Variable frequency controlled zero-voltage switching single-ended current-fed DC-to-AC converter with output isolation

A power converter circuit for converting a DC voltage level across a power and a common terminal of a voltage source to a controlled AC voltage level when supplying a load, the circuit comprising:

• an input choke having an input and an output terminal, said input terminal being connected to the power terminal of the voltage source;
• a main switching means comprising a first switch and a parallel connected diode between the output terminal of the choke and the common terminal for selectively establishing a current through said choke from said voltage source;
• a transformer having a primary and a secondary winding, said primary winding having a first and a second input terminal, said first input terminal being connected to said output terminal of said choke;
• a secondary switching means connected between the second input terminal of the transformer and the common terminal for selectively establishing a current through said transformer primary winding, said secondary switching means comprising a parallel combination of a capacitor, a diode and a second switch connected between said second input terminal and the common terminal;
• a non-rectifying output interface circuit coupling said secondary winding of said transformer to the load;
• and
• means for complementarily enabling and disabling said main and said secondary switching means to control current through the transformer primary winding.