US3239750A - Magnetic voltage stabilizer - Google Patents

Magnetic voltage stabilizer Download PDF

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Publication number
US3239750A
US3239750A US228793A US22879362A US3239750A US 3239750 A US3239750 A US 3239750A US 228793 A US228793 A US 228793A US 22879362 A US22879362 A US 22879362A US 3239750 A US3239750 A US 3239750A
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Prior art keywords
voltage
transformer
stabilizer
choke
current
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Expired - Lifetime
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US228793A
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English (en)
Inventor
Weber Paul
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Fritz Hellige und Co GmbH
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Fritz Hellige und Co GmbH
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    • G—PHYSICS
    • G05—CONTROLLING; REGULATING
    • G05F—SYSTEMS FOR REGULATING ELECTRIC OR MAGNETIC VARIABLES
    • G05F3/00—Non-retroactive systems for regulating electric variables by using an uncontrolled element, or an uncontrolled combination of elements, such element or such combination having self-regulating properties
    • G05F3/02—Regulating voltage or current
    • G05F3/04—Regulating voltage or current wherein the variable is AC
    • G05F3/06—Regulating voltage or current wherein the variable is AC using combinations of saturated and unsaturated inductive devices, e.g. combined with resonant circuit

Definitions

  • One class of devices of this type frequently used and well known in the art are the so-called magnetic voltage'stabilizers, which depend on the properties of a saturable reactor or transformer to achieve the desired regulating response. Generally, such arrangements are capable of providing a stabilized output voltage in the face of line voltage fluctuations of i%.
  • magnetic wide range stabilizers have been developed. Such devices permit operation from either 110 or 220 volt sources without switching as an additional advantage.
  • the knownvarieties of wide range stabilizers are, however,-cumbersome and heavy.
  • the apparent power input increases approximately as the square of the line voltage, so that the power factor decreases to a value of less than 0.5 in the vicinity of the upper regulation limit.
  • the poor power factor may be compensated by connecting an additional capacitor across the input, the device itself still draws heavy currents at higher input voltages. These heavy currents introduce additional significant losses which may result in overheating, unless a corresponding significant increase in the size of the regulator elements has been made.
  • an object of the present invention to provide a magnetic voltage stabilizer for producing a constant output voltage over a wide range of applied line voltages.
  • a further object of the present invention is to provide amagnetic voltage regulator which operates at substantially unity power factor and high efliciency while providing a stabilized output voltage over a wide range of applied line voltage fluctuations.
  • Yet another object of the present invention is to provide a magnetic voltage regulator which is comparatively light and compact, and easily fabricated from relatively inexpensive, non-critical components.
  • FIG. 1 is a schematic diagram of an embodiment of a magnetic voltage stabilizer according to the present invention
  • FIG. 2 is a vector diagram of currents and voltages in a voltage stabilizer typical of the prior art.
  • FIG. 3 is a vector diagram of currents and voltages in a voltage stabilizer according to the embodiment of the invention shown in FIG. 1.
  • FIG. 1 there is shown a schematic diagram of an embodiment of a magnetic voltage stabilizer according to the present invention.
  • the embodiment comprises a pair of input terminals 1, 2 for applying line voltage through a series choke 3 to a shunt circuit generally designated 12.
  • the shunt circuit includes the primary 5 of a transformer generally designated 4, across which the seriescombination of a capacitor 9 and choke 10 are connected.
  • the secondary 6 of transformer 4 is connected to a pair of output terminals 7,, 8, from which the stabilized output voltage may be supplied to a load 11.
  • series choke 3 is a saturable reactor, while transformer 4 is a saturable transformer.
  • Capacitor 9 and choke 10 form a series circuit which'is tuned to the third harmonic of the line frequency, and operate to improve the output waveshape of the stabilizer by removing third harmonic distortion introduced by'the non-linear magnetic elements of the circuit.
  • the improved voltage waveshape is accompanied by a significant decrease in copper losses in' the inductive elements of the circuit.
  • the tuned series circuit also suppresses self-oscillations or jump phenomena which might otherwise occur.
  • the series combination of capacitor 9 and choke 10 appears as a capacitor which should be proportioned to resonate with transformer 4 in its satu Operation of the magnetic voltage stabilizer of the present invention and its improved characteristics may be most readily illustrated by a direct comparison of a vector diagram of the currents and voltages in a voltage stabilizer typical of the prior art with a similar vector diagramof' a voltage stabilizer according to the present invention.
  • FIG. 2 there is shown a vector diagram of currents and voltages in a voltage stabilizer typical of the prior art, thelengthsof each vector'repre'-' senting'amplitude, while the directions or angles indicate the mutual phase relationship of the various voltage andcurrents depicted.
  • a prior art regulator generally known as a similar to that of the present invention, as shown in FIG.
  • series choke 3 is a conventional, nonsaturable reactor, andshunt resonant circuit 12 is tuned to resonate at the supply frequency when the mean or nominal value of line voltage is applied to the regulator.
  • the input current I through series choke 3 is the vectorial sum of I I, and I Since the load current I is constant, the geometric locus of supply current 1 and transformer current I for various applied voltages V may be represented by line A-A' which is perpendicular to the vector 1,.
  • the line B-B similarly represents the geometric locus of supply voltage V for various values of V Line B-B is rotated 90 with respect to line AA', since the voltage V across series choke 3 has a constant ratio to current I and leads the current by 90, so that its vector must always be perpendicular to current vector 1
  • shunt circuit 12 resonates at a nominal supply voltage V and the related vectors are also designated by the subindex 0.
  • vectors corresponding to the minimum input supply voltage within the regulating range are designated by the subindex 1
  • vectors corresponding to the maximum input supply voltage within the regulating range are designated by the subindex 2.
  • the input current is a minimum at nominal line voltage, and increases with either increased or decreased line voltage. It will also be seen that the supply voltage and current, represented by vectors V and 11 respectively, are almost in phase when the supply voltage is at its minimum and shunt circuit 12 and series choke 3 move toward series resonance. Under these conditions, the power factor of the stabilizer approaches unity.
  • the above and other disadvantages of the prior art stabilizer may be overcome by utilizing a saturable reactor as series choke 3, and adjusting shunt circuit 12 to resonate with transformer 5 in its saturated state in the upper range of input voltage fluctuations.
  • Series choke 3 should be selected to be unsaturated when shunt circuit 12 is in resonance, and to saturate at a level of line input voltage somewhat less than that at which shunt circuit resonance occurs with maximum load connected.
  • FIG. 3 there is shown a vector diagram of current and voltages in a voltage stabilizer according to the embodiment of the invention shown in FIG. 1.
  • the vector diagram is similar to FIG. 2, and may be derived therefrom by appropriate scale and other changes.
  • Shunt resonance conditions represented by the fact that V and V, are mutually perpendicular, occur at a comparatively high level input supply voltage V which, for purposes of illustration, has been taken to be a value of supply voltage which would produce a primary voltage V which is 1.6 times its value as shown in FIG. 2.
  • the number of turns of primary 5 must be increased, but the value of capacitor 9 may be reduced.
  • the inductance of series choke 3 should be significantly higher than in prior art designs, and the choke should be selected so as to operate slightly below saturation when the shunt circuit in resonance, and to have a substantially constant voltage drop despite current changes when in a state of saturation.
  • a significant advantage resulting from these conditions is that transformer 4 need not operate at its upper saturation level, and accordingly, excessive magnetizing currents with consequent high copper losses within primary 5 may be avoided.
  • the maximum primary current 1 which occurs at maximum supply voltage V is about 25% smaller than the corresponding current 1 of FIG. 2, and therefore an approximately 45% reduction in power losses is achieved.
  • the range of saturation of the iron core of the transformer is significantly reduced, as may be seen by comparing current vectors 1 and 1 of FIG. 3 with the corresponding vectors of FIG. 2. Accordingly, V will in practice have a smaller change of voltage over the stabilizing range, and enhanced stabilization will be achieved.
  • the maximum saturation of the transformer core is not to be reduced in order to reduce cooper losses, the maximum reactive current I of FIG. 2 may be maintained as a design parameter. Under these conditions, transformer 5 may be made significantly smaller, or, with the same size transformer, a correspondingly higher level of power may be transferred and stabilized. As a further possibility under such conditions, the range of stabilization may be significantly extended without changing the size of the transformer.
  • series choke 3 will include an air gap in its core, but it is a particular feature of the present invention that the width of the air gap is comparatively noncritical. Only voltage V associated with the unsaturated state is a function of the air gap width, but voltage V corresponding to a state of saturation in the choke is comparatively unaffected by changes in air gap width which merely results in a change in the degree of saturation of choke 3 but has little effect on the reluctance of its magnetic circuit, since a change in reluctance of the air gap produces an equivalent reluctance change in the iron because of its saturation characteristic. In contrast, in the stabilizer of FIG.
  • capacitor 9 handles a greater apparent power than in the prior art design, and if advantage is taken of the lower transformer saturation levels possible, less distortion of waveform will occur in the output waveshape.
  • the power factor presented to the line is always close to 1 over the full regulating range. It varies from capacitive values close to 1 With low line voltages, to inductive values close to 1 with high line voltages. This relationship is shown in FIG. 3 by the relatively small phase angle between corresponding values of V and 1 and results in enhanced efficiency for the stabilizer.
  • the stabilizer of the present invention operates independently from the load within predetermined limits. If desired, well known circuits may be included to compensate further for load fluctuations or variations.
  • transformer 4 has been described as a saturable transformer, it will be appreciated that the transformer may be replaced by a saturable reactor, where voltage or current transformation is not required. On the other hand, advantage may be taken of the presence of the transformer to provide output voltages different from the line voltage where desired or required.
  • a magnetic voltage stabilizer comprising:
  • non-linear saturable transformer having a primary and a secondary winding
  • a capacitor connected in shunt with the primary winding of said saturable transformer, said reactor, transformer and capacitor being selected to respond to applied input voltages to cause said saturable transformer to operate in its linear region at the maximum range of input voltages, and to cause said reactor to operate in its non-linear region in response to input voltages less than the maximum producing linear operation.
  • a voltage stabilizer for providing a substantially constant output voltage in response to widely varying applied input voltages comprising:
  • a parallel resonant circuit including a second saturable reactor and a capacitor

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • General Physics & Mathematics (AREA)
  • Radar, Positioning & Navigation (AREA)
  • Automation & Control Theory (AREA)
  • Control Of Electrical Variables (AREA)
US228793A 1961-10-05 1962-10-04 Magnetic voltage stabilizer Expired - Lifetime US3239750A (en)

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Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3477017A (en) * 1967-01-09 1969-11-04 Avery Ltd W & T Transducer excitation circuits
US4130790A (en) * 1977-04-25 1978-12-19 Hobart Brothers Company Ferroresonant transformer power supply
US4212053A (en) * 1978-07-31 1980-07-08 Venus Scientific Inc. D.C. to D.C. Converter utilizing resonant inductor to neutralize capacitive losses
EP0034018A3 (en) * 1980-02-11 1982-01-20 Liebert Corporation Power conditioning apparatus
US4656412A (en) * 1985-07-08 1987-04-07 California Institute Of Technology Ferroresonant flux coupled battery charger
US11206722B2 (en) 2017-09-01 2021-12-21 Trestoto Pty Limited Lighting control circuit, lighting installation and method

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
RU2168261C2 (ru) * 1999-05-31 2001-05-27 Поляков Сергей Александрович Усилитель мощности низкой частоты с питанием от сети переменного тока

Citations (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB315844A (en) * 1928-07-19 1930-05-15 Telefunken Gmbh Improvements in or relating to constant potential supply devices for use in alternating current systems
US1948704A (en) * 1926-01-30 1934-02-27 Lorenz C Ag Method of operating high frequency furnaces
US2088621A (en) * 1936-10-19 1937-08-03 E M Heavens Electrical system
GB583497A (en) * 1943-05-06 1946-12-19 Automatic Elect Lab Improvements in frequency changers
US2436925A (en) * 1943-12-31 1948-03-02 Eugene H Haug Electric regulating apparatus
US2801383A (en) * 1956-09-24 1957-07-30 Sorensen & Company Inc Voltage regulator
US2814738A (en) * 1957-02-13 1957-11-26 Westinghouse Electric Corp Magnetic modulator
DE1032387B (de) * 1955-06-30 1958-06-19 Gen Electric Anordnung zur Kompensation des Einflusses der Temperaturabhaengigkeit der magnetischen Induktion auf elektrische Geraete, z. B. Spannungsgleichhalter
US2858455A (en) * 1953-02-20 1958-10-28 Comp Generale Electricite Electric circuit comprising of a transformer and a series condenser in one of the windings
US2983862A (en) * 1958-08-28 1961-05-09 Gen Dynamics Corp Magnetic voltage reference device
US2997644A (en) * 1956-11-30 1961-08-22 Westinghouse Electric Corp Bias circuit

Patent Citations (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1948704A (en) * 1926-01-30 1934-02-27 Lorenz C Ag Method of operating high frequency furnaces
GB315844A (en) * 1928-07-19 1930-05-15 Telefunken Gmbh Improvements in or relating to constant potential supply devices for use in alternating current systems
US2088621A (en) * 1936-10-19 1937-08-03 E M Heavens Electrical system
GB583497A (en) * 1943-05-06 1946-12-19 Automatic Elect Lab Improvements in frequency changers
US2436925A (en) * 1943-12-31 1948-03-02 Eugene H Haug Electric regulating apparatus
US2858455A (en) * 1953-02-20 1958-10-28 Comp Generale Electricite Electric circuit comprising of a transformer and a series condenser in one of the windings
DE1032387B (de) * 1955-06-30 1958-06-19 Gen Electric Anordnung zur Kompensation des Einflusses der Temperaturabhaengigkeit der magnetischen Induktion auf elektrische Geraete, z. B. Spannungsgleichhalter
US2801383A (en) * 1956-09-24 1957-07-30 Sorensen & Company Inc Voltage regulator
US2997644A (en) * 1956-11-30 1961-08-22 Westinghouse Electric Corp Bias circuit
US2814738A (en) * 1957-02-13 1957-11-26 Westinghouse Electric Corp Magnetic modulator
US2983862A (en) * 1958-08-28 1961-05-09 Gen Dynamics Corp Magnetic voltage reference device

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3477017A (en) * 1967-01-09 1969-11-04 Avery Ltd W & T Transducer excitation circuits
US4130790A (en) * 1977-04-25 1978-12-19 Hobart Brothers Company Ferroresonant transformer power supply
US4212053A (en) * 1978-07-31 1980-07-08 Venus Scientific Inc. D.C. to D.C. Converter utilizing resonant inductor to neutralize capacitive losses
EP0034018A3 (en) * 1980-02-11 1982-01-20 Liebert Corporation Power conditioning apparatus
US4656412A (en) * 1985-07-08 1987-04-07 California Institute Of Technology Ferroresonant flux coupled battery charger
US11206722B2 (en) 2017-09-01 2021-12-21 Trestoto Pty Limited Lighting control circuit, lighting installation and method

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