Voest-alpine Automotive M.b.h.

Karl-Heinz Schmidt

Artur Seibt

A circuit for a function generator, or resolver, employing large air gaps between its stator and rotor and between primary and secondary coils of an automatic transformer supplying its excitation signal is disclosed. The circuit operates to insure that the rotor signal is of sufficient voltage to convey the angular position of the rotor. The voltage of the rotor signal is otherwise subject to variations which are temperature dependent. The function generator and circuit of the present invention allows the use of economic function generators without excess drain on associated power supplies. Frequency of the excitation signal is established by a capacitor in parallel with the excitation terminals. A negative feedback path about an excitation amplifier include a nonlinear member comprising antiparallel diodes. The excitation amplifier determines the amplitude of the excitation signal and hence the amplitude of the rotor signal conveying angular rotor position information. Gain of the negative feedback paths is varied by means of a nonlinear resistor which is responsive to a control signal generated by a microcomputer and combined with feedback from the excitation amplifier.

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Vienna, Austria

Karl-Heinz Schmidt