Frequency conversion cycloconverter system for both single- and multi-phase applications

Claim 1

An apparatus for decreasing the frequency of an input alternating current signal from an external power source to produce an output alternating current signal of a lower frequency to drive a load, comprising: a signal generator which produces a signal at said lower frequency; means for reversing the polarity of said input signal to produce said output signal, said means comprising: a first selectively energizable rectifying means connected in series with said input power source and said load, said first rectifying means being connected to prevent current flow from said power source to said load when said first rectifying means is deenergized, and to allow current to flow only in a first direction when sad first rectifying means is energized, said first direction current flow resulting in a first polarity across said load; a second selectively energizable rectifying means connected in series with said input power source and said load, said second rectifying means being connected to prevent current flow from said power source to said load when said second rectifying means is deenergized, and to allow current to flow only in a second direction when said second rectifying means is energized, said second direction current flow resulting in a second polarity across said load; self-energized triggering means for energizing said first rectifying means, said means being responsively coupled to the input signal applied to said second rectifying means so that (i) said first rectifying means is energized only when said second rectifying means is deenergized and (ii) the energizing power for said first rectifying means is derived directly from the alternating current input signal supplied by said external power source; self-energized triggering means for energizing said second rectifying means, said means being responsively coupled to the input signal applied to said first rectifying means so that (i) said second rectifying means is energized only when said first rectifying means is deenergized and (ii) the energizing power for said second rectifying means is derived directly from the alternating current input signal supplied by said external power source; means responsive to said signal generator and coupled between said means for energizing said first rectifying means and said first rectifying means for preventing energization of said first rectifying means when said signal produced by said signal generator has a first polarity; and means responsive to said signal generator and coupled between said means for energizing said second rectifying means and said second rectifying means for preventing energization of said second rectifying means when said signal produced by said signal generator has a second polarity, said second polarity being opposite said first polarity of said signal generator.

Claim 2

An apparatus for decreasing the frequency of an input alternating current signal from an external power source to produce an output alternating current signal of a lower frequency to drive a load, comprising: a signal generator which produces a signal at said lower frequency; means for reversing the polarity of said input signal to produce said output signal, said means comprising: a first selectively energizable rectifying means connected in series with said input power source and said load, said first rectifying means being connected to prevent current flow from said power source to said load when said first rectifying means is deenergized, and to allow current to flow only in a first direction when sad first rectifying means is energized, said first direction current flow resulting in a first polarity across said load; a second selectively energizable rectifying means connected in series with said input power source and said load, said second rectifying means being connected to prevent current flow from said power source to said load when said second rectifying means is deenergized, and to allow current to flow only in a second direction when said second rectifying means is energized, said second direction current flow resulting in a second polarity across said load; self-energized triggering means for energizing said first rectifying means, said means being responsively coupled to the input signal applied to said second rectifying means so that (i) said first rectifying means is energized only when said second rectifying means is deenergized and (ii) the energizing power for said first rectifying means is derived directly from the alternating current input signal supplied by said external power source; self-energized triggering means for energizing said second rectifying means, said means being responsively coupled to the input signal applied to said first rectifying means so that (i) said second rectifying means is energized only when said first rectifying means is deenergized and (ii) the energizing power for said second rectifying means is derived directly from the alternating current input signal supplied by said external power source; means responsive to said signal generator and coupled between said means for energizing said first rectifying means and said first rectifying means for preventing energization of said first rectifying means when said signal produced by said signal generator has a first polarity; and means responsive to said signal generator and coupled between said means for energizing said second rectifying means and said second rectifying means for preventing energization of said second rectifying means when said signal produced by said signal generator has a second polarity, said second polarity being opposite said first polarity of said signal generator.

Claim 6

An apparatus for decreasing the frequency of a three-phase alternating current input signal to produce an output three-phase alternating current signal of lower frequency to drive a three-phase load comprising: a signal generator which produces a three-phase signal at said lower frequency, three polarity-reversing means coupled to said three-phase input signal for producing said three-phase output signal, each of said polarity reversing means comprising a first selectively energizable rectifying means connected to prevent current flow from one phase of said input signal to one phase of said load when said first rectifying means is deenergized, and to allow current to flow only in a first direction when said first rectifying means is energized, said first direction current flow resulting in a first polarity across one phase of said load; a second selectively energizable rectifying means connected to prevent current flow from one phase of said input signal to one phase of said load when said second rectifying means is deenergized, and to allow current to flow only in a second direction when said second rectifying means is energized, said second direction current flow resulting in a second polarity across one phase of said load; said first and second rectifying means of each of said polarity reversing means being coupled between respectively different phases of said input signal and the corresponding phase of said three-phase load so that each polarity reversing means independently controls the phase reversal of a respectively different one of the three phases of said input signal; three independent energizing means respectively associated with said three polarity-reversing means, each of said energizing means including means for energizing the first rectifying means of its associated polarity-reversing means only when the second rectifying means thereof is deenergized, means for energizing the second rectifying means of its associated polarity-reversing means only when the first rectifying means thereof is deenergized; three independent control means respectively associated with said three polarity-reversing means and responsively coupled to respectively different phases of the signal produced by said signal generator, each of said control means including means responsive to a single phase of said signal generator and coupled between the energizing means of the first rectifying means and the associated first rectifying means for preventing energization of the first rectifying means when the signal produced by said signal generator has a first polarity, and means responsive to the same phase of said signal generator and coupled between the energizing means of the second rectifying means and the associated second rectifying means for preventing energization of the first rectifying means when the signal produced by said signal generator has a second polarity, said second polarity being opposite of said first polarity of said signal generator.

Claim 7

An apparatus for decreasing the frequency of a three-phase alternating current input signal to produce an output three-phase alternating current signal of lower frequency to drive a three-phase load comprising: a signal generator which produces a three-phase signal at said lower frequency, three polarity-reversing means coupled to said three-phase input signal for producing said three-phase output signal, each of said polarity reversing means comprising a first selectively energizable rectifying means connected to prevent current flow from one phase of said input signal to one phase of said load when said first rectifying means is deenergized, and to allow current to flow only in a first direction when said first rectifying means is energized, said first direction current flow resulting in a first polarity across one phase of said load; a second selectively energizable rectifying means connected to prevent current flow from one phase of said input signal to one phase of said load when said second rectifying means is deenergized, and to allow current to flow only in a second direction when said second rectifying means is energized, said second direction current flow resulting in a second polarity across one phase of said load; said first and second rectifying means of each of said polarity reversing means being coupled between respectively different phases of said input signal and the corresponding phase of said three-phase load so that each polarity reversing means independently controls the phase reversal of a respectively different one of the three phases of said input signal; three independent energizing means respectively associated with said three polarity-reversing means, each of said energizing means including means for energizing the first rectifying means of its associated polarity-reversing means only when the second rectifying means thereof is deenergized, means for energizing the second rectifying means of its associated polarity-reversing means only when the first rectifying means thereof is deenergized; three independent control means respectively associated with said three polarity-reversing means and responsively coupled to respectively different phases of the signal produced by said signal generator, each of said control means including means responsive to a single phase of said signal generator and coupled between the energizing means of the first rectifying means and the associated first rectifying means for preventing energization of the first rectifying means when the signal produced by said signal generator has a first polarity, and means responsive to the same phase of said signal generator and coupled between the energizing means of the second rectifying means and the associated second rectifying means for preventing energization of the first rectifying means when the signal produced by said signal generator has a second polarity, said second polarity being opposite of said first polarity of said signal generator.

Claim 10

An apparatus for decreasing the frequency of a multiphase alternating current input signal to produce an output multiphase alternating current signal of lower frequency to drive a multiphase load comprising: a signal generator which produces a multiphase signal at said lower frequency, multiple polarity-reversing means coupled to said multiphase input signal for producing said multiphase output signal, each of said polarity-reversing means comprising a first selectively energizable rectifying means connected to prevent current flow from one phase of said input signal to one phase of said load when said first rectifying means is deenergized, and to allow current to flow only in a first direction when said first rectifying means is energized, said first direction current flow resulting in a first polarity across one phase of said load; a second selectively energizable rectifying means connected to prevent current flow from one phase of said input signal to one phase of said load when said second rectifying means is deenergized, and to allow current to flow only in a second direction when said second rectifying means is energized, said second direction current flow resulting in a second polarity across one phase of said load; said first and second rectifying means of each of said polarity-reversing means being coupled between respectively different phases of said input signal and the corresponding phase of said multiphase load so that each polarity-reversing means independently controls the phase reversal of a respectively different one of the multiple phases of said input signal; multiple independent energizing means respectively associated with said multiple polarity-reversing means, each of said energizing means including means for energizing the first rectifying means of its associated polarity-reversing means only when the second rectifying means thereof is deenergized, means for energizing the second rectifying means of its associated polarity-reversing means only when the first rectifying means thereof is deenergized; multiple independent control means respectively associated with said multiple polarity-reversing means and responsively coupled to respectively different phases of the signal produced by said signal generator, each of said control means including means responsive to a single phase of said signal generator and coupled between the energizing means of the first rectifying means and the associated first rectifying means for preventing energization of the first rectifying means when the signal produced by said signal generator has a first polarity, and means responsive to the same phase of said signal generator and coupled between the energizing means of the second rectifying means and the associated second rectifying means for preventing energization of the first rectifying means when the signal produced by said signal generator has a second polarity, said second polarity being opposite of said first polarity of said signal generator.

Claim 11

An apparatus for decreasing the frequency of a multiphase alternating current input signal to produce an output multiphase alternating current signal of lower frequency to drive a multiphase load comprising: a signal generator which produces a multiphase signal at said lower frequency, multiple polarity-reversing means coupled to said multiphase input signal for producing said multiphase output signal, each of said polarity-reversing means comprising a first selectively energizable rectifying means connected to prevent current flow from one phase of said input signal to one phase of said load when said first rectifying means is deenergized, and to allow current to flow only in a first direction when said first rectifying means is energized, said first direction current flow resulting in a first polarity across one phase of said load; a second selectively energizable rectifying means connected to prevent current flow from one phase of said input signal to one phase of said load when said second rectifying means is deenergized, and to allow current to flow only in a second direction when said second rectifying means is energized, said second direction current flow resulting in a second polarity across one phase of said load; said first and second rectifying means of each of said polarity-reversing means being coupled between respectively different phases of said input signal and the corresponding phase of said multiphase load so that each polarity-reversing means independently controls the phase reversal of a respectively different one of the multiple phases of said input signal; multiple independent energizing means respectively associated with said multiple polarity-reversing means, each of said energizing means including means for energizing the first rectifying means of its associated polarity-reversing means only when the second rectifying means thereof is deenergized, means for energizing the second rectifying means of its associated polarity-reversing means only when the first rectifying means thereof is deenergized; multiple independent control means respectively associated with said multiple polarity-reversing means and responsively coupled to respectively different phases of the signal produced by said signal generator, each of said control means including means responsive to a single phase of said signal generator and coupled between the energizing means of the first rectifying means and the associated first rectifying means for preventing energization of the first rectifying means when the signal produced by said signal generator has a first polarity, and means responsive to the same phase of said signal generator and coupled between the energizing means of the second rectifying means and the associated second rectifying means for preventing energization of the first rectifying means when the signal produced by said signal generator has a second polarity, said second polarity being opposite of said first polarity of said signal generator.

Claim 12

An apparatus for decreasing the frequency of an input alternating current signal from an external power source to produce an output alternating current signal of a lower frequency to drive a load comprising: means for selecting the magnitude of said lower frequency including a selectively variable signal generator which produces a signal at said selected lower frequency; means for reversing the polarity of saiD input signal to produce said output signal, said means comprising a first selectively energizable rectifying means connected in series with said input power source and said load, said first rectifying means being connected to prevent current flow from said power source to said load when said first rectifying means is deenergized, and to allow current to flow only in a first direction when said first rectifying means is energized, said first direction current flow resulting in a first polarity across said load; a second selectively energizable rectifying means connected in series with said input power source and said load, said second rectifying means being connected to prevent current flow from said power source to said load when said second rectifying means is deenergized, and to allow current to flow only in a second direction when said second rectifying means is energized, said second direction current flow resulting in a second polarity across said load; triggering means responsive to said signal generator and operatively coupled to said first and second selectively energizable rectifying means for energizing either said first or said second selectively energizable rectifying means; means for varying the voltage of said output alternating current signal as a function of the frequency of said output signal, said means being responsively coupled to said means for selecting the magnitude of said lower frequency and operatively coupled to said triggering means for limiting the portion of each half cycle of said lower frequency during which said rectifying circuits are energized by said triggering means.

Claim 13

An apparatus for decreasing the frequency of an input alternating current signal from an external power source to produce an output alternating current signal of a lower frequency to drive a load comprising: means for selecting the magnitude of said lower frequency including a selectively variable signal generator which produces a signal at said selected lower frequency; means for reversing the polarity of saiD input signal to produce said output signal, said means comprising a first selectively energizable rectifying means connected in series with said input power source and said load, said first rectifying means being connected to prevent current flow from said power source to said load when said first rectifying means is deenergized, and to allow current to flow only in a first direction when said first rectifying means is energized, said first direction current flow resulting in a first polarity across said load; a second selectively energizable rectifying means connected in series with said input power source and said load, said second rectifying means being connected to prevent current flow from said power source to said load when said second rectifying means is deenergized, and to allow current to flow only in a second direction when said second rectifying means is energized, said second direction current flow resulting in a second polarity across said load; triggering means responsive to said signal generator and operatively coupled to said first and second selectively energizable rectifying means for energizing either said first or said second selectively energizable rectifying means; means for varying the voltage of said output alternating current signal as a function of the frequency of said output signal, said means being responsively coupled to said means for selecting the magnitude of said lower frequency and operatively coupled to said triggering means for limiting the portion of each half cycle of said lower frequency during which said rectifying circuits are energized by said triggering means.