Patent ID: 7265507

Claim:
For a system that derives an estimated rotor electrical position {circumflex over (θ)} r and electrical frequency {circumflex over (ω)} r for the rotor of a polyphase alternating current (AC) dynamoelectric machine with an extended rotor flux estimation calculation system that generates uncorrected estimated values of extended rotor flux {circumflex over (λ)} α ext unc and {circumflex over (λ)} β ext unc based on derived values of estimated stator flux {circumflex over (λ)} α and {circumflex over (λ)} β the α-β two-axis stationary reference frame using a lag function 1 s + ω i that approximates a pure integrator function 1 s , wherein ω i represents a corner frequency of the lag function, and a digital phase lock loop (PLL) to determine values of estimated rotor electrical position {circumflex over (θ)} r and electrical frequency {circumflex over (ω)} r based upon the estimated values of extended rotor flux {circumflex over (λ)} α ext and {circumflex over (λ)} β ext , a method of correcting the estimated α-axis and β-axis values of estimated extended rotor flux to more closely approximate values generated with a pure integrator function 1 s , comprising the steps of: dividing the lag function 1 s + ω i corner frequency ω i by the estimated rotary frequency {circumflex over (ω)} r to generate a signal ω i /{circumflex over (ω)} r ; multiplying the signal ω i /{circumflex over (ω)} r by the derived values of estimated stator flux {circumflex over (λ)} α and {circumflex over (λ)} β to produce signals (ω i /{circumflex over (ω)} r ){circumflex over (λ)} α and (ω i /{circumflex over (ω)} r ){circumflex over (λ)} β ; adding signal (ω i /{circumflex over (ω)} r ){circumflex over (λ)} β to {circumflex over (λ)} α ext unc as represented by {circumflex over (λ)} α −(i α ×{circumflex over (L)} q ) to produce a signal {circumflex over (λ)} α (i α ×{circumflex over (L)} q )+(ω i /{circumflex over (ω)} r ){circumflex over (λ)} β that represents a corrected value of estimated extended rotor flux {circumflex over (λ)} α ext ; and subtracting signal (ω i /{circumflex over (ω)} r ){circumflex over (λ)} α from {circumflex over (λ)} β ext unc as represented by {circumflex over (λ)} β −(i β ×{circumflex over (L)} q ) to produce a signal {circumflex over (λ)} β −(i β ×{circumflex over (L)} q )−(ω i /{circumflex over (ω)} r ){circumflex over (λ)} α representing {circumflex over (λ)} β ext .