A method of handling a gear pump, the gear pump including a driving gear wheel having a plurality of driving teeth and a driven gear wheel having a plurality of driven teeth meshing with the driving teeth, the method including controlling the gear pump in a testing mode including commanding driving of the gear pump to pump liquid towards a downstream device and commanding an increase of rotational speed of the gear pump; monitoring rotation values indicative of the rotational speeds during the testing mode; monitoring pressure values by means of at least a downstream pressure sensor during the testing mode, the downstream pressure sensor being arranged to measure a downstream pressure of the liquid between the gear pump and the downstream device; and determining at least one operational condition of the gear pump based on the pressure values and the rotation values.

An in-vehicle motor-driven compressor includes a temperature rise estimator configured to estimate a temperature rise of the diode based on an expected reverse current, an on-voltage of the diode, and a heat resistance of the diode. The in-vehicle motor-driven compressor further includes a rotation speed controller configured to set a rotation speed limit of the electric motor, based on the estimated temperature rise of the diode so that a temperature of the diode does not exceed a junction temperature of the diode even when the electric motor is stopped and the reverse current flows through the diode, and limit a rotation speed of the electric motor to lower than or equal to the rotation speed limit.

The present disclosure relates to a multi-stage compression system in which the drive speed of each compressor that constitutes the multi-stage compression system is individually controlled to increase compression efficiency, and a control method thereof. To this end, the present disclosure includes at least two compressors, at least two driving devices connected to each of the compressors in series to drive the compressors connected in series, at least two pressure detectors installed at a discharge end of each of the compressors to detect a discharge pressure of each compressor, and a control unit configured to individually control a drive speed of each driving device based on the discharge pressure of each compressor detected through each of the pressure detectors.

A method for expulsion of a fluid inside a compressor at start-up including the steps: applying a first signal to the motor windings for a first duration of time to align the motor rotor to the initial position; applying a second signal to the motor windings to start rotation of the compressor shaft; applying a third signal to the motor windings for a second duration of time to hold the compressor shaft in place; and applying a fourth signal to the motor windings to accelerate the motor to an operational speed.

A method of operating exhaust gas recirculation pump for an internal combustion engine including: providing an EGR pump assembly including an electric motor coupled to a roots device having rotors, the EGR pump operably connected to an internal combustion engine; providing an EGR control unit linked to the EGR pump assembly; providing sensors linked to the EGR control unit; determining if a motor speed is within a predetermined target in step S1 wherein when motor speed=predetermined target then; determining if a motor torque is within a predetermined target in step S2 wherein when motor torque=predetermined target then; determining if a motor temperature is within a predetermined target in step S3 wherein when motor temperature=predetermined target then; and maintaining operation of the exhaust gas recirculation pump.

A method for controlling the rotational speed (S) of an electric motor driven air compressor (2) that supplies compressed air to a pneumatically operated system (5) of a vehicle (1), characterized by the preliminary steps of: a) determining the efficiency (e) of the air compressor (2) for different values (Si) of the rotational speed (S) of the air compressor (2), the efficiency (e) of the air compressor (2) corresponding to the ratio between the pneumatic power (PI) produced by the air compressor (2) and the power (PO) given to the air compressor (2); b) determining one or several specific values (S2, S4) among said different values (Si), for which the efficiency (e) of the air compressor (2) is higher than a threshold value (emin) and/or comparatively higher than those determined for values (SI, S3) close to said specific value(s) (S2, S4); the preliminary steps a) and b) being preferably implemented only once; and characterized by the further repetitive steps of: c) determining the air consumption rate of the pneumatically operated system (5) receiving compressed air from the air compressor (2); d) determining a minimum rotational speed (Smin) of the air compressor (2) to obtain an air production rate of the air compressor (2) that is equal or substantially equal to said determined air consumption rate; e) determining if the specific value or one of the specific values (S2, S4) is greater than said determined minimum rotational speed (Smin); f) if no specific value is greater than said determined minimum rotational speed (Smin), controlling the rotational speed (S) of the air compressor (2) based on said minimum rotational speed (Smin); g) if only one specific value (S4) is greater than said determined minimum rotational speed (Smin), controlling the rotational speed (S) of the air compressor (2) based on said only one specific value (S4); h) if a plurality of specific values (S2, S4) is greater than said determined minimum rotational speed (Smin), determining the specific value (S2) with the best efficiency among said plurality of specific values (S2, S4) and controlling the rotational speed (S) of the air compressor (2) based on said specific value (S2) with the best efficiency.

An electric oil pump includes a pump unit, rotating to make oil flow, a motor driving the pump unit, a control unit exerting driving control on the motor, and a housing accommodating the pump unit, the motor, and the motor control unit. In the electric oil pump, the motor control unit directly receives detection information of a temperature sensor detecting a temperature of the oil and exerts driving control on the motor based on the detection information.

A fluid-driven actuator system includes a fluid-driven actuator and at least one proportional control valve and at least one pump connected to the fluid-driven actuator to provide fluid to operate the fluid-driven actuator. The at least one pump includes at least one fluid driver having a prime mover and a fluid displacement assembly to be driven by the prime mover such that fluid is transferred from the pump inlet to the pump outlet. The fluid driven actuator system also includes a controller that establishes at least one of a speed and a torque of the at least one prime mover to adjust at least one of a flow in the fluid system to a flow set point and a pressure in the fluid system to pressure set point and a concurrently establishes an opening of the at least one proportional control valve to adjust at least one of the flow to the flow set point and the pressure to the pressure set point.

In order to reduce operation in a rotation-prohibited frequency range and to prevent resonance in a gas compressor wherein inverter control is performed, this gas compressor has: a compressor main body that compresses a gas; a motor that rotationally drives the compressor main body; an inverter that changes the rotational speed of the motor; a check valve arranged downstream from the compressor main body; a pressure detection means that detects load-side pressure downstream from the check valve; and a control device that, in accordance with the pressure detected by the pressure detection means, controls the frequency output by the inverter. The control device performs a control whereby compressed gas having a prescribed pressure is generated/maintained by increasing/decreasing the frequency, and when the frequency that generates the compressed gas having the prescribed pressure includes a specific frequency, the inverter's output frequency is increased or decreased when the pressure detected by the pressure detection means reaches a pressure corresponding to a frequency that has a more constant pressure width than the prescribed pressure and does not include the specific frequency.

A method for controlling the speed of a compressor with a controller as a function of the available gas flow comprising the following steps: setting a desired value for the inlet pressure; determining the inlet pressure; determining the speed; controlling the speed of the compressor by reducing or increasing it depending on whether the inlet pressure is less than or greater than the set desired value until the inlet pressure is equal to the set desired value; providing the characteristic data of the compressor relating to the efficiency and/or the Specific Energy Requirement (SER) as a function of the speed and the inlet pressure; adjusting the desired value of the inlet pressure on the basis of the aforementioned characteristic data and in such a way that the efficiency of the compressor is a maximum or the SER is a minimum.