JPS56153988A - Controlling system for allowable commutation angle for commutatorless motor - Google Patents

Abstract

PURPOSE:To stably control the set controlling leading angle betaO by digitally detecting the allowable commutation angle of a commutatorless motor and sampling and controlling to calculate and produce the set leading angle in response to the deviation with the set leading angle at every predetermined time. CONSTITUTION:The voltages and the currents of the respective phases of an armature and a speed signal from a pulse oscillator 5 are inputted to an allowable commutation angle detecting circuit 6, an allowable commutation angle gammaf is detected by the detecting circuit 6, the digital signal of the angle gammaf is inputted to an arithmetic unit 7, which thus calculates and produces a set controlling leading angle betaO by the deviations between the set allowable commutation angle gammaS1, the upper limit set allowable commutation angle gammaS2 and the detected allowable commutation angle gammaf, the output is inputted to a pulse distributor 8 to control a cyclo converter 2. The calculation is performed as shown in Figs. (a)-(d) for the set controlling leading angle betaO', by betaO=betaO'+K(gammaS1-gammaf) in Fig. (a), betaO=betaO' in Fig.(b), betaO= betaO'-DELTAbetaO in Fig.(c), where DELTAbetaO is fixed constant value, in Fig. (c) and betaO= betaO' continuously by the set times of (n) in Fig. (d).