Method and apparatus for determining the initial rotor angle in a rotating field machine

Claim 3

The method according to claim 1 wherein said machine is a converter fed, rotating field machine controlled by field orientation and having a bidirectional counter and sine-cosine generator for transforming the count of the counter into components of the rotor angle and wherein: a. the sine and cosine components of the measured angular position referred to the stator are determined from the voltages induced in the stator winding; b. the sine and cosine of the simulated angular position referred to the rotor are computed in the simulation network; c. the sine and cosine of an aggregate angle representing the simulated angular position referred to the stator is computed from said sine and cosine of the simulated angular position referred to the rotor and the sine and cosine values representing the rotor position stored in the counter; d. the sine and cosine components of the angular difference are determined from the sine and cosine components of the measured angular position and the sine and coSine components of the simulated angular position; e. the sine and cosine of the angular difference are used to form a quantity which depends on the angular difference, said quantity being the quantity used to influence the counter.

Claim 4

Apparatus for determining the initial rotor angle in a converter fed, rotating field maching controlled by field orientation and having a bidirectional counter and a sine-cosine generator for transforming the count of the counter into sine and cosine components of the rotor angle comprising: a. a clock generator for generating a pulse sequence; b. a simulated network comprising: i. first means for simulating the exciter machine; ii. second means for simulating the stator voltage vector of the rotating machine referred to the rotor having the output of said first means as an input; iii. a vector rotator having as inputs the output of said second means and the output of the sine-cosine generator for forming the sine and cosine of a simulated stator voltage vector referred to the stator; c. means coupling the output of said clock generator to the excitation winding of the rotating field machine and to the input of said first means; d. third means coupled to the stator windings for transforming the voltages induced therein into sine and cosine components of the stator voltage vector; e. an inverse vector rotator having as inputs the outputs of said vector rotator and of said third means to develop as outputs the sine and cosine of the angular difference between the angular positions represented by said inputs; f. means coupled to the output of said ininverse vector rotator for generating an output proportional to the angular difference represented; g. a voltage to frequency converter coupled to the output of said fourth means providing a pulse train output; and i. means coupling the output of said voltage to frequency converter to the counter.

Claim 5

Apparatus for determining the initial rotor angle in a converter fed, rotating field maching controlled by field orientation and having a bidirectional counter and a sine-cosine generator for transforming the count of the counter into sine and cosine components of the rotor angle comprising: a. a clock generator for generating a pulse sequence; b. a simulated network comprising: i. first means for simulating the exciter machine; ii. second means for simulating the stator voltage vector of the rotating machine referred to the rotor having the output of said first means as an input; iii. a vector rotator having as inputs the output of said second means and the output of the sine-cosine generator for forming the sine and cosine of a simulated stator voltage vector referred to the stator; c. means coupling the output of said clock generator to the excitation winding of the rotating field machine and to the input of said first means; d. third means coupled to the stator windings for transforming the voltages induced therein into sine and cosine components of the stator voltage vector; e. an inverse vector rotator having as inputs the outputs of said vector rotator and of said third means to develop as outputs the sine and cosine of the angular difference between the angular positions represented by said inputs; f. means coupled to the output of said ininverse vector rotator for generating an output proportional to the angular difference represented; g. a voltage to frequency converter coupled to the output of said fourth means providing a pulse train output; and i. means coupling the output of said voltage to frequency converter to the counter.

Claim 6

Apparatus according to claim 2 for use with a synchronous machine wherein said second means includes: a. a lead circuit; b. an integrating circuit having its input coupled to the output of said lead circuit; c. a multiplier having as inputs a quantity proportional to the speed of rotation of the synchronous machine and the output of said integrator; d. a vector analyzer having as inputs the output of said lead circuit and the output of said multiplier; and e. and means for feeding back the output of said integrating circuit to said lead circuit.

Claim 7

Apparatus according to claim 1 wherein said lead circuit is replaced by a proportional circuit having a gain of one-half.