Patent ID: 8024120

Claim:
A method of estimating an instantaneous frequency of a component of interest in a complex primary signal via a complex Phase Locked Loop (PLL), the method comprising: calculating a complex incident signal including a complex exponential evaluated at a synthesis frequency, according to a complex Voltage Controlled Oscillator (VCO) function; calculating a complex mixed signal according to a function that includes multiplying the complex primary signal by a representation of the complex incident signal; calculating a complex baseband signal according to a function that includes filtering the complex mixed signal such that the bandwidth of the complex baseband signal is less than or equal to the bandwidth of the complex mixed signal; calculating a residual frequency of the complex baseband signal via a complex Phase Discriminator (PD); modifying the synthesis frequency according to a function that includes the synthesis frequency and the residual frequency, such that the residual frequency is minimized; calculating the instantaneous frequency according to a function that includes a representation of the synthesis frequency; and estimating a transient slip of a motor based on the calculated instantaneous frequency.