Control of an electrical reluctance machine

摘要

An electrical machine having stator ( 30 ) and rotor ( 31 ) is disclosed. The motor has field windings (F) and armature windings (A) energized by a suitable power electronic controller ( 401 ). A controller ( 400 ) sends signals to the power electronic controller ( 401 ) to control the armature current to control operation of the machine. When the machine is operating as a motor, the armature windings (A) will be supplied with electrical current from the power electronic controller by the application of applied voltage in synchronism with the rotation of the rotor ( 31 ). A mutually induced first electrical signal dependent on rotational position of the rotor will be induced within the field windings (F). This will create a superimposed gradient in the field current delivered by the power electronic controller ( 401 ). The mutually induced first electrical signal can be extracted from the field current by block ( 402 ) which may be a differentiator circuit or may be a coil coupled to the magnetic field around the field current conductor. A signal conditioning circuit ( 403 ) is provided which may contain a filter circuit. Block ( 404 ) creates a reference voltage for the comparator ( 405 ). The reference voltage can be zero such that the comparator ( 405 ) determines the polarity of the mutually induced first electrical signal. The output from the comparator is a digital signal indicating if the mutually induced first electrical signal is less than or greater than the threshold applied by block ( 404 ). This comparator output, a second electrical signal, represents the rotational position of the rotor relative to the stator and is supplied to the controller ( 400 ) to maintain synchronism between the armature excitation and the rotor position.