Resonant type current regulator providing a continuous regulation

Claim 2

A resonant type current regulator comprising: input winding means having terminals for connection to an alternating supply voltage, resonant circuit magnetically coupled to said input winding means with a leakage inductance therebetween, said circuit being arranged to provide a current substantially proportional to the supply voltage, load means coupled to the resonant circuit for energization thereby at a current which is independent of the impedance of said load means, sensing means coupled to said load means and adapted to sense the value of the current through the load to provide a first signal representing said current value, comparing means coupled to said sensing means to compare said first signal from said sensing means with a reference value and provide a second signal representing the deviation of the load current from said reference value, controlled inductive impedance means connected in shunt with said load means, and control means responsive to said second signal from the comparing means for varying the impedance value of said controlled inductive impedance means thereby to vary the shunted portion of the current provided by the resonant circuit such that the current through the load is maintained at a substantially predetermined value independent of supply voltage or load impedance variations.

Claim 3

A device as set forth in claim 1, wherein the controlled inductive impedance means comprises a parallel arrangement of oppositely poled controlled semiconductor devices, the control gates thereof being connected to two outputs of said control means such that said controlled semiconductor devices are made to conduct for a longer time interval within each half period of the current as the magnitude of the load current deviates increasingly from said reference value.

Claim 4

A resonant type current regulator comprising: a transformer having a first winding connectable to an alternating supply voltage and a second winding coupled to the first winding with a leakage inductance therebetween. a capacitor serially connected with said second winding, said capacitor together with said leakage inductance forming a resonant circuit, said resonant circuit providing a current substantially proportional to said supply voltage, load means coupled to said second winding, sensing means coupled to said load means and adapted to sense the value of the current through said load means and provide a signal representing the value of said current, comparison means coupled to said sensing means for comparing the signal from said sensing means with a reference value to provide a signal representing the deviation of said load current from said reference value, controlled inductive impedance means connected between a tap on said first winding and a tap on said second winding, and control means coupled to said comparing means and responsive to said deviation signal from said comparing means for providing control signals, said controlled inductive impedance responsive to said control signals for varying the impedance of said controlled inductive impedance, the shunted portion of the current provided by the resonant circuit also varying thereby such that the current through said load is maintained at a substantially predetermined value.

Claim 5

A resonant type current regulator comprising: a transformer having a first winding connectable to an alternating supply voltage and a second winding coupled to the first winding with a leakage inductance therebetween. a capacitor serially connected with said second winding, said capacitor together with said leakage inductance forming a resonant circuit, said resonant circuit providing a current substantially proportional to said supply voltage, load means coupled to said second winding, sensing means coupled to said load means and adapted to sense the value of the current through said load means and provide a signal representing the value of said current, comparison means coupled to said sensing means for comparing the signal from said sensing means with a reference value to provide a signal representing the deviation of said load current from said reference value, controlled inductive impedance means connected between a tap on said first winding and a tap on said second winding, and control means coupled to said comparing means and responsive to said deviation signal from said comparing means for providing control signals, said controlled inductive impedance responsive to said control signals for varying the impedance of said controlled inductive impedance, the shunted portion of the current provided by the resonant circuit also varying thereby such that the current through said load is maintained at a substantially predetermined value.

Claim 6

A device as set forth in claim 3, wherein the controlled inductive means comprises a parallel arrangement of oppositely poled controlled semiconductor devices, the control gates thereof being connected to two outputs of said control means such that said controlled semiconductor devices are made to conduct for a longer time interval within each half period of the current as the magnitude of the load current deviates increasingly from said reference value.