Ac regulator employing a control rectifier switching circuit

Claim 1

An AC regulator for generating a regulated AC output voltage independent of changes in line frequency, line voltage or load, said AC regulator comprising a. input and output terminals; b. a line resonant circuit tuned to resonate at the frequency of the input line voltage, said line resonant circuit being connected between said input and output terminals; c. parallel choke means connected in serial relationship between said input and said line resonant circuit; d. switching means connected in serial relationship with each of said choke means for regulating the flow of current between said input and output terminals, said switching means comprising oppositely poled controlled rectifiers; e. control means responsive to the peak and average values of the output voltage appearing at said output terminals and operatively coupled to said switching means for controlling the firing times of said switching means, said control means comprising: i. a bridge rectifier having input and output terminals, said input terminals being operatively coupled to said output terminals of the regulator; ii. an RC network operatively coupled to said output terminals of said bridge rectifier, the resistance and capacitance of said network being serially coupled and proportioned to generate a signal in response to the peak and average values of said ouTput voltage; iii. a detector circuit for converting said peak and average signal values to a signal indicative of the r.m.s. value of the output independent of wave shape; iv. means for applying said signal to a solid-state device for regulating the conductivity of said device; v. a transformer having a primary circuit comprising a primary winding with serially coupled capacitance and a secondary circuit comprising a secondary winding, said primary circuit being operatively connected across said input terminals while said secondary winding is operatively connected across the output of said solid-state device, the conductivity of said solid-state device being determinative of the impedance characteristics of said primary circuit so as to vary the phase relationship between the voltage appearing across said input terminals and the voltage appearing across the serially coupled capacitance of said primary circuit; vi. a bilateral switch operatively coupled to said serially coupled capacitance responsive to a minimum voltage appearing across said serially coupled capacitance, said switch being capable of conducting current in one of two directions dependent upon the characteristics of the voltage appearing across the capacitance serially coupled with said primary winding; vii. means responsive to the flow of current passed by said bilateral switch for generating a voltage capable of actuating said switching means such that a regulated output voltage appears at said output terminals.