Methods and apparatus are disclosed for detecting and preventing compressor surge. A transmitter determines a derivative process value of a compressor. A controller obtains the derivative process value from the transmitter. The transmitter is separate from the controller. The controller compares the derivative process value to a threshold value. The threshold value is indicative of the initiation of a surge event in the compressor. In response to determining that the derivative process value fails to satisfy the threshold value, the controller actuates a valve operatively coupled to the compressor to enable an additional derivative process value of the compressor determined by the transmitter to satisfy the threshold value.

Methods and systems for controlling a bleed-off valve of a gas turbine engine are described. The method comprises maintaining a first bleed-off valve associated with a first compressor of the gas turbine engine at least partially open upon detection of an unintended engine disturbance causing a drop in pressure of a combustion chamber of the engine; monitoring a rotor acceleration of the first compressor; and controlling closure of the first bleed-off valve when the rotor acceleration of the first compressor reaches a first threshold for a first duration.

A system includes a dynamic compressor, a variable frequency drive (VFD), and a controller. The dynamic compressor includes a motor having a driveshaft rotatably supported within the dynamic compressor, and a compression mechanism connected to the driveshaft and operable to compress a working fluid upon rotation of the driveshaft. The VFD includes a sensor configured to sense a current provided to the motor. The controller is connected to the motor and includes a processor and a memory. The memory stores instructions that program the processor to operate the motor using the VFD to compress the working fluid, receive signals representing the current from the VFD to the motor, and determine when a surge event has occurred based at least in part on the received signals representing the current from the VFD to the motor.

A system has an electric motor having a stator and a rotor. The rotor rotates with a shaft and the shaft drives a fluid rotor. A control senses a fault condition on the electric motor. The control actuates a speed reduction feature when a fault is detected to bring rotation of the motor rotor and the fluid rotor to a stop more rapidly than if the speed reduction feature had not been actuated.

A system for bleeding air from a core flow path of a gas turbine engine is disclosed. In various embodiments, the system includes a bleed valve having a bleed valve inlet configured to receive a bleed air from a first access point to the core flow path and a bleed valve outlet; and an air motor having a first air motor inlet configured to receive the bleed air from the bleed valve outlet and a first air motor outlet configured to exhaust the bleed air, the air motor configured to pump the bleed air from the core flow path of the gas turbine engine.

An apparatus and method of controlling a multi-stage compressor of a gas turbine engine having a front-block of stages with variable stator vanes (VSVs), a rear block of stages downstream of the front-block, and a bleed air off-take from at least one of the stages. The method includes sensing the pressure of the bleed air from the bleed air off-take and adjusting the position of the VSV for the front-block.

Systems, apparatus and methods for operating a chiller plant while minimizing or eliminating the occurrence of centrifugal compressor surge. Taking into account chiller design specifications and current operating conditions, a compressor lift point at which surge is predicted to occur is established. Minima and maxima for various chiller setpoints that avoid or eliminate the occurrence of compressor surge are imposed on setpoints provided by a conventional optimizing chiller controller. The chiller system is operated in accordance with the resultant anti-surge setpoints. Coolant tower flow is modulated to enable the compressor to operate at near-surge conditions while preventing the onset of actual surge.

A system (16) for pumping a fluid, comprising: a pump (17) comprising a suction side (18) and a discharge side (19); a motor (20) for driving the pump, which motor is drivingly connected to the pump via a shaft (21); a return line (23) providing a feed-back conduit for the fluid from the discharge side to the suction side; a control valve (24) controlling the flow of the fluid through the return line; and a first sensor device (27) for monitoring a first system parameter which is a function of the differential pressure across the pump. The system further comprises: a second sensor device (28) for monitoring a second system parameter which is a function of the torque of the pump; and a control unit (25) arranged to: receive monitored first system parameter values from the first sensor device and, for each monitored first system parameter value, identify a minimum allowable second system parameter value; receive monitored second system parameter values from the second sensor device and, for each monitored second system parameter value, compare the monitored second system parameter value with the identified minimum allowable second parameter value; and regulate the control valve such that the monitored second parameter value does not fall below the minimum allowable second parameter value. A method of operating such a system is also disclosed.

A compressor control system includes a compressor compressing a fluid, an anti-surge valve preventing backflow in the compressor, the anti-surge valve being arranged on a line connecting an inlet and an outlet of the compressor and operated by a first signal, an inlet guide vane controlling an opening area of the inlet, the inlet guide vane being arranged at the inlet and operated by a second signal, and a controller connected to the anti-surge valve and the inlet guide vane and generating the first signal to control the anti-surge valve, a vane control signal to control the inlet guide vane, a pressure compensation signal to control the inlet guide vane to compensate for a change in pressure at the outlet of the compressor according to the first signal, and the second signal by combining the pressure compensation signal with the vane control signal.

The present application provides a process for preventing rotating stall and surge in a turbomachine compressor. The compressor may include air extraction pipes connecting the compressor to a turbomachine exhaust area or to the atmosphere, at least one of the pipes is fitted with a flow regulation valve, and each valve has an adjustable degree of opening. The process includes, for at least one of the valves, a complete opening command when the compressor rotation speed is less than a predetermined threshold value beyond which there is no longer any risk of rotating stall and surge and a command for lowering the degree of opening of the valve when the rotation speed of the compressor exceeds the threshold value.