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US 4,590,548 AGranted
A.C. supply converter
AssigneeTexas Instruments Incorporated
InventorMichael J. Maytum
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AssigneeTexas Instruments Incorporated
InventorMichael J. Maytum
Estimating the term…
A direct a.c. supply converter for converting an N (.gtoreq.2) phase input voltage system into an a.c. output voltage system of different frequency, amplitude, and/or phase using width-modulated contributions from the phases of the input voltage system to produce the output voltage system suffers from the disadvantage that the maximum output voltage amplitude can be limited to the minimum instantaneous voltage of the input voltage system because of the arbitrary timing relationship between the two voltage systems. This limitation is relieved by the addition of a component at the N.sup.th harmonic of the input system frequency to the width-modulation so that the effective minimum instantaneous voltage of the input system is increased. An increase in the maximum output voltage amplitude can also be obtained by adding to the width-modulation a component at the P.sup.th harmonic of the output system frequency; this can be used along or in conjunction with the component at the N.sup.th harmonic of the input system frequency.
A direct a.c. converter having N input conductors for an N-phase a.c. input voltage system, where N is an odd integer greater than 2, one or more output conductors for carrying respective phases of an a.c. output voltage system having at least one characteristic such as frequency, amplitude, phase angle or phase displacement which is different from that of the input voltage system, a plurality of bidirectional switches which individually connect each input conductor to the or each output conductor, and a control system including timing means which produces for the or each output conductor a repeating sequence of mutually abutting width modulated pulses, there being N pulses in the sequence respectively allocated to the phases of the input voltage system, the control system being connected to the switches so that the pulses cause the switches to be closed in such a way that each phase of the input voltage system is connected in turn to the or each phase of the output voltage system and that at any given instant only one of the switches connected to the or each output conductor is closed, wherein the width modulation of the pulses includes a component at the N.sup.th harmonic of the input voltage frequency which is of such an amplitude and so phased as to permit the amplitude of the output voltage system to be larger than the minimum instantaneous voltage of the input voltage system.
A direct a.c. converter having N input conductors for an N-phase a.c. input voltage system, P output conductors for carrying respective phases of a polyphase a.c. output voltage system having at least one characteristic such as frequency, amplitude, phase angle or phase displacement which is different from that of the input voltage system, where P is an odd integer greater than 2, a plurality of bidirectional switches which individually connect each input conductor to each output conductor, and a control system including timing means which produces for each output conductor a repeating sequence of mutually abutting width modulated pulses, there being N pulses in the sequence respectively allocated to the phases of the input voltage system, the control system being connected to the switches so that the pulses cause the switches to be closed in such a way that each phase of the input voltage system is connected in turn to each phase of the output voltage system and that at any given instant only one of the switches connected to each output conductor is closed, wherein the width modulation of the pulses includes a component at the P.sup.th harmonic of the output voltage frequency which is of such an amplitude and so phased as to permit the amplitude of the output voltage system to be larger than the minimum instantaneous voltage of the input voltage system.
A direct a.c. converter having N input conductors for an N-phase a.c. input voltage system, where N is an odd integer greater than 2, P output conductors for carrying respective phases of a polyphase a.c. output voltage system having at least one characteristic such as frequency, amplitude, phase angle, or phase displacement which is different from that of the input voltage system, where P is an odd integer greater than 2, a plurality of bidirectional switches which individually connect each input conductor to each output conductor, and a control system including timing means which produces for each output conductor a repeating sequence of mutually abutting width modulated pulses, there being N pulses in the sequence respectively allocated to the phases of the input voltage system, the control system being connected to the switches so that the pulses cause the switches to be closed in such a way that each phase of the input voltage system is connected in turn to each phase of the output voltage system and that at any given instant only one of the switches connected to each output conductor is closed, wherein the width modulation of the pulses includes components at the N.sup.th harmonic of the input voltage frequency and the P.sup.th harmonic of the output voltage frequency, the components being of such amplitudes and so phased as to permit the amplitude of the output voltage system to be larger than the minimum instantaneous voltage of the input voltage system.
A method of converting an N-phase a.c. input voltage system, wherein N is an odd integer greater than 2, into an a.c. output voltage system having at least one characteristic such as frequency, amplitude, phase angle or phase displacement which is different from that of the input voltage system comprising the steps of generating each voltage of the output system by producing a repeating sequence of mutually abutting width-modulated samples of the voltages of the input system taken in turn and modified to include a component at the N.sup.th harmonic of the input system frequency applying said samples directly from the input system to the output system;
Dependencies are inferred from the claim text.