Claims Analysis
Total Claims: 24
Claim 1
Independent Claim
103 words
A method for determining a stator fundamental operating frequency in a three phase induction machine where the machine is characterized by a system specific dominant harmonic frequency number, the method comprising the steps of: injecting a high frequency voltage signal having a high frequency into the machine thereby generating a high frequency current within the stator windings; identifying stationary two phase high frequency feedback signal components that includes stator field position information; identifying a low frequency spectrum corresponding to the feedback signal components; mathematically combining the low frequency spectrum and the system specific dominant harmonic number to generate a stator fundamental frequency estimate.
Claim 2
Independent Claim
103 words
A method for determining a stator fundamental operating frequency in a three phase induction machine where the machine is characterized by a system specific dominant harmonic frequency number, the method comprising the steps of: injecting a high frequency voltage signal having a high frequency into the machine thereby generating a high frequency current within the stator windings; identifying stationary two phase high frequency feedback signal components that includes stator field position information; identifying a low frequency spectrum corresponding to the feedback signal components; mathematically combining the low frequency spectrum and the system specific dominant harmonic number to generate a stator fundamental frequency estimate.
Claim 3
Dependent Claim
29 words
The method of claim 1 wherein the step of identifying the feedback signal includes identifying the stationary two phase negative sequence components of the high frequency stator winding current.
Claim 4
Dependent Claim
95 words
The method of claim 2 wherein the high frequency signal is characterized by a high frequency phase angle and the step of identifying the stationary two phase negative sequence components of the high frequency stator winding current includes the steps sensing two of the three-phase currents from the stator windings, converting the two three-phase currents to synchronous two phase currents using the high frequency phase angle, filtering the synchronous currents to generate intermediate synchronous two phase negative-sequence components and converting the intermediate components to stationary two phase negative sequence components using the high frequency angle.
Claim 5
Dependent Claim
20 words
The method of claim 3 wherein the step of filtering the synchronous currents includes the step of high pass filtering.
Claim 6
Dependent Claim
20 words
The method of claim 3 wherein the step of filtering the synchronous currents includes the step of low pass filtering.
Claim 7
Dependent Claim
65 words
The method of claim 1 wherein the step of identifying a low frequency spectrum includes converting the stationary high frequency components to synchronous two phase high frequency negative sequence components using a high frequency angle estimate, subtracting one of the synchronous negative sequence components from a DC value to generate a difference value and stepping up the difference value to generate the low frequency spectrum.
Claim 8
Dependent Claim
33 words
The method of claim 6 wherein the angle estimate is determined by adding the low frequency spectrum and the high frequency to generate a combined frequency spectrum and integrating the combined frequency spectrum.
Claim 9
Dependent Claim
11 words
The method of claim 6 wherein the DC value is zero.
Claim 10
Dependent Claim
27 words
The method of claim 1 wherein the step of mathematically combining includes the step of dividing the low frequency spectrum by the system specific dominant harmonic number.
Claim 11
Dependent Claim
30 words
The method of claim 1 further including the step of identifying the system specific dominant harmonic number during a commissioning procedure and storing the dominant harmonic number for subsequent use.
Claim 12
Dependent Claim
80 words
The method of claim 1 wherein the step of identifying the feedback signal includes identifying one of a high frequency zero sequence voltage component and a high frequency zero sequence current component as a first of the two phase components, integrating the first component to generate an integrated signal, low pass filtering the integrated signal to generate a low frequency component and subtracting the low frequency component from the integrated signal to generate the second of the two phase components.
Claim 13
Independent Claim
113 words
An apparatus for determining a stator fundamental operating frequency in a three phase induction machine where the machine is characterized by a system specific dominant harmonic frequency number, the apparatus comprising: a generator for injecting a high frequency voltage signal having a high frequency into the machine thereby generating a high frequency current within the stator windings; a module for identifying stationary two phase high frequency feedback signal components that includes stator field position information; a module for identifying a low frequency spectrum corresponding to the feedback signal components; and a module for mathematically combining the low frequency spectrum and the system specific dominant harmonic number to generate a stator fundamental frequency estimate.
Claim 14
Independent Claim
113 words
An apparatus for determining a stator fundamental operating frequency in a three phase induction machine where the machine is characterized by a system specific dominant harmonic frequency number, the apparatus comprising: a generator for injecting a high frequency voltage signal having a high frequency into the machine thereby generating a high frequency current within the stator windings; a module for identifying stationary two phase high frequency feedback signal components that includes stator field position information; a module for identifying a low frequency spectrum corresponding to the feedback signal components; and a module for mathematically combining the low frequency spectrum and the system specific dominant harmonic number to generate a stator fundamental frequency estimate.
Claim 15
Dependent Claim
34 words
The apparatus of claim 12 wherein the module for identifying the feedback signal includes a module for identifying the stationary two phase high frequency negative sequence components of the high frequency stator winding current.
Claim 16
Dependent Claim
112 words
The apparatus of claim 13 wherein the high frequency signal is characterized by a high frequency phase angle and the module for identifying the stationary two phase high frequency negative sequence components of the high frequency stator winding current includes a sensor for sensing at least two of the three-phase currents from the stator windings, a converter for converting the three-phase currents to synchronous two phase currents using the high frequency phase angle, a filter for filtering the synchronous currents to generate intermediate synchronous two phase high frequency negative-sequence components and a converter for converting the intermediate components to stationary two phase high frequency negative sequence components using the high frequency angle.
Claim 17
Dependent Claim
18 words
The apparatus of claim 14 wherein the filter for filtering the synchronous currents includes a high pass filter.
Claim 18
Dependent Claim
18 words
The apparatus of claim 14 wherein the filter for filtering the synchronous currents includes a low pass filter.
Claim 19
Dependent Claim
72 words
The apparatus of claim 12 wherein the module for identifying a low frequency spectrum includes a converter for converting the stationary components to synchronous two phase high frequency negative sequence components using a high frequency angle estimate, a summer for subtracting one of the synchronous negative sequence components from a DC value to generate a difference value and a controller for stepping up the difference value to generate the low frequency spectrum.
Claim 20
Dependent Claim
38 words
The apparatus of claim 17 further including a summer for adding the low frequency spectrum and the high frequency to generate a combined frequency spectrum and an integrator for integrating the combined spectrum to generate the angle estimate.
Claim 21
Dependent Claim
11 words
The apparatus of claim 17 wherein the DC value is zero.
Claim 22
Dependent Claim
27 words
The apparatus of claim 12 wherein the module for mathematically combining includes a multiplier for dividing the low frequency spectrum by the system specific dominant harmonic number.
Claim 23
Dependent Claim
30 words
The apparatus of claim 12 further including a module for identifying the system specific dominant harmonic number during a commissioning procedure and storing the dominant harmonic number for subsequent use.
Claim 24
Dependent Claim
92 words
The apparatus of claim 12 wherein the module for identifying the feedback signal includes a module for identifying one of a high frequency zero sequence voltage component and a high frequency zero sequence current component as a first of the two phase components, an integrator for integrating the first component to generate an integrated signal, a low pass filter for filtering the integrated signal to generate a low frequency component and a summer for subtracting the low frequency component from the integrated signal to generate the second of the two phase components.