Abstract

A motor system comprises a motor comprising: a stator with a plurality of subwindings each having a plurality of phase connections for receiving phase voltages, wherein each of the subwindings is electrically insulated from each of the other subwindings; a rotor comprising a plurality of permanent magnets or energisable electromagnets; a controller comprising a plurality of control parts, each control part associated with a respective subwinding, each control part being configured to monitor phase voltages of the associated subwinding, between phase connections; The system further comprises a controller configured to: obtain, from each control part, at set discrete time intervals, a plurality of back measured electromotive force, EMF, readings for each of the respective subwindings; using the plurality of measured back EMF readings and an a priori knowledge of the motor's construction to estimate a commutation event timing.

IPC Classes  ?

• H02P 5/46 - Arrangements specially adapted for regulating or controlling the speed or torque of two or more electric motors for speed regulation of two or more dynamo-electric motors in relation to one another
• H02P 5/74 - Arrangements specially adapted for regulating or controlling the speed or torque of two or more electric motors controlling two or more AC dynamo-electric motors
• H02P 6/15 - Controlling commutation time
• H02P 6/182 - Circuit arrangements for detecting position without separate position detecting elements using back-emf in windings
• H02P 21/14 - Estimation or adaptation of machine parameters, e.g. flux, current or voltage
• H02P 23/14 - Estimation or adaptation of motor parameters, e.g. rotor time constant, flux, speed, current or voltage
• H02P 25/03 - Synchronous motors with brushless excitation
• H02P 25/16 - Arrangements or methods for the control of AC motors characterised by the kind of AC motor or by structural details characterised by the circuit arrangement or by the kind of wiring
• H02P 25/22 - Multiple windingsWindings for more than three phases
• H02P 25/32 - Arrangements or methods for the control of AC motors characterised by the kind of AC motor or by structural details characterised by the circuit arrangement or by the kind of wiring using discharge tubes

Abstract

A controller for a motor is capable of extrapolation, interpolation, and frequency domain analysis to improve estimates of back-EMF that are used to estimate the motor's absolute position and electrical positions and the timing of commutation events. The controller is programmed with the ability to estimate when during its operation freewheeling is likely to occur. The controller makes use of this estimate to discount phase voltage data collected during potential freewheeling events so that they do not distort the controller's estimate of the motor's back-EMF waveforms and thus the motor's angular position. The controller can apply historical data and other data to supplement measured data. The controller is capable of identifying a fundamental frequency domain component amongst a plurality of frequency domain components and using the identified fundamental frequency to inform commutation timing. The controller is capable of detecting periodic anomalous readings and using those readings to inform an estimate of mechanical or absolute motor position. The controller is capable of merging periodic anomalous readings with other readings to maintain an estimate of mechanical or absolute motor position that is updated more frequently than the anomalous periodic readings occur.

IPC Classes  ?

• H02P 6/182 - Circuit arrangements for detecting position without separate position detecting elements using back-emf in windings
• H02P 6/18 - Circuit arrangements for detecting position without separate position detecting elements