Abstract: In an embodiment, a power module may include: a plurality of first stages, each having an H-bridge to receive an incoming AC voltage at a first frequency and rectify the incoming AC voltage to a DC voltage; a plurality of DC buses, each to receive the DC voltage from one of the plurality of first stages; a plurality of second stages, each coupled to one of the plurality of DC buses to receive the DC voltage and output a second AC voltage at a second frequency; and a hardware configuration system having fixed components and optional components to provide different configurations for the power module.

Abstract: A PMSM sensorless composite control method with dual sliding-mode observers is provided. In particular, two sliding-mode observers are designed, one provides an exponential piecewise sliding-mode function for observation of back electromotive force, and the other sliding-mode observer is for observation of load torque and fine-tuning parameters of a piecewise PI controller while introducing an estimated load torque onto a q-axis for feedforward compensation. A q-axis current inner loop is designed with a second-order sliding-mode controller, which can improve tracking performance of q-axis current and indirectly control an electromagnetic torque. The exponential piecewise sliding-mode function is more conductive to the observation of back electromotive force and can weaken the buffeting phenomenon. The sliding-mode observer for observing the load torque fine-tunes parameters of the piecewise PI controller while performing the feedforward compensation, the load capability of the system is improved.

Abstract: A sensor device for an electric machine includes a rotor shaft mounted rotatably in a housing, with a signal generator that is or can be joined non-rotatably to the rotor shaft and is or can be arranged axially on the end face of the rotor shaft. A signal sensor is fixed to the housing opposite on the end face of the signal generator and at a distance from the signal generator. The signal sensor acquires an axial distance from the signal generator.

Abstract: To provide a servo motor controller allowing to eliminate the risk of abnormal driving in a servo motor caused due to the inability to detect abnormality prior to establishment of absolute position. A device is configured to control a servo motor of an industrial machine. The device includes a position detection part configured to detect a position of the servo motor, a magnetic pole detection part configured to detect a magnetic pole position of the servo motor, and a pole position calculation part configured to, at least in initial calculation, obtain the magnetic pole position detected by the magnetic pole detection part as an initial magnetic pole position, prior to establishment of absolute position, and in the following calculation, incrementally obtain the magnetic pole position on the basis of data of the position detected by the position detection part and a magnetic pole interval of the motor.

Abstract: A motor driver includes a low-side drive transistor, a comparator, a sense transistor, first switch, and a second switch. The low-side drive transistor is adapted to be coupled to a motor. The comparator is configured to determine a direction of a drive current flowing in the low-side drive transistor. The sense transistor is coupled to the low-side side drive transistor and is configured to pass a replica of the drive current. The first switch is configured to couple the sense transistor to the low-side drive transistor responsive to the drive current flowing in a first direction through the low-side drive transistor. The second switch is configured to couple the sense transistor to a ground responsive to the drive current flowing in a second direction, that is opposite the first direction, through the low-side drive transistor.

Abstract: A power tool is provided including a housing, a brushless motor disposed within the housing, a power switch circuit that supplies power from a power source to the brushless motor, and a controller configured to receive at least one signal associated with a phase current of the motor, detect an angular position of the rotor based on the phase current of the motor, and apply a drive signal to the power switch circuit to control a commutation of the motor based on the detected angular position of the rotor. The controller detects an initial sector within which the rotor is located at start-up, apply the drive signal so as to rotate the motor to a parking angle associated with the detected initial sector, and control a commutation sequence to drive the motor beginning at the parking angle.

Abstract: A pole direction detection device for detecting a pole direction of a synchronous motor having saliency comprises a high-frequency voltage application unit that applies a high-frequency voltage to the motor; an excitation phase change unit that changes an excitation phase of the motor to an arbitrary phase; a driving current detection unit that detects a driving current value of the motor; a pole direction estimation unit that detects a pole direction based on the excitation phase and the driving current value; a measurement unit that measures an inductance value of the motor; and a control unit that changes a frequency of the high-frequency voltage to be applied by the high-frequency voltage application unit based on the inductance value measured by the measurement unit.

Abstract: A method of operating a Brushless Direct Current Motor (BLDCM), the BLDCM of the type including: a series of concentric independently activated electromagnetic phase coils interacting with a series of permanent magnets to provide relative movement therebetween, the phase coils having temporal periods of activation time and deactivation time, the method including the steps of: (a) activating at least one of the phase coils for a short period of activation; and (b) measuring the voltage response across the phase coil of the deactivated phase coil during the short period of activation to determine the rotor position.

Abstract: A sensorless control method and an apparatus for a three-phase switched reluctance motor. The sensorless control method obtains line inductances of three phases according to real-time phase inductances of the three-phase switched reluctance motor and then determines feature points of the line inductances of the three phases. A position angle of the rotor at any time in the next corresponding region is calculated according to an average rotation speed of the rotor in the region corresponding to two adjacent feature points. A control signal is output to realize a precise sensorless control for the three-phase switched reluctance motor. The control apparatus includes a microcontroller, a power conversion circuit, a drive module for the power conversion circuit, a current detection module, a voltage detection module, an input and output module and a direct current regulated power supply.

Abstract: An electric vehicle propulsion control device includes a power converter that applies an alternating-current voltage to an induction machine and a controller that controls the power converter based on an external operation command. The controller includes a first calculation unit. The first calculation unit calculates, from current information (id and iq) detected at the induction machine and current command values (id*1 and iq*1) that are based on the operation command, a d-axis voltage command (Vd*1) and a q-axis voltage command (Vq*1) for the power converter, and a primary magnetic flux ?ds and a secondary magnetic flux ?dr of the induction machine. The first calculation unit also adds to or subtracts from a term including the q-axis voltage command (Vq*1) an interference term stemming from the d-axis voltage command (Vd*1) in calculating a first speed ?1 that is a free-run speed of the induction machine.

Abstract: A power conversion device for an electric vehicle includes an inverter that drives a motor mounted in an electric vehicle, and a controller that controls the inverter based on an operation command. The controller includes a sensorless control unit, and corrects an initial resistance value set in the controller, based on temperature information of a temperature sensor mounted in a cooler, sets a resistance value of the motor to the corrected initial resistance value, and causes the sensorless control unit to operate based on the set resistance value.

Abstract: A DC motor including a continuous rotation rotor; a first inductor characterized by first parameters; a second inductor characterized by second parameters; a voltage supply unit; a measurement unit for detecting time instants when a first induced voltage in the first inductor equals a second induced voltage in the second inductor; and a control unit for controlling the application of drive voltage pulses to the inductors. The rotor faces first the second inductor before facing the first inductor when being rotated. At least one of the second parameters is selected different from a corresponding parameter of the first parameters such that a maximum induced voltage in the first inductor is greater than a maximum induced voltage in the second inductor. The control unit is arranged to trigger each of the drive voltage pulses after a detection of an equal induced voltage in the first and second inductors.

Abstract: A method and a device are disclosed for monitoring and compensating an electric machine of an electrically driven vehicle. The method includes the following steps: determining a first value of a position of a rotor using an angle sensor when the rotor is in a first position; determining a second value of the position of the rotor using an injection method when the rotor is in the first position; determining a first difference between the first value and the second value of the position of the rotor at the first position of the rotor; and checking whether the first difference falls below a predetermined threshold.

Abstract: In some examples, a controller device includes processing circuitry configured to determine an alpha voltage and a beta voltage based on time durations for control signals for power-conversion circuitry that drives an electric motor including a rotor. In some examples, the controller device also includes a flux estimator configured to estimate a speed of the rotor and an angle of the rotor based on the alpha voltage and the beta voltage.

Abstract: At least one example embodiment discloses a method of estimating a position of a rotor in a motor. The method includes obtaining a current regulation quality index based on a current command and a measured current, determining an estimated position of the rotor based on the current regulation quality index and position estimation data and controlling the motor based on the estimated position of the rotor.

Abstract: A system comprises an aircraft hydraulic system motor, a position sensor, and a programmable controller. The aircraft hydraulic system motor includes a rotor whose position is detected by the position sensor. The position sensor produces an output representative of that position. The programmable controller is configured to receive the output of the position sensor and calculate an estimated velocity of the aircraft hydraulic system motor based on the output of the position sensor. The calculation of the estimated velocity comprises determining both a high bandwidth velocity estimation and a low bandwidth velocity estimation. The programmable controller is additionally configured to compare the estimated velocity to a desired velocity and direct the aircraft hydraulic system motor to increase or decrease velocity based on the comparison.

Abstract: A method and device for controlling the n LLM coils of an LLM stator making it possible to change the polarity of the coil voltage of the n LLM coils more easily and with little circuit complexity. It is proposed to apply a first operating potential to n first input terminals of n half bridges, and apply a second operating potential to n second input terminals of the n half bridges. For each half bridge, a first switch is connected between a center point of the respective half bridge and the first input terminal, and a second switch is connected between the center point of the relevant half bridge and the second input terminal. The center point of the n half bridges is connected in each case to n first terminals of then LLM coils, and the second terminals of then LLM coils are connected in a control point that is regulated to a predetermined potential.

Abstract: A system and method for position sensorless control of an AC electric machine is disclosed. A drive system for driving an AC electric machine provides a primary current excitation to drive the AC electric machine, the primary current excitation comprising a current vector having a magnitude and angle. The drive system injects a carrier signal to the AC electric machine that is superimposed onto the current vector, with the carrier signal generating a carrier response signal responsive to the injected carrier signal. The drive system measures at least one magnetic alignment signature of the AC electric machine from the generated carrier response signal and controls an orientation of the current vector using the measured at least one magnetic alignment signature to operate the AC electric machine.

Abstract: A control device outputs, to a to-be-controlled system which operates based on a control input and from which an observable amount varying cyclically is obtained, the control input based on the observable amount. The control device includes a deviation processing unit performing at least proportional integral control on a deviation between the observable amount and a command value being a target value of the observable amount and varying cyclically, and a totaling unit totaling an output of the deviation processing unit for each cycle of the command value to generate the control input.

Abstract: A motor controller coupled to a motor is provided. The motor controller is configured to transmit a first instruction to the motor to perform a first start attempt utilizing at least one parameter in a first set of parameters, wherein the first set of parameters are not preconfigured for a specific application in which the motor is being installed. The motor controller is additionally configured to receive feedback associated with the first start attempt from the motor, and transmit, in response to the feedback, a second instruction to the motor to perform a second start attempt utilizing at least one parameter in a second set of parameters, wherein the second set of parameters differ from the first set of parameters.

Abstract: A servo control apparatus includes a sensor unit for detecting a motor speed; an amplifier for driving a motor and feeding back a current; a magnetic pole position detector; a position controller for outputting a speed command; a speed controller for outputting a current command; a current controller for outputting a voltage command; a speed estimator for calculating an estimated speed from the voltage command; a magnetic pole position estimator for calculating an estimated magnetic pole position from the estimated speed; a sensor malfunction detector; a stop position command generator; and a first switch for switching from the position command to the stop position command, a second switch for switching from the magnetic pole position to the estimated magnetic pole position, and a third switch for switching from the detected speed to the estimated speed, when the sensor malfunction detector has detected a malfunction.

Abstract: A servo control apparatus includes a sensor unit for detecting a motor speed; an amplifier for driving a motor and feeding back a current; a magnetic pole position detector; a position controller for outputting a speed command; a speed controller for outputting a current command; a current controller for outputting a voltage command; a speed estimator for calculating an estimated speed from the voltage command; a magnetic pole position estimator for calculating an estimated magnetic pole position from the estimated speed; a sensor malfunction detector; a stop position command generator; and a first switch for switching from the position command to the stop position command, a second switch for switching from the magnetic pole position to the estimated magnetic pole position, and a third switch for switching from the detected speed to the estimated speed, when the sensor malfunction detector has detected a malfunction.

Abstract: In one example embodiment, a motor control unit includes a processor configured to tune a current regulator regulating a supply of electrical current to an electric motor by determining a plurality of variables, the plurality of variables including a stator resistance value, a first inductance value and a second inductance value, the stator resistance value being a resistance value of a stator of the electric motor, the first inductance value being a d-axis inductance of the electric motor and the second inductance value being a q-axis inductance of the electric motor. The processor is further configured to tune the current regulator by determining a plurality of gains based on the determined plurality of variables and generating current commands for operating the electric motor based on the determined plurality of gains.

Abstract: The present invention performs pulse shift control in such a manner that a difference between switching timings of PWM duty signals can reach or exceed a second predetermined value when the difference between the switching timings of the PWM duty signals of phases falls below the first predetermined value, and determines a correction amount for the phase by the pulse shift control in such a manner that a correction amount after switching becomes smaller than a correction amount before the switching of a phase on which the pulse shift control is performed in pulse shift phase switching control.

Abstract: A recording head unit is described that can use a pulsed drive signal. The head unit can include a recording head to interact with a storage media, an actuator connected to the recording head and configured to move the recording head relative to the storage media, and control circuitry to send a control signal to the actuator, wherein the control circuitry includes a pulse driven switching circuitry to control current flow to the actuator. An H-bridge can be used to drive the actuator and move the read head.

Abstract: A method for driving a BLDC motor comprising at least three stator windings, comprising: a) determining a time period, and energizing during the time period two of the windings and leaving a third winding un-energized, based on a first motor state; b) measuring a first voltage representative for the back-EMF generated in the un-energized winding shortly before expiry of the time period; c) applying a commutation at expiry of the current time period; d) measuring a second voltage shortly after the commutation, and calculating a subsequent time period; e) repeating steps b) and c). An electrical circuit and a controller are provided for performing these methods.

Abstract: A rotating electrical machine control device that applies a high frequency current to a rotating electrical machine including a rotor having saliency, estimates a magnetic pole direction of the rotor on the basis of a high frequency component contained in a voltage command as a response component to the high frequency current, and controls the rotating electrical machine. A high frequency superimposing section sets an estimated d-q axis rotating coordinate system, and a magnetic pole direction adjusting section sets a high frequency coordinate system having a phase difference of the high frequency current command with respect to the estimated d-q axis rotating coordinate system. A steady estimation error correcting section calculates a magnetic flux interference estimation error as an error of the estimated value of the magnetic pole direction which is caused by the d-q axis magnetic flux interference.

Abstract: In a synchronous machine starting device, a timing detection unit outputs a first position signal indicating a timing at which a value of an armature voltage passes a prescribed reference level. A feedback operation unit calculates an error of an estimated phase based on the estimated phase, an estimated rotational speed of a rotor, an armature voltage, and an armature current, updates the estimated phase and the estimated rotational speed based on the calculated phase error, and outputs a second position signal indicating the updated estimated phase. A frequency detection unit detects a current rotational speed of the rotor based on the first position signal, as an initial value of the estimated rotational speed. A selector circuit selects the first position signal and the second position signal in this order, and outputs a selected position signal to the power conversion control unit.

Abstract: An engine system may include a specified number of individual injectors, and an engine control unit (ECU) having a specified number of pins coupling to the individual injectors. The ECU may include a controller capable of dynamically switching between different multiplexing configurations, with each multiplexing configuration coupling individual injectors across corresponding pairs of pins. Each pin may internally couple to one half of an H-bridge structure, with an injector coupled across two pins thereby completing a full H-bridge structure, providing the flexibility to achieve combined solenoid and Piezo injection control.

Abstract: A motor control apparatus includes: a supply unit configured to supply a current for excitation to a plurality of coils of a motor; a first detection unit configured to detect a physical quantity which varies depending on a change in inductance of at least one of the plurality of coils; a determination unit configured to determine a rotational position of a rotor of the motor based on the physical quantity detected by the first detection unit; and a control unit configured to control the rotational position of the rotor of the motor based on a determination result by the determination unit.

Abstract: An electrical controller for electric motors is provided. A control system for an electric motor comprises a supply for supplying excitation current to different windings of the motor at any given time. Furthermore, the amplitude of the excitation current is independently variable of the timing and duration of the application of the excitation current to the windings. This allows increased control of the motor and facilitates the operation of the motor at high mechanical and/or electrical speeds.

Abstract: A sensorless brushless motor control device includes a first amplification module common to all motor phases and generating an intermediary voltage signal, a voltage divider between each motor phase and a node on which the intermediary voltage signal is generated, and a computation unit. Each voltage divider generates a first corrected electromotive force with a predetermined average value. The computation unit controls the motor on the basis of the first corrected electromotive forces. By using only hardware components, the control device maintains the average of the corrected electromotive forces at the center of the analog acquisition zone of the computation unit.

Abstract: A motor control device that can improve stability of sensorless control of a permanent magnetic synchronous motor. Rotor position detection (10) includes motor parameter correction (30) for correcting a parameter (winding resistance of a coil, a magnetic flux amount of a permanent magnet), which is a machine constant of a motor, in order to eliminate an induced voltage difference between a detected induced voltage peak value and a detected estimated induced voltage peak value. The rotor position is detected on the basis of the corrected parameter.

Abstract: A brushless motor driving apparatus that rotates and drives a brushless motor, which has a plurality of coils, by switching energization modes corresponding to phases of the brushless motor, sequentially switches the energization modes based on a non-energized phase voltage and a voltage threshold. Also, the brushless motor driving apparatus regulates an upper threshold for energization amount based on the voltage threshold and a change in the non-energized phase voltage at timing of switching the energization mode.

Abstract: A system and method of controlling a motor are disclosed. The system comprises a current observer for observing a motor current at a sampling rate and a proportionate-integral controller that provides a proportionate path and an integral path and at least forms part of a proportionate-integral control loop based on the motor current. The current observer observes a motor current of the motor at a sampling rate. The proportionate path calculates, for a present cycle of the sampling rate, a proportionate path term for the proportionate-integral control loop based on the motor current. The system outputs a respective motor output voltage to the motor in conformity with the proportionate path term calculated for the present cycle. In conformity with the motor current, the integral path calculates an integral path term for another respective motor output voltage to be used in a later cycle of the sampling rate.

Abstract: A method for determining a position of an armature of a synchronous machine relative to a stator of the synchronous machine includes the steps of applying to the synchronous machine a plurality of test current vectors, with each test current vector having identical current magnitude and a different angle in relation to an armature-related d,q coordinate system, during application of the test current vectors to the synchronous machine, determining values of a physical response quantity of the armature proportional to the q component of the test current vectors, determining a first harmonic of the determined values of the physical response quantity as a function of the angle, and determining the position of the armature relative to the stator as a zero crossing of the first harmonic where a first derivative of the first harmonic is positive.

Abstract: A motor driving apparatus includes an automatic gain control circuit on a signal path for transmitting a rotor-position detecting signal (hall voltage signal), and the automatic gain control circuit includes: an amplifier, configured to perform differential amplification on an input signal (step-angle hall current signal) to generate an output signal (amplified hall current signal); and a feedback control portion, configured to monitor the output signal (monitored current signal) to decide a gain of the amplifier.

Abstract: There are provided a motor driving apparatus and method, the motor driving apparatus including: a filter controlling unit detecting a frequency of a pulse width modulation (PWM) signal and generating a control signal; a first filtering unit filtering a back electromotive force (BEMF) signal according to the control signal; a second filtering unit filtering a reference signal according to the control signal; and a comparing unit comparing output of the first and second filtering units and generating a motor rotor detection signal.

Abstract: A circuit configuration for driving an electric motor includes a signal evaluation module, which stores a number of output patterns. An input pattern is specified, and as a function of the input pattern, one of the output patterns is output, by which the electric motor is driven.

Abstract: A motor constant calculating method for a PM motor according to the present invention includes a voltage applying step of applying an applied voltage including a DC component and a plurality of frequency components to a PM motor, a motor current detecting step of detecting a motor current flowing depending on the applied voltage applied in the voltage applying step, and a motor constant calculating step of calculating a motor constant of the PM motor based on the applied voltage and the motor current.

Abstract: The system and method disclose for the controlling of motor switching. The system includes a controller unit having a control signal generator, a memory device, a processing unit, a signal acquisition device, and an analog-to-digital converter. A power stage has a plurality of switches and receives a control signal from the control signal generator and a power signal from a power source. The power stage drives two windings of the set of three stator windings with a multi-state pulse and leaves one stator of the three stator windings undriven. The processing unit acquires a demodulated measured voltage on the undriven winding. The processing unit communicates with the power stage to change which two windings of the three stator windings are driven when the demodulated measured voltage surpasses a threshold.

Abstract: A brushless motor drive device switches energization modes for supplying power to two phases of a three-phase brushless motor, based on an induced voltage induced in a non-energized phase. In a case in which a target duty ratio Dt, which is a duty ratio of a PWM signal according to a manipulated variable of the brushless motor becomes less than a detection limit value Dlim, which is the lower limit of a duty ratio capable of detecting an induced voltage, there is set a detection timing (1/N) for detecting an induced voltage according to the cycle of a PWM signal, and a detection time duty ratio D1, which is a duty ratio of the PWM signal at the detection timing, is restricted to Dlim.

Abstract: The system and method disclose for the controlling of sequential phase switching in driving a set of stator windings of a multi-phase sensorless brushless permanent magnet DC motor. A motor controller controls a power stage that drives two windings of a set of three windings in the motor with pulse width modulated signal. A plurality of voltage values on an undriven winding of the set of three windings are sampled within a window of time, wherein a period beginning when the driven windings are energized and ending when the driven windings are de-energized encompasses the window of time. The sampled voltage values are processed. When the processed voltage values exceed a threshold, the motor controller changes which two windings are driven.

Abstract: A system includes a motor, an inverter bridge, a voltage detection circuit, and a controller. The motor has a stator and a rotor. The inverter bridge is configured to provide a voltage to the stator, and includes a first switch connected in a series-type relationship with a second switch, a first diode coupled across the first switch, and a second diode coupled across the second switch. The voltage detection circuit is configured to detect a back EMF voltage in the winding. The controller is configured to control the first switch and the second switch to drive the motor, and to receive an indication of the back EMF voltage in the winding from the voltage detection circuit. The controller is also configured to determine a fault has occurred, and to drive one of the first switch and the second switch when a fault has occurred.

Abstract: A motor control apparatus according to the embodiment includes a rotational position estimating unit, a change amount estimating unit, and an inductance estimating unit. The rotational position estimating unit estimates a rotational position of a rotor from a motor parameter including a q-axis inductance of a motor on a basis of an output current to the motor and a voltage reference. The change amount estimating unit estimates a change amount of an output torque with respect to a current phase change of the motor corresponding to a high frequency signal whose frequency is higher than a drive frequency of the motor. The inductance estimating unit estimates an inductance value that obtains a maximum torque on a basis of the change amount as the q-axis inductance.

Abstract: A method for determining a time for a zero crossing of a phase current in a polyphase electrical machine (2). The method including driving a driver circuit (31; 50) for providing phase voltages to operate the electrical machine (2); deactivating a pulse-width-modulated driving by at least one power switch (36, 37; 52, 53), such that no potential is applied to connecting nodes (AI, A2, B1, B2) by the driver circuit (31; 50), at least during a time segment in each cycle of the pulse width modulation; detecting a diode voltage via a freewheeling diode, with which the deactivated power switch (36, 37; 52, 53) has been provided, within the time segment; and fixing the time for the zero crossing of the phase current as the time after which there is no longer a diode voltage present across the freewheeling diode (40; 54) within the time segment.

Abstract: A sensorless control apparatus of a motor may include: a position estimator configured to compensate for a resistance and a magnetic flux of a permanent magnet of the motor according to a temperature of the motor, and/or configured to generate an estimated speed of a rotor of the motor based on the compensated resistance and the compensated magnetic flux of the permanent magnet; and/or a speed controller configured to generate a command current based on a command speed of the rotor and the estimated speed of the rotor.

Abstract: A motor control device includes a control condition storage unit storing at least one of a control condition defined by an equivalent voltage supplied to a three-phase motor and a control condition defined by relationship between the equivalent voltage supplied to the three-phase motor and a frequency of PWM signal, a control condition extracting unit extracting the control condition from the control condition storage unit in response to a temperature of a viscous fluid supplied by a pump having the three-phase motor as a power source, and a PWM controlling unit controlling a switching element included in an inverter circuit based on a PWM signal related to the extracted control condition when the three-phase motor is started.

Abstract: An apparatus detects the position of a rotor of an electric motor having three phases and a plurality of windings. The apparatus includes circuitry configured to connect at least two of said windings between first and second reference voltages according to a first current path disconnect said at least two windings, and allow the current stored in said two windings to be discharged through a second current path. The apparatus comprises a measuring circuit configured to measure the time period between the starting instant of storing the current in the two windings and the final instant of discharging the two windings and a rotor detector configured to detect the rotor position based at least in part on the measured time period.

Abstract: An apparatus, comprises three driver FETs coupled at their sources; note-driver circuit; a first sense FET coupled to the sources of the three driver FETs; a current mirror having the first sense FET and a mirror FET; wherein the first sense FET is coupled to the mirror FET; a first transconductance amplifier coupled to the first sense FET; a second amplifier coupled to the current mirror, and an output of the first transconductance amplifier is an input to the second amplifier.