Abstract: Boost switching power conversion involves an apparatus for controlling transfer of power from an input voltage source to an output voltage sink. The apparatus includes a switch for controllably permitting or inhibiting delivery of current from the source to the output sink when the switch is off or on, respectively. Circuit elements of the apparatus define a characteristic time scale for time variation of the flow of current in the switch after the switch is turned on, and a switch controller is provided for turning the switch on and off at times when the current in the switch is zero. The rate at which the switch is turned on is controlled to regulate the ratio of the voltage across the output voltage sink to the average value of voltage across the input source such that the ratio is greater than or equal to one.

Abstract: A current source consists of a transistor having an emitting electrode connected to one end of a first resistor and a first operational amplifier that compares the voltage of the emitting electrode with a control voltage and controls a control electrode of the transistor through a second resistor. The voltage at the emitting electrode of the transistor is kept at a predetermined voltage by a second operational amplifier that compares the voltage at the emitting electrode with the predetermined voltage and controls the voltage at the other end of the first resistor. The control voltage source has a known source resistance. A third resistor is inserted between the non-inverting input and output terminals of the first operational amplifier. The second operational amplifier serves to make the maximum output voltage at the collecting electrode of the transistor high so that a power voltage usage efficiency of an electronic load is improved.

Abstract: An optical voltage reference for providing an alternative to a battery source. The optical reference apparatus provides a temperature stable, high precision, isolated voltage reference through the use of optical isolation techniques to eliminate current and impedance coupling errors. Pulse rate frequency modulation is employed to eliminate errors in the optical transmission link while phase-lock feedback is employed to stabilize the frequency to voltage transfer function.

Abstract: A current ratio device is used for forming a current transformer that can accurately scale down high currents to usable metering levels. The transformer has associated circuitry that renders it capable of functioning not only with ac and a mixture of ac and dc, but also when dc alone is present in the primary winding. The device employs a toroidal core and winding assembly that is cut along a plane containing the toroidal axis through a pair of diametrically opposite sections of the assembly that contain no windings, in order to separate the device into a pair of sub-assemblies that can be readily placed over a single turn primary, e.g. a busbar, without dismantling the same.

Abstract: Method and apparatus are provided responsive to the circuit parameters at one or more locations of an electrical power transmission and/or distribution network for detecting protective device operation. The detection of the protective device operation is utilized to locate faults and also to ascertain the status of protective devices. This information is useful in automated power systems for desirable isolation and sectionalizing of faults for optimum restoration of the network. A fault detection unit of the present invention is responsive to sensed circuit parameters and provides at least first and second outputs indicative of protective device operations that open the circuit. The first output is provided upon the occurrence of an overcurrent followed by the loss of a circuit parameter, such as voltage, for a specified time duration. In a preferred arrangement, the timing for a specified time duration is started when the overcurrent ends.

Abstract: A three-phase a.c. uninterruptible power supply includes a transformer providing isolation between an input and an output, a single-phase inverter, and a cycloconverter. The uninterruptible power supply operates to convert a d.c. voltage into a high-frequency a.c. voltage in the single-phase inverter, transmit the output voltage of the single-phase inverter in an isolated state, and convert the output of the transformer into a three-phase voltage having a lower frequency, such as 50 or 60 Hz, than the frequency of the output voltage of the single-phase inverter. This enables the transformer providing isolation to operate at a high frequency, thereby enabling the size of the transformer to be reduced.

Abstract: A voltage regulator circuit includes a variable resistance formed by diode configuration of NMOS depletion transistors connected in a parallel relation with a supply voltage divider connected at a node by a further variable resistance formed by a serial arrangement of NMOS transistors with ground and having each of their gates coupled to the supply voltage.

Abstract: An electronic device for controlling and monitoring the electric power supply to welding equipment includes an inverter driven by a rectifier that supplies voltage to the primary winding of a welding transformer. A secondary winding of the welding transformer delivers welding current that is a function of the voltage applied to the primary winding. The inverter is also interlocked to and piloted by a regulator in such a way that an essentially square wave voltage signal appears with a succession of paired pulses in each half-period of the fundamental frequency, alternately positive and negative and of a given absolute crest value and finite spacing. A periodic welding current is produced of which the pulses are triangular, all positive or negative within the same half-period, and geared to rise and fall once during each cycle of two paired alternating voltage pulses, such that fundamental frequencies can be reduced without loss of operating speed.

Abstract: A full bridge DC to DC converter which provides zero voltage switching (ZVS) for one leg of the bridge and zero current switching (ZCS) for the other leg of the bridge is described. ZVS is achieved with parallel capacitors, while ZCS is achieved by using the reverse breakdown characteristics of the various diode and switching devices. This technique provides a significant reduction in the switching losses of the switching devices, which allows for higher power and frequency combinations.

Abstract: A flexible reference voltage circuit includes a circuit for producing a first digital signal representative of a range of reference voltage levels; a circuit for producing a second digital signal representative of a selected reference voltage level within the range of reference voltage levels; an adder for adding the first and second digital signals to produce a third digital signal; and a digital to analog converter for providing an output voltage in response to the third digital signal. The method of producing a flexible reference voltage performed by the circuit is also claimed. The invention can be used with a differential protection circuit to provide a series of trip level ranges, with a series of selectable trip levels in each range. This is accomplished in a high accuracy circuit which is relatively simple to construct, thereby minimizing size and complexity of the current sensor module, in differential protection applications, or the circuitry, if used in a power system controller.

Abstract: A circuit for neutralizing very fast current fluctuations in a power consumer circuit, such as an integrated circuit having a pair of input or output conductors includes a bipolar transistor 17 whose collector is connected via a parallel connection of a semiconductor diode and a resistor to one of the conductors. The emitter of the transistor is grounded and the base is connected to the other conductor. Another parallel connection of a diode and a resistor is connected between the two conductors to bias the transistor to a preset current when a standard current of a constant magnitude flows through the consumer circuit. If current surges or breaks occur in the standard current, the preset current flowing through the collector resistor undergoes corresponding changes and a compensating current is very fast loaded to the conductors through the capacitance of the barrier layer of the p-n junction of the collector diode to neutralize the changes of the standard current.

Abstract: Circuits are provided whereby rechargeable batteries and cells are charged very fast by a controlled current, and substantially at a rate never exceeding the ability of the battery or cell to accept current--i.e., to convert electrical current to stored chemical energy. The resistance free terminal voltage of the battery or cell is detected during an interval when the charging current is interrupted, and compared against an independent reference voltage to control the charging current when a difference between the reference voltage and the sensed resistance free terminal voltage exists. The reference voltage may be altered at any instant in time, as a function of the ambient temperature, or the internal temperature or pressure of the battery, as a function of the charging current when it is within a predetermined range, or if a particular change in the value of the charging current occurs over a predetermined period of time.

Abstract: The energy replenishment system offers uninterrupted operation for electric vehicles by instantly removing batteries (3A, 3B) by lifting device (15) from their compartment (2) when discharged, transferring them into charging shelf (57) having similar compartments (2C), and by placing recharged batteries in the vehicle's compartments (2). Automatic connector devices (31-51) instantly operated by the lifting device (15) provides high contact pressure and low contact resistance for the heavy currents on the battery terminals.

Abstract: An electronic contactor controller circuit able to handle high currents and voltages includes an integrated circuit power circuit switch which provides a measuring output signal representative of the load current to an operational amplifier current to voltage convertor. The output voltage of the operational amplifier is provided to an input of a comparator, and at least one reference voltage, from reference voltage generating circuitry, is provided to the other input of the comparator. The comparator outputs a signal to control a timer circuit, which in turn controls the current switch.

Abstract: A fault tolerant power supply comprises a first rectifier and a second rectifier with a boost circuit for correcting line current harmonics. The second rectifier, the boost circuit and output diodes are connected in parallel with the first rectifier. A capacitor circuit is charged through the second rectifier and boost converter when a 240 volt line input is present, but the circuit is charged through the first rectifier when a 120 volt line input is present. With failure of the boost converter circuit or with removal of the boost converter circuit from the system, the capacitor circuit is charged through the first rectifier.

Abstract: An adjustable temperature dependent current generator includes a transconductance current multiplier, a current mirror, two temperature dependent current generating circuits and a current source to generate currents capable of having an adjustable linear relation to temperature.

Abstract: Phase shifter to which are applied two signals in a phase opposition (v, -v) is constituted by a first series circuit of a resistor and a capacitor (R.sub.1, C.sub.1), and a second series circuit of a resistor and a capacitor (R.sub.2, C.sub.2). So that neither the relative amplitudes nor the relative phases of all the signals used at the outputs (5, 6, 7, 8) are degraded by the impedance of the stages that follow, the phase shifter includes a first network of a resistor and a capacitor connected in parallel (C.sub.3, R.sub.3), and a second network of a resistor and a capacitor connected in parallel (C.sub.4, R.sub.4). Both the four resistors and the four capacitors of the phase shifter are each substantially equal in value.