Abstract: The electrical dampening circuit for dampening resonance of a power signal in a power distribution network, comprises a capacitor C, an inductance L connected in parallel to capacitor C, and a resistance R connected in series with capacitor C and inductance L, values of capacitor C and inductance L being calculated so that (2.pi.f).sup.2 LC=1, where f is frequency of the power signal. The value of R is calculated so that 3.sqroot.L/C <R<(2/3) .sqroot.L/C whereby dampening of resonance is obtained.

Abstract: An active damper for an L-C filter suppresses transients that appear on the DC link from a power supply. The damper suppresses the transients by filtering the line voltage to obtain its steady-state component and comparing the steady-state voltage to the instantaneous voltage on the DC link. When the two voltages differ, the active damper cancels the transient by dissipating the energy on the DC link and the energy stored in the filter's inductor.

Abstract: A circuit for correcting perturbations in a power system signal operating at a system line frequency includes a capacitor for drawing a capacitive current and a first inductor for drawing an inductive current substantially equal in amplitude and substantially one hundred eighty degrees out of phase with the capacitive current. The first inductor is connected in parallel with the capacitor to form a storage module for storing energy therein wherein the storage module is tuned to resonate at the system line frequency and wherein the storage module is connected in parallel across the load. A second inductor connected in series between a power source and the load isolates the power source from the load.

Abstract: A power supply circuit for driving a magnetron equipped in a microwave oven, provides a stable power to the magnetron by preventing instability of output voltage due to LC resonance between a high voltage condenser (HVC) for driving a secondary winding of a transformer and the magnetron, and by good insulation between the secondary windings of the transformer in a switching mode power supply employing pulse width modulation.

Abstract: An inverter device has a full-wave rectifier providing a pulsating DC voltage from an input AC voltage, a smoothing circuit. The smoothing circuit includes a choke coil, a smoothing capacitor and a switching element chopping the pulsating DC voltage through the choke coil into a smoothed DC voltage at the smoothing capacitor. An inverter is included to have the element common to the smoothing circuit and operating to switch the smoothed DC voltage to apply a resulting voltage to a load circuit including a load, inductance and capacitor. The inductance and capacitor define an oscillation circuit providing to the load an oscillating current composed of first and second currents of opposite directions. The oscillating current alternating to flow for a nominal on-time duration determined by a circuit constant of the oscillation circuit itself.

Abstract: The problem of filtering DC power on a DC bus (46) in an electrical power generating system (10) is resolved using an active damper circuit (44). The active damper circuit (44) comprises a capacitor (CD) and a switching circuit (70) for alternately switching the capacitor (CD) into and out of parallel relationship with the DC bus (46).

Abstract: A smoothing filter for a rectifier (LR) includes a series inductance (L) and a parallel capacitance (C). Because the capacitive voltage drop (V.sub.c) is in counterphase relative to the inductive voltage drop (V.sub.c) there is found on the series inductance (L) a point (K) where the voltage drop towards earth is zero for a given frequency (fg). The load (Z) on the rectifier is connected to this point (K) in order to achieve high attenuation the fundamental harmonic of the ripple voltage at this frequency.

Abstract: A voltage-compliant power converter module which converts power from an input source for delivery to a load, the load being external to the voltage-compliant converter module and including an external filter capacitance of value Ce for providing ripple filtering of the load voltage delivered to the load, the load being connected to the voltage-compliant converter module via load interconnections external to the voltage-compliant power converter module, the load interconnections being characterized by a total parasitic load inductance of value L1. The converter module includes input terminations for connection to the input source and output terminations for connection to the load interconnections. Switching power conversion circuitry is connected to receive input power via the input terminations from the input source, the power conversion circuitry including one or more switching devices, the switching devices delivering a pulsating voltage waveform at switching frequencies within a nominal operating range.

Abstract: A balanced T-section low-pass common mode filter is connected in series with balanced data I/O lines to remove common mode signals from balanced line difference mode signals. The filter includes input and output series transformers configured so that the magnetic fields in the transformers are subtractive for out-of-phase difference mode signals and additive for in-phase common mode signals and a shunt transformer coupled to ground configured so that the magnetic fields in the transformer are additive for out-of-phase difference mode signals and subtractive for in-phase common mode signals. Accordingly, the difference mode signals are not attenuated and common mode signals react to a short circuit to ground and are thereby attenuated by the filter.

Abstract: An improvement is provided for a circuit having a first winding of N.sub.1 turns connected in series with a total inductance of L across a first voltage V.sub.1 and a second steering winding of N.sub.2 turns connected in series with a total inductance L.sub.2 across a second voltage V.sub.2 with the second winding magnetically coupled to the first winding and the first winding having an inductance L.sub.c produced by the N.sub.1 turns as seen across the first winding comprising L.sub.1 set substantially greater to zero and L.sub.2 set substantially equal to (L.sub.c) (N.sub.2 /N.sub.1).sup.2 ((V.sub.2 /V.sub.1) (N.sub.1 /N.sub.2)-1)). The setting of L.sub.1 and the setting of L.sub.2 providing an improvement to reduce ac ripple current.

Abstract: A filter system for removing selected frequencies from AC power provided on at least two phase lines and a neutral line includes a phase-to-phase filter for removing a first selected AC component at a first frequency from the AC power wherein the frequency component has a line-to-phase displacement within first or second ranges. A phase-to-neutral filter is also provided for removing a second selected AC component at a second frequency different from the first frequency from the AC power wherein the second frequency component has a line-to-line phase displacement outside of the first and second ranges.

Abstract: The present invention discloses an apparatus for damping resonance of an LC type low-pass filter provided on the DC input side of a power converter having a DC input terminal. The apparatus comprises an electric circuit connected in parallel to a reactor constituting the LC type low-pass filter. The electric circuit has an impedance which takes a substantially minimum value at a frequency equal to the resonance frequency of the LC type low-pass filter.

Abstract: Instability resulting from the presence of reactive components in the output filter of regulated power supplies of the general type in which regulation is obtained by feeding back the output voltage to the regulator circuitry is eliminated by deriving a feedback signal from the output voltage which includes not only a direct component, but also separately derived first and second derivative components referenced to the reactive characteristics of a series output choke and parallel output capacitor of the output filter circuit. The amplitude ratios of the feedback signal components are selected in accordance with a key aspect of the invention to eliminate the output filter from the characteristic equation of the power supply to thereby eliminate instability whatever its source.

Abstract: Damping resistance is introduced via transformer coupling into a circuit which includes an inductance-capacitance (LC) filter arrangement to smooth the current pulses applied to a load.

Abstract: Instability resulting from the presence of reactive components in the output filter of regulated power supplies of the general type in which regulation is obtained by feeding back the output voltage to the regulator circuitry is eliminated by deriving a feedback signal from the output voltage which includes not only a direct component, but also separately derived first and second derivative components referenced to the reactive characteristics of a series output choke and parallel output capacitor of the output filter circuit. The amplitude ratios of the feedback signal components and the elements of the local feedback loop of the regulator error amplifier are selected in accordance with key aspects of the invention to eliminate the output filter (including the effective series resistance of the output filter capacitor) from the characteristic equation of the power supply to thereby eliminate instability whatever its source.

Abstract: A power supply with a pulse width modulation switching mode voltage regulator having an output filter with an attenuation notch at the switching frequency of the pulse width modulator. The output filter comprises an input inductor and a series connected tank circuit with a shunt capacitor. The tank circuit is comprised of a shunt connected L-C circuit tuned to the switching frequency.

Abstract: A filter for a switching power supply. The filter includes a common mode inductor with coil configurations allowing differential mode current from a dc source to pass through but attenuating common mode noise from the power supply so that the noise does not reach the dc source. The invention also includes the use of feed through capacitors at the switching power supply input terminals to provide further high-frequency noise attenuation.

Abstract: A highly innovative new technique of developing AC to DC power sources for various applications has been described. Such technique of generating DC power is different from the conventional linear and switching power conversion techniques and this new technology has been called the Solid State Power Supply (SSPS) Technology. The principle of operation depends upon high-frequency pulsed power switching followed by high energy charge-discharge principles as applied to power conversion technology. The use of fast turn-on power MOSFETs enables the application of high frequency switching on this power technology. While the non-isolated SSPS is claimed to be transformerless, the isolated SSPS requires the use of a transformer for input-output isolation. The input and output filtering is reduced tremendously, thereby reducing the size of such power supplies.

Abstract: Novel switched mode boost-buck integrated magnetic power converters are disclosed featuring two winding bobbins, a new boost section with enhanced gain, means for operating the converter in a continuous mode of energy storage under minimum output loading conditions while providing adequate time for removing the magnetization energy of the transformer part of the integrated magnetics, and other new and different converter topologies.

Abstract: A filter unit for a static converter, notably an inverter, comprises at least one module having four capacitors arranged on a support with a square base in two groups connected in parallel to the power supply terminals of opposite polarities, each group comprising two series-mounted capacitors. The voltage at the mid-points of the two groups is fixed by a voltage divider comprising two balancing resistors, and an auxiliary impedance formed by the intermediate part of the connecting device. The support base is provided with coupling means to enable modular assembly by associating several modules identical on the four sides of the base.

Abstract: A crystal growing method for growing a crystal from a raw material melt highly magnetic field is being applied to the raw material melt, the electromagnet for applying the magnetic field being supplied with a direct current having a ripple factor of less than 5% to thereby grow a crystal with good crystallinity properties.

Abstract: An elevator control apparatus comprises an inverter device for supplying an induction motor for driving an elevator cage with AC electric power of variable voltage and frequencies and control equipment for controlling the output voltage and frequencies of the inverter device in response to signals produced in floors served by the elevator and in an elevator cage. The inverter device is constructed by a converter unit for converting AC electric power to DC electric power, at the input end of which a capacitor is connected in parallel with an AC electric source, an inverter unit for inverting the DC electric power converted in the converter unit into AC electric power, at the output end of which a capacitor is connected in parallel with an induction motor for driving the elevator cage and a DC reactor connected between the converter unit and the inverter unit.The thus constructed elevator control apparatus does not cause interference in electric appliances such as audio equipment, computer etc.

Abstract: A power filter resonant frequency modulation network for coupling between a load and a variable voltage direct current power source which is subjected to superposition of alternating current thereon at various frequencies and at various voltage levels, the filter including first and second series inductor arrangements in the positive and negative buses between the power supply and the load, with capacitive elements in parallel between the two buses. Each series inductor arrangement includes a first inductor in series with a frequency and voltage responsive inductive load device, which is a second inductor having a tertiary winding loaded with a coil wound about the core of a saturable reactor. The firing angles of the reactors are directly proportional to voltage and inversely proportional to voltage to provide a phase staggered change of inductance in the network.

Abstract: A noise filter connected to power lines includes two coils connected to the power lines in series, respectively, two capacitances connected to one end of the coils, respectively, and at least one resistance for reducing the gain of a resonance frequency of the filter the resistance being connected to the capacitances and grounded.

Abstract: A synchronous machine with alternating-current exciter, wherein the stator of the exciter machine, the rotor of which runs in the opposite direction of rotation to that of the stator field, is fed from a three-phase power controller. The voltages induced in the rotor of the alternating-current machine are rectified by diodes in a three-phase star circuit. In order to minimize the effect of the voltage peaks originating from the hole-storage effect during the commutation of the diodes, which peaks are abnormally high as a result of the mutual interaction of the harmonics, there is produced a parallel path for high-frequency currents in the form of a protection circuit having low-pass characteristic so that the mutual interaction between stator and rotor harmonics if greatly reduced. Because of the risk of self-excitation, the elements of the protection circuit are matched to the machine and cause as few additional losses as possible.

Abstract: A self-oscillating power converter utilizes a MOSFET power transistor switch with its output electrode coupled to a tuned network that operatively limits the voltage waveform across the power switch to periodic unipolar pulses. The transistor switch may be operated at a high radio frequency so that its drain to gate interelectrode capacitance is sufficient to comprise the sole oscillatory sustaining feedback path of the converter. A reactive network which is inductive at the operating frequency couples the gate to source electrodes of the transistor switch and includes a variable capacitance as a means of adjusting the overall reactance, and hence the converter's switching frequency in order to provide voltage regulation. A resonant rectifier includes a tuned circuit to shape the voltage waveform across the rectifying diodes as a time inverse of the power switch waveform.

Abstract: A power source for providing a high frequency ac output voltage is provided with a rectifier, a smoothing circuit with an inductor and a smoothing capacitor, and an inverter having a switching device for switching the input dc voltage from the rectifier to provide a high frequency ac voltage output with reduced ripple. Also included in the smoothing circuit is a charge storage device by the operation of which the inductor receives electromagnetic energy from the current therein when the switching device is switched on and electromagnetic energy is fed to the smoothing capacitor to charge the same when the switching device is switched off, with the resulting voltage developed across the capacitor being applied to the inverter input.

Abstract: An electrical power supply system of the kind in which an input alternating voltage or current is rectified in a rectifier circuit (II) and the output is fed to a load (8) via a smoothing filter (III). The combination of the smoothing filter and load are arranged so that the input impedance of the smoothing filter is substantially real for the overall frequency spectrum applied thereto and has substantially the same value for each component of this spectrum thereby reducing distortion of the current and voltage of the AC power supply. In the circuit illustrated this is achieved by choosing the value R of the resistor (11) in the filter to be equal to the resistance of the load and by choosing the values L and C of the inductor (6) and capacitor (7) in the filter so that L/C=R.sub.2.

Abstract: There is provided by this invention a novel high power resonance filter utilizing a resistive element between two resonant branches disposed to dampen resonant harmonic currents or voltages while maintaining minimal losses at the fundamental frequency.

Abstract: A control unit for regulating an asynchronous motor supplied with power from a three phase network by a line-controlled power converter which is DC coupled to a self-commutated inverter has a function generator and a current regulator which controls the stator current of the motor by the controlling rectifier valves in the inverter. Control of the stator current is a function of a predeterminable value of flux fed into the function generator. In a parallel control system, an actual-value computer and a load state control regulate the stator frequency by generating a signal for controlling the self-commutating converter as a function of the actual values of the stator current, the stator voltage, and a value calculated from the function generator input variable. The computer forms signals corresponding to the amplitude of the flux vector, and to a stator current component perpendicular to the flux vector.

Abstract: A bleeder circuit is utilized to insure proper operation of a filter inductor in a pulsed power system. A control arrangement couples a bleeder resistor to the filter inductor in response to actual current discontinuities in the inductor. The control arrangement responds to actual current discontinuities by responding to a voltage collapse in the inductor and activates a switch to couple the bleeder resistor to the inductor.

Abstract: A static convertor with forced commutation is connected between an alternating voltage network and a direct voltage network. A filter is connected in parallel with a smoothing capacitor on the DC side of the convertor. The filter consists of the series-connection of an inductor, a filter capacitor and two controllable semiconductor valves that are connected in parallel in opposed relation. The natural frequency of the filter is higher than the product of the frequency of the alternating voltage network and the pulse number of the converter. The valves are made to carry current in time with the fundamental tone of the AC component present in the direct current of the convertor. In this way, the variations of the direct voltage of the convertor, caused by the AC direct current component, may be practically eliminated.

Abstract: Current spikes in a buck power converter due to commutating diode turn-off time is eliminated by using a tapped inductor in the converter with the tap connected to the switching transistor, without the commutating diode in the usual place, and instead connected to conduct current from one end of the tapped inductor remote from the load during the interval in which the transistor is not conducting. In the case of a converter having a center-tapped (primary and secondary) transformer between two switching power transistors operated in a push-pull mode and two rectifying diodes in the secondary circuit, current spikes due to transformer saturation are also eliminated by using a tapped inductor in the converter with the tap connected to the rectifying diodes and a diode connected to conduct current from one end of the tapped inductor remote from the load during the interval in which the transistors are not conducting.

Abstract: A magnetic recording and playback apparatus adapted to decrease tape hiss noises, wherein an amplifier power supply circuit or an output circuit for coupling an output from a recording amplifier to a magnetic head is provided with a capacitor block whose internal loss decreases as frequency increases and consisting of a plurality of capacitors. The capacitor block is formed by connecting with an electrolytic capacitor of a large capacitance included in the power supply circuit or output circuit at least one nonpolarized capacitor having a smaller capacitance and smaller internal loss than the electrolytic capacitor.