Patent ID: RE39076

Claim:
Apparatus for controlling a brushless electric motor having motor coils, the apparatus comprising: a power stage having a plurality of switching means, and output terminals for supplying power to the motor coils of a motor to be controlled; and control means coupled to the power stage and arranged to apply commutation signals to the power stage to selectively switch said switching means whereby power is selectively applied to said motor by way of said switching means, and wherein the control means is arranged to receive sequence of samples of a component of the power fed to the motor, the control means further comprising means for determining parameters of a function depending on variable inductance in the motor and defined by the sequence of samples, including means for performing a vector addition or a complex number addition for each set of a plurality of the samples, wherein the parameter determining means operates repeatedly for multiple successive applications of power to the motor and from the parameters determines position-dependent and/or inductance-dependent electrical motor values.