Driving system comprising a reluctance motor having both position and speed feedback

Claim 1

A. Driving system intended for a power of at least 0.5 kW and comprising a reluctance motor, the stator (4) of which has a number of stator pole bodies arranged circumferentially one after the other and supporting a stator winding (6) and the rotor (7) of which has a plurality of rotor poles arranged circumferentially one after the other with a constant pole pitch, the permeance between a rotor pole and the stator always having its maximum value when the rotor pole is substantially opposite a stator pole; B. speed measuring means (18) for furnishing a signal representative of the speed of said rotor; C. a rotor position responsive pulse device (20); D. a current source (9); E. a controllable semiconductor converter (10) with input-, output- and control terminals and having two possible power directions and one current direction only; F. first connecting means connecting the input terminals of said controllable converter to said current source; G. current transducing means (19) having input and output terminals; H. second connecting means including said current transducing means and connecting the output of said controllable converter to the winding of said reluctance motor; I. a closed control circuit (Y) including said controllable semiconductor convertEr (10), a current comparison device (12) with terminals for a current reference value (IRY), and a negative feed-back connection between said current transducing means (19) and said current comparison device (12); J. a two-position, pulse-controlled reference value switching means having an output , terminal (101), a control terminal (102) and first (103) and second (104) input terminals, the magnitude of the input value of said first input terminal determining the output value during one control pulse, and the said second input terminal determining the output value during the next control pulse; K. a first electrical circuit connecting the control terminal of said switching means with said rotor position responsive pulse device (20); L. a first reference value transmitter (17) for supplying a motor speed reference value; M. a speed comparison device (16) connected to the output of said first reference value transmitter (17) and the output of said speed measuring means (18) for furnishing an output signal representing the difference therebetween; N. a second electrical circuit (15) connecting the output of said speed-comparison device (16) to said first input terminal of the switching means (13); O. a second reference value transmitter (14) connected to the second input terminal of the switching means; P. said rotor-position responsive pulse device (20) including means to supply two pulses at each passage of a rotor pole in relation to a stator pole, one of said pulses being emitted at a first rotor position corresponding to said maximum value of the permeance and the other pulse at a second rotor position substantially half a rotor pole pitch behind said first rotor position.