US3839667A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Inverters
Assignee: Siemens Mobility Ltd
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Filing: 1972-07-03
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Granted: 1974-10-01
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Expires: 1992-07-03
Abstract
Abstract A polyphase, floating neutral, inverter in which harmonics of the operating frequency are added to the fundamental to increase the line-to-line output voltage for a given input voltage. In the three-phase three-wire case the Triplen harmonics are used. The inverter uses single phase amplifiers and a polyphase drive signal generator. One generator is described in detail. The inverter also includes a rapid acting semiconductor device protection circuit which employs an electrical network analog of the thermal characteristics of the device.
Inventors
- 👤 K King
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 20:36
CPC Classifications
H; H02; H02M; H02M7/00; H02M7/42; H02M7/44; H02M7/48; H02M7/53; H02M7/537; H02M7/5387; H02M7/53871; H02M7/53875
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
122 words
An inverter arrangement comprising inverter means including input terminals for connection to a d.c. source, and output terminals, for supplying a three-wire, three-phase sinusoidal alternating current output, and a drive signal generator for generating a drive signal for said inverter means which includes the fundamental frequency of said alternating current output and 3x harmonics thereof, where x is a positive integer; said inverter means including means responsiVe to said drive signal for amplifying said signal waveform to the amplitude of the d.c. source so that each phase output waveform includes harmonic components which in conjunction with the harmonic components of the other phase voltages provide a sinusoidal line-to-line waveform of higher value than that formed by the fundamental of each phase voltage.
Claim 2
Dependent Claim
122 words
An inverter arrangement comprising inverter means including input terminals for connection to a d.c. source, and output terminals, for supplying a three-wire, three-phase sinusoidal alternating current output, and a drive signal generator for generating a drive signal for said inverter means which includes the fundamental frequency of said alternating current output and 3x harmonics thereof, where x is a positive integer; said inverter means including means responsiVe to said drive signal for amplifying said signal waveform to the amplitude of the d.c. source so that each phase output waveform includes harmonic components which in conjunction with the harmonic components of the other phase voltages provide a sinusoidal line-to-line waveform of higher value than that formed by the fundamental of each phase voltage.
Claim 3
Dependent Claim
114 words
An arrangement as claimed in claim 1 in which the means responsive to the drive signal comprises an electrical power conversion circuit responsive to a control signal having an alternating waveform to produce an output of alternating potential from a source of unidirectional potential, said conversion circuit including means responsive to a zero of the control waveform for interrupting a supply path between the said source and one output terminal for an interval when said zero does not coincide with a current zero in said supply path, and means for completing an alternative current path across the output terminals of the circuit for a period between the control signal zero and the current zero.
Claim 4
Dependent Claim
63 words
An arrangement as claimed in claim 1 wherein said drive signal generator includes, in an oscillatory loop, an integrator for each phase for generating a three-phase four-wire output at the fundamental of the alternating current together with means for combining a portion of the peak of each phase waveform as a 3x harmonic signal to displace the neutral point of said three-phase signal.
Claim 5
Dependent Claim
92 words
A generator as claimed in claim 3 in which the means for combining said peak waveforms includes a voltage sensitive network, a common load resistor connected at the remote end to a reference voltage and at the adjacent end to a neutral connection, and unidirectional paths for supplying the peak of each phase waveform, in turn, to said voltage sensitive network to permit only the waveform above a selected value to pass to said common load resistor whereby the neutral connection to the adjacent end of said load resistor is so displaced.
Claim 6
Dependent Claim
23 words
A generator as claimed in claim 4 in which the voltage sensitive network includes a Zener diode for setting the selected voltage value.
Claim 7
Dependent Claim
31 words
A generator as claimed in claim 4 in which the voltage sensitive network comprising a limiter including means to adjust the symmetry of the limiter with respect to the reference voltage.
Claim 8
Dependent Claim
97 words
An inverter arrangement as claimed in claim 1 and including a protection circuit for a semi-conductor device in the inverter means including means responsive to the instantaneous values of current in and voltage across the device to produce a signal representing the instantaneous power dissipation in the device when operated in the linear mode, an electrical network for simulating the thermal characteristics of the device over a range of time intervals and means responsive to the output of said network when supplied with said signal for indicating whether or not an allowable thermal operating condition is exceeded.
Claim 9
Dependent Claim
43 words
An inverter arrnagement as claimed in claim 7 in which said means for producing the signal representing the instantaneous power compirses means for approximating this signal based on the sum of signals proportional to the instantaneous voltage and instantaneous current at the device.
Claim 10
Dependent Claim
47 words
An inverter arrangement as claimed in claim 7 in which the electrical network comprises a combination of electrical wave-shaping circuit elements for simulating the variation of the relative thermal impedance of the device with the variation of the pulse form of a signal applied to the device.
Claim 11
Dependent Claim
23 words
An inverter arrangement as claimed in claim 9 in which the electrical network includes the circuit elements of a step and a time-constant.
Claim 12
Dependent Claim
27 words
An arrangement as claimed in claim 1 in which the means responsive to the drive signal comprises a class B amplifier for each phase of the output.
Claim 13
Dependent Claim
44 words
An arrangement as claimed in 1 including an output transformer for each means responsive to the drive signal to isolate the output terminals from said means and to ensure tHat there is no direct current path from any input terminal to any output terminal.
Claim 14
Dependent Claim
36 words
An arrangement as claimed in claim 1 in which the output terminals are connected to a delta-star transformer so that the star-point of the transformer secondary provides the neutral terminal for a three-phase four-wire a.c. output.
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) | 1977-09-30 | 1978-04-01 | 1978-10-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-09-30 | 1982-04-01 | 1982-10-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-09-30 | 1986-04-01 | 1986-10-01 | $7700.00 | Window Closed / Lapsed |