Output power factor control of pulse-width modulated inverter
First Claim
1. A method of supplying high power factor electrical power to a load from an inverter having first and second switching legs connected to a first common output of the inverter and to first and second DC bus terminals of the inverter, respectively, and third and fourth switching legs connected to a second common output of the inverter and to said first and second DC bus terminals, respectively, the method comprising:
- producing a scaled rectified voltage signal in response to a rectified output voltage signal representing rectified instantaneous output voltage of the inverter, a power signal inversely proportional to an average amplitude of the rectified instantaneous output voltage of the inverter, and a reference power signal, wherein producing said scaled rectified output voltage signal comprises multiplying said rectified output voltage signal by a ratio of said reference power signal to said power signal, such that said scaled rectified voltage signal is a scaled version of said rectified output voltage signal that increases when said average amplitude of the rectified output voltage of the inverter increases, and decreases when said average amplitude of the rectified output voltage of the inverter decreases;
producing a pulse width modulation (PWM) signal in response to said scaled rectified voltage signal and a rectified output current signal representing output current of the inverter; and
controlling said first, second, third and fourth switching legs in response to said PWM signal and a sign signal representing a sign of the instantaneous output voltage of the inverter, such that current supplied by the inverter increases when said average amplitude of the rectified output voltage of the inverter increases, and decreases when said average amplitude of the rectified output voltage of the inverter decreases.
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Abstract
An inverter operable to supply high power factor electrical power to an AC load including an AC power grid includes a DC bus and a DC to AC converter section of the full bridge type. The inverter further includes a voltage sensor configured to produce an instantaneous output voltage signal representing instantaneous output voltage of the inverter, a rectification circuit configured to produce a rectified output voltage signal, a power signal generator, an output current sensor configured for sensing an output current of the inverter, a rectification circuit configured to produce the rectified output current signal, a sign circuit for producing a signal representing the sign of the output voltage and a control apparatus. The control apparatus includes a scaled rectified voltage signal generator, a pulse width modulation (PWM) signal generator configured to produce a pulse width modulation signal in response to the scaled rectified voltage signal and the rectified output current signal and a switching leg controller circuit configured to control the full bridge switches.
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Citations
54 Claims
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1. A method of supplying high power factor electrical power to a load from an inverter having first and second switching legs connected to a first common output of the inverter and to first and second DC bus terminals of the inverter, respectively, and third and fourth switching legs connected to a second common output of the inverter and to said first and second DC bus terminals, respectively, the method comprising:
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producing a scaled rectified voltage signal in response to a rectified output voltage signal representing rectified instantaneous output voltage of the inverter, a power signal inversely proportional to an average amplitude of the rectified instantaneous output voltage of the inverter, and a reference power signal, wherein producing said scaled rectified output voltage signal comprises multiplying said rectified output voltage signal by a ratio of said reference power signal to said power signal, such that said scaled rectified voltage signal is a scaled version of said rectified output voltage signal that increases when said average amplitude of the rectified output voltage of the inverter increases, and decreases when said average amplitude of the rectified output voltage of the inverter decreases; producing a pulse width modulation (PWM) signal in response to said scaled rectified voltage signal and a rectified output current signal representing output current of the inverter; and controlling said first, second, third and fourth switching legs in response to said PWM signal and a sign signal representing a sign of the instantaneous output voltage of the inverter, such that current supplied by the inverter increases when said average amplitude of the rectified output voltage of the inverter increases, and decreases when said average amplitude of the rectified output voltage of the inverter decreases. - View Dependent Claims (2, 3, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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4. The method of 1 further comprising receiving said power signal.
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17. An apparatus for supplying high power factor electrical power to a load from an inverter having first and second switching legs connected to a first common output of the inverter and first and second DC terminals of the inverter respectively, and third and fourth switching legs connected to a second common output of the inverter and said first and second DC terminals respectively, the apparatus comprising:
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means for producing a scaled rectified voltage signal in response to a rectified output voltage signal representing rectified instantaneous output voltage of the inverter, a power signal inversely proportional to an average amplitude of the rectified instantaneous output voltage of the inverter, and a reference power signal, wherein said means for producing said scaled rectified output voltage signal is configured to multiply said rectified output voltage signal by a ratio of said reference power signal to said power signal such that said scaled rectified voltage signal is a scaled version of said rectified output voltage signal that increases when said average amplitude of the rectified output voltage of the inverter increases, and decreases when said average amplitude of the rectified output voltage of the inverter decreases; means for producing a pulse width modulation (PWM) signal in response to said scaled rectified voltage signal and a rectified output current signal representing output current of the inverter; and means for controlling said first, second, third and fourth switching legs in response to said PWM signal and a sign signal representing a sign of said instantaneous output voltage of said inverter such that current supplied by the inverter increases when said average amplitude of the rectified output voltage of the inverter increases, and decreases when said average amplitude of the rectified output voltage of the inverter decreases. - View Dependent Claims (18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33)
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34. An apparatus for supplying high power factor electrical power to a load from an inverter having first and second switching legs connected to a first common output of the inverter and first and second DC terminals of the inverter respectively, and third and fourth switching legs connected to a second common output of the inverter and said first and second DC terminals respectively, the apparatus comprising:
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a scaled rectified voltage signal generator configured to produce a scaled rectified voltage signal in response to a rectified output voltage signal representing rectified instantaneous output voltage of the inverter, a power signal inversely proportional to an average amplitude of the rectified instantaneous output voltage of the inverter and a reference power signal, wherein said scaled rectified voltage signal generator includes a multiplier configured to multiply said rectified output voltage signal by a ratio of said reference power level signal to said power signal such that said scaled rectified voltage signal is a scaled version of said rectified output voltage signal that increases when said average amplitude of the rectified output voltage of the inverter increases, and decreases when said average amplitude of the rectified output voltage of the inverter decreases; a pulse width modulation (PWM) signal generator configured to produce a pulse width modulation signal in response to said scaled rectified voltage signal and a rectified output current signal representing output current of the inverter; and a switching leg controller circuit configured to control said first, second, third and fourth switching legs in response to said PWM signal and a sign signal representing a sign of said instantaneous output voltage of said inverter such that current supplied by the inverter increases when said average amplitude of the rectified output voltage of the inverter increases, and decreases when said average amplitude of the rectified output voltage of the inverter decreases. - View Dependent Claims (35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46)
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47. An inverter operable to supply high power factor electrical power to an AC load including an AC power grid, the inverter comprising:
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a DC bus having first and second DC terminals operable to be supplied with power from a DC source; a DC to AC converter section having; first and second switching legs connected to a first common AC output and said first and second DC terminals, respectively; and third and fourth switching legs connected to a second common output of the inverter and said first and second DC terminals respectively; a voltage sensor configured to produce an instantaneous output voltage signal representing instantaneous output voltage of the inverter; a first rectification circuit configured to produce a rectified output voltage signal in response to said instantaneous output voltage; a power signal generator for generating a power signal inversely proportional to an average amplitude of the rectified output voltage; an output current sensor configured for sensing an output current of the inverter to produce an instantaneous output current signal; a second rectification circuit configured to produce a rectified output current signal in response to said instantaneous output current signal; a sign circuit for producing a signal representing the sign of the instantaneous output voltage; a control apparatus comprising; a scaled rectified voltage signal generator configured to produce a scaled rectified voltage signal in response to said rectified output voltage signal, said power signal and a reference power signal, wherein said scaled rectified voltage signal generator includes a multiplier configured to multiply said rectified output voltage signal by a ratio of said reference power level signal to said power signal such that said scaled rectified voltage signal is a scaled version of said rectified output voltage signal that increases when said average amplitude of the rectified output voltage of the inverter increases, and decreases when said average amplitude of the rectified output voltage of the inverter decreases; a pulse width modulation (PWM) signal generator configured to produce a pulse width modulation signal in response to said scaled rectified voltage signal and said rectified output current signal; and a switching leg controller circuit configured to control said first, second, third and fourth switching legs in response to said PWM signal and said sign signal such that current supplied by the inverter increases when said average amplitude of the rectified output voltage of the inverter increases, and decreases when said average amplitude of the rectified output voltage of the inverter decreases. - View Dependent Claims (48, 49, 50)
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51. An inverter operable to supply high power factor electrical power to an AC load including an AC power grid, the inverter comprising:
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a DC bus having first and second DC terminals operable to be supplied with power from a DC source; a DC to AC converter section having; first and second switching legs connected to a first common AC output and said first and second DC terminals, respectively; and third and fourth switching legs connected to a second common output of the inverter and said first and second DC terminals respectively; means for producing a rectified output voltage signal representing rectified output voltage of the inverter; means for generating a power signal inversely proportional to an average amplitude of the rectified output voltage; means for producing a rectified output current signal representing instantaneous output current of the inverter; means for producing a sign signal representing the sign of the output voltage; a control apparatus comprising; means for producing a scaled rectified voltage signal in response to said rectified output voltage signal, said power signal and a reference power signal, wherein said means for producing said scaled rectified output voltage signal is configured to multiply said rectified output voltage signal by a ratio of said reference power signal to said power signal such that said scaled rectified voltage signal is a scaled version of said rectified output voltage signal; means for producing a pulse width modulation signal in response to said scaled rectified voltage signal and said rectified output current signal; and means for controlling said first, second, third and fourth switching legs in response to said PWM signal and said sign signal such that current supplied by the inverter increases when said average amplitude of the rectified output voltage of the inverter increases, and decreases when said average amplitude of the rectified output voltage of the inverter decreases. - View Dependent Claims (52, 53, 54)
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Specification