Closed Loop Frequency Control for an Hyperthermia Magnetic Field Applicator

S. GONZALEZ; E. SPINELLI; A. VEIGA

Ciudad Autónoma de Buenos Aires

Congreso; XXVII Congreso Argentino de Control Automático AADECA2020; 2020

AADECA

An automatic frequency control for a magnetic fieldapplicator is presented. It operates at a frequency between100kHz and 200 kHz. It is intended for a magnetic hyperthermiaequipment used in oncology therapy experiments on small animals.The proposed scheme is based on a phase locked loop (PLL)which ensures operation at the natural frequency of a high Qresonant circuit, which includes a coil that produces the magneticfield. An analysis of the different blocks composing the systemis presented along with a study of its stability and perturbationrejection features. Preliminary experimental results obtained ona low power prototype allowed to verify the theoretical modelsassumed for the different transfer functions the circuit involves.It presents a recovery time smaller than 10 ms for variations inthe inductance value.