Electrical converter

Claim 2

An alternating current waveform generator comprising a source of unidirectional power pulses in one direction for defining one half cycle of a waveform; another source of unidirectional power pulses in another direction for defining a second half cycle of said waveform; an inductor winding having a first tap connected to said source, a second tap connected to said another source and a center tap for providing said alternating current waveform; controlled conducting means connected between said first tap and said second tap; control means connected to a control input of said controlled conducting means rendering said conducting means conductive as each half cycle of said alternating current waveform is ending to allow energy stored in said inductor during one of said half cycles to be retained in said inductor and released from said inductor during a next half cycle thereby substantially preventing unwanted waveform distorting voltages from being developed.

Claim 3

The waveform generator of claim 1 wherein said controlled conducting means is a controlled rectifier.

Claim 4

The inverter of claim 2 further comprising a resistor connected in series with said controlled rectifier between said first and second taps for dissipating energy.

Claim 5

A DC to AC inverter comprising: a transformer having a primary and a secondary winding, each of said windings have first and second taps and a center tap, said center tap of said primary winding being connected to a first terminal of a DC power source; a first switch means connected between said first primary winding tap and a second terminal of said DC power source; a second switch means connected between said second primary winding tap and said second terminal of said DC power source; control means connected to said first and to said second switch means for alternately causing said first and second switch means to be conductive for predetermined periods of time whereby alternating current pulses are produced in said second winding; first and second controlled rectifiers, the anodes of said first and second controlled rectifiers being connected to said first and second taps of said secondary winding respectively, the cathodes of said first and second controlled rectifiers being connected together for providing unidirectional current pulses in one direction, third and fourth controlled rectifiers, the cathodes of said third and fourth controlled rectifiers being connected to said first and and second taps of said secondary winding respectively, the anodes of said third and fourth controlled rectifiers being connected together for providing said unidirectional current pulses in another direction, the control inputs of each of said controlled rectifiers being connected to said control means for rendering said first and second controlled rectifiers conductive and said third and fourth controlled rectifiers non-conducting, and alternately for rendering said third and fourth controlled rectifiers conductive and said first and second controlled rectifiers non-conducting; an inductor winding having first and second taps and a center tap, said first and second taps connected to said cathodes of said first and second controlled rectifiers and to said anodes of said third and fourth controlled rectifiers respectively, said center tap providing said alternating current waveform; a fifth controlled rectifier having a cathode and an anode connected to said first tap and to said second tap of said inductor winding respectively, a control input of said fifth controlled rectifier connected to said control means for rendering said fifth controlled rectifier conductive whenever said first and second and whenever said third and fourth controlled rectifiers are to be rendered non-conducting, said fifth controlled rectifier providing a current path around said inductor winding to allow energy stored in said inductor during one half cycle of said alternating current waveform and energy transferred to said inductor from a load having a non-zero power factor to be retained in said inductor and released from said inductor during the next one half cycle of said alternating current waveform and preventing excessive voltages from being generated.

Claim 6

A DC to AC inverter comprising: a transformer having a primary and a secondary winding, each of said windings have first and second taps and a center tap, said center tap of said primary winding being connected to a first terminal of a DC power source; a first switch means connected between said first primary winding tap and a second terminal of said DC power source; a second switch means connected between said second primary winding tap and said second terminal of said DC power source; control means connected to said first and to said second switch means for alternately causing said first and second switch means to be conductive for predetermined periods of time whereby alternating current pulses are produced in said second winding; first and second controlled rectifiers, the anodes of said first and second controlled rectifiers being connected to said first and second taps of said secondary winding respectively, the cathodes of said first and second controlled rectifiers being connected together for providing unidirectional current pulses in one direction, third and fourth controlled rectifiers, the cathodes of said third and fourth controlled rectifiers being connected to said first and and second taps of said secondary winding respectively, the anodes of said third and fourth controlled rectifiers being connected together for providing said unidirectional current pulses in another direction, the control inputs of each of said controlled rectifiers being connected to said control means for rendering said first and second controlled rectifiers conductive and said third and fourth controlled rectifiers non-conducting, and alternately for rendering said third and fourth controlled rectifiers conductive and said first and second controlled rectifiers non-conducting; an inductor winding having first and second taps and a center tap, said first and second taps connected to said cathodes of said first and second controlled rectifiers and to said anodes of said third and fourth controlled rectifiers respectively, said center tap providing said alternating current waveform; a fifth controlled rectifier having a cathode and an anode connected to said first tap and to said second tap of said inductor winding respectively, a control input of said fifth controlled rectifier connected to said control means for rendering said fifth controlled rectifier conductive whenever said first and second and whenever said third and fourth controlled rectifiers are to be rendered non-conducting, said fifth controlled rectifier providing a current path around said inductor winding to allow energy stored in said inductor during one half cycle of said alternating current waveform and energy transferred to said inductor from a load having a non-zero power factor to be retained in said inductor and released from said inductor during the next one half cycle of said alternating current waveform and preventing excessive voltages from being generated.

Claim 7

The inverter of claim 4 further comprising: a resistor connected in series with said fifth controlled rectifier between said first and second taps for dissipating energy.