Vector addition sine wave power control using single inverter and return of energy to inverter source

Claim 2

In combination, an unregulated sine wave source, a sine wave inverter fed by a direct current source and including a parallel resonant circuit across which a sine wave output voltage is taken, means including a transformer having a primary winding coupled to said sine wave output voltage and a secondary winding coupled in series with said unregulated sine wave source for deriving a resultant output voltage from said inverter sine wave output voltage and said unregulated sine wave source, means for varying the phase relationship of said sine wave output voltage and said unregulated sine wave source with respect to the amplitude of their resultant output voltage, and means for returning to said direct current source energy entering said inverter from said unregulated sine wave source by way of said transformer.

Claim 3

In combination, an unregulated sine wave source, a source of direct current, a sine wave inverter coupled to said source of direct current and including serial-connected inductor windings connected by way of switching means to said source of direct current, a capacitor connected to form a parallel resonant circuit with said inductor windings, means including a transformer having a primary winding coupled to said sine wave inverter and said secondary winding connected in series with said unregulated sine wave source for coupling the output of said sine wave inverter to said unregulated sine wave source to produce a resultant output voltage, means for varying the phase of said sine wave inverter with respect to the phase of said unregulated sine wave source in response to said resultant output voltage, and means for returning to said source of direct current the energy entering said sine wave inverter from said unregulated sine wave source as a result of regulation thereof.

Claim 4

In combination, an unregulated sine wave source, a source of direct current, a sine wave inverter coupled to said source of direct current and including serial-connected inductor windings connected by way of switching means to said source of direct current, a capacitor connected to form a parallel resonant circuit with said inductor windings, means including a transformer having a primary winding coupled to said sine wave inverter and said secondary winding connected in series with said unregulated sine wave source for coupling the output of said sine wave inverter to said unregulated sine wave source to produce a resultant output voltage, means for varying the phase of said sine wave inverter with respect to the phase of said unregulated sine wave source in response to said resultant output voltage, and means for returning to said source of direct current the energy entering said sine wave inverter from said unregulated sine wave source as a result of regulation thereof.

Claim 5

The combination as set forth in claim 2 in which the switching means comprises SCR''s.

Claim 6

The combination as set forth in claim 2 in which the means for returning to said source of direct current the energy entering said sine wave inverter from said unregUlated sine wave source includes a semiconductor diode connected in shunt with said switching means and poled in a direction to provide a voltage drop adapted to render said switching means nonconductive on alternate half cycles of the frequency of said resultant output voltage.

Claim 7

In combination, an alternating current supply circuit providing an unregulated voltage, a source of direct current, an inverter having a parallel resonant circuit across which appears an alternating current output voltage, means including a coupling device having a secondary winding connected in series with said unregulated voltage and a primary winding coupled to said alternating current output voltage for deriving from said alternating current output voltage and the unregulated voltage of said alternating current supply circuit a resultant output voltage, means for returning to said source of direct current reverse current used to commutate said inverter and energy entering said inverter from said supply circuit, and means including means for sensing said resultant output voltage for maintaining said resultant output voltage substantially constant by varying the phase relationship of said alternating current output voltage of said inverter with respect to said unregulated voltage.

Claim 8

In combination, an alternating current supply circuit providing an unregulated voltage, a source of direct current, an inverter having a parallel resonant circuit across which appears an alternating current output voltage, means including a coupling device having a secondary winding connected in series with said unregulated voltage and a primary winding coupled to said alternating current output voltage for deriving from said alternating current output voltage and the unregulated voltage of said alternating current supply circuit a resultant output voltage, means for returning to said source of direct current reverse current used to commutate said inverter and energy entering said inverter from said supply circuit, and means including means for sensing said resultant output voltage for maintaining said resultant output voltage substantially constant by varying the phase relationship of said alternating current output voltage of said inverter with respect to said unregulated voltage.

Claim 9

An inverter power supply comprising a source of direct current, an unregulated sine wave source, a sine wave inverter coupled to said source of direct current and including a parallel resonant circuit adapted to present a constant voltage output to a load, said parallel resonant circuit including a pair of serially-connected inductor windings, a semiconductor switch connected in series with the opposite end of each inductor winding and said source of direct current, a capacitor connected from the junction of said inductor windings and one side of said source of direct current, means including a diode connected in shunt with each semiconductor switch through which energy from said resonant circuit flows toward said source of direct current to back bias said semiconductor switch to nonconduction during its normal recovery period, means including a buck-boost transformer having a secondary winding coupled in series with said unregulated sine wave source and said load and a primary winding connected to said parallel resonant circuit for deriving a vectorial summed output signal from the unregulated sine wave source and the voltage output of said parallel resonant circuit, means for varying the phase relationship of said sine wave inverter with respect to that of said unregulated sine wave source to vary the amplitude of said summed output signal, said diode also coupled for returning to said source of direct current excess energy not used for commutation of said semiconductor switches flowing in said inverter from said unregulated sine wave source when said transformer is in the buck mode.

Claim 10

An inverter power supply comprising a source of direct current, an unregulated sine wave source, a sine wave inverter coupled to said source of direct current and including a parallel resonant circuit adapted to present a constant voltage output to a load, said parallel resonant circuit including a pair of serially-connected inductor windings, a semiconductor switch connected in series with the opposite end of each inductor winding and said source of direct current, a capacitor connected from the junction of said inductor windings and one side of said source of direct current, means including a diode connected in shunt with each semiconductor switch through which energy from said resonant circuit flows toward said source of direct current to back bias said semiconductor switch to nonconduction during its normal recovery period, means including a buck-boost transformer having a secondary winding coupled in series with said unregulated sine wave source and said load and a primary winding connected to said parallel resonant circuit for deriving a vectorial summed output signal from the unregulated sine wave source and the voltage output of said parallel resonant circuit, means for varying the phase relationship of said sine wave inverter with respect to that of said unregulated sine wave source to vary the amplitude of said summed output signal, said diode also coupled for returning to said source of direct current excess energy not used for commutation of said semiconductor switches flowing in said inverter from said unregulated sine wave source when said transformer is in the buck mode.

Claim 11

An inverter power supply comprising a source of direct current, an unregulated sine wave source, a sine wave inverter coupled to said source of direct current and including a parallel resonant circuit adapted to present a constant voltage output to a load, means including a buck-boost transformer coupled in series with said unregulated sine wave source and said load to provide a resultant output signal from the output of said inverter and said unregulated sine wave source, diode means coupled to return to said source of direct current the energy used to commutate said sine wave inverter and energy entering said inverter from said unregulated sine wave source by way of said buck-boost transformer, and means for delaying the output of said sine wave inverter with respect to said unregulated sine wave source to actuate said buck-boost transformer to add or subtract therefrom an incremental voltage to maintain substantially constant the amplitude of said resultant output signal.

Claim 12

An inverter power supply comprising a source of direct current, an unregulated sine wave source, a sine wave inverter coupled to said source of direct current and including a parallel resonant circuit adapted to present a constant voltage output to a load, means including a buck-boost transformer coupled in series with said unregulated sine wave source and said load to provide a resultant output signal from the output of said inverter and said unregulated sine wave source, diode means coupled to return to said source of direct current the energy used to commutate said sine wave inverter and energy entering said inverter from said unregulated sine wave source by way of said buck-boost transformer, and means for delaying the output of said sine wave inverter with respect to said unregulated sine wave source to actuate said buck-boost transformer to add or subtract therefrom an incremental voltage to maintain substantially constant the amplitude of said resultant output signal.

Claim 13

In combination, a source of direct current, an inverter including a pair of serially-connected inductor windings, a semiconductor switch connectEd in series with the opposite end of each inductor winding and said source of direct current, a capacitor connected from the common junction of said inductor windings and one side of said source of direct current to provide a parallel resonant output, an unregulated source of alternating current, means including coupling means having a secondary winding coupled to said unregulated source of alternating current and a primary winding connected to the parallel resonant output for deriving a vectorial summed output signal from the unregulated source of alternating and the parallel resonant out-put of said inverter, means for back biasing each semiconductor switch and directing to said source of direct current the energy entering said inverter from said unregulated source of alternating current by way of said coupling means, means for comparing said output signal with a reference source to provide a control signal, and means in response to said control signal to delay the triggering into conduction of the semiconductor switches of said inverter to maintain the amplitude of said resultant output signal substantially constant.

Claim 14

In combination, a source of direct current, an inverter including a pair of serially-connected inductor windings, a semiconductor switch connectEd in series with the opposite end of each inductor winding and said source of direct current, a capacitor connected from the common junction of said inductor windings and one side of said source of direct current to provide a parallel resonant output, an unregulated source of alternating current, means including coupling means having a secondary winding coupled to said unregulated source of alternating current and a primary winding connected to the parallel resonant output for deriving a vectorial summed output signal from the unregulated source of alternating and the parallel resonant out-put of said inverter, means for back biasing each semiconductor switch and directing to said source of direct current the energy entering said inverter from said unregulated source of alternating current by way of said coupling means, means for comparing said output signal with a reference source to provide a control signal, and means in response to said control signal to delay the triggering into conduction of the semiconductor switches of said inverter to maintain the amplitude of said resultant output signal substantially constant.

Claim 15

An inverter power supply comprising a direct current source, a sine wave inverter circuit including a pair of serial-connected inductor windings, a semiconductor switch connected in series with each inductor winding and said direct current source to provide intermittent current flow through said inductor windings, a capacitor connected from the common junction of said inductor windings to one side of the direct current source to provide a resonant circuit upon triggering of said semiconductor switches, diode means connected in shunt with each of said semiconductor switches and poled in a direction to provide a voltage drop to back bias each semiconductor switch in response to reverse current flow through said diode means, an unregulated sine wave source having substantially the same frequency as said sine wave inverter circuit, an output circuit including an output terminal connected to the common junction of said serially-connected inductors and adapted to present a constant voltage source to a load, a coupling device having an output winding coupled in series with said unregulated sine wave source and said load and a primary winding for coupling said output circuit to said unregulated sine wave source for deriving a resultant output voltage, means in response to the amplitude of said resultant output voltage to delay the triggering of said sine wave inverter circuit to vary the phase thereof with respect to the phase of said unregulated sine wave source to maintain the amplitude of said resultant output voltage substantially constant, said diode means back biasing each semiconductor switch and returning to said direct current source the energy flowing in said inductor windings from said unregulated source by way of said coupling device.

Claim 16

An inverter power supply comprising a direct current source, a sine wave inverter circuit including a pair of serial-connected inductor windings, a semiconductor switch connected in series with each inductor winding and said direct current source to provide intermittent current flow through said inductor windings, a capacitor connected from the common junction of said inductor windings to one side of the direct current source to provide a resonant circuit upon triggering of said semiconductor switches, diode means connected in shunt with each of said semiconductor switches and poled in a direction to provide a voltage drop to back bias each semiconductor switch in response to reverse current flow through said diode means, an unregulated sine wave source having substantially the same frequency as said sine wave inverter circuit, an output circuit including an output terminal connected to the common junction of said serially-connected inductors and adapted to present a constant voltage source to a load, a coupling device having an output winding coupled in series with said unregulated sine wave source and said load and a primary winding for coupling said output circuit to said unregulated sine wave source for deriving a resultant output voltage, means in response to the amplitude of said resultant output voltage to delay the triggering of said sine wave inverter circuit to vary the phase thereof with respect to the phase of said unregulated sine wave source to maintain the amplitude of said resultant output voltage substantially constant, said diode means back biasing each semiconductor switch and returning to said direct current source the energy flowing in said inductor windings from said unregulated source by way of said coupling device.

Claim 17

The inverter power supply as set forth in claim 9 in which the direct current source is derived from rectification of said unregulated sine wave source.

Claim 18

The inverter power supply as set forth in claim 9 in which the coupling device is a transformer adapted to operate in the buck-boost mode with respect to said unregulated sine wave source.