, the standby power supply system actively neutralizes undesirable harmonic components in the input current drawn by the load. The standby power supply system includes a power conversion device having a DC side coupled to a back-up power source and an AC side in parallel with the load and the AC source. A harmonic distortion sensor senses a harmonic distortion current component of a load current drawn by the load during normal operating conditions. A controller is responsive to the harmonic distortion sensor for causing the power conversion device to produce a harmonics neutralizing current to substantially neutralize the harmonic distortion current component produced by the load.
Abstract: A transformer having a core of soft magnetic material around which a first winding and a second winding are wound and a leakage inductance based on the magnetic coupling between these windings. The effective leakage reactance is minimized by adding a third transformer winding serially connected to a capacitor, the latter of which is varied to reduce the leakage reactance over a broad frequency range.
Abstract: This device for converting a very-low-amplitude steady voltage signal into an alternating voltage signal, of the type comprising a centre-tapped transformer (1) associated with a transistor (3,4) chopper (2), is characterised in that the transformer (1) and the transistors (3,4) are arranged in a housing (15) held at very low temperature and in which is arranged a material (20) for thermal insulation of the transistors (3,4) with respect to the rest of the housing so as to reduce temperature fluctuations and allow operation of these transistors by self-heating due to their drive current.
January 7, 1993
Date of Patent:
July 12, 1994
Framatome, Centre National de la Recherche Scientifique (CNRS)
Jacques Chaussy, Jean-Louis Bret, Bernard Picot, Jacques Meyer
Abstract: An inductor uses high temperature superconductors in order to obtain high Q for high frequency operation. The superconductors are applied as thin films to substrates. In some embodiments, superconductor thin films are applied to opposite sides of the same substrate. Superconductive thin films are applied outside the magnetic field establishing superconductive thin films in order to shield against leakage of the magnetic field beyond the inductor. The inductor is connected to a capacitor to realize a resonant circuit used in a power conversion system.
November 2, 1992
Date of Patent:
July 12, 1994
General Electric Co.
Waseem A. Roshen, Antonio A. Mogro-Campero, James W. Bray, Charles S. Korman
Abstract: A DC-DC converter utilizes a tapped transformer secondary winding as a means of achieving output voltage ripple cancellation. This ripple cancellation occurs at a specified input voltage. It operates by fixing the location of a tap on the secondary winding of the power transformer so that the output voltage ripple cancellation occurs at the specified input voltage. It also minimizes the volt seconds that must be sustained by the output filter inductor over a specified range of input voltage for the converter.
November 25, 1992
Date of Patent:
July 5, 1994
AT&T Bell Laboratories
Jeffrey J. Boylan, Mark E. Jacobs, Thomas P. Loftus, Jr., Allen F. Rozman
Abstract: A current resonance DC-DC converter has a ZCS resonance switch circuit which comprises a semiconductor switch device 7 and a diode 8 connected together into a parallel circuit, the diode 8 being connected at its cathode to one end of a DC power supply 1, a center-tapped resonance inductance 13 adapted to produce voltages of the same polarity across the center tap and its respective opposite ends and connected at its resonance side to the anode of the diode 8, and a resonance capacitor 6 connected to the center tap of the resonance inductance 13 and to the above-mentioned one end of the power supply 1, the resonance inductance 13 being connected at a transformerside terminal thereof to one end of the primary inductance 4 of a high-frequency transformer HT, the other end of the primary inductance 4 being connected to the other end of the power supply 1.
Abstract: The present invention relates to a control apparatus of a three-level inverter and intends to provide a control apparatus of simplified construction which can suppress a fluctuation in neutral point voltage effectively. Only a third harmonic component which is particularly large in the fluctuation in neutral point voltage is suppressed, a third harmonic component for suppression has a ratio of amplitude to that of a fundamental wave and a phase which are set to be constant regardless of the inverter frequency, and this third harmonic component is applied to a command of the fundamental wave.
Abstract: A DC to DC switch mode power supply for a service subscriber interface unit of a fiber optic network includes a source of DC primary power, a main DC to DC switched mode power supply connected to the source of DC primary power and including switching circuitry and rectifier circuitry for supplying DC operating power to the service subscriber interface unit including central office battery power to at least one subscriber loop connected thereto, and a ringing voltage DC to AC switched mode generator connected to the source of DC primary power and including switching circuitry and synchronous rectification circuitry for generating ringing ringing voltage approximating a sine wave supplied as a reference to the synchronous rectification circuitry. A Johnson counter and resistor capacitor network is preferably employed to convert a reference ringing square wave into a sine wave.
Abstract: A three phase power conditioner. The inventive power conditioner (10) converts an alternating current input signal from a three phase source (12) into a direct current output signal and includes a first circuit (20) for converting a first phase of the input signal into a first direct current output signal. A second circuit (22) is included for converting a second phase of the input signal into a second direct current output signal. Likewise, a third circuit (24) converts a third phase of the input signal into a third direct current output signal. A control circuit (30) regulates the power supplied by the first, second and third circuits to balance the loads (26) for all load values dynamically. In an illustrative implementation, the first, second and third circuits (20, 22, and 24) are implemented with boost converters and the controller (30) is implemented with a load share controller. The inventive power conditioner is adapted for use with Wye and Delta configured three phase power sources.
Abstract: An inverter power supply for use with various voltage inputs is provided. The inverter power supply generally receives 208 VAC single-phase, 230 VAC three-phase, 230 VAC single-phase, 460 VAC single-phase, 208 VAC three-phrase or 460 VAC three-phase power and provides a DC output current for welding, heating or cutting applications. The power inverter circuit includes a first tank circuit and a second tank circuit which are configured in serial or parallel according to a particular voltage input. Contactors, relays, or semiconductor switches respond to control signals from an AC sense circuit in order to configure the inverter power supply for the appropriate voltage input.
Abstract: In a power supply circuit, upon turning on of a switching element, a sinusoidal resonance current flows through a series resonance circuit and a smoothing capacitor of a dc output circuit is thereby charged. This resonance current is reversed after a half cycle and a rectifying diode is thereby reversely biased whereby the resonance path is cut off and the resonance current is automatically ceased. While the switching element is on, exciting of an inductance and charging of a capacitor are made in a parallel resonance circuit, though resonance is not made therein. By turning off the switching element in a current zero state thereafter, a parallel resonance by the parallel resonance circuit is started. The switching element is turned on at a timing when voltage of the parallel resonance circuit has returned to a power source voltage.
Abstract: The electric machine, advantageously a generator, includes a machine housing with two end shields, a lamination bundle provided with a stator winding having winding heads and a rotor in the housing. To improve the cooling effect and reduce aerodynamic flow noise the machine housing is provided with at least one air guiding duct enclosing circularly at least one winding head on one side of the lamination bundle and the at least one air guiding duct is provided with at least one inlet opening and at least one outlet opening for cooling air to carry away heat dissipated during operation, and each of the at least one air guiding ducts is bounded exteriorly by one of the end shields of the machine housing and interiorly by one of the two annular walls inserted between the lamination bundle and the end shield bounding the at least one air guiding duct exteriorly.
Abstract: A direct-current converter has an electronic switch which can be made conductive by switch-on pulses and has current limiting by suppression of switch-on pulses. In order to make do with a low-loss current sensor which is easy to realize, a direct voltage corresponding to the peak value of the current is obtained with the aid of an additional switch, in phase with the electronic switch, which is preferably a reverse-operated field-effect transistor. The converter is particularly suitable for applications in which low-impedance short circuits at the output of the converter have to be taken into account.
Abstract: A current resonance converter including a resonant circuit composed of an inductance Lr and a capacitor Cr, a switching element SW connected to the resonant circuit in series so as to turn on and off the resonant circuit, an oscillating circuit VCO for driving the switching element SW, a strobe pulse generating circuit SPG adapted to generate a strobe pulse after a predetermined period of time elapses from the time when the switching element SW is turned on, and a controlling circuit CTL serving to reduce an oscillation frequency derived from the voltage controlled oscillator VCO or stop oscillation of the same while the case where an electric current flows through the resonant circuit in the forward direction when a strobe pulse is generated is recognized as a case where the converter is loaded with an overload is disclosed. With this construction, the converter can be constructed in smaller dimensions with a lighter weight while assuring protection when the converter is loaded with an overload.
Abstract: A high-voltage generating circuit suitable for a light receiving circuit includes a pulse oscillating circuit, a current drive circuit, a first capacitor, a second capacitor, a Cockcroft-Walton circuit, a low-pass filter. The pulse oscillating circuit produces a train of repetitive pulses. The current drive circuit produces a train of repetitive pulses which are in phase opposite to the train of repetitive pulses. The first capacitor couples the current drive circuit with the first input terminal of the Cockcroft-Walton circuit. The second capacitor couples the pulse oscillating circuit with the second input terminal of the Cockcroft-Walton circuit. The Cockcroft-Walton circuit boost the pulse voltage applied between the first and second inputs to produce a high direct current voltage. The low-pass filter removes the ripple components of the high direct current voltage. The Cockcroft-Walton circuit can be formed with a small number of circuit components.
Abstract: A drive control apparatus for controlling a motor to drive the compressor of an air conditioner, according to the present invention, includes a rectifying circuit for converting an AC voltage into a DC voltage, an inverter having a combination of a plurality of power controlling semiconductor devices and which controls the DC voltage from the rectifying circuit in accordance with a drive signal supplied to the combination of the semiconductor devices so as to generate an AC drive current to the drive, and a drive circuit for generating the drive signal to the inverter. The drive circuit formed as a monolithic integrated circuit having a dielectric separation structure, with the monolithic integrated circuit and the inverter being mounted on a common module substrate.
Abstract: A DC/DC power transformer is provided which is an arrangement for direct transformation of high electric power from one DC voltage level to another DC voltage level without an intermediate AC voltage network. The DC voltage is today basically used for transmission of high electric power at long distances. The DC voltage levels for these transmissions are normally high. The DC/DC power transformer allows several DC voltage levels to be used in one and the same DC voltage network. The principle for this arrangement is that the valve windings (43, 45) from one or several converter transformers (47) are connected to two valve bridges, which generate opposing cyclically variating magnetic flows in the transformer cores (44). One of the valve bridges is operated as an inverter (42) and the other as a rectifier (46) and in this manner the power is transformed from one DC voltage level (U.sub.d1) to another (U.sub.d2).