Low distortion variable output power supply

Claim 1

An apparatus for generating at least single phase AC of a selected output frequency from a battery comprising: a control element; a plurality of bidirectional, bridge-type inverters coupled to said control element wherein said inverters include first and second nodes; a plurality of transformers wherein one of said transformers is associated with respective first and second nodes of each said inverter and is coupled thereto by a first coil and wherein said transformers each include a second coil with said second coils series coupled to one another and wherein said control element switches said inverters such that each said inverter generates at a said respective first coil a varying output signal with a frequency which is substantially the same as said selected output frequency.

Claim 2

An apparatus for generating at least single phase AC of a selected output frequency from a battery comprising: a control element; a plurality of bidirectional, bridge-type inverters coupled to said control element wherein said inverters include first and second nodes; a plurality of transformers wherein one of said transformers is associated with respective first and second nodes of each said inverter and is coupled thereto by a first coil and wherein said transformers each include a second coil with said second coils series coupled to one another and wherein said control element switches said inverters such that each said inverter generates at a said respective first coil a varying output signal with a frequency which is substantially the same as said selected output frequency.

Claim 6

A method of generating a periodic output waveform having a selected frequency comprising: providing a plurality of substantially identical, inverters; setting an output frequency of each member of said plurality of inverters to a selected common frequency; providing a plurality of transformers; coupling the inverters together by coupling a respective transformer with each member of said plurality of inverters and linking the coupled transformers in series; and energizing each of said inverters so as to generate an output signal at each, at the selected common frequency, wherein at least some of said output signals are different from others; and combining the output signals using the transformers to produce a periodic output waveform at the selected common frequency.

Claim 7

A method of generating a periodic output waveform having a selected frequency comprising: providing a plurality of substantially identical, inverters; setting an output frequency of each member of said plurality of inverters to a selected common frequency; providing a plurality of transformers; coupling the inverters together by coupling a respective transformer with each member of said plurality of inverters and linking the coupled transformers in series; and energizing each of said inverters so as to generate an output signal at each, at the selected common frequency, wherein at least some of said output signals are different from others; and combining the output signals using the transformers to produce a periodic output waveform at the selected common frequency.

Claim 10

An apparatus for generating an AC-type output voltage from a unipolar voltage source comprising: first and second output terminals; at least two transformers wherein each transformer has a primary coil and a secondary coil, wherein said secondary coils are coupled in series with one another and to said terminals thereby forming a transformer coupled output circuit between one of said terminals, said series coupled secondary coils and said other terminal; at least two inverter modules wherein said modules each have a unipolar voltage input terminal, first and second varying voltage output terminals and at least one control input terminal wherein said voltage output terminals of each inverter module are coupled to a respective transformer primary coil whereby all of said inverter modules are transformer coupled to said output circuit; a control element coupled to said control inputs of all of said inverter modules wherein said control element switches said inverter modules so as to convert an applied unipolar voltage to a varying output voltage at each said respective primary coil, wherein all of said varying output voltages have a common frequency and wherein only said varying output voltages are combined in said transformer coupled output circuit to form at said terminals an AC-type output voltage having the common frequency.

Claim 11

An apparatus for generating an AC-type output voltage from a unipolar voltage source comprising: first and second output terminals; at least two transformers wherein each transformer has a primary coil and a secondary coil, wherein said secondary coils are coupled in series with one another and to said terminals thereby forming a transformer coupled output circuit between one of said terminals, said series coupled secondary coils and said other terminal; at least two inverter modules wherein said modules each have a unipolar voltage input terminal, first and second varying voltage output terminals and at least one control input terminal wherein said voltage output terminals of each inverter module are coupled to a respective transformer primary coil whereby all of said inverter modules are transformer coupled to said output circuit; a control element coupled to said control inputs of all of said inverter modules wherein said control element switches said inverter modules so as to convert an applied unipolar voltage to a varying output voltage at each said respective primary coil, wherein all of said varying output voltages have a common frequency and wherein only said varying output voltages are combined in said transformer coupled output circuit to form at said terminals an AC-type output voltage having the common frequency.