An axial piston pump controller for an axial piston pump having a fixed valve plate and a variable displacement is provided. The axial piston pump controller is configured to determine a displacement of the axial piston pump, and to calculate a pump displacement control current to be supplied to the axial piston pump to control the displacement of the axial piston pump. Calculating the pump displacement control current comprises calculating a nominal value for the pump displacement control current based on a rotational speed of the axial piston pump, calculating a pump stiffness adjustment factor based on a pump stiffness control map having as inputs: an output pressure of the axial piston pump; and the estimated pump displacement, and calculating the pump displacement control current to be supplied to the axial piston pump based on the nominal value and the pump stiffness adjustment factor. The controller is further configured to output an instruction to output the calculated pump displacement control current to the axial piston pump in order to control the displacement of the axial piston pump.

Provided is an air conditioning apparatus that is capable of suppressing increases in volume and cost of the apparatus and performing more suitable overheating protection. An electric compressor is an inverter-integrated electric compressor (10) integrally including a compressor (5), an electric motor (6) that drives the compressor (5), and an inverter (7) including a temperature sensor (11) that detects the temperature in the vicinity of a semiconductor switching device, wherein a controller (3) estimates a discharge temperature of the compressor (5) on the basis of a correlation of respective pressure loading characteristics for the detected temperature of the inverter (7), for the rotational speed of the compressor (5), and for the motive force of the compressor (5) in a refrigerating cycle (2).

[Problems] To provide a driving method for a metering pump, a driving apparatus for a metering pump, a vaporizer and an anesthesia apparatus which are capable of suppressing a pulsation in the metering pump, and lowering the costs and reducing the sizes of the vaporizer and the anesthesia apparatus.

[Means for solving the Problems] A metering pump 16 is joined to the stepping motor 15, includes an eccentric mechanism converting a revolving motion of the stepping motor 15 into a reciprocating motion of a plunger 16A, and makes a constant liquid delivery by sucking and discharging an anesthetic agent through variations in the cubic volume of a cylinder 16D caused by the reciprocating motion of the plunger 16A. The control section 12: calculates a suction and discharge cycle T of the metering pump 16 on the basis of a set anesthetic-gas concentration and a fresh-gas flow rate; sets a discharge period T2 of the cycle T to be longer than a suction period T1 of the cycle T; and controls the revolution speed of the stepping motor 15 so that the travelling speed of the plunger 16A is kept constant during the discharge period T2.

A pump unit includes an electric motor and a pump with a duct. The pump is rotationally driven by the electric motor to provide a setpoint volumetric flow to the duct. A rotational speed controller is configured to, during operation of the pump, determine a setpoint rotational speed based on a fixed-point iteration of an initial rotational speed. The setpoint rotational speed is associated with a setpoint volumetric flow. The rotational speed controller is further configured to operate the pump at the setpoint rotational speed.

Disclosed herein is an integrated pump system in which a motor is directly coupled to a pump, preferably using a modular connection. The integrated pump system may operate in a uni-directional or bi-directional mode. The integrated pump system incorporates an internal cooling channel which directs the returning low pressure hydraulic fluid past the controller and the motor for cooling purposes. The low pressure hydraulic fluid is also directly fed into the coupling between the motor and the pump to provide both cooling and lubrication.

A method includes supplying a plurality of generators, each generator in electrical communication with a switchgear with each switchgear in data communication with a generator data management system. The method also includes supplying a plurality of electrically driven fracturing pumps with each electrically driven fracturing pump in data communication with pump data management system. Further, the method includes supplying a load shedding system, the load shedding system in data communication with the generator data management system and a pump control system, the pump control system in data communication with the pump data management system. The method includes determining which pumps should have speed reduced by the load shedding system and reducing the speed of the pumps determined by the load shedding system using the pump control system.

Provided is a tube pump system which includes: a pair of roller units which are rotated around an axis line from a closing position to a releasing position; a pair of drive units which are configured to respectively rotate the pair of roller units; a control unit which is configured to control each of the pair of drive units; and a pressure sensor which is configured to detect a pressure of a liquid in a pipe connected to the other end of the tube, wherein the control unit controls a first rotation angle when the first roller unit passes through the closing position and a second rotation angle when the second roller unit passes through the releasing position such that fluctuation of the pressure of the liquid when the pair of roller units are rotated through at least one revolution falls within a predetermined value.

A centrifuge system includes a centrifuge and a feed line fluidly connected to centrifuge with the centrifuge driven by a hydraulic system. The hydraulic system includes an electric motor driving a hydraulic pump connected to a fluid reservoir with the hydraulic pump providing hydraulic fluid to one or more hydraulic motors which in turn rotate the centrifuge. The system includes a pressure sensor for measuring fluid pressure and a speed sensor for measuring the rotational speed of the centrifuge. A controller can be in communication with the hydraulic system and the sensors and can receive measurements from the sensors and adjust the pressure of hydraulic fluid flowing to the one or more hydraulic motors to maintain a rotational speed of the centrifuge based on differing loads. The system can include one or more valves, controlled by the controller, which can also adjust the hydraulic pressure of the system.

A compressor control apparatus and method differently compensate for a duty ratio of a control signal during a period in which the compressor performs a compression stroke and a period in which the compressor performs a suction stroke, respectively, to generate the control signal for controlling a compressor.

A method for controlling a DC pump motor, preferably a brushed DC motor for pumping lubricant, which motor is controlled by a pulse-width modulated (PWM) control signal, wherein current parameters are acquired in an acquisition step and a duty cycle (D) of the PWM control signal (S.sub.PWM) is adapted and/or changed on the basis of the detected parameters in an adaptation step, wherein the acquisition of current parameters comprises at least the acquisition of a current input voltage (U.sub.B).