High-voltage converter circuit

• US 4,203,151 A
• Filed: 09/21/1978
• Issued: 05/13/1980
• Est. Priority Date: 09/21/1978
• Status: Expired due to Term

• Current Assignee: Exxon Research and Engineering Company (Exxon Mobil Corporation)
• Original Assignee: Exxon Research and Engineering Company (Exxon Mobil Corporation)
• Inventors: Baker, Richard H.
• Primary Examiner(s): Miller, J. D.
• Assistant Examiner(s): Wong, Peter S.
• Application Number:
  US05/944,634
• Time in Patent Office: 600 Days
• Field of Search: 363/17, 363/41-43, 363/59-61, 363/131-132, 307/106-107, 307/110, 307/227, 307/241
• US Class Current: 363/43
• CPC Class Codes: H02M 1/007 Plural converter units in cascade push-pull DC/DC converters with pre-regulator H02M3/3374; DC-AC converters following a DC-DC stage including a high frequency transformer H02M7/4807; DC-AC converters following a DC-DC conversion stage generating periodically varying voltages H02M7/4826
• CPC Class Codes: H02M 7/487 Neutral point clamped inverters
• CPC Class Codes: H02M 7/501 sinusoidal output voltages being obtained by the combination of several pulse-voltages having different amplitude and width

Abstract

An inverter circuit includes a DC voltage supply having a plurality of voltage taps coupled via (1) a first plurality of diodes for unidirectional current flow therefrom to successive common connections between the upper half of a plurality of first transistors connected in cascade across the voltage supply, (2) a second plurality of diodes for unidirectional current flow therefrom to successive common connections between the upper half of a plurality of capacitors, of like number to the first transistors, connected in series and across the DC voltage supply via a pair of diodes providing unidirectional current between the voltage supply and capacitors, (3) a third plurality of diodes for unidirectional current flow thereto from successive common connections between the lower half of the plurality of first transistors, (4) a fourth plurality of diodes for unidirectional current flow thereto from the successive common connections between the lower half of the plurality of capacitors; and a plurality of second transistors connected in cascade across the series string of capacitors, their centralmost common connection being connected to an output terminal, individual ones of a fifth plurality of diodes being connected between successive common connections of the capacitors to and for unidirectional current flow (1) therefrom to the successive common connections between the upper half of, and (2) thereto from the successive common connections between the lower half, of the second transistors, the pluralities of first and second transistors being operable to different combinations of their conductive and nonconductive states for predetermined periods of time for producing a multitiered AC waveform at the output terminal.

Claims

1. An inverter circuit for converting DC voltages in a range between +NE volts into an AC voltage having a multitier waveform, where N is any integer number 1, 2, 3, 4, 5 . . . , comprising:

first and second terminals for receiving first and second operation voltages, respectively;

third, fourth and fifth terminals;

an output terminal;

a reference voltage terminal for connection to a point of reference potential;

a plurality of N first and N second switching means each having a main current conduction path, each being selectively operable to one of a first condition or a second condition, for opening and closing, respectively, their main current conduction path, the main current conduction path of said N first switching means being connected in series between said first and fourth terminals, the main current conduction paths of said N first and N second switching means being connected in series between said first and fourth, and second and fourth terminals, respectively;

a plurality of N first and N second electrical charge storage means connected in series between said third and fourth, and fourth and fifth terminals, respectively;

first unidirectional current means connected between and polarized for passing current from said first to said third terminals;

second unidirectional current means connected between and polarized for passing current from said fifth to said second terminals;

a plurality of (N-1) pairs of third and (N-1) pairs of fourth unidirectional current means, said (N-1) pairs of third unidirectional current means being connected individually in series between the common connection points of each succeeding different two of said plurality of N first switching devices, and the corresponding levels of common connection points relative to said third terminal of each succeeding different two of said plurality of N first electrical charge storage means, respectively, each pair of third unidirectional current means being polarized for permitting current to flow from their own common connection point to their associative common connection points of said N first switching means and said N first charge storage means, respectively, said (N-1) pairs of fourth unidirectional current means each being connected individually in series between the common connection points of each succeeding different two of said plurality of N second switching devices, and the corresponding levels of common connection points relative to said fourth terminal of said plurality of N second electrical charge storage means, respectively, each pair of fourth unidirectional current means being polarized for conducting current from their own common connection point to their associative common connection points of said N second switching means and said N second charge storage means, respectively;

a plurality of 2N third and 2N fourth switching means each having a main current conduction path, the main current conduction paths of said 2N third switching means being connected in series between said third and output terminals, the main current conduction paths of said 2N fourth switching means being connected in series between said output and fifth terinals, each one of said 2N third and 2N fourth switching means being selectively operable to one of a first condition or a second condition, for opening and closing, respectively, their main current conduction paths;

a plurality of (2N-1) fifth and (2N-1) sixth unidirectional current means, said (2N-1) fifth unidirectional means being individually connected between the common connection points of each succeeding different two of the series string of said N first and N second electrical charge storage means, and the corresponding levels of common connection points relative to said third terminal of each succeeding different two of said plurality of 2N third switching means, said (2N-1) fifth unidirectional means each being polarized for conducting current from the associative connection point in said string of N first and N second electrical charge storage means to their associative point in said series string of 2N third switching means, said (2N-1)sixth unidirectional means each being polarized for conducting current from their associative connection point in said string of 2N fourth switching means to their associative connection point in said string of said N first and N second electrical charge storage means;

DC voltage supply means connected between said first and second terminals, for supplying +2NE volts and -2NE volts to these terminals, respectively, and for individually applying progressively less positive fixed levels of voltage to the midpoints of each one of said (N-1) pairs of third unidirectional current means relative to said first terminal, the midpoints of said (N-1) pairs of fourth unidirectional current means relative to said fourth terminal being connected individually to like positioned midpoints of said (N-1) pairs of third unidirectional current means relative to said first terminal, said DC voltage supply means having a common point connected to said reference voltage terminal;

said pluralities of N first, N second, 2N third and 2N fourth switching means being operable to various combinations of their first and second conditions for producing substantially any practical AC voltage having a multitiered waveform with a peak-to-peak amplitude of up to +NE volts, and a predetermined frequency.

2. The inverter circuit of claim 1 wherein said N first and N second switching means consist of like conductivity transistors connected in cascode.

3. The inverter circuit of claim 1, wherein said 2N third and 2N fourth switching means consist of like conductivity transistors connected in cascode.

4. The inverter circuit of claim 1, wherein said first and second unidirectional current means each include a diode.

5. The inverter circuit of claim 1, wherein said (N-1) pairs of third and fourth unidirectional current means each include two diodes.

6. The inverter circuit of claim 1, wherein said (2N-1) fifth and sixth unidirectional current means each include a diode.

7. The inverter circuit of claim 1, wherein said plurality of N first and N second electrical charge storage means each include a capacitor.

8. A DC to AC converter circuit comprising:

first and second operating voltage terminals;

an output terminal;

a reference voltage terminal for connection to a point of reference potential;

a plurality of DC voltage supply means connected in series between and for applying positive and negative voltages to said first and second operating voltage terminals, respectively, the connections between said DC voltage supply means forming a plurality of nodal points, a substantially intermediate one of said nodal points being connected to said reference voltage terminal, thereby causing the polarity of the voltages at said nodal points between said reference voltage terminal and first operating voltage terminal to be positive, and between said reference voltage terminal and second operating voltage terminal to be negative, with respect to said point of reference potential;

a plurality of first single-pole-single-throw switching means connected in series between said first and second operating voltage terminals;

a plurality of electrical charge storage means connected in a series string, the number of said charge storage means being the same as the number of said plurality of first switching means, the common connection point between the centralmost two of the latter being connected to the common connection point between the centralmost two of the former;

a plurality of second single-pole-single-throw switching means connected in series with one another, the intermediate point of this series string of second switching means being connected to said output terminal, the number of said plurality of second switching means being twice that of said plurality of first switching means;

first unidirectional current means connected between and polarized for conducting current from said first operating terminal to one end of said series string of second single-pole-single-throw switching means, and to one end of said string of electrical charge storage means;

second unidirectional current means connected between and polarized for conducting current from the other ends of said series strings of second switching means and of electrical charge storage means to said second operating voltage terminal;

a plurality of third unidirectional current means, one less in number than one-half of said plurality of first switching means, individually connected between and polarized for passing current from substantially successive nodes of said plurality of series-connected DC voltage supply means, relative to said first operating terminal, to successive common connections between each successive two of said plurality of first switching means located between said first operating voltage terminal and the intermediate common connection of the former, and also relative to said first operating voltage terminal, respectively;

a plurality of fourth unidirectional current means, one less in number than one-half of said plurality of first switching means, individually connected between and polarized for passing current from successive common connections between each successive two of said plurality of first switching means located between the intermediate common connection of the latter and said second operating voltage terminal, relative to this intermediate common connection, to substantially successive nodes of said plurality of series-connected DC voltage supply means, relative to said first operating voltage terminal, respectively;

a plurality of fifth unidirectional current means, equal in number to said plurality of third unidirectional current means, individually connected between and polarized for passing current from substantially successive nodes of said plurality of series-connected DC voltage supply means, relative to said first operating terminal, to successive common connections between each successive two of the half of said plurality of electrical charge storage means relative to said first unidirectional current means, respectively;

a plurality of sixth unidirectional current means equal in number to said plurality of fourth unidirectional current means, individually connected between and polarized for passing current from the successive common connections between the other half of said plurality of electrical charge storage means relative to said second unidirectional circuit means, to the substantially successive nodes of said plurality of series-connected DC voltage supply means, relative to said second operating voltage terminal, respectively;

a plurality of seventh unidirectional current means, one less in number than one-half of said plurality of second switching means, individually connected between and polarized for passing current from the successive common connections between each successive two of said plurality of electrical charge storage means to the successive common connections between each successive two of the half of said plurality of second switching means located between said first unidirectional current means and said output terminal, relative to the connection point of said first unidirectional current means with one end of each one of said strings of electrical charge storage means and first unidirectional current means, respectively; and

a plurality of eighth unidirectional current means, one less in number than one-half of said plurality of second switching means, individually connected between and polarized for passing current from the successive common connections of the other half of said plurality of second switching means, relative to said output terminal, to the common connections between each successive two of said plurality of electrical charge storage means relative to the end thereof connected to said first unidirectional current means, respectively;

the individual ones of said pluralities of first and second single-pole-single-throw switching means being operable to different combinations of their open and closed circuit conditions for predetermined periods of time for producing a desired multitiered AC waveform at said output terminal for driving either one of resistive and reactive loads.

9. The converter circuit of claim 8, wherein said plurality of first single-pole-single-throw switching means includes a plurality of like-conductivity transistors connected in cascode.

10. The converter circuit of claim 8, wherein said plurality of electrical charge storage means each include a capacitor.

11. The converter circuit of claim 8, wherein said plurality of second single-pole-single-throw switching means includes a plurality of like-conductivity transistors connected in cascode.

12. The converter circuit of claim 8, wherein said first and second unidirectional current means each include a diode.

13. The converter circuit of claim 8, wherein each individual one of said pluralities of third through eighth unidirectional current means includes a diode.