US6067243A — AC-AC/DC converter

Claim 1

Independent Claim 388 words

An AC/AC-DC converter, comprising: a) a first pair of AC switches including first and second AC switches that are connected in series with each other; b) a second pair of AC switches including third and fourth AC switches that are connected in series with each other; c) an AC input across which the first and second pair of AC switches are connected in parallel with each other; d) a third pair of AC switches including fifth and sixth AC switches that are connected in series with each other; e) a first output formed by connecting ends of the fifth and sixth AC switches; f) a transformer having: 1) a primary winding connected between (i) a connecting point between the first and second AC switches and (ii) a connecting point between the third and fourth AC switches; and 2) a secondary winding across which the third pair of AC switches is connected, the secondary winding having a center point constituting a second output; g) control means for causing alternate operation of (i) the first, third and fifth AC switches and (ii) the second, fourth and sixth AC switches, at a frequency higher than an input waveform; h) first and second capacitors that are connected in series across the AC input, closer to the AC input than are the pairs of AC switches; and i) switching means for switching connection of a terminal of the primary winding between (i) the connecting point between the first and second AC switches and (ii) a connecting point between the first and second capacitors; wherein, when an AC input having a positive phase and a negative phase is applied, an output AC voltage is controlled to have a value in a range from a maximum value of the positive phase, passing through zero, to a maximum value of the negative phase by using pulse phase modulation between the first and second pairs of AC switches and the third pair of AC switches; and wherein, when a DC input is applied, an output DC voltage can be continuously varied to have a value in a range from a maximum value of positive polarity, passing through zero, to a maximum value of negative polarity, by phase controlling a driving pulse phase of the first, second and third pairs of AC switches between 0 and 180 degrees.

Claim 2

Dependent Claim 388 words

An AC/AC-DC converter, comprising: a) a first pair of AC switches including first and second AC switches that are connected in series with each other; b) a second pair of AC switches including third and fourth AC switches that are connected in series with each other; c) an AC input across which the first and second pair of AC switches are connected in parallel with each other; d) a third pair of AC switches including fifth and sixth AC switches that are connected in series with each other; e) a first output formed by connecting ends of the fifth and sixth AC switches; f) a transformer having: 1) a primary winding connected between (i) a connecting point between the first and second AC switches and (ii) a connecting point between the third and fourth AC switches; and 2) a secondary winding across which the third pair of AC switches is connected, the secondary winding having a center point constituting a second output; g) control means for causing alternate operation of (i) the first, third and fifth AC switches and (ii) the second, fourth and sixth AC switches, at a frequency higher than an input waveform; h) first and second capacitors that are connected in series across the AC input, closer to the AC input than are the pairs of AC switches; and i) switching means for switching connection of a terminal of the primary winding between (i) the connecting point between the first and second AC switches and (ii) a connecting point between the first and second capacitors; wherein, when an AC input having a positive phase and a negative phase is applied, an output AC voltage is controlled to have a value in a range from a maximum value of the positive phase, passing through zero, to a maximum value of the negative phase by using pulse phase modulation between the first and second pairs of AC switches and the third pair of AC switches; and wherein, when a DC input is applied, an output DC voltage can be continuously varied to have a value in a range from a maximum value of positive polarity, passing through zero, to a maximum value of negative polarity, by phase controlling a driving pulse phase of the first, second and third pairs of AC switches between 0 and 180 degrees.

Claim 3

Dependent Claim 64 words

The AC/AC converter of claim 1, wherein at least one of the AC switches includes: first and second semiconductor devices having same-polarity terminals connected to each other and respective first and second gates that both receive a control signal; and first and second diodes connected across the respective first and second semiconductor devices in a direction inverse to the semiconductor devices' respective conducting directions.

Claim 4

Dependent Claim 36 words

The AC/AC converter of claim 1, wherein the control means includes: means for causing operation of the fifth and sixth AC switches to be reversed when the AC input moves between a positive and negative half-cycle.

Claim 5

Dependent Claim 24 words

The AC/AC converter of claim 1, wherein the control means includes: means for controlling respective duty cycles of the fifth and sixth AC switches.

Claim 6

Dependent Claim 24 words

The AC/AC converter of claim 1, wherein the control means includes: means for controlling respective pulse phases of the fifth and sixth AC switches.

Claim 7

Dependent Claim 31 words

The AC/AC converter of claim 1, wherein the control means includes: means for controlling duty cycles of either the first pair of AC switches or the second pair of AC switches.

Claim 8

Dependent Claim 35 words

The AC/AC converter of claim 1, wherein: a first output end constitutes a full-wave-rectified output of two ends of the secondary winding; and a second output end is the center point of the secondary winding.

Claim 9

Dependent Claim 24 words

The AC/AC converter of claim 1, wherein: an output of the AC/AC converter is combined with an AC input to provide a composite output.

Claim 10

Dependent Claim 16 words

The AC/AC converter of claim 1, wherein: plural AC/AC converters are applied to a three-phase circuit.

Claim 11

Dependent Claim 299 words

An AC-AC/DC converter comprising: a first AC switch and a second AC switch connected in series, and a third AC switch and a fourth AC switch connected in series, all of said switches being connected in parallel across a first end and a second end of an AC input; a transformer having a primary winding and a secondary winding, a first end of said primary winding connected between said first AC switch and said second AC switch, and a second end of said primary winding connected between said third AC switch and said fourth AC switch; a fifth AC switch having a first end and a second end, the first end connected to a first end of said secondary winding; a sixth AC switch having a first end and a second end, said first end connected to a second end of said secondary winding; a first end of an output formed by connecting said second end of said fifth switch and said second end of said sixth switch, and a second end of the output formed by a center point of said secondary winding; control means for alternately operating, at a frequency higher than an input frequency, a first set of said first AC switch, said third AC switch and said fifth AC switch, and a second set of said second AC switch, said fourth AC switch and said sixth AC switch; two capacitors connected in series and disposed at a position closer to said AC input than are said AC switches and between said first end and said second end of said AC input; and switching means for selectively connecting said first end of said primary winding to one of a connecting point of said two capacitors, and a connecting point of said first and second AC switches.

Claim 12

Dependent Claim 299 words

An AC-AC/DC converter comprising: a first AC switch and a second AC switch connected in series, and a third AC switch and a fourth AC switch connected in series, all of said switches being connected in parallel across a first end and a second end of an AC input; a transformer having a primary winding and a secondary winding, a first end of said primary winding connected between said first AC switch and said second AC switch, and a second end of said primary winding connected between said third AC switch and said fourth AC switch; a fifth AC switch having a first end and a second end, the first end connected to a first end of said secondary winding; a sixth AC switch having a first end and a second end, said first end connected to a second end of said secondary winding; a first end of an output formed by connecting said second end of said fifth switch and said second end of said sixth switch, and a second end of the output formed by a center point of said secondary winding; control means for alternately operating, at a frequency higher than an input frequency, a first set of said first AC switch, said third AC switch and said fifth AC switch, and a second set of said second AC switch, said fourth AC switch and said sixth AC switch; two capacitors connected in series and disposed at a position closer to said AC input than are said AC switches and between said first end and said second end of said AC input; and switching means for selectively connecting said first end of said primary winding to one of a connecting point of said two capacitors, and a connecting point of said first and second AC switches.

Claim 13

Dependent Claim 51 words

The AC-AC/DC converter as set forth in claim 11, wherein said control means reverses operation of said fifth AC switch and said sixth AC switch when the AC input shifts from a positive half cycle to a negative half cycle, or from a negative half cycle to a positive half cycle.

Claim 14

Dependent Claim 28 words

The AC-AC/DC converter as set forth in claim 11, wherein said control means performs pulse phase modulation control for said fifth AC switch and said sixth AC switch.

Claim 15

Dependent Claim 28 words

The AC-AC/DC converter as set forth in claim 11, wherein an AC output obtained by the converter is combined with an AC input to produce a composite output.

Claim 16

Dependent Claim 140 words

The AC-AC/DC converter as set forth in claim 11 wherein when an AC input having a positive phase and a negative phase is applied, an output AC voltage is controlled to have a value in a range from a maximum value of the positive phase, passing through zero, to a maximum value of the negative phase by using pulse phase modulation between the first, second, third and fourth AC switches and the fifth and sixth AC switches; and wherein, when a DC input is applied, an output DC voltage can be continuously varied to have a value in a range from a maximum value of positive polarity, passing through zero, to a maximum value of negative polarity, by phase controlling a driving pulse phase of said first, second, third, fourth, fifth and sixth AC switches between 0 and 180 degrees.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	2003-05-23	2003-11-22	2004-05-23	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	2007-05-23	2007-11-22	2008-05-23	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	2011-05-23	2011-11-22	2012-05-23	$7700.00	Window Closed / Lapsed

AC-AC/DC converter

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