Abstract: A variable-frequency motor device that runs on alternating current includes a first converting circuit, a second converting circuit, and a DC variable-frequency motor. An operation module is coupled to the variable-frequency motor device, and provides the alternating current to the first or second converting circuit. The first converting circuit receives the alternating current, and generates a first rotation-speed signal. The second converting circuit receives the alternating current, and generates a second rotation-speed signal. The DC variable-frequency motor is driven at a rotation speed according to the first or second rotation-speed signal.

Abstract: Systems and methods are used to control operation of a rotary compressor of a refrigeration system to limit or prevent movement of rotors due to axial thrust loading resulting from rapid changes in speed of the rotors of the compressor. The operational profile of the motor is controlled to maintain acceleration torque and deceleration torque within predefined limits. The acceleration torque and deceleration torque are maintained within the predefined limits by controlling the speed of the motor, or by controlling the torque applied by the motor to the rotors during acceleration or deceleration.

Abstract: To provide a hybrid type or battery type working machine which hardly gives a feeling of strangeness on an operation to an operator and in which electric power stored in a storage battery can be used effectively within an operation scheduled time set in advance. An amount of reduction in the amount of electricity stored in an electric storage device 60 in a predetermined time t1 after an working machine starts up is obtained, and an operation possible time t2 is obtained from the obtained amount of reduction and a residual amount of the electricity stored in the electric storage device 60. Further, determination is made as to whether the obtained operation possible time t2 reaches a remaining time of an operation scheduled time obtained by subtracting a currently spent real operation time from the operation schedule time set in advance.

Abstract: An apparatus and method for controlling an operation of a compressor are disclosed to enhance a compressor efficiency in each operation mode in operating a compressor in a power mode or power saving mode according to an external load. The apparatus for controlling an operation of a compressor, including: a controller that generates a control signal to select an operation mode of the compressor according to an operation load of the compressor; a compressor motor that includes a main coil and a sub-coil and is driven in one of a plurality of operation modes according to a control signal of the controller; and a power supply unit that applies power via capacitors each having a different capacitance to the sub-coil of the compressor motor according to a control signal of the controller.

Abstract: A control circuit controls a fan to cool an integrated baseboard management controller (iBMC) in a server. The control circuit includes a state determination module. When the server is powered off and the iBMC is operating, the system power signal from a power supply unit (PSU) of the server is at a low level, the state signal from the iBMC is at a low level signal, the fan operates. When the server and the iBMC are powered off, the system power signal from the PSU is at a low level, and the state signal from the iBMC is at a high level, the fan is powered off. When the server is operating, the system power signal from the PSU is at a high level, the fan is powered off.

Abstract: A piston type compressor wherein the position of the piston highest pressure point is indicated and the rotor of the motor at the optimal starting angle aligned prior to the actual compression operation by providing a pre-pulse to rotate the rotor of the motor at least one full rotation at a certain frequency, during rotation measuring the load torque by the frequency converter as well as indicating the maximum load torque point and at the end aligning the rotor of the motor at the optimal starting angle of about 180° from the maximum pressure angle, and at the beginning of the actual compression operation setting the rotor position opposite to the maximum torque angle by feeding direct current to the stator winding and starting the motor by supplying maximum motor current to the motor to give the maximum torque and acceleration.

Abstract: A control circuit controls a fan to cool an integrated baseboard management controller (iBMC) in a server. The control circuit includes a state determination module. When the server is powered off and the iBMC is operating, the state determination module receives low level signals from a power supply unit (PSU) and the iBMC. The state determination module connects the PSU and the fan, such that the fan is operating. When the server and the iBMC are powered off, the state determination module receives a low level signal from the PSU and a high level signal from the iBMC. The state determination module disconnects the PSU from the fan, turning the fan off. When the server is operating, the state determination module receives a high level signal from the PSU. The state determination module disconnects the PSU from the fan, turning the fan off.

Abstract: Disclosed herein is a propulsion apparatus for ships. The propulsion apparatus, which includes a front propeller and a rear propeller to rotate in opposite directions and provides propulsion power to propel a hull of a ship, includes a power unit to supply power to rotate the rear propeller, a main shaft to transfer the power supplied from the power unit to the rear propeller, a hollow shaft extending in a longitudinal direction of the main shaft to allow the main shaft to pass therethrough and coupled to the front propeller, a drive motor including a rotor coupled to an outer circumferential surface of the hollow shaft and a stator supported by the hull, the drive motor rotating the hollow shaft in a direction opposite to a direction of rotation of the main shaft, and an electricity supply unit to supply electricity to the drive motor.

Abstract: A system and method are disclosed for turning off the voltage to a pump jack electric motor during predetermined periods of time to save energy. In the method, the motor's response to closed-loop control may be evaluated over several pump strokes. The periods of the pump stroke when it is feasible to turn off the motor may be identified. The consistency of the measurements over several strokes may be evaluated. The motor may be turned off during predetermined periods on subsequent pump strokes when each pump stroke shows sufficiently similar behavior to that predicted during the closed-loop control process. The system may return to the closed-loop control process after a predetermined period of time to adjust to any changes in the system.

Abstract: A system and method are provided for reducing the energy consumed by a pump jack electric motor by reducing the supply voltage to the motor when the motor would be generating energy in open loop mode. By substantially eliminating the energy generation mode, the braking action of the utility grid in limiting the acceleration of the motor and system that would otherwise occur is substantially removed. The motor and system will speed up, allowing the natural kinetic energy of the cyclic motion to perform part of the pumping action.

Abstract: The invention relates to a centrifugal pump assembly with an electric drive motor and with a control device having a frequency converter, for the control of the rotational speed of the drive motor, wherein the control device is designed in a manner such that in at least one control region, a field weakening is produced in the drive motor, by way of which the rotational speed of the drive motor is increased.

Abstract: An electric motor communication system for use with a fluid moving system is provided. The electric motor communication system includes an electric motor including a wireless communication device configured to transmit and receive wireless signals, and a processing device coupled to the wireless communication device and configured to control the electric motor based at least in part on wireless signals received at the wireless communication device. The electric motor communication system further includes at least one external device configured to communicate wirelessly with the electric motor.

Abstract: Techniques herein describe a pumping system, adapted to reduce or eliminate fluid cavitation. Optionally, the pumping system is adapted for application to a passive fluid recovery system. In one example, the pumping system includes a pump and a thermal sub-cooling device. The thermal sub-cooling device may sub-cool fluid input to a pump and heat fluid output from the pump, particularly under start-up conditions. In a further example, a controller manages power supplied to both the pump and the thermal sub-cooling device, to transition from an ambient temperature start-up condition to an elevated temperature operating condition.

Abstract: A compressor apparatus includes a power source (26), a shell (12; 42), an electric motor (28; 52; 100; 200) having motor windings, and a control assembly (106; 206). The electric motor (28; 52; 100; 200) is located within the shell (12; 42). The control assembly a control assembly (106; 206) provides power to the motor windings from the power source (26) in two modes. A first mode provides power to the motor windings to generate heat without producing force output with the motor (28; 52; 100; 200). A second mode provides power to the motor windings to produce force output with the motor (28; 52; 100; 200). The control assembly (106; 206) activates the first mode for a selected time period prior to activation of the second mode in order to drive out a fluid (36) to reduce a risk of a flooded compressor start.

Abstract: A liquid feed pump includes a pump housing, a diaphragm forming a pump chamber together with the recessed portion surface and partitioning the pump chamber from the hole, a reciprocating member reciprocatably inserted into the hole and reciprocating to press the diaphragm to deform, a driving member displacing the reciprocating member periodically in a direction of reciprocation, a seal portion sandwiching the diaphragm to seal the diaphragm in a position around an outer peripheral side of the recessed portion surface, a diaphragm receiving surface provided between the seal portion and the opening portion, and its contact area contacting the diaphragm decreases in response to an increase in the displacement of the reciprocating member to the recessed portion surface side and increases in response to an increase in the internal pressure of the pump chamber.

Abstract: This disclosure relates to medical fluid cassettes and related systems and methods. In some aspects, a medical fluid cassette includes a base and a magnetically attractive member overlying a fluid pump chamber of the cassette. The magnetically attractive member defines a cavity sized and shaped to receive a portion of a piston.

Abstract: Having a correlative relation indicator for indicating a correlative relation so that the supply current to be supplied to an inverter circuit may be varied proportionally to the voltage applied to the inverter circuit, a supply current value controller controls the average current to be supplied to the inverter circuit so as to be equal to the value of the supply current indicated by the correlative relation indicator, and therefore if the pressure loss or the static pressure is changed, a wind volume-static pressure of high precision extremely small in the changing amount of wind volume is realized.

Abstract: The present invention has an object to detect a three-phase AC motor current with high accuracy only with DC input current measuring means to a three-phase PWM inverter, and reduce resonance of a DC power supply by a ripple current in driving an AC motor with a DC current via a three-phase PWM inverter. A carrier wave Cry_e earlier than that of a V phase is used to sample a U phase and a carrier wave Cry_l always later than that of the V phase is used to sample a W phase. Thus, a sampling time sufficiently longer than an interval Ts of the carrier waves Cry_e, Cry_m and Cry_l can be ensured, and the current can be easily detected.

Abstract: A pumping set includes an electrical drive motor and electronic controller, wherein the controller is divided into two functional modules arranged on at least two separate circuit boards, of which a first functional module represents a supply part, which provides the input voltage for the second functional module, and wherein the second functional module exhibits engine electronics that are connected with stator coils of the drive motor to supply the latter with current.

Abstract: An electric pump device of an aspect of the invention includes a state determination unit and a gain adjusting unit. The state determination unit determines whether or not the electric pump device is in a stable state where a required oil pressure is supplied to a hydraulic operating device by maintaining a rotation state of a motor. The gain adjusting unit adjusts a gain for a current feedback control so as to reduce responsiveness of the current feedback control when the state determination unit determines that the electric pump device is in the stable state.

Abstract: A voltage-command correction-value computation unit outputs a correction value for correcting a voltage command value according to a bus voltage. A multiplier calculates a voltage command value acquired by correcting the voltage command value based on the correction value. A voltage-command generation unit generates and outputs three-phase voltage command values based on the corrected voltage command value calculated by the multiplier and a phase. A PWM-signal generation unit generates six drive signals corresponding to switching elements of an inverter based on the three-phase voltage command values outputted by the voltage-command generation unit and a carrier signal. The PWM-signal generation unit outputs the generated drive signals to the corresponding switching elements of the three-phase inverter, to cause the inerter to generate a high-frequency AC voltage.

Abstract: A method and apparatus for a pump control system. One or more embodiments of the invention include a pump controller that can perform a self-calibration procedure, can provide precise motor speed control, can provide a limp mode before shutting down the motor when system parameters are exceeded and/or fault conditions occur, can detect fault conditions, and can store fault conditions for later retrieval.

Abstract: A linear compressor includes a fixed member provided with a compression space, a movable member which linearly reciprocates inside the fixed member to compress refrigerant, one or more springs installed to elastically support the movable member in a motion direction, a first stator applied with a current to produce a magnetic field, a second stator spaced apart from the first stator at a certain interval, a conductor member electromagnetically induced by the magnetic field produced by the first stator and the second stator to make the movable member linearly reciprocate, and a control unit which controls supply of the current with respect to the first stator.

Abstract: A compressor control apparatus, and a refrigerator including the same are provided. The operation of two compressors may be controlled using an alternating current (AC) switch, thereby minimizing a number of components, as well as increasing compressor capacity and enhancing operation efficiency. A plurality of operation modes may be used to correspond to a load or freezing capacity using two compressors, and the two compressors may be operated in a separate or simultaneous manner using a drive including two (AC) switches, thereby simplifying the configuration of the system.

Abstract: A compressor control apparatus, and a refrigerator including the same are provided. Operation of two compressors may be controlled using one inverter, thereby reducing a number of components, increasing compressor capacity, and enhancing operation efficiency of the system. Commonly used switching elements may be switched at an operating frequency, allowing the simultaneous operation of two compressors, reducing switching losses, and improving the efficiency and stability of the system.

Abstract: A system and a control method for the piston of a resonant linear compressor (100), especially designed for operating at their maximum efficiency, such a system being capable of actuating said compressor without the use of sensors for measuring mechanical magnitudes or variables. A method of controlling the piston of a resonant linear compressor, the steps of which enable one to estimate the velocity and the displacement of said piston, in order to control the compressor motor efficiently. A resonant linear compressor (100) provided with a control system as proposed.

Abstract: A system for determining whether a motor in an electrical submersible pump is backspinning is described herein. The system comprises a sensor mounted in a well bore proximate to a ground surface, the sensor outputting a backspin signal; a communication link connected to the sensor, the communications link communicating the backspin signal; and a controller receiving the backspin signal from the communications link and processing the backspin signal to determine whether the motor is backspinning.

Abstract: In a system comprising a fuel and a rotating electrical machine, damage of a switching element is prevented when the rotating electrical machine becomes a locked state. In a power controller, it is monitored whether the rotating electrical machine is in the locked state or not. When the rotating electrical machines is judged to be in the locked state, a command for dropping output voltage is given to the fuel cell. Thus, inverter input voltage can be dropped, loss power of the switching element in the rotating electrical machine is dropped and damage can be suppressed. The rotating electrical machine is monitored to cancel the locked state or not while dropping of inverter input voltage is controlled. When the locked state is judged to be canceled, control of the fuel cell is returned to a state of regular operation control.

Abstract: Embodiments of the invention provide a pumping system for at least one aquatic application controlled by a user. The pumping system includes a pump, a variable speed motor, a memory, and a controller. The pumping system includes a user interface with a first speed button, a second speed button, an increase button, and a decrease button. The buttons provide an actuate and release operation, a first touch and hold operation, and a second touch and hold operation. The controller operates the variable speed motor at a substantially constant speed based on a current speed value selected by the user using the buttons.

Abstract: Control process for a piezoelectric pump (100) of an electric household appliance comprising a pump chamber (110) equipped with a mobile wall (111) displaceable under the action of a piezoelectric actuator (111A), characterized in that during a startup phase of the pump (100), the piezoelectric actuator (111A) is supplied during a plurality of alternations with an alternating supply signal having a voltage U bringing about a substantial deformation of the piezoelectric actuator (111A) for a maximum sweeping of the volume of the pump chamber (110) by the mobile wall (111), and further characterized in that the pump startup phase is followed by a normal operation phase during which the supply signal is modified so that the mean flow rate provided by the pump (100) is less than the flow rate provided during the startup phase.

Abstract: A piston type compressor wherein the position of the piston highest pressure point is indicated and the rotor of the motor at the optimal starting angle aligned prior to the actual compression operation by providing a pre-pulse to rotate the rotor of the motor at least one full rotation at a certain frequency, during rotation measuring the load torque by the frequency converter as well as indicating the maximum load torque point and at the end aligning the rotor of the motor at the optimal starting angle of about 180° from the maximum pressure angle, and at the beginning of the actual compression operation setting the rotor position opposite to the maximum torque angle by feeding direct current to the stator winding and starting the motor by supplying maximum motor current to the motor to give the maximum torque and acceleration.

Abstract: An electric motor is configured to provide mechanical power to a fuel pump. A method for monitoring the fuel pump includes estimating a pump speed and a nominal pump motor current in relation to a pump motor control signal and a fuel pressure. An armature resistance and a back-emf constant for the electric motor are determined corresponding to the estimated pump speed, a monitored pump motor current, and the pump motor control signal. A nominal armature resistance and a nominal back-emf constant for the electric motor are adjusted in relation to a pump motor temperature. A plurality of residuals are calculated based upon the adjusted nominal armature resistance, the adjusted nominal back-emf constant for the electric motor, the estimated armature resistance and the estimated back-emf constant for the electric motor. The residuals are compared with corresponding thresholds. A fault in the electric motor is detected based upon the comparisons of the residuals with the corresponding thresholds.

Abstract: A universal controller (16) for an electric motorized pump (18) having a mechanical switch (19) for turning on and off electrical power to the pump, and method of operation of same. The controller controls output pressure of the pump based on controlling the speed of the pump (for example by applying voltage over a greater portion of a duty cycle), so as to provide an optimal operating pressure derived from an automatically determined value for the pressure at which the mechanical switch opens and disrupts electrical power to the pump. It is manufactured as a standalone assembly, not attached to a pump. It can be operated so as to automatically seek and determine a switch-opening pressure for the switch (19), at which the pump pressure switch opens and so interrupts electrical power to the motor, and to then choose an operating pressure below the switch-opening pressure.

Abstract: A method for operating a vehicle heater dosing pump for conveying fuel having a piston which can be moved back and forth between a start position and an end position, and a drive unit which can be electrically excited by applying a voltage, having the following procedure: controlling and/or regulating the voltage for generating an effective voltage to transfer the piston from the start position to the end position, wherein the effective voltage reaches a first maximum (U1) in a start phase (t0-t1), and is lower than the first maximum in a subsequent intermediate phase (t1-t2). The effective voltage reaches a second maximum (U3) in an end phase (t2-t3) following the intermediate phase. A device is also provided having a dosing pump and a control/regulation unit. The control/regulation unit is suitable for controlling voltage applied to a drive unit of the dosing pump.

Abstract: A fan control unit measures the rotating speeds of the first and second fans to calculate the relative work intensities of the two fans. The control unit determines whether a difference between the first work intensity and the second work intensity is within a predetermined range. If the difference between the first work intensity and second work intensity is not in the predetermined range, the control unit adjusts a duty cycle of a pulse signal output to one of the first and second fans to change the rotating speed of one of the first and second fans to bring the difference between the first work intensity and the second work intensity within the predetermined range.

Abstract: This invention demonstrates an improved method of constructing an artificial lift device for deep wells, in which the deadload of the pump mechanism is supported by a continuously-controlled gas spring. The reciprocating motion is produced by a very unusual form of linear motor using a plurality of radially disposed conducting vanes and having no wire coils. The machine is highly efficient and is able to deduce many of the conditions obtaining at the pump by computations from the measured power demand at each point of the pumping cycle. The device is self-protecting and self-optimising.

Abstract: The present invention relates to a linear compressor which can perform the natural cooling capacity modulation, even if a capacitor connected to a motor is removed. The linear compressor includes a fixed member having a compression space therein, a movable member linearly reciprocated in the fixed member to compress a refrigerant sucked into the compression space, one or more springs provided to elastically support the movable member in the motion direction of the movable member, a motor connected to the movable member to linearly reciprocate the movable member in the axial direction, and a motor control unit performing the cooling capacity modulation by the reciprocation of the movable member according to a load, by controlling an AC voltage applied to the motor so that a stroke of the movable member can be proportional to the magnitude of the AC voltage applied to the motor.

Abstract: A method for regulating a motor-driven pump of an SCR system, the pump delivering a pressure, being subjected to a hydraulic torque in relation to this pressure and also to a resistive torque and being driven by an electric motor including coils supplied with a current and developing a torque in relation to this current, according to which to regulate the pump, use is made of a mechanism to measure the current in the coils of the motor, of a regulator of overall current consumed by the motor, and of a model of the relation between the current and the pressure using an estimate of part of the resistive torque, namely the dry frictions, obtained by rotating the pump under no-load conditions at different speeds and by measuring the associated current.

Abstract: The present invention relates to a system and to a method of controlling a fluid pump, as well as to a linear compressor and a cooler configured to calibrate the respective functioning at the time of the first use or in cases of problems caused by electric or mechanical failures. According to the teachings of the present invention, the fluid pump is provided with a piston-position sensing assembly, the electronic controller monitoring the piston displacement within the respective cylinder by detecting an impact signal. The impact signal is transmitted by the sensing assembly upon occurrence of an impact of the piston with the stroke end, the electronic controller successively incrementing the piston displacement stroke upon a trigger signal as far as the occurrence of the impact to store a maximum value of piston displacement.

Abstract: Embodiments of the invention provide a pump control circuit for use with a pump. The circuit includes a pressure sensor capable of sensing a pressure in the pump and a microcontroller coupled to the pressure sensor and to the pump. The microcontroller switches operation of the pump between a high-flow mode and a low-flow mode. When in the high flow mode, the microcontroller limits a current provided to the pump to a high-flow current limit value that is not dependent on the sensed pressure. When in the low flow mode, the microcontroller limits the current provided to the pump to a low-flow current limit value that is less than the high-flow current limit value and that changes depending on the sensed pressure.

Abstract: The present invention relates to a system and method of controlling a linear compressor (10), which is capable of fine-tuning the compressor when necessary, throughout the operating period of the compressor, so that said compressor operates at maximum capacity, wherein the piston (1) achieves a maximum displacement amplitude, closely approaching the cylinder head (2) without colliding with it. The system and the method according to the invention are also intended to control the operation of the linear compressor throughout its operating period, also seeking to maximize its performance and to reduce or optimize its power consumption. According to the present invention, the fine-tuning and control of the operation of the linear compressor are carried out by means of the combination of a technique for controlling a compressor without a sensor, and a technique for controlling the compressor with the aid of a sensor.

Abstract: A pump assembly and estimation and control system therefor, the pump adapted for continuous flow pumping of blood. In a particular form, the pump is a centrifugal pump wherein the impeller is entirely sealed within the pump housing and is exclusively hydrodynamically suspended therein against movement in three translational and two rotational degrees of freedom as the impeller rotates within the fluid urged by electromagnetic means external to the pump cavity. Hydrodynamic suspension is assisted by the impeller having deformities therein such as blades with surfaces tapered from the leading edges to the trailing edges of bottom and top surfaces thereof.

Abstract: Methods and apparatus for measuring phase flow rate of the components of a multiphase fluid in a conduit. A pumping system pumps out a multiphase fluid from a wellbore. At least one processor, which may also control the pump, is used to determine the total liquid flow rate over time. An optical phase fraction meter (e.g., an infrared filter photometer) is used to determine the real-time phase fraction of the components of the multiphase fluid. Algorithms are used to calculate the volumetric flow rates of the individual components of the multiphase fluid based upon the total liquid flow rate and the phase fraction. Embodiments of the present invention provide an inexpensive system capable of measuring real time water-to-oil ratios in mature fields, where the water-to-oil ratio is high and the oil per-well production is low.

Abstract: A control system for a fan includes a control housing that is external to a fan housing for the fan. At least one fan control module is within the control housing and communicates remotely with terminals within the fan housing via at least one wire. The at least one fan control module includes a detection module. The detection module detects induced voltages in at least one of a plurality of stator coils within the fan housing via the at least one wire without receiving signals from a sensor in the fan housing.

Abstract: A fuel pump system for pumping fuel to an engine in a vehicle includes a pump motor having a carbon-based commutator and brushes in a position exposed to fuel, resulting in a tendency to form a film between the commutator and brushes that can reduce pump performance by increasing the electrical resistance of the brush-commutator interface. The pump motor has a nominal voltage rating. A power circuit is coupled to the pump motor for selectably providing an operating voltage and a boost voltage, wherein the boost voltage is greater than the nominal voltage rating. A controller selecting the operating voltage during an ordinary run cycle and selects the boost voltage during a clean-up cycle. The controller selects the clean-up cycle for a limited time that is sufficiently short to avoid damage to the pump motor from exceeding the nominal voltage rating and sufficiently long to create arcing between the commutator and brushes that reverses formation of the film.

Abstract: The present invention relates to a linear compressor which can provide greater power by changing a frequency at a high load.

Abstract: A motor controlling method and apparatus of an air conditioner are disclosed. It is checked whether or not an operation frequency of a compressor motor is the same as or greater than a certain frequency and it is also checked whether or not a detected velocity of a fan motor is the same as or lower than a certain velocity during a certain time period. If the operation frequency is the same as or greater than the certain frequency and the detected velocity is the same as or lower than the certain velocity during a certain time period, the compressor motor is temporarily stopped. Because the compressor motor operates according to operational conditions of the fan motor, an overload can be prevented.

Abstract: A system for defogging doors to a display case is described and includes an electric motor and an air moving device. The air moving device is operatively coupled to the electric motor and positioned to provide an output proximate to at least one door of the display case. The motor is configured to operate at a first speed under standard closed door conditions, at a second speed when the door of the display case is open, and at a third speed for a predetermined length of time after the door is moved from an open position to a closed position.

Abstract: A piston-type fuel pump is provided. The fuel pump includes a housing bounding an internal cavity with a cylindrical tube disposed in the internal cavity. The cylindrical tube provides a bore extending along an axis and a piston is disposed in the bore. A spring is configured to bias the piston in a first direction along the axis. A coil is disposed about the cylindrical tube and a control circuit is disposed in the internal cavity. The control circuit is configured in electrical communication with the coil. The voltage supplied to the control circuit can be varied, with the control circuit compensating for the variable supply voltage to regulate the actuation of the coil from a de-energized state to an energized state. The piston is biased in a second direction opposite the first direction in response to the coil being actuated.

Abstract: A linear compressor (100) applicable to a cooling system (20) includes a piston (1) driven by a linear motor (10), the piston (1) having displacement range controlled by means of a controlled voltage (VM), the controlled voltage (VM) having a voltage frequency (?P) applied to the linear motor (10) and adjusted by a processing unit (22), the range of piston (1) displacement being dynamically controlled in function of a variable demand of the cooling system (20), the linear compressor (100) having a resonance frequency, the processing unit (22) adjusting the range of piston (1) displacement, so that the linear compressor (100) will be dynamically kept on resonance throughout the variations in demand of the cooling system (20).