High efficiency power converter

A power converter comprising:

• a power source;
• first and second primary transformer windings connected to the source;
• first and second primary switches in series with the first and second primary windings, respectively;
• first and second secondary transformer windings, not tightly coupled, coupled to the first and second primary windings, respectively;
• first and second controlled rectifiers, each having a parallel uncontrolled rectifier, in series with the first and second secondary windings, respectively;
• and
• a controller which turns on the first and second primary switches in opposition, each for approximately one half of the switching cycle with transition times which are short relative to the on-state and off-state times of the first and second controlled rectifiers, the first and second controlled rectifiers being controlled to be on at substantially the same times that the first and second primary switches, respectively, are on.

A power converter comprising:

• first and second secondary transformer windings, not tightly coupled, coupled to first and second primary transformer windings;
• means for providing a source of power to the first and second primary transformer windings;
• means for controlling a voltage waveform across the first and second primary transformer windings with a fixed duty cycle;
• means for controlling first and second controlled rectifiers, each having a parallel uncontrolled rectifier, each controlled rectifier being turned on and off in synchronization with the voltage waveform across a primary winding over transitions times which are short relative to the on-state and off-state times of the controlled rectifiers;
• and
• means for regulating the output while the fixed duty cycle is maintained.

A method of converting power comprising:

• providing power to first and second primary transformer windings having at least one secondary winding coupled to at least one of the first and second primary windings and not tightly coupled to another secondary winding;
• controlling voltage waveforms across the first and second primary transformer windings with a fixed duty cycle;
• controlling first and second controlled rectifiers, each having a parallel uncontrolled rectifier, each controlled rectifier being turned on and off in synchronization with the voltage waveform across a primary winding over transitions times which are short relative to the on-state and off-state times of the controlled rectifiers;
• and regulating the output while the fixed duty cycle is maintained.