PWM inverter circuit having a filtered fundamental feedback DC link variation circuit
First Claim
1. An AC power source, comprising:
- converter means for receiving a DC signal and applying a PWM pattern of switching transients to said DC signal to produce an AC signal from said DC signal; and
feedback means for receiving said AC signal, said feedback means modulating said DC signal to eliminate short duration switching transients in said PWM pattern.
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Accused Products
Abstract
This invention relates to a VSCF system for aircraft power generation having a DC source, the DC source producing a substantially constant voltage DC signal. An inverter is coupled to the DC source and receives the DC signal, applying a PWM pattern of switching transients to the DC signal to produce an AC signal from the DC signal. The subject invention contemplates the addition of a feedback circuit which comprises a transformer providing an inductive coupling between the AC signal at a point of regulation and the DC signal at a point between the DC source and the inverter to eliminate short duration switching transients in the PWM pattern. Modulation of the DC signal allows short duration switching transients in the PWM pattern to be lengthened, thereby avoiding physical minimum time switching limitations in the switches of the inverter. Feedback of the AC signal allows inverter frequency to be changed while maintaining synchronization between the DC signal modulation and PWM pattern fed to the inverter.
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Citations
20 Claims
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1. An AC power source, comprising:
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converter means for receiving a DC signal and applying a PWM pattern of switching transients to said DC signal to produce an AC signal from said DC signal; and feedback means for receiving said AC signal, said feedback means modulating said DC signal to eliminate short duration switching transients in said PWM pattern. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. In a VSCF system having a DC source, said DC source producing a substantially constant voltage DC signal and inverter means for receiving said DC signal and applying a PWM pattern of switching transients to said DC signal to produce an AC signal from said DC signal, and AC feedback modulator, comprising:
feedback means for receiving said AC signal, said feedback means modulating said DC signal to eliminate short duration switching transients in said PWM pattern. - View Dependent Claims (9, 10, 11, 12, 13, 14)
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15. A method for providing AC power, comprising the steps of:
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receiving a DC signal; applying a PWM pattern of switching transients to said DC signal to produce an AC signal from said DC signal from said DC signal; receiving said AC signal into a feedback means; and modulating said DC signal with said feedback means to eliminate short duration switching transients in said PWM pattern. - View Dependent Claims (16, 17, 18, 19, 20)
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Specification