56 results about "Mass imbalance" patented technology

A method for detecting ice on a wind turbine having a rotor and one or more rotor blades each having blade roots includes monitoring meteorological conditions relating to icing conditions and monitoring one or more physical characteristics of the wind turbine in operation that vary in accordance with at least one of the mass of the one or more rotor blades or a mass imbalance between the rotor blades. The method also includes using the one or more monitored physical characteristics to determine whether a blade mass anomaly exists, determining whether the monitored meteorological conditions are consistent with blade icing; and signaling an icing-related blade mass anomaly when a blade mass anomaly is determined to exist and the monitored meteorological conditions are determined to be consistent with icing.

A symmetrical differential capacitive sensor (60) includes a movable element (66) pivotable about a geometrically centered rotational axis (70). The element (66) includes sections (86, 88). Each of the sections (86, 88) has a stop (94, 96) spaced equally away from the rotational axis (70). Each of the sections (86, 88) also has a different configuration (104, 108) of apertures (102, 106). The configurations (104, 108) of apertures (102, 106) create a mass imbalance between the sections (86, 88) so that the element (66) pivots about the rotational axis (70) in response to acceleration. The apertures (102, 106) also facilitate etch release during manufacturing and reduce air damping when the element (66) rotates. Apertures (126, 128) are formed in electrodes (78, 80) underlying the apertures (102, 106) to match the capacitance between the two sections (86, 88) of movable element (86) to provide the same bi-directional actuation capability.

The invention discloses a novel method and apparatus to determine the degree of residual mass unbalance and a corrective balance solution for a rotating assembly having a non-vertical axis of rotation. When the center of mass of the rotating assembly is not concentric with the axis of rotation, the condition of unbalance exists. When the rotating assembly is driven by a motor or drives a generator, fluctuations in power are produced proportional to the degree of unbalance. The method and apparatus to determine the degree of mass imbalance consists of measuring the average instantaneous real power over an interval of time, calculating the Fourier Transform of the demodulated signal, establishing the peak amplitude and phase associated with the angular velocity of the rotating assembly and calculating the amount of unbalance. The method and apparatus to provide for a corrective solution consists of simultaneously acquiring a position reference signal of the rotating assembly with the average instantaneous real power signal, calculating the phase difference between the two acquired signals at the angular velocity of the rotating assembly, calculating the magnitude of the unbalance, and calculating the quantity and location of corrective weight necessary to minimize the unbalance to an acceptable level.

The present invention relates to a method of correcting rotor imbalance and a wind turbine thereof. The correction method comprises measuring the vibrations within at least one time window and determining an imbalance factor and an imbalance phase. The values of the parameters in the equation for calculating the correction action are then updated based on the imbalance factor and an imbalance phase. A correction angle for each of the wind turbine blades is calculated using these adjusted parameters. The correction angle is used to aerodynamically balance the rotor, and a model may be used to determine the initial values of the parameters. Another imbalance factor and imbalance phase is determined based on another set of measurements. This imbalance factor is then used to calculate a mass moment for correcting the mass imbalance in the wind turbine blades. The weight and location of a balancing mass is finally calculated based on this mass moment and installed in the respective wind turbine blades.

A method and system for detecting asymmetric utilizing lateral tower acceleration data may include: providing a lateral tower acceleration monitoring system; determining from the lateral tower acceleration monitoring system whether a lateral tower acceleration is above an acceleration limit; determining whether a rotor-mass imbalance condition exists; and determining whether the lateral tower acceleration coincides with icing on a rotor.

The invention relates to a magnetic suspension flywheel vibration moment suppression method based on a synchronous rotation coordinate transformation algorithm, and belongs to the field of magnetic suspension flywheel vibration suppression. The method comprises the steps of: establishing a magnetic suspension flywheel kinetic model; establishing an unbalanced force and an unbalanced moment model based on the model; reconstructing a control system with complex coefficients to simplify the structure of the system and to reduce the orders; introducing the synchronous rotation coordinate transformation by establishing a stationary coordinate system and a rotation coordinate system; and identifying the same-frequency component in the vibration moment using the synchronous rotation coordinate transformation, and taking the obtained same-frequency component as the input of a controller to suppress the same-frequency vibration moment. According to the magnetic suspension flywheel vibration moment suppression method based on the synchronous rotation coordinate transformation algorithm, the vibration moment generated by the mass imbalance of magnetic suspension rotors is suppressed based onthe synchronous rotation coordinate transformation algorithm, thereby achieving the control effect of effectively suppressing the vibration moment under the condition of full speed range and ensuringthe system stability.

The invention discloses a phase-lag-compensation-based same-frequency vibration force suppression method and control system of a magnetically suspended flywheel. For a magnetically suspended flywheel,a magnetically suspended rotor kinetic model including a same-frequency vibration force is established by considering rotor mass imbalance; with a phase-shift trap filter, a same-frequency disturbance component in a control current at a time-varying rotation speed frequency is eliminated effectively; and then a residual same-frequency vibration force in displacement stiffness is eliminated completely by using a proportional compensation term and an additional compensation term. Therefore, the high-precision and high-robustness time-varying same-frequency vibration force suppression performance is obtained; and the suppression method and control system have the reference significance in active vibration control of a magnetic suspension-rotor system.

A method (200) for detecting asymmetric utilizing longitudinal tower acceleration data may include: providing a rotorspeed acceleration monitoring system; determining from the rotorspeed acceleration monitoring system whether a rotorspeed acceleration is above a rotorspeed acceleration limit (215); determining whether a rotor-mass imbalance condition exists (235,245); and determining whether a longitudinal tower acceleration coincides with icing on a rotor.

A stator for a dynamoelectric machine includes an annular stator core in which a large number of slots extending in an axial direction are disposed in a circumferential direction so as to open radially inward; a stator winding having a plurality of winding phase portions installed in the stator core, lead wires of the plurality of winding phase portions being led axially outward within a predetermined circumferential range from an axial end of a first coil end group formed at a first axial end of the stator core; and a first mass adjusting portion disposed at a first end of the stator core, the first mass adjusting portion adjusting a circumferential mass imbalance relative to a central axis of the stator core resulting from a circumferential bias in positions from which the lead wires are led out.

The invention discloses a magnetic suspension rotor harmonic vibration force inhibition method based on a multi-synchronous coordinate transformation method. The method comprises the steps of firstlybuilding a magnetic suspension rotor dynamic model comprising mass imbalance and sensor harmonic waves, and then employing the MSRFT-based magnetic suspension rotor harmonic vibration force inhibitionmethod. The MSRFT can accurately suppress harmonic vibration force, and one controller is used for suppressing vibration in the X direction and the Y direction at the same time, so that hardware computing resources are reduced, and the dynamic process of suppression is accelerated. Meanwhile, the introduction of the phase compensation angle can guarantee the absolute stability of the system in alarger frequency range. The MSRFT controller is simple in structure, convenient to use in practical application, capable of restraining harmonic vibration force in the magnetic suspension rotor, and suitable for restraining harmonic vibration force of a magnetic suspension rotor system with mass imbalance and sensor harmonic waves.

The present disclosure is directed to a method for detecting a mass imbalance in a rotor of a wind turbine. The method includes receiving, with a computing device, sensor data indicative of an operating characteristic of the wind turbine. The method also includes determining, with the computing device, a mean amplitude of a designated frequency component of the operating characteristic. Furthermore, the method includes determining, with the computing device, when a mass imbalance is present within the rotor based on the mean amplitude of the designated frequency component.

A method for detecting and diagnosing aerodynamic imbalance of the impellers of a wind turbine is provided which comprises steps of: obtaining a comparison between an impeller radial vibration amplitude and historical data under the same working condition, and assigning 0 to an impeller radial vibration influence coefficient in the case of an unobvious vibration amplitude change; performing FFT on a radial vibration signal and assigning 1 to the radial vibration influence coefficient if a first-harmonic signal relative to the impeller rotating speed in the frequency spectrum is dominant in the low-frequency band and an vibration amplitude change is obvious, or assigning 0 to the radial vibration influence coefficient; performing the same diagnosis method on impeller radial vibration data and impeller hub radial displacement data; multiplying the obtained influence coefficients to obtain the probability of occurrence of the aerodynamic imbalance of the impellers of the wind turbine, and determining that the impellers of the wind turbine generates aerodynamic imbalance when the probability is equal to 1, and assigning 0 to the probability of occurrence of the aerodynamic imbalance of the impellers of the wind turbine as long as one of the three influence coefficients is 0. The method can effectively distinguish between impeller aerodynamic imbalance and mass imbalance of the impellers of the wind turbine, more accurately determines the aerodynamic imbalance of the impellers of the wind turbine, and increases the work efficiency and accuracy in the detection and diagnosis of the aerodynamic imbalance of the impellers of the wind turbine.

A laying head for forming coils using continuous and substantially rectilinear rolled products such as rods or wire, having vibration damping means integrated in one of two rotor supports (3), preferably the one on the rolled product outlet side. Said means comprise a plurality of coils (6, 6′, 6″) arranged around the rotor (3), rotating about its axis (X), which generate a magnetic field actively controlled by a computer, the resultant force of which is perpendicular to the axis (X) and of a predetermined intensity so as to eliminate the inertial forces generated by the mass imbalances. Alternatively, the damping means incorporated in one of the supports are comprised of oil film bearings.

The invention discloses a harmonic current suppression method based on virtual sampling second-order repetitive control. The method comprises the following steps: firstly, establishing a magnetic suspension rotor kinetic model containing mass imbalance and sensor harmonic waves; secondly, using virtual sampling to ensure that the ratio of a disturbance basic period to a sampling period is an integer under the condition that the physical sampling frequency is not changed, enhancing the robustness of the system through second-order repetitive control, and keeping a good suppression effect when the frequency fluctuates to a certain extent; and a novel stability analysis method is provided for solving the problem that the high-order repetitive control stability is difficult to prove. Accordingto the virtual sampling second-order repetitive controller, the robustness of the system is improved by changing the implementation mode of unit delay, the virtual sampling second-order repetitive controller is suitable for harmonic current suppression of the magnetic suspension rotor with mass imbalance and sensor harmonic waves, a novel stability analysis method is provided, and the calculatedamount is reduced to a great extent.