US3867643A
Expired / Lapsed
US
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Electric power converter
Assignee: Massachusetts Institute of Technology
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Filing: 1974-01-14
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Granted: 1975-02-18
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Expires: 1994-01-14
Abstract
Abstract A programmed switching system for converting direct current into alternating current or some other variable current, or for converting alternating current of one frequency into alternating current of another frequency. The system employs a number of stages connected in cascade. Each stage includes an electrical energy source or an electrical energy storage unit and switch means adapted to bypass the energy source or storage unit, to interconnect the source or storage unit with other electrical energy source or storage units across a load in a programmed fashion, and to reverse the direction of current flow in the load to apply, for example, a quasi-sinusoidal voltage across the load.
Inventors
- 👤 Richard H Baker
- 👤 Lawrence H Bannister
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 09:12
CPC Classifications
H; H02; H02M; H02M7/00; H02M7/42; H02M7/44; H02M7/48; H02M7/483; H02M7/49
Claims Analysis
Total Claims: 32
Claim 1
Independent Claim
138 words
An electric power system comprising a plurality of stages connected in cascade, each stage including, in combination: supply voltage means; first bilateral solid-state switch means connected between the supply voltage means and one terminal of the stage; and second bilateral solid-state switch means connected between the supply voltage means and another terminal of the stage, one terminal acting as input to the stage at one state of operation of the stage and the other terminal operating as output during said one state, the roles of the two terminals being reversed at another state of operation of the stage, the first switch means and the second switch means acting in combination to connect one side or the other of the supply voltage means to either terminal as alternate conditions of stage operation or to bypass the supply voltge means.
Claim 2
Dependent Claim
138 words
An electric power system comprising a plurality of stages connected in cascade, each stage including, in combination: supply voltage means; first bilateral solid-state switch means connected between the supply voltage means and one terminal of the stage; and second bilateral solid-state switch means connected between the supply voltage means and another terminal of the stage, one terminal acting as input to the stage at one state of operation of the stage and the other terminal operating as output during said one state, the roles of the two terminals being reversed at another state of operation of the stage, the first switch means and the second switch means acting in combination to connect one side or the other of the supply voltage means to either terminal as alternate conditions of stage operation or to bypass the supply voltge means.
Claim 3
Dependent Claim
90 words
An electric power system as claimed in claim 1 in which the supply voltage means is a d-c source of electric energy in each stage, the first switch means and the second switch means acting, in combination, to connect the positive side of the d-c source to one terminal or the other of the stage as alternate conditions of stage operations while simultaneously connecting the negative side of the d-c source respectively to said other terminal and said one terminal, or said switch means acting to bypass the d-c source.
Claim 4
Dependent Claim
51 words
An electric power system as claimed in claim 2 that further includes logic control means to establish logical sequencing of the first switch means and the second switch means to provide an a-c output from the system, said a-c output being effected by combining the d-c sources in a determined sequence.
Claim 5
Dependent Claim
96 words
An electric power system as claimed in claim 3 in which the first switch means in each stage comprises a set of two semiconductor switches and the second switch means in each stage comprises a set of two semiconductor switches, one switch in each set acting to conneCt the positive side of the d-c source to one or the other of the two terminals of the stage and the other switch of each set acting to connect the negative side of the d-c source to one or the other of the two terminals of the stage.
Claim 6
Dependent Claim
83 words
An electric system as claimed in claim 4 in which the set of two semiconductor switches forming the first switch means act in pairs in that one switch of the set turns ON when the other switch of the set turns OFF and vice versa, and in which the set of two semiconductor switches forming the second switch means act in pairs in that one switch of the set turns ON when the other switch of the set turns OFF and vice versa.
Claim 7
Dependent Claim
64 words
An electric system as claimed in claim 5 in which the logic control means switches each of the four switches in a stage individually, thereby connecting the positive side of the d-c source or the negative side of the d-c source in each stage to either terminal or effecting a bypass of the d-c source in a stage to provide an a-c system output.
Claim 8
Dependent Claim
21 words
An electric system as claimed in claim 5 in which the a-c output is a close approximation of a sine wave.
Claim 9
Dependent Claim
34 words
An electric system as claimed in claim 7 in which the logic control means acts to vary the sequencing rate of the switch means thereby to vary the fundamental frequency of the a-c output.
Claim 10
Dependent Claim
56 words
An electric system as claimed in claim 7 that consists of two stages connected in cascade, in which the d-c voltage of the source in one stage is about 2Vp/3, where Vp is the peak voltage of the sine wave, and in which the d-c voltage of the source in the other stage is about Vp/3.
Claim 11
Dependent Claim
48 words
An electric power system as claimed in claim 9 in which the logic control means effects switching between one state of system operation and another state of system operation at predetermined time intervals which are determined to provide an acceptable level of harmonics in the output sine-wave approximation.
Claim 12
Dependent Claim
18 words
An electric power system as claimed in claim 10 in which the sequencing pattern for one cycle is
Claim 13
Dependent Claim
55 words
An electric power system as claimed in claim 7 that consists of three stages connected in cascade, in which the d-c voltage of the source in one stage is about Vp/2, in another stage is about Vp/3 and in the other stage is about Vp/6, where Vp is the peak voltage of the sine wave.
Claim 14
Dependent Claim
18 words
An electric power system as claimed in claim 7 that comprises more than three stages connected in cascade.
Claim 15
Dependent Claim
102 words
An electric power system stage having an input and an output, said stage including: supply voltage means; first bilateral solid-state switch means; and second bilateral solid-state switch means, the first switch means and the second switch means acting in combination to connect the supply voltage means between the input and the output and to effect a bypass of the supply voltage means as well as to effect reversal of the polarity of the supply voltage means connection within the stage, thereby to effect a change of roles of the input and the output of the system as alternate conditions of system operation.
Claim 16
Dependent Claim
102 words
An electric power system stage having an input and an output, said stage including: supply voltage means; first bilateral solid-state switch means; and second bilateral solid-state switch means, the first switch means and the second switch means acting in combination to connect the supply voltage means between the input and the output and to effect a bypass of the supply voltage means as well as to effect reversal of the polarity of the supply voltage means connection within the stage, thereby to effect a change of roles of the input and the output of the system as alternate conditions of system operation.
Claim 17
Dependent Claim
100 words
An electric power system stage having an input and an output, said stage including: supply voltage means; first bilateral switch means; and second bilateral switch means, the first switch means and the second switch means acting in combination to connect the supply voltage means between the input and the output and to effect a bypass of the supply voltage means as well as to effect reversal of the polarity of the supply voltage means connection within the stage, thereby to effect a change of roles of the input and the output of the system as alternate conditions of system operation.
Claim 18
Dependent Claim
100 words
An electric power system stage having an input and an output, said stage including: supply voltage means; first bilateral switch means; and second bilateral switch means, the first switch means and the second switch means acting in combination to connect the supply voltage means between the input and the output and to effect a bypass of the supply voltage means as well as to effect reversal of the polarity of the supply voltage means connection within the stage, thereby to effect a change of roles of the input and the output of the system as alternate conditions of system operation.
Claim 19
Dependent Claim
107 words
An electric system that comprises a plurality of stages connected in cascade, each stage of the plurality of stages having an input and an output and including supply voltage means, first bilateral switch means, and second bilateral switch means, the first bilaterial switch means and the second bilateral switch means acting in combination such that the input and output are connected together and therefore at equal potential or that the supply voltage means is connected between the input and the output such that the output is positive with respect to the input or the output is negative with respect to the input as conditions of system operations.
Claim 20
Dependent Claim
107 words
An electric system that comprises a plurality of stages connected in cascade, each stage of the plurality of stages having an input and an output and including supply voltage means, first bilateral switch means, and second bilateral switch means, the first bilaterial switch means and the second bilateral switch means acting in combination such that the input and output are connected together and therefore at equal potential or that the supply voltage means is connected between the input and the output such that the output is positive with respect to the input or the output is negative with respect to the input as conditions of system operations.
Claim 21
Dependent Claim
31 words
An electric system as claimed in claim 16 in which the the supply voltage means in each stage comprises battery means and that further includes means for charging the battery means.
Claim 22
Dependent Claim
26 words
An electric system as claimed in claim 17 in which the means for charging comprises a source of alternating current connected to charge the battery means.
Claim 23
Dependent Claim
53 words
An electric system as claimed in claim 18 in which the source of alternating current is a source of variable frequency alternating current and that further includes control means that controls the first bilateral switch means and the second bilateral switch means to supply as system output an alternating current of another frequency.
Claim 24
Dependent Claim
28 words
An electric system as claimed in claim 19 in which the control means acts to vary the frequency of the output of the alternating current from the system.
Claim 25
Dependent Claim
19 words
An electric system as claimed in claim 20 in combination with like systems, interconnected to provide a variable-frequency output.
Claim 26
Dependent Claim
20 words
The combination as claimed in claim 21 in which the systems are connected in parallel to provide said variable-frequency output.
Claim 27
Dependent Claim
23 words
The combination as claimed in claim 21 in which the systems are connected in a polyphase connection to provide a variable-frequency polyphase output.
Claim 28
Dependent Claim
34 words
The combination as claimed in claim 23 that further includes a polyphase motor connected to receive the variable-frequency polyphase output and to operate at variable speed as a consequence of variation in the frequency.
Claim 29
Dependent Claim
33 words
A system as claimed in claim 16 that further includes control means to control the first bilateral switch means and the second bilateral switch emasn to give a system output that is a-c.
Claim 30
Dependent Claim
16 words
A system as claimed in claim 25 in which the system output is variable in frequency.
Claim 31
Dependent Claim
109 words
Electrical apparatus that comprises a plurality of electrical systems connected in cascade, each said system comprising a plurality of stages connected in cascade, each of the plurality of stages having an input and an output and including supply voltage means, first switch means, and second switch means, means whereby the first switch means and the second switch means are operable to connect the supply voltage means between the input and the output of the stage such that the input and the output can be at equal potential or the output caN be positive with respect to the input or the output can be negative with respect to the input.
Claim 32
Dependent Claim
109 words
Electrical apparatus that comprises a plurality of electrical systems connected in cascade, each said system comprising a plurality of stages connected in cascade, each of the plurality of stages having an input and an output and including supply voltage means, first switch means, and second switch means, means whereby the first switch means and the second switch means are operable to connect the supply voltage means between the input and the output of the stage such that the input and the output can be at equal potential or the output caN be positive with respect to the input or the output can be negative with respect to the input.
References Cited (Backward Citations)
US3748492A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-02-17 | 1978-08-19 | 1979-02-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-02-17 | 1982-08-19 | 1983-02-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-02-17 | 1986-08-19 | 1987-02-18 | $7700.00 | Window Closed / Lapsed |