US5060129A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of controlling three-phase, three-level inverter
Assignee: Mitsubishi Electric Corp
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Filing: 1991-01-08
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Granted: 1991-10-22
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Expires: 2011-01-08
Abstract
Abstract A method of controlling a three-phase, three-level inverter comprises the steps of: jugding whether the current of the output terminal of an inverter of the phase such that the electrical potential of the output terminal equals to the neutral-point terminal of the capacitor among three-output terminals of the inverter is in a positive direction in which current flows into a load connected to this output terminal or in a negative direction in which current flows from the load when another on/off mode having the same instantaneous space voltage vector as the instantaneous space voltage vector in a tentatively selected on/off mode exists; actually selecting the tentatively selected on/off mode if the result of the judgment is positive and actually selecting another on/off mode instead of the tenatively selected on/off mode when the result of the judgement is negative in the case where the electrical potential of the neutral-point terminal of the capacitor is above a preset upper-limit value; and actually selecting the tentatively selected on/off mode if the result of the judgment is negative and actually selecting another on/off mode instead of the tentatively selected on/off mode when the result of the judgment is positive in the case where the electrical potential of the neutral-point terminal of the capacitor is below a preset lower-limit value.
Inventors
- 👤 Takafumi Maruyama
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 16:52
CPC Classifications
H; H02; H02M; H02M7/00; H02M7/42; H02M7/44; H02M7/48; H02M7/483; H02M7/487
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
315 words
A method of controlling a three-phase, three-level inverter, in which a plurality of on/off modes are in turn switched in order to control an instantaneous space voltage vector determined by a combination of the electrical potentials of both terminals and the neutral-point terminal of the capacitor of said three-phase, three-level inverter comprising a DC voltage source, a capacitor both terminals of which connected to said DC voltage source and having a neutral-point terminal positioned between both of these terminals, and a plurality of switch elements connected to the section between both terminals and the neutral-point terminal of said capacitor and three output terminals of the inverter, comprising the steps of: judging whether the current of the output terminal of an inverter of the phase such that the electrical potential of the output terminal equals to that of the neutral-point terminal of said capacitor among three-output terminals of said inverter is in a positive direction in which current flows into a load connected to this output terminal or in a negative direction in which current flows from the load when another on/off mode having the same instantaneous space voltage vector as the instantaneous space voltage vector in a tentatively selected on/off mode exists; actually selecting the tentatively selected on/off mode if the result of said judgment is positive and actually selecting another on/off mode instead of the tentatively selected on/off mode when the result of said judgment is negative in the case where the electrical potential of the neutral-point terminal of said capacitor is above a preset upper-limit value; and actually selecting the tentatively selected on/off mode if the result of said judgment is negative and actually selecting another on/off mode instead of the tentatively selected on/off mode when the result of said judgment is positive in the case where the electrical potential of the neutral-point terminal of said capacitor is below a preset lower-limit value.
Claim 2
Independent Claim
315 words
A method of controlling a three-phase, three-level inverter, in which a plurality of on/off modes are in turn switched in order to control an instantaneous space voltage vector determined by a combination of the electrical potentials of both terminals and the neutral-point terminal of the capacitor of said three-phase, three-level inverter comprising a DC voltage source, a capacitor both terminals of which connected to said DC voltage source and having a neutral-point terminal positioned between both of these terminals, and a plurality of switch elements connected to the section between both terminals and the neutral-point terminal of said capacitor and three output terminals of the inverter, comprising the steps of: judging whether the current of the output terminal of an inverter of the phase such that the electrical potential of the output terminal equals to that of the neutral-point terminal of said capacitor among three-output terminals of said inverter is in a positive direction in which current flows into a load connected to this output terminal or in a negative direction in which current flows from the load when another on/off mode having the same instantaneous space voltage vector as the instantaneous space voltage vector in a tentatively selected on/off mode exists; actually selecting the tentatively selected on/off mode if the result of said judgment is positive and actually selecting another on/off mode instead of the tentatively selected on/off mode when the result of said judgment is negative in the case where the electrical potential of the neutral-point terminal of said capacitor is above a preset upper-limit value; and actually selecting the tentatively selected on/off mode if the result of said judgment is negative and actually selecting another on/off mode instead of the tentatively selected on/off mode when the result of said judgment is positive in the case where the electrical potential of the neutral-point terminal of said capacitor is below a preset lower-limit value.
Claim 3
Dependent Claim
58 words
A control method as claimed in claim 1, further comprising the step of selecting the mode in which the variation of on/off states of switching elements from the on/off mode previously selected is smaller when the electrical potential of the neutral-point terminal of said capacitor is between the upper-limit value and the lower-limit value which have been preset.
Claim 4
Dependent Claim
35 words
A control method as claimed in claim 1, wherein said upper-limit value is a value that an allowable voltage width is added to the electrical potential instruction value of the neutral-point terminal of said capacitor.
Claim 5
Dependent Claim
35 words
A control method as claimed in claim 1, wherein said lower-limit value is a value that an allowable voltage width is subtracted from the electrical potential instruction value of the neutral-point terminal of said capacitor.
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) | 1994-10-21 | 1995-04-22 | 1995-10-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-10-21 | 1999-04-22 | 1999-10-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-10-21 | 2003-04-22 | 2003-10-22 | $7700.00 | Window Closed / Lapsed |