Patent ID: 6031965
Filing Date: 2000-02-29
Classification: H02P

Abstract:
A motor control system comprising:an electrically charged battery characterized by an operating battery voltage;an electrical motor coupled to said battery, said electrical motor includingan armature assembly responsive to an armature current, wherein a magnitude of said armature current is a function of a predetermined armature current setpoint signal I.sub.a.sbsb.--.sub.SET anda field assembly responsive to a field current, wherein a magnitude of said field current is a function of a predetermined field current setpoint signal I.sub.f.sbsb.--.sub.SET and a field current de-boost signal I.sub.f.sbsb.--.sub.DE-BOOST ;a battery voltage sensor arranged to generate an operating battery voltage signal V.sub.BAT from said operating battery voltage;an armature voltage sensor arranged to generate a measured armature voltage signal V.sub.a from an electrical potential of said armature assembly;an armature current sensor arranged to generate a measured armature current signal I.sub.a indicative of an amount of current flowing through said armature assembly;a microprocessor programmed togenerate the armature current setpoint signal I.sub.a.sbsb.--.sub.SET and the field current setpoint signal I.sub.f.sbsb.--.sub.SET,generate an armature-to-field current check function, wherein said check function defines a set of armature current to field current ratio values (I.sub.a /I.sub.f).sub.CHECK as a function of armature current,calculate a ratio of said measured armature current signal I.sub.a to said field current setpoint signal I.sub.f.sbsb.--.sub.SET to establish an operating ratio value I.sub.a /I.sub.f.sbsb.--.sub.SET,compare said operating ratio value I.sub.a /I.sub.f.sbsb.--.sub.SET to a corresponding armature current to field current ratio value (I.sub.a /I.sub.f).sub.CHECK of said armature-to-field current check function, andestablish said field current de-boost signal I.sub.f.sbsb.--.sub.DE-BOOST, wherein the magnitude of said field current de-boost signal I.sub.f.sbsb.--.sub.DE-BOOST is a function of said measured armature current signal I.sub.a and said comparison of said operating ratio value I.sub.a /I.sub.f.sbsb.--.sub.SET to said corresponding ratio value (I.sub.a /I.sub.f).sub.CHECK.