US 5,109,185 A · Phase-controlled reversible power converter presenting a controllable counter emf to a source of an impressed voltage

Abstract

A universal phase-controlled reversible power converter having one transformer with multiple windings (i) couples a fixed d.c. voltage to an associated transformer winding through a fixed port having switches controlled for switching by fixed-phase signals, and (ii) couples any number of voltages having any waveform(s) whatsoever each to an associated transformer winding each through an associated variable port that has a filter with an inductor and controllable switches. Variable-phase switching control signals control the variable ports to produce any desired three-state demodulated waveform. A three-state demodulated waveform is filtered to present (i) a corresponding counter emf of any desired waveform to an input source or power, or (ii) any desired output waveform to a sink of power. Controllably producing the counter emf as a picture-of-the-line-input-voltage makes the load factor of the power converter, and all its loads, unity. Controllably producing the counter emf to either lead or lag an input power waveform gives the power converter a correspondingly controllable power factor, and permits it to serve as a power factor corrector. Controllably producing the counter emf as a pure sinusoid causes the power converter to reduce distortion on an a.c. power grid to which it is connected.

Claims22

Dependent claims

A power converter comprising:

a transformer including a plurality of windings;
a plurality of port means, at least one of which is for coupling, from an associated external reservoir of electrical energy, electrical energy having any of an a.c., d.c., combination a.c. and d.c., or stochastic voltage waveform, to an associated transformer winding;
and
means for controlling the at least one port means so that it presents a counter emf to the external reservoir of electrical energy, which counter emf is controllable in its waveform so as to produce any desired current waveform and any desired direction of current flow between the external reservoir of electrical energy and the at least one port means.

1 more element

A phase-controlled power converter comprising:

a transformer including a plurality of inductively coupled windings;
a plurality of ports each including (i) a pair of terminals to which are connectable an associated external source of electrical energy having a voltage waveform, and (ii) a switching circuit, having controllable switches, connected between the terminals and an associated winding of the transformer;
and
control means for rendering conductive at least one switch in the switching circuit of one of the plurality of ports simultaneously that another switch within the same switching circuit is rendered non-conductive, and for continuing the rendering in phased sequence between all the switches of the switching circuit of the one port and among all the switches of all the switching circuit of all the plurality of ports, so that at least one port presents a controllable counter emf to its associated source of electrical energy, this counter emf being controlled so as to produce at the at least one port a current waveform that is in a predetermined point-by-point relationship to the voltage waveform regardless that the voltage waveform should be any of a.c., d.c., combination a.c. and d.c., or stochastic.

1 more element

A phase-controlled power converter comprising:

a transformer including a plurality of inductively coupled windings;
a plurality of ports each including (i) a pair of terminals to which are connectable an associated external electrical potential, and (ii) a switching circuit, having controllable switches, connected between the terminals and an associated winding of the transformer wherein each of the plurality of ports comprises:
a switching circuit including switches;
wherein at least a one, called an INPUT LINE PORT, of the plurality of ports comprises:
a pair of terminals to which is connected an external source of electrical potential, and in which appears an impressed voltage;
and
control means for rendering conductive at least one switch in the switching circuit of one of the plurality of ports simultaneously that another switch within the same switching circuit is rendered non-conductive, and for continuing the rendering in phased sequence between all the switches of the switching circuit of the one port and among all the switches of all the switching circuits of all the plurality of ports, so that at least one port presents a controllable counter emf to its associated external electrical potential, wherein the control means comprises:
a switching control means for temporally rendering conductive at least one switch in each of the switching circuits, and for alternately temporally rendering conductive another switch in each of the switching circuits, at a switching frequency that is relatively high compared to a frequency of the impressed voltage appearing at the pair of terminals of the INPUT LINE PORT, wherein the switching control means comprises:
an oscillator producing an a.c. carrier waveform at a frequency that is relatively high compared to the frequency of the impressed voltage;
a d.c. reference source producing a substantially constant reference d.c. voltage;
first means, responsive to the a.c. carrier waveform, for controlling the switches of a one, called a FIXED D.C. PORT, of the plurality of ports to couple a first external d.c. voltage to a corresponding transformer winding so as to maintain therein a square wave of a frequency and a phase equal to the a.c. carrier waveform and of an amplitude equal to the first external d.c. voltage;
second means, responsive to any difference between the first external d.c. voltage and the reference d.c. voltage, for controlling the switches of another one, a so-called VARIABLE D.C. PORT, of the plurality of ports so that the first external d.c. voltage equals the reference d.c. voltage;
and
third means, responsive to any difference between another, variable, second external d.c. voltage and the reference d.c. voltage, for controlling the switches of the INPUT LINE PORT so that an emf presented this one of the plurality of ports to the external source of electrical potential has an equivalent waveform to the impressed voltage, whatsoever its shape and distortion, thereby making the power factor of the power converter circuit to be essentially unity.

11 more elements

A phase-controlled reversible power conversion method performed in a power converter circuit having (i) a high frequency power transformer with a plurality of inductively-coupled windings, and (ii) a plurality of ports, each with a switching circuit employing controlled switches, connected between an associated electrical potential and an associated transformer winding, the method comprising:

rendering in phased sequence switches in two of the ports to be conductive, and alternately rendering other switches in two of the ports to be conductive, in such a sequence, and phase, so that one of the two ports presents to its associated electrical potential a counter emf of controlled waveshape and controlled amplitude to it's terminals, with the amplitude determining the direction and magnitude of the flow of power at the terminals, the rendering comprising:
first coupling, in a first port including a first switching circuit under first switching control, a.c. power, called IMPRESSED VOLTAGE, received from a source of power to a first winding of a transformer in which appears an a.c. waveform of relatively higher frequency than the a.c. power;
inductively coupling the a.c. waveform in the first winding of the transformer to additional second and subsequent windings of the transformer;
second coupling, in a second port including a second switching circuit under second switching control, the inductively coupled a.c. waveform appearing in a second winding of the transformer to a voltage, called OUTPUT VOLTAGE, that is delivered into a load;
third coupling, in a third port including a third switching circuit under third switching control, the inductively coupled a.c. waveform appearing in a third winding of the transformer to a direct current electrical potential, called D.C. VOLTAGE, that becomes fixed by operation of the power converter circuit;
fourth coupling, in a fourth port including a fourth switching circuit under forth switching control, the inductively coupled a.c. waveform appearing in a fourth winding of the transformer to an electrical potential appearing across a capacitor, called an ENERGY CAPACITOR;
first generating an a.c. carrier waveform of relatively higher frequency than the IMPRESSED VOLTAGE;
second generating a fixed d.c. reference voltage;
first developing, in a first control circuit responsive to the a.c. carrier waveform, the first switching control;
second developing, in a second control circuit proportionately to a difference between the D.C. VOLTAGE and the fixed d.c. reference voltage, the fourth switching control;
and
third developing, in a third control circuit proportionately to a difference between the electrical potential across the ENERGY CAPACITOR and the fixed d.c. reference voltage, the first switching control so that, when this third-developed first switching control is used to control switching in the first port's first switching circuit, the emf presented to the source of electrical power will be of equivalent waveform to the IMPRESSED VOLTAGE, whatsoever its shape and distortion.

9 more elements

Dependencies are inferred from the claim text.

Phase-controlled reversible power converter presenting a controllable counter emf to a source of an impressed voltage

Life of this patent

Phase-controlled reversible power converter presenting a controllable counter emf to a source of an impressed voltage

Life of this patent

Abstract

Claims22