Quasi-sine wave and stepped square wave AC to AC converter
First Claim
1. An AC to AC converter circuit for generating a quasi-sine wave electrical signal, comprising:
- a rectifying circuit which generates a rectified output signal from multi-phase alternating voltage input energy source; and
switching means, operatively coupled to the rectifying circuit and including at least one switching device associated with each voltage phase arranged to switch each voltage phase individually, for controllably switching polarity of the rectified output signal to form a quasi-sine wave electrical signal having a selected alternating period and a selected voltage level, the selected voltage level of the quasi-sine wave electrical signal being approximately zero for approximately one third of the particular alternating period and approximately a peak voltage level for approximately two thirds of the particular alternating period under stable load conditions.
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Accused Products
Abstract
A switched AC to AC converter circuit comprises a rectifying circuit, which generates a rectified output signal from an alternating input voltage signal, and a switching circuit for controllably switching the polarity of the output from the rectifying circuit to generate a quasi-sine wave or a stepped wave output voltage signal. The switching circuit is included in the rectifying circuit to form a switched rectifier. The switched AC to AC converter controls the integral number of half input wave cycles comprising a half cycle of the quasi-sine wave output in order to maintain the frequency and root mean square (rms) voltage of the output signal between predetermined limits. The switched AC to AC converter further controls the shape of the output voltage wave output to provide instantaneous control over the maintenance of the rms output voltage.
67 Citations
38 Claims
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1. An AC to AC converter circuit for generating a quasi-sine wave electrical signal, comprising:
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a rectifying circuit which generates a rectified output signal from multi-phase alternating voltage input energy source; and switching means, operatively coupled to the rectifying circuit and including at least one switching device associated with each voltage phase arranged to switch each voltage phase individually, for controllably switching polarity of the rectified output signal to form a quasi-sine wave electrical signal having a selected alternating period and a selected voltage level, the selected voltage level of the quasi-sine wave electrical signal being approximately zero for approximately one third of the particular alternating period and approximately a peak voltage level for approximately two thirds of the particular alternating period under stable load conditions. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. An AC to AC converter circuit for supplying power to a load, the circuit comprising:
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a multiple phase source of alternating voltage having a first frequency; a plurality of switches, each phase of the multiple phase source being connectable to the load by a respective switch of the plurality of switches; and a control unit to control operation of the switches so as to apply a single phase, quasi-sine wave output voltage to the load. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16)
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17. An AC to AC converter circuit for generating a stepped wave electrical signal, comprising:
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a rectifying circuit which generates a rectified output signal from a multi-phased alternating voltage input energy source; and switching means, operatively coupled to the rectifying circuit, for controllably switching polarity of the rectified output signal to form a stepped wave electrical signal having a selected alternating period, a first voltage level and a second voltage level, the stepped wave electrical signal having a magnitude approximately equal to the first voltage level for around two thirds of the selected alternating period and a magnitude of approximately the second voltage level for around one third of the selected alternating period under stable load conditions, the switching means including at least one switching device for switching each voltage phase before combining the switched voltage phases. - View Dependent Claims (18, 19, 20, 21)
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22. An AC to AC converter circuit for supplying power to a load, the circuit comprising:
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a multiple phase source of alternating voltage having a first frequency; a plurality of switches, each phase of the multiple phase source connectable to the load through either of two respective switches of the plurality of switches; and a control unit to control operation of the switches so as to apply a single phase, stepped wave output voltage to the load. - View Dependent Claims (23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36)
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37. An AC to AC converter circuit for supplying power to a load from a multiple phase source of alternating voltage, the circuit comprising:
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a plurality of switches, each phase of the multiple phase source being connectable to the load by a respective switch of the plurality of switches; and a control unit to control operation of the switches so as to apply a single phase, quasi-sine wave output voltage to the load.
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38. An AC to AC converter circuit for supplying power to a load from a multiple phase source of alternating voltage, the circuit comprising:
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a plurality of switches, each phase of the multiple phase source connectable to the load through a respective switch of the plurality of switches; and a control unit to control operation of the switches so as to apply a single phase, stepped wave output voltage to the load.
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Specification