Solid state regulated power transformer with waveform conditioning capability

Claim 1

A solid state regulating power transformer which provides variable step up or step down voltage transformation and which provides a regulated AC output signal from an unregulated AC input signal comprising: a. means for chopping said AC input signal at a chopper frequency to provide a chopped signal, said means for chopping being controllable for adjusting the duty cycle of said means for chopping; b. filter means for removing the chopper frequency from said chopped signal to provide a filtered signal, said filtered signal being said regulated AC output signal; c. means for providing a reference signal at the frequency of said AC input signal; d. means for providing a feedback signal derived from the filtered signal; e. means for adjusting the gain of the transformer by providing one of means for varying the amplitude of said reference signal and means for varying the amplitude of said feedback signal; f. means for comparing the amplitude of the reference signal with the amplitude of the feedback signal derived from the filtered signal to produce an error signal related to the difference therebetween, said error signal being coupled to said means for chopping to adjust the duty cycle of said means for chopping wherein the amplitude of said AC output signal is adjusted so that the error signal is driven toward zero and the AC output signal is regulated; g. said means for comparing including: differential amplifier means having a first input coupled to receive said feedback signal, a second input coupled to receive said reference signal, and an output, said differential amplifier means providing a signal related to the difference between its two inputs at its output; and pulse-width-modulated oscillator means coupled to receive the output of said differential amplifier means for adjusting the duty cycle of said pulse-width-modulated oscillator means, the output of said pulse-width-modulated oscillator means being coupled to said means for chopping to adjust the duty cycle of said means for chopping; h. said means for chopping and said filter means including: a first bidirectional switching means having a first terminal and a second terminal, the signal side of said AC input signal being coupled to the first terminal of said first bidirectional switching means; an inductor means coupled between the second terminal of said first bidirectional switching means and the return side of said AC input signal; a second bidirectional switching means having a first terminal and a second terminal, the first terminal of said second bidirectional switching means being coupled to the second terminal of said first bidirectional switching means, and a capacitor means coupled between the second terminal of said second bidirectional switching means and the return side of said AC input signal.