Abstract: An AC/DC voltage converter achieving a relatively low loss of power includes a rectifier circuit connected directly to a step-up converter circuit. The voltage converter further includes a storage capacitor and a resistor connected to outputs of the step-up converter circuit. One electrode of the storage capacitor is connected through the resistor to one output of the step-up converter circuit.

Abstract: A protection device for an inverter which is connected to an AC power system, converts DC power into AC power, supplies the AC power to a load and includes a control circuit for detecting a phase and a frequency of an output voltage, for generating a current reference synchronized with the output voltage and for controlling the inverter such that an output current is coincident with the current reference. The protection device includes a first detection circuit for detecting that an AC output is disconnected from the AC power system based on an electrical quantity of the output voltage and for generating a detection signal based on a detection result, and a correction circuit connected to receive the detection signal for generating a correction signal to break a power balance between an output power and a power consumed by the load.

Abstract: A high efficiency, high power factor, low voltage power converter includes a dual active bridge converter (DABC) having transformer-coupled primary-side and secondary-side bridge connections of switching devices and providing two output voltages. One output voltage drives a resonant boost converter coupled in series between an ac rectifier for rectifying an ac line voltage and the DABC. The boost converter, which is controlled by frequency modulation, boosts a dc bus voltage above the peak line voltage, thereby providing a high power factor. The other output is a low dc voltage which is regulated by controlling the phase shift between the voltages respectively produced by the primary-side and secondary-side connections of switching devices of the DABC. Advantageously, the leakage inductance of the DABC transformer coupling the primary and secondary sides of the DABC is efficiently used for energy transfer therebetween such that an output filter inductor is not needed.

Abstract: A stator for miniature motors having a permanent magnet fixedly fitted to the inner circumferential surface of a housing formed into a bottomed hollow cylindrical shape, in which the circumferential surface of the housing consists of two opposing flat parts and two concave cylindrical surfaces; engaging projections are provided on the flat parts, and flat surfaces coming in contact with said flat parts, and engaging surfaces facing coming in contact with the engaging projections are provided on the axial edge of the permanent magnet made of a flexible ferromagnetic material, and formed into an arc-segment shape in cross section; and the permanent magnet is fixedly fitted in the housing by bringing the arc-segment-shaped outer circumferential surfaces of the permanent magnet in contact with the cylindrical surfaces of the housing, and bringing the flat surfaces on the axial edges of the permanent magnet in contact with the flat parts by causing the engaging projections to cut into the engaging surfaces by the

Abstract: A magnetic bearing has electromagnets which are actively controlled to maintain a rotor at a prescribed position relative to a stator. Radial and axial bearings are disclosed. In each, conductive loops travel relatively through field zones which are associated with the electromagnets. Sensors provide signals indicative of deviations of the loops from their prescribed circular path, and these signals control the electromagnets selectively to change the magnetic field strengths. A loop current will be induced by the movement of a loop through a magnetic field. This current, in the presence of the magnetic field or fields will exert Lorentz forces on the loop in a radial and/or axial direction. These forces return the rotor to its prescribed position.

Abstract: Flywheel-based energy storage devices are provided along with methods for their use and fabrication. The devices have the capacity to store electric energy as kinetic energy and to generate electric energy from the stored kinetic energy. Preferred devices comprise a pair of counter-rotating anisotropic flywheels which are designed to rapidly rotate within an evacuated housing. The flywheels comprise a lightweight hub and a circumferentially-wound fiber rim. The hub and rim are fabricated from materials having high tensile strength and are connected with system of novel tube assemblies positioned around the hub parallel to the axis of rotation, The flywheel are principally supported by magnetic bearings and are further stabilized during rotation by a self-restoring liquid bearing system.

Abstract: An electric motor that includes a case having an axially oriented stamped steel endhead, a motor output shaft projecting from the endhead for coupling to a motor load, and a self-aligning spherical bearing mounted on the endhead for rotatably supporting the shaft. The bearing has a cylindrical extension that projects axially outwardly from the motor case coaxially with the shaft. The bearing extension is constructed and arranged to be engaged by the support structure and/or load coupled to the shaft for locating the same coaxially with the shaft. The bearing, including the extension, is of homogeneously integral unitary construction, preferably of lubricant-impregnated porous metal.

Abstract: A current controller for controlling an input current carried by a primary conductor. The current controller has a gapped core of magnetic material magnetically coupled to the primary conductor, as for example by the primary conductor being wound around the core. A secondary conductor is magnetically coupled to the core of magnetic material in an opposite manner to the primary conductor such that current flowing in the secondary conductor generates a second magnetic field in the core opposed to the first magnetic field. A Hall effect latch is located in the air gap and has output voltage corresponding to a hysteresis function of the difference in the first and second magnetic fields.

Abstract: A bipolar current source which provides negative and positive currents have been equalized by magnitude. During the majority of the time, the bipolar current source is operating both positive and negative currents are output by the circuit. For a small percentage of the time, both the negative and positive currents are fed into current equalizing circuitry. The current equalizing circuitry generates a feedback signal which is transmitted to either the positive or negative current sources and the magnitude of that current is adjusted until the magnitudes of the positive and negative currents are equal. The bipolar current source then resumes normal operation.

Abstract: A boost converter power supply circuit uses energy from a diode recovery current which flows in the blocking diode at diode commutation to discharge a capacitance associated with the main switch of the boost converter in order to achieve zero voltage switching. The diode recovery current energy is initially captured in an inductor, is then transferred to a capacitor, and is then transferred back to the inductor prior to the main switch being switched on. In accordance with another embodiment, a control circuit for controlling a boost converter to achieve power factor correction is disclosed which does not use a high gain input current feedback loop. The control circuit responds relatively quickly to output load changes, thereby overcoming disadvantages of prior art control circuits. Because the control circuit does not require an X-Y multiplier, the control circuit lends itself to realization in integrated circuit form.

Abstract: An integrated circuit of the present invention includes power regulating circuitry for reducing preregulator bias current. In one embodiment, power regulating circuitry includes a two stage preregulator for supplying current to a charge pump and a primary regulator. The first stage includes a high power operational amplifier for quickly establishing substrate bias and other pumped voltages before primary voltage is coupled to the remainder of the integrated circuit. Preregulated and pumped voltages are used to establish a reference voltage for the primary regulator. The second stage preregulator includes a low power series regulator to power the charge pumps and so maintain the reference voltage. When the primary regulator has generated the primary voltage level, the power regulating circuitry couples the primary voltage to the remainder of the integrated circuit and disables the first stage preregulator.

Abstract: Electrical lines for two axially located housings are molded into an inelastic carrier and covered at both faces of the carrier. A seal is injection-molded onto the inelastic carrier. In one implementation in which the carrier is disposed between a commutator housing and a gear housing, the inelastic carrier engages a brush holder that is inserted into one housing of the commutator motor. The design enables the electrical lines to pass into the interior of two axially located housings in a simple manner, while guaranteeing a reliable moisture seal between the housings.

Abstract: A power supply for providing an ac/dc output to a load, includes a first source of dc power and an inverter that provides an ac output to the load. A second source of dc power is provided and selectably connects the first and second sources of dc power in series with the load when the output current reverses. In one embodiment the power sources are connected in series with every output current reversal. The first source of dc power is controllable and the magnitude of the dc current is responsive to a current reference signal. A control circuit provides the current reference signal, wherein the current reference signal is pulsed immediately prior to the ac output reversing polarity. The first source of dc power source preferably includes a buck converter that is switched at a variable frequency, depending upon the desired output current. In the event the user selects either an ac or dc electrode negative output a period of electrode positive dc energy is provided at start up to help establish the arc.

Abstract: A Variable Frequency Drive Power Center incorporating a new passive Harmonic Filter in an improved housing structure for Variable Frequency Drives (VFDs). The new harmonic filter improves the overall system performance by drastically reducing the line side current harmonics generated by all VFDs. The harmonic filter includes a series inductance, a parallel capacitance, and a buck transformer. The filter provides a low impedance path for the harmonic currents generated by VFD and therefore prevents them from flowing into the input ac power lines. The filter also improves the input power factor of the VFD system because of its increased inductive reactance under full-load conditions. Although the filter causes an overvoltage across the VFD terminals because of its increased capacitive reactance at the fundamental frequency this problem is overcome by using the buck transformer.

Abstract: A novel isolated, capacitive idling, Cuk switching-mode converter features two separate nonisolated feedback loops, one on the primary side to regulate against input voltage changes and the other on the secondary side to regulate against load current changes only. While preserving cost, size and simplicity of conventional multiple output switching-mode converters, the new converter and feedback control approach offers the advantages of simple feedback control implementation due to elimination of isolation requirements in the feedback control circuits, simultaneous regulation of all output voltages from no load to full load, and greatly improved bandwidth and step-load transient response. For operation from a rectified ac line, feedback control on the input to the transformer is modified to force the average input current to follow the full-wave rectified ac line voltage for unity power factor (UPF) performance on the input and wide bandwidth voltage regulation on the output.

Abstract: A NO-BLO-FUSE comprising a current sensing device is used to generate a voltage drop proportional to the current flowing through the device. When the voltage drop reaches a predetermined level, resulting from an over-current condition, it trips a control means that opens a solid state switch in the line. After a defined delay interval the circuit will automatically reset to close the solid state switch. If the over-current condition still exists, the control means will again open the solid state switch. This cycle is repeated at the delay interval until the over-current condition has subsided. Circuits are also disclosed which provide over-voltage protection, through detectors which trigger the control means when an over-voltage condition is detected. The application of the invention to lightning or surge protection is also disclosed, for single line and multi-line environments.

Abstract: A switching regulator having a series resonance push-pull converter (GW) and two clocked boost regulators (AR1, AR2) connected in series with the converter, wherein: the converter comprises a transformer (Tr) having two primary windings (w1, w2) which are galvanically isolated from one another, and two push-pull switches (S1, S2) each connected in series with a respective one of the primary windings; each of the boost regulators comprises a series inductance (L1, L2) and an output capacitor (C1, C2); and the boost regulators are connected to the converter to form two push-pull branches, each of the push-pull branches being composed of the series inductance of one of the boost regulators connected in series with a respective one of the primary windings and a respective one of the push-pull switches, and the output capacitor of each of the boost regulators constituting a resonance capacitor of the converter.

Abstract: A continuous mode full wave power converter topology which integrates the buck-boost (flyback) and buck converter properties. The voltage transfer function is M=(D/(1-D)), characteristic of the buck-boost (flyback) converter. Characteristic of the full wave buck converter, the inductor current is source continuous during the alternate D intervals, source discontinuous during the simultaneous (1-D) intervals, and load continuous during both the D and (1-D) intervals.

Abstract: A phase adaptable AC/DC converter having three input terminals capable of connection to either a single phase or dual phase electrical power service. A feedback circuit in a control portion of the converter sums a first voltage and a second voltage which are proportional to first and second output voltages, respectively, to control a first bidirectional switch in a voltage boost circuit. The feedback circuit also sums the first and second voltage with a difference between the first and second output voltages to control a second bidirectional switch in the voltage boost circuit.

Abstract: A modified boost converter accomplishes power transfer to a load with an electrical isolation, a zero-voltage and a zero-current switching, a transformer core resetting mechanism, and component stresses identical to those in the conventional boost converters. The power converter contains two switching devices, a main one connected in parallel and a secondary one connected in series with a transformer primary winding. A secondary winding of the transformer is connected through an output rectifier to the load. Zero-voltage switching and proper transformer-core resetting are achieved from the resonance that exists between the parasitic capacitance of the secondary switching device and the magnetization inductance of the transformer. A transformer leakage inductance facilitates zero-current switching; thus, reducing the recovery time and current in the output rectifier, and the turn-on switching loss in the conventional main switching device.