DC content control for an inverter
First Claim
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1. A control for an inverter having a switch which is operated in accordance with a waveform having spaced rising and falling edges wherein the inverter produces AC output power, comprising:
- means for detecting the magnitude and polarity of a DC component in the AC output power; and
an adder/subtractor responsive to the detecting means for adjusting at least one of a rising and falling edge of the waveform to reduce the magnitude of the DC component.
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Abstract
A control for an inverter having a switch which is operated in accordance with a PWM waveform having spaced rising and falling edges includes circuitry which detects the magnitude and polarity of a DC component in the AC output power produced by the inverter and an adder/subtractor which adjusts at least one of a rising and falling edge of the waveform to reduce the magnitude of the DC component.
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Citations
15 Claims
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1. A control for an inverter having a switch which is operated in accordance with a waveform having spaced rising and falling edges wherein the inverter produces AC output power, comprising:
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means for detecting the magnitude and polarity of a DC component in the AC output power; and an adder/subtractor responsive to the detecting means for adjusting at least one of a rising and falling edge of the waveform to reduce the magnitude of the DC component. - View Dependent Claims (2, 3, 4)
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5. A control for a pulse-width modulated (PWM) inverter having a pair of switches which are alternately operated in accordance with a PWM control waveform having rising and falling edges to develop AC output power, comprising:
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a memory having a series of digital words stored therein representing intervals between rising and falling edges of a stored PWM waveform; means for detecting the magnitude and polarity of a DC component in the AC output power; an adder/subtractor having a first set of add/subtract inputs coupled to the memory, a second set of add/subtract inputs which receive a signal representing the magnitude of the DC component, a control input which receives a signal representing the polarity of the DC component and an output at which a series of modified interval words are developed; a counter which develops a counter output; and a comparator which compares each modified interval word against the counter output to produce the PWM control waveform; wherein a rising or falling edge of the PWM control waveform is adjusted by the adder/subtractor relative to a corresponding rising or falling edge of the stored PWM waveform to reduce the magnitude of the DC component. - View Dependent Claims (6, 7)
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8. A control for a pulse-width modulated (PWM) inverter having a pair of switches which are alternately operated in accordance with a PWM control waveform having rising and falling edges to develop AC output power, comprising:
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a memory having a plurality of series of digital words stored therein wherein each series represents intervals between rising and falling edges of a stored PWM waveform; means for detecting the magnitude and polarity of a DC component in the AC output power; an adder/subtractor having a first set of add/subtract inputs coupled to the memory, a second set of add/subtract inputs which receive a signal representing the magnitude of the DC component, a control input which receives a signal representing the polarity of the DC component and an output at which a series of modified interval words are developed; a counter which develops a counter output; and
a comparator which compares each modified interval word against the counter output to produce the PWM control waveform;wherein a rising or falling edge of the PWM control waveform is adjusted by the adder/subtractor relative to a corresponding rising or falling edge of the stored PWM waveform to reduce the magnitude of the DC component. - View Dependent Claims (9)
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10. A method of controlling an inverter having a switch which is operated in accordance with a waveform having spaced rising and failing edges wherein the inverter produces AC output power, the method comprising the steps of:
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detecting the magnitude and polarity of a DC component in the AC output power; and providing an adder/subtractor responsive to the detecting means for adjusting at least one of a rising and falling edge of the waveform to reduce the magnitude of the DC component. - View Dependent Claims (11, 12, 13)
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14. A method of controlling a pulse-width modulated (PWM) inverter having a pair of switches which are alternately operated in accordance with a PWM control waveform having rising and falling edges to develop AC output power, the method comprising the steps of:
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providing a memory having a plurality of series of digital words stored therein wherein each series represents intervals between rising and falling edges of a stored PWM waveform; detecting the magnitude and polarity of a DC component in the AC output power; providing an adder/subtractor having a first set of add/subtract inputs coupled to the memory, a second set of add/subtract inputs which receive a signal representing the magnitude of the DC component, a control input which receives a signal representing the polarity of the DC component and an output at which a series of modified interval words are developed; providing a counter which develops a counter output; and sequentially comparing each modified interval word against the counter output to produce the PWM control waveform; wherein a rising or falling edge of the PWM control waveform is adjusted by the adder/subtractor relative to a corresponding rising or falling edge of the stored PWM waveform to reduce the magnitude of the DC component. - View Dependent Claims (15)
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Specification