US3757321A
Expired / Lapsed
US
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Transducer drive apparatus and method
Assignee: Inductosyn Corp
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Filing: 1971-12-27
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Granted: 1973-09-04
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Expires: 1991-12-27
Abstract
Abstract Disclosed is a power drive circuit for driving loads such as the sine and cosine windings of a position-measuring transformer. The windings of the transformer are driven bilaterally by convertercontrolled drive circuits with substantially constant magnitude currents in both directions for selected durations to produce pulse-width modulated signals. Unwanted signals due to undesired cross coupling between sine and cosine windings are avoided by providing a constant power drain from the power source which is connected in common to all of the drive circuits. To avoid the presence of undesired even harmonic signal components, the load is supplied with a bilateral current which is symmetrical over each cycle.
Inventors
- 👤 R Tripp
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 21:17
CPC Classifications
G; G08; G08C; G08C19/00; G08C19/38; G08C19/46; H; H03; H03M; H03M1/00; H03M1/12; H03M1/48; H03M1/485
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
245 words
An apparatus for supplying electrical signals having a cycle 1/F to bilaterally drive a load comprising, a first drive circuit connected to one side of said load and a second drive circuit connected to the other side of said load, each drive circuit selectably energizable in first and second conduction states, a power source connected to conduct current through said device circuits to energize said load, means for selecting said drive circuits in said first conduction states for a first duration of each cycle to produce a substantially constant current for said first duration through said load in one direction and in second conduction states for a second duration of each cycle to produce a substantially constant current for said second duration through said load in the opposite direction, wherein said means for selecting includes means for maintaining said first duration equal to said second duration whereby said signals contain substantially only the odd harmonics of the fundamental frequency F, an alternate load, a third drive circuit selectably energizable in third and fourth conduction states, said third drive circuit coperative to energize said alternate load with the current from said power source when in said third conduction state, logic means for selecting said third drive circuit in said third conduction state when said first and second drive circuits have the same conduction state, said load and said alternate load together drawing a constant current from said power source for the full duration of each cycle.
Claim 2
Independent Claim
245 words
An apparatus for supplying electrical signals having a cycle 1/F to bilaterally drive a load comprising, a first drive circuit connected to one side of said load and a second drive circuit connected to the other side of said load, each drive circuit selectably energizable in first and second conduction states, a power source connected to conduct current through said device circuits to energize said load, means for selecting said drive circuits in said first conduction states for a first duration of each cycle to produce a substantially constant current for said first duration through said load in one direction and in second conduction states for a second duration of each cycle to produce a substantially constant current for said second duration through said load in the opposite direction, wherein said means for selecting includes means for maintaining said first duration equal to said second duration whereby said signals contain substantially only the odd harmonics of the fundamental frequency F, an alternate load, a third drive circuit selectably energizable in third and fourth conduction states, said third drive circuit coperative to energize said alternate load with the current from said power source when in said third conduction state, logic means for selecting said third drive circuit in said third conduction state when said first and second drive circuits have the same conduction state, said load and said alternate load together drawing a constant current from said power source for the full duration of each cycle.
Claim 3
Dependent Claim
79 words
The apparatus of claim 1 wherein said means for selecting includes, means for maintaining said first and second drive circuits in said first and second conduction states for the full duration of each cycle whereby the current supplies by said power source to said load is of substantially constant magnitude and is in one direction through said load when in said first conduction states and is in the other direction through said load when in said second conduction states.
Claim 4
Dependent Claim
57 words
The apparatus of Claim 1 wherein said means for selecting includes first and second cyclically stepped counters producing counter output signals having a phase shift, logic means responsive to the phase shift between said counter output signals to control the conduction state of said drive circuits and produce a pulse-width modulation of the current through said load.
Claim 5
Dependent Claim
49 words
The apparatus of claim 1 wherein said load comprises sine and cosine windings of a position-measuring transformer on one member, and said transformer having a scale winding on another member, said members relatively movable with respect to each other and said windings electrically coupled to define a space cycle.
Claim 6
Dependent Claim
176 words
Transducer drive apparatus comprising, first and second bistate drive circuits, a common power source for said drive circuits, said drive circuits being connected respectively at oppositE ends of a primary load consisting of the sine and cosine windings of a position-measuring transformer, means providing control signals, logic gates responsive to said control signals to maintain said drive circuits in first or in second opposite states, a change from first opposite states to second opposite states of said drive circuits changing the direction of current in the load without altering the amount of current supplied from said source to said load, the resultant current drive signal in said load having a pulse-width modulated rectangular form having a modulation resulting from controlling the time at which said drive circuits change back and forth between said first and second opposite states, and an alternate load and drive circuit for each of said windings, whereby each of said windings draws substantially constant power from said power source so that substantially no cross modulation occurs between said sine and cosine windings.
Claim 7
Dependent Claim
176 words
Transducer drive apparatus comprising, first and second bistate drive circuits, a common power source for said drive circuits, said drive circuits being connected respectively at oppositE ends of a primary load consisting of the sine and cosine windings of a position-measuring transformer, means providing control signals, logic gates responsive to said control signals to maintain said drive circuits in first or in second opposite states, a change from first opposite states to second opposite states of said drive circuits changing the direction of current in the load without altering the amount of current supplied from said source to said load, the resultant current drive signal in said load having a pulse-width modulated rectangular form having a modulation resulting from controlling the time at which said drive circuits change back and forth between said first and second opposite states, and an alternate load and drive circuit for each of said windings, whereby each of said windings draws substantially constant power from said power source so that substantially no cross modulation occurs between said sine and cosine windings.
Claim 8
Independent Claim
435 words
An apparatus for supplying electrical signals having a cycle 1/F to bilaterally drive a position-measuring transformer having sine and cosine windings on one member and having a scale winding on another member, said members relatively movable with respect to each other and said windings electrically coupled to define a space cycle, a converter for dividing said space cycle into N parts, said converter being responsive to a stored digital value ''''n'''', between O and N, to form sine and cosine pulse-width modulated drive signals for energizing said sine and cosine windings, respectively, said signals including fundamental frequency components having an electrical cycle 1/F and having an amplitude proportional to sine theta and cosine theta , respectively, where theta equals (''''n''''/N) 360*, the improvement comprising, a plurality of drive circuits, each selectably energizable in two opposite conduction states, said drive circuits including first and second drive circuits connected, respectively, at opposite ends of the sine winding, and including third and fourth drive circuits connected, respectively, at opposite ends of said cosine winding, a power source connected to said drive circuits for energizing said sine and cosine windings, first logic means for selecting said first and second drive circuits in opposite conduction states for a first duration of each electrical cycle to produce a current through said sine winding in one direction, and for switching the states of said first and second drive circuits to produce a current through said sine winding in the opposite direction for a second duration of each cycle, second logic means for selecting said third and fourth drive circuits in opposite conduction states for a third duration of each electrical cycle to produce a current through said cosine winding in one direction, and for switching the states of said third and fourth drive circuits to produce a current through said cosine winding in the opposite direction for a fourth duration of each cycle, said first logic means including a first alternate NAND gate for receiving the output signals from said first NAND gate and said first OR gate to produce an output to an alternate drive circuit which drives a first alternate load whereby the power output from said power source to said cosine winding and said first alternate load is a constant, said second logic means including second alternate NAND gate for receiving the output signals from said second NAND gate and said second OR gate to produce an output to a second alternate drive circuit which drives a second alternate load whereby the power output from said power source to said sine winding and said alternate load is a constant.
Claim 9
Independent Claim
435 words
An apparatus for supplying electrical signals having a cycle 1/F to bilaterally drive a position-measuring transformer having sine and cosine windings on one member and having a scale winding on another member, said members relatively movable with respect to each other and said windings electrically coupled to define a space cycle, a converter for dividing said space cycle into N parts, said converter being responsive to a stored digital value ''''n'''', between O and N, to form sine and cosine pulse-width modulated drive signals for energizing said sine and cosine windings, respectively, said signals including fundamental frequency components having an electrical cycle 1/F and having an amplitude proportional to sine theta and cosine theta , respectively, where theta equals (''''n''''/N) 360*, the improvement comprising, a plurality of drive circuits, each selectably energizable in two opposite conduction states, said drive circuits including first and second drive circuits connected, respectively, at opposite ends of the sine winding, and including third and fourth drive circuits connected, respectively, at opposite ends of said cosine winding, a power source connected to said drive circuits for energizing said sine and cosine windings, first logic means for selecting said first and second drive circuits in opposite conduction states for a first duration of each electrical cycle to produce a current through said sine winding in one direction, and for switching the states of said first and second drive circuits to produce a current through said sine winding in the opposite direction for a second duration of each cycle, second logic means for selecting said third and fourth drive circuits in opposite conduction states for a third duration of each electrical cycle to produce a current through said cosine winding in one direction, and for switching the states of said third and fourth drive circuits to produce a current through said cosine winding in the opposite direction for a fourth duration of each cycle, said first logic means including a first alternate NAND gate for receiving the output signals from said first NAND gate and said first OR gate to produce an output to an alternate drive circuit which drives a first alternate load whereby the power output from said power source to said cosine winding and said first alternate load is a constant, said second logic means including second alternate NAND gate for receiving the output signals from said second NAND gate and said second OR gate to produce an output to a second alternate drive circuit which drives a second alternate load whereby the power output from said power source to said sine winding and said alternate load is a constant.
Claim 10
Dependent Claim
86 words
The apparatus of claim 6 wherein, said first logic means comprises means for maintaining said first duration and said second duration equal to the full electrical cycle 1/F, said second logic means comprises means for maintaining the sum of said third duration and said fourth duratiOn equal to the full electrical cycle 1/F, whereby the power drawn by said sine winding is a constant and the power drawn by said cosine winding is a constant thereby preventing cross coupling between the sine and cosine drive signals.
Claim 11
Dependent Claim
184 words
The apparatus of claim 6 wherein said converter includes first and second counters cyclically stepped through a count range representing N/2, said first and second counters each terminating in two parallel divide-by-two stages where one stage receives the inverted output of the other, said stages for each counter providing a counter output signal and a 90-degree phase-shifted counter output signal, said first logic means connected to receive the 90-degree phase-shifted counter output signals as inputs to a first logical NAND gate and a first logical OR gate for energizing said first and second drive circuits, respectively, making said first duration equal to said second duration and forming the pulse-width modulated cosine drive signal with substantially no even harmonics of the fundamental frequency F, said second logic means connected to receive the counter output signals as input to a second logical NAND gate and a second logical OR gate for energizing said third and fourth drive circuits, respectively, making said third duration equal to said fourth duration and forming the pulse-width modulated sine drive signal having substantially no even harmonics of the fundamental frequency F.
Claim 12
Dependent Claim
82 words
The apparatus of claim 6 wherein, said first logic means comprises means for maintaining said first duration equal to said second duration, said second logic means comprises means for maintaining said third duration equal to said fourth duration, whereby the current magnitude and duration in one direction through each of said windings equals the current magnitude and duration in the opposite direction through each of said windings, respectively, thereby providing drive signals with substantially no even harmonics of the fundamental frequency F.
Claim 13
Dependent Claim
114 words
The apparatus of claim 9 further including, a first alternate load and drive circuit for conducting current from said power source for the duration 1/F minus said first duration and minus said second duration, a second alternate load and drive circuit for conducting current from said power source for the duration 1/F minus said third duration and minus said fourth duration, whereby the power drawn by said sine winding and said first alternate load is a constant and the power drawn by said cosine winding and said second alternate load is a constant, thereby preventing fluctuations in the output from said power source and preventing cross coupling between the sine and cosine drive signals.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-09-03 | 1977-03-05 | 1977-09-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-09-03 | 1981-03-05 | 1981-09-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-09-03 | 1985-03-05 | 1985-09-04 | $7700.00 | Window Closed / Lapsed |