US3916285A
Expired / Lapsed
US
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Generation of gate pulses for control of PWM thyristor inverter
Assignee: Shinko Electric Co Ltd
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Filing: 1974-09-11
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Granted: 1975-10-28
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Expires: 1994-09-11
Abstract
Abstract A set of timed gate pulse series for control of a PWM thyristor inverter is generated through the steps of generating three phased series of triangular waveform signals the repetition frequencies of which are proportional to the level of an input command and have a ratio therebetween of 4:2:1, level-comparing the three series of triangular waveform signals with the input command and, on the basis of crossover points therebetween, generating three series of pulses having a pulse width ratio therebetween of 1:2:4, selecting one of the three series of the generated pulses depending upon the level of the input command, and converting the selected series of pulses to a set of desired timed gate pulse series for control of the PWM thyristor inverter.
Inventors
- 👤 Masahiko Iwata
- 👤 Hitoshi Kawano
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 11:17
CPC Classifications
H; H02; H02M; H02M7/00; H02M7/42; H02M7/44; H02M7/48; H02M7/505; H02M7/515; H02M7/525; H02M7/527
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
252 words
An apparatus for generating gate pulses for control of a PWM thyristor inverter in response to an input command of level variable designating the inverter output frequency, comprising a. three triangular waveform signal generators responsive to the input command to generate three phased series of triangular waveform signals the repetition frequencies of which are proportional to the level of the input command and which have the ratio therebetween of 4:2:1, b. three comparators for comparing in terms of level the corresponding triangular waveform signal series provided by said generators with the input command to generate corresponding three series of pulses on the basis of crossover points therebetween of which the pulse width ratio therebetween is 1:2:4, c. a zone selector circuit for comparing the input command with predetermined zone set levels defining three operation zones to provide a bit signal identifying which one of the three operation zones is to be assumed by the inverter, d. a matrix circuit responsive to the bit signal provided by said zone selector circuit to gate one of the three pulse series provided by said three comparators in accordance with the identified operation zone, e. a counter and decoder responsive to a clock signal provided by one of said three generators to generate a set of timing reference signals, and f. means for converting in response to the reference timing signals provide by said counter and decoder the gated pulse series provided by said matrix circuit to desired gate pulse series for control of the inverter.
Claim 2
Independent Claim
252 words
An apparatus for generating gate pulses for control of a PWM thyristor inverter in response to an input command of level variable designating the inverter output frequency, comprising a. three triangular waveform signal generators responsive to the input command to generate three phased series of triangular waveform signals the repetition frequencies of which are proportional to the level of the input command and which have the ratio therebetween of 4:2:1, b. three comparators for comparing in terms of level the corresponding triangular waveform signal series provided by said generators with the input command to generate corresponding three series of pulses on the basis of crossover points therebetween of which the pulse width ratio therebetween is 1:2:4, c. a zone selector circuit for comparing the input command with predetermined zone set levels defining three operation zones to provide a bit signal identifying which one of the three operation zones is to be assumed by the inverter, d. a matrix circuit responsive to the bit signal provided by said zone selector circuit to gate one of the three pulse series provided by said three comparators in accordance with the identified operation zone, e. a counter and decoder responsive to a clock signal provided by one of said three generators to generate a set of timing reference signals, and f. means for converting in response to the reference timing signals provide by said counter and decoder the gated pulse series provided by said matrix circuit to desired gate pulse series for control of the inverter.
Claim 3
Dependent Claim
55 words
An apparatus as set forth in claim 1, further including g. a biasing circuit receiving the input command for modifying the level of the input command at and around the lower limit frequency of the inverter operation frequency range to supply the thus modified input command to said three comparators and said zone selector circuit.
Claim 4
Dependent Claim
67 words
An apparatus as set forth in claim 1, wherein said counter and decoder generates three sets of reference timing signals corresponding to three phases, and said converting means are operable in response to the three sets of reference timing signals to convert the gated pulse series provided by said matrix circuit to three sets of desired gate pulse series for control of a three-phase PWM thyristor inverter.
Claim 5
Dependent Claim
34 words
An apparatus as set forth in claim 1, wherein the number of inverter output voltage pulses per half cycle is nine, five and three in correspondence with low, medium and high frequency operation zone.
Claim 6
Dependent Claim
35 words
An apparatus as set forth in claim 4, wherein the number of inverter output voltage pulses per half cycle is one if the input command designates an inverter frequency higher than the three operation zones.
Claim 7
Dependent Claim
31 words
An apparatus as set forth in claim 1, wherein the inverter output voltage waveform has the quiescent interval of pi /6 in electric angle on either end of each half cycle.
Claim 8
Independent Claim
161 words
A method of generating gate pulses for control of a PWM thyristor inverter in response to an input command of level variable designating the inverter output frequency, comprising the steps of a. generating three phased series of triangular waveform signals of the same peak amplitude the repetition frequencies of which are propoRtional to the level of the input command with the repetition frequency ratio therebetween of 4:2:1, b. comparing in terms of level the three generated series of triangular waveform signals with the input command to generate three series of pulses on the basis of crossover points therebetween of which the pulse width ratio therebetween is 1: 2:4, c. selecting one of the three generated series of pulses in response to which one of three operation zones the input command designates, and d. converting the selected pulse series to desired gate pulses for control of the inverter on the basis of timing reference signals derived from the generated triangular waveform signals.
Claim 9
Independent Claim
161 words
A method of generating gate pulses for control of a PWM thyristor inverter in response to an input command of level variable designating the inverter output frequency, comprising the steps of a. generating three phased series of triangular waveform signals of the same peak amplitude the repetition frequencies of which are propoRtional to the level of the input command with the repetition frequency ratio therebetween of 4:2:1, b. comparing in terms of level the three generated series of triangular waveform signals with the input command to generate three series of pulses on the basis of crossover points therebetween of which the pulse width ratio therebetween is 1: 2:4, c. selecting one of the three generated series of pulses in response to which one of three operation zones the input command designates, and d. converting the selected pulse series to desired gate pulses for control of the inverter on the basis of timing reference signals derived from the generated triangular waveform signals.
Claim 10
Dependent Claim
47 words
A method as set forth in claim 7, wherein, before applying to the steps of comparing and of selecting, the input command is modified in level to increase the inverter output voltage mean value at and around the lower limit frequency of the inverter operation frequency range.
Claim 11
Dependent Claim
34 words
A method as set forth in claim 7, wherein the step of converting is effected so as to provide three desired sets of gate pulse series for control of a three-phase PWM thyristor inverter.
Claim 12
Dependent Claim
39 words
A method as set forth in claim 7, wherein the number of resulting inverter output pulses is nine, five or three per half cycle of the inverter operation frequency in correspondence with low, medium or high frequency operation zone.
Claim 13
Dependent Claim
42 words
A method as set forth in claim 7, wherein the desired gate pulse series generated in the step of converting have the quiescent interval of pi /6 in electric angle on either end of each half cycle of the inverter operation frequency.
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) | 1978-10-27 | 1979-04-28 | 1979-10-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-10-27 | 1983-04-28 | 1983-10-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-10-27 | 1987-04-28 | 1987-10-28 | $7700.00 | Window Closed / Lapsed |