A rotation locking system of a motor of a fan is provided. A closed-loop control circuit outputs an initial duty cycle signal according to a current rotational speed and a target rotational speed. A driver circuit outputs a driving signal to the motor to drive the motor to rotate according to the initial duty cycle signal. A lookup table arithmetic circuit looks up, from a lookup table, two reference duty cycles correspond to two reference rotational speeds that are respectively equal to the current rotational speed and the target rotational speed. The lookup table arithmetic circuit calculates a difference between the two reference duty cycles. A speed feedback control circuit compensates the initial duty cycle signal according to the difference to output a final duty cycle signal to the driver circuit. The driver circuit drives the motor to rotate according to the final duty cycle signal.

A vacuum pump and a stator column wherein partition walls from an outer peripheral surface of the stator column toward an inner periphery of a rotor blade are provided at two spots, and a groove-shaped channel in a circumferential direction is provided. A sectional area of the channel changes in the circumferential direction. As a result, the pressure difference between a front and a rear of the partition wall on a downstream side is made uniform regardless of a location, and a flowrate of the gas passing through a gap between the partition wall on the downstream side and the inner peripheral surface of the rotor blade is made uniform regardless of the location. The change in the sectional area is achieved either by changing a depth of the groove-shaped channel or by changing an interval between the partition walls at the two spots.

A control system is provided to optimize a compressor that has a variable guide vane position and a variable speed set point. One or more controllers receive a process set point for a main process variable for a first performance control application and a deviation set point for a surge deviation level for a second performance control application. The first performance control application operates a first independent primary control loop to control the main process variable at the process set point by manipulating the variable guide vane position. The second performance control application operates a second independent primary control loop to control a surge deviation level at the deviation set point by manipulating the variable speed set point. The second performance control application also executes a limit control loop to limit the main process variable at a limit set point by manipulating the variable speed set point.

This disclosure describes a novel methodology for anti-surge and anti-choke control systems protecting centrifugal and axial compressors. The methodology, based on Buckingham's π-theorem for compressors, presents compressor performance maps in dimensionless rectangular π-term coordinates that are independent of compressor inlet conditions, fluid molecular weight and rotational speed. The full range of compressor operating points from surge to choke is monitored and controlled when surge and choke limits are available. This is accomplished by converting rectangular coordinates presented in π-terms to polar coordinates, and then converting them to a controlled variable used in the closed-loop controllers. The methodology provides control algorithms for variable speed compressors, variable geometry compressors equipped with inlet guide vanes or stator vanes that exhibit displacement of surge and choke limits. The methodology most accurately estimates the location of the operating point relative to its limit in polar coordinates if only the surge or choke limit is available. The presented protection methods are applicable to any known types of dynamic compressors for industrial, commercial, jet engines, turbochargers.

A compressor is provided. The compressor according to the present disclosure includes: one or more impellers suctioning and compressing refrigerant; a motor rotating the impeller; a rotation shaft to which the impeller and the motor are connected; a gap sensor measuring a displacement change of the rotation shaft as a frequency change; a temperature compensation sensor determining a frequency compensation value according to a temperature change around the gap sensor; and a control unit calculating a displacement amount of the rotation shaft by reflecting the frequency compensation value provided by the temperature compensation sensor and the frequency change measured by the gap sensor.

Pneumatic air systems for use onboard aircraft include a compressor configured to receive air from an air supply and increase a pressure of said received air to generate compressed air, a heat exchanger configured to receive the compressed air as a first working fluid and a treating air as a second working fluid, the heat exchanger configured to convert the compressed air to compressed and temperature treated air, one or more aircraft systems configured to receive the compressed and temperature treated air, and a surge prevention circuit arranged to prevent surge of air at the compressor, wherein the surge prevention circuit comprises a mechanical valve that is actuated based on a detected pressure within a sense line operably coupled to the mechanical valve.

A two-way flow control device including: a housing defining a first opening interface and a second opening interface, a rotor having a plurality of blades, each blade controllable to be angled in a range of positive and negative blade angles to generate respective positive and negative flows between the first opening interface and the second opening interface, first stator vanes mounted to the housing between the blades and the first opening interface, each including a respective stator vane slope having a stator vane angle which are collectively positive or negative angled; second stator vanes mounted to the housing between the blades and the second opening interface, each including a respective stator vane slope having a stator vane angle which are collectively opposite angled to the stator vane angles of the first stator vanes, the second stator vanes mounted to be circumferentially offset with respect to the first stator vanes.

A rotor assembly (30) comprising a rotor (32) having an annular array of rotor blades (34), the rotor mounted to a shaft (38). A phonic wheel (40) coupled to the shaft. A speed sensor (44) axially aligned with the phonic wheel and configured to measure voltage (V), amplitude of the voltage being proportional to clearance (46) between the sensor and phonic wheel. A processor (48) configured to: receive the voltage measurement; derive shaft speed (ω) from the voltage measurement; identify modulation of the voltage amplitude at a frequency which is an integer multiple of the shaft speed; compare voltage amplitude to a threshold; and output a rotor damage signal based on the comparison.

A compressor control system includes: a compressor; an inlet guide vane (IGV) arranged at an inlet of the compressor, and configured to adjust opening of the inlet based on a supplementary surge control signal or a performance control signal; an anti-surge valve (ASV) connected to an outlet of the compressor, and configured to prevent a surge based on a surge control signal; and a controller configured to generate the surge control signal for controlling the ASV when an operating point enters a surge control range, generate the supplementary surge control signal for controlling the IGV in an anti-surge mode when the operating point enters a supplementary surge control range set between the surge control range and a surge range, and generate the performance control signal for controlling the IGV in a performance mode until the operating point enters the surge control range.

Examples described herein provide a computer-implemented method that includes receiving training data indicative of incipient compressor surge for cabin air compressors. The method further includes generating, using the training data, a training spectrogram. The method further includes training, by a processing system, a machine learning model to detect incipient compressor surge events for the cabin air compressors using the spectrogram. The method further includes receiving, at a microcontroller associated with a cabin air compressor, operating data associated with the cabin air compressor. The method further includes generating, at the microcontroller and using the operating data, an operating spectrogram. The method further includes detecting, by the microcontroller associated with the cabin air compressor, an incipient compressor surge event by applying the machine learning model to the operating spectrogram. The method further includes implementing a corrective action to correct the incipient compressor surge event.