Abstract: Examples include a method for controlling a variable speed drive driving an electric motor. The variable speed drive is connected to an electric power source and comprises a passive DC-link and an inverter stage controlled by a first controller of the variable speed drive. The passive DC-link is connected to the inverter stage. The method comprises running the electric motor to reach a steady-state operating point, measuring a plurality of values of current or voltage of the passive DC-link, and computing, by a second controller, a frequency spectrum of the DC-link based on the plurality of values of current or voltage measured. The method further comprises detecting a specific resonance frequency by comparing amplitudes of the frequency spectrum to a predetermined pattern, and modifying filter parameters of a digital filter of the DC-link or control parameters of a control law of the electric motor based on the specific resonance frequency.

Abstract: A higher control unit 1 generates a command current i* based on a command value. A model predictive control unit 2 sets a plurality of assumed voltage vectors for each switching cycle of an output voltage, divides the switching cycle of the output voltage into two periods according to a ratio between a dead time and the switching cycle of the output voltage, calculates a predicted current of the assumed voltage vector for each of the two periods obtained by the two-dividing, determines an evaluation function between the assumed voltage vector and the predicted current, sets the assumed voltage vector which has highest evaluation function result, as a command voltage vector. A gate signal g for outputting a voltage expressed by the command voltage vector from the power converter is output. The power converter is driven and controlled based on the gate signal.

Abstract: An output inductance value controlling method, apparatus, and computer device for a multi-tap reactor. A single output port of the multi-tap reactor is correspondingly connected to a single relay, and each relay is connected to a general power supply of all air conditioner internal units. When in use, an air conditioning system acquires a motor speed and a phase current of each air conditioner internal unit separately, and then calculates a sum of motor powers of all the air conditioner internal units according to the motor speeds and the phase currents. The system matches a basic inductance value required by the air conditioner internal units according to the sum of motor powers, sets a current output inductance value of the multi-tap reactor according to the basic inductance value, and inputs the output inductance value into the corresponding air conditioner internal units.

Abstract: A motor control system includes a reference current generator that generates a reference current based on a command, a motor voltage providing device that generates a phase voltage based on the reference current, a high frequency voltage, and a feedback current and provides a motor with the phase voltage, and a high frequency voltage generator that generates the high frequency voltage corresponding to a magnitude of voltage generated based on the reference current and the feedback current.

Abstract: A method of controlling a brushless permanent magnet motor includes measuring a mains power supply voltage of the motor. The method includes determining whether the mains power supply voltage lies within a first range representative of a first country's mains power supply or a second range representative of a second country's mains power supply. The method includes advancing commutation of a winding of the motor relative to a zero-crossing of back EMF in the winding where the mains power supply voltage lies within the first range, and retarding commutation of the winding relative to a zero-crossing of back EMF in the winding where the mains power supply voltage lies within the second range.

Abstract: A method is provided for electrically driving a motor having a plurality of phase windings such that EMC (electromagnetic compatibility) is improved and the running performance of the motor is simultaneously kept constant. At least one of the phase windings is not supplied with a current pulse during a complete revolution of the rotor, or at least one switchable electrical resistor is switched on, for at least one subsequent commutation phase by means of an electrical switching element, if the detected rotor speed is greater than the specified target speed.

Abstract: An input device includes a first part and a second part configured to move relative to each other according to an input operation, a magnetic viscous fluid whose viscosity changes according to a magnetic field, and a magnetic-field generator that generates the magnetic field applied to the magnetic viscous fluid. The second part includes a first surface and a second surface that are arranged in a direction orthogonal to a direction of relative movement between the first part and the second part. Gaps are formed between the first surface and the first part and between the second surface and the first part, and the magnetic viscous fluid is present in at least a part of the gaps.

Abstract: A method for controlling a three-phase electrical converter includes selecting a three-phase optimized pulse pattern from a table of pre-computed optimized pulse patterns based on a reference flux. The method includes determining a two-component optimal flux from the optimized pulse pattern and a one-component optimal third variable. The method includes determining a two-component flux error from a difference of the optimal flux and an estimated flux estimated based on measurements in the electrical converter. A one-component third variable error is determined from a difference of the optimal third variable and an estimated third variable. The optimized pulse pattern is modified by time-shifting switching instants of the optimized pulse pattern such that a cost function depending on the time-shifts is minimized. The method includes applying the modified optimized pulse pattern to the electrical converter.

Abstract: An inrush current limiting circuit in aspects of the present disclosure may have one or more of the following features: a printed circuit board, an electrical input disposed on the circuit board, one or more electrical outputs disposed on the circuit board, a current limiting circuit connected between the electrical input and the one or more electrical outputs, at least one microcontroller connected within the current limiting circuit, at least one current sensor connected within the current limiting circuit, one or more current limiting components within the current limiting circuit for increasing voltage and current over time from the electrical input to the one or more electrical outputs by operation of the current sensor and the microcontroller.

Abstract: An electrical machine is provided including a stator assembly having a stator core and a plurality of windings. A rotor assembly is arranged concentrically with the stator assembly and is configured to rotate about an axis. The rotor assembly includes a rotor core and a cage surrounding a periphery of the rotor core. The cage includes a plurality of impeller fins positioned adjacent at least one end of the rotor core.

Abstract: A system for determining an absolute position of a device includes a high resolution track, a sensor and processing unit associated with the high resolution track, a reference track having a plurality of pole pairs arranged to define a plurality of single-track Gray code segments, and an array of Hall effect sensors associated with the reference track to output a reference signal to the sensor and processing unit indicative of the coarse absolute position of the device over the Gray code segments. A third track has at least one pole pair. At least one sensor associated with the third track outputs a signal used to determine a location within one of the plurality of Gray code segments. The sensor and processing unit combines the third track signal, the reference signal, and the position of the device over the high resolution track to determine an initial, fine absolute position.

Abstract: An electric machine (21) having a stator (20) and having a rotor (29) rotatably mounted to the stator (20) is specified. The stator (20) comprises a stator winding (24), at least three teeth (23), and at least three grooves (22). In each case, one tooth (23) of the stator (20) is arranged between two grooves (22) along a circumference of the stator (20), and the stator winding (24) has at least three coils (25), wherein each of the coils (25) is wound around a tooth (23) of the stator (20), so that the stator winding (24) is a concentrated winding. In addition, the winding direction of all coils (25) is the same, each of the coils (25) is designed to be fed with its own phase current, and the stator (20) is designed to generate at least two rotary fields having different numbers of pole pairs independently of each other, in particular simultaneously. In addition, an activation unit (40) for the electric machine (21) and a method for operating an electric machine (21) are specified.

Abstract: A controller of a rotating electric machine includes a current detector detecting a voltage of each of shunt resistors in at least two phases from among the shunt resistors in three phases during an electric current flowing period in which the shunt resistors in the at least two phases have an electric current flowing therein; and a signal generator setting a switching mode of each of switches forming an inverter for controlling an estimated angular velocity to an instruction angular velocity based on the detected voltage. The signal generator sets a switching mode to flow the electric current in the shunt resistors in the at least two phases during at least part of one half of a modulation cycle of control of the estimated angular velocity.

Abstract: A device for driving a plurality of motors and an electric apparatus having the same is disclosed. The device includes an inverter connected to a DC terminal, a multi-phase motor connected to the inverter, a single-phase motor serially connected to the multi-phase motor, and a first capacitor and a second capacitor connected in series between a first end and a second end of the DC terminal, wherein the single-phase motor is connected to the multi-phase motor, and a node between the first capacitor and the second capacitor. Accordingly, a plurality of motors serially connected with each other can be driven by using a single inverter.

Abstract: A method for controlling transient operation of a rotary electric machine in an electric powertrain or other electrical system includes, during a shunt angle transition occurring during a maximum torque per ampere (MTPA) control region, determining an estimated output torque of the electric machine via a torque estimation block using d-axis and q-axis current commands and an additional value, i.e., an actual shunt angle or a machine temperature. The method includes subtracting the estimated output torque from a commanded output torque to derive an adjusted commanded torque value or torque error, and calculating, from the torque error, a delta d-axis current command and a delta q-axis current command. The method includes adjusting d-axis and q-axis current commands using the delta commands to produce adjusted d-axis and q-axis current commands, which are then used as closed-loop feedback control terms by the torque estimation block.

Abstract: A control method and system for driving of a motor and a control method of driving of an air compressor of a fuel cell system using the same include calculating an electrical rotation frequency of a motor, calculating a driving torque frequency of the motor based on the calculated electrical rotation frequency of the motor, and controlling torque of the motor to be repeatedly turned on/off at the calculated driving torque frequency.

Abstract: The disclosure relates to a method for determining a rotor position of an electric rotating machine. The electric machine comprises at least one first, multi-phase subsystem and one second multi-phase subsystem, which each comprise a PWM-controlled inverter for feeding respective winding groups. The winding groups of the at least first and second subsystems are arranged substantially electrically offset from one another by 360°. In the method, voltages predefined by a controller are altered by feeding high-frequency voltages in order to attain high-frequency current changes. The current changes are then detected in that a current curve of phase currents is ascertained for each subsystem by measuring at least one first phase current and one second phase current. The rotor position is then determined depending on the ascertained current curves and the fed high-frequency voltages. The disclosure additionally relates to an electric machine which is designed for carrying out the method.

Abstract: A control apparatus is provided for controlling energization of a multiple-winding rotating electric machine. The control apparatus includes inverters respectively corresponding to winding sets of the machine and a controller. The unit of a group of components provided for the energization of one winding set is defined as a system. The controller is configured to: (1) offset switching timings of switch elements of each of the inverters from those of switch elements of any other of the inverters; and (2) determine switching patterns of systems, based on an evaluation function of common-mode voltages of the systems, so as to minimize electro-magnetic interference due to the common-mode voltages. In each of the systems, the common-mode voltage of the system is defined as the difference in electric potential between a neutral point in voltage of a DC power source and a neutral point of the winding set corresponding to the system.

Abstract: When a voltage application command is outputted to a three-phase winding of one system, a d-axis proportionality constant and a q-axis proportionality constant are set with Ld and Lq, respectively, as parameters; when voltage application commands are outputted to three-phase windings of two systems, a d-axis proportionality constant and a q-axis proportionality constant are set with [Ld+Md] and [Lq+Mq], respectively, as parameters.

Abstract: A semiconductor device for vector control of an AC motor via an inverter, includes a dq-axis reference current value generator which generates dq-axis reference current values, a three-phase/two-phase converter which generates dq-axis detected current values from three-phase current values of the inverter and a rotor position of the AC motor, a current controller generates dq-axis reference voltage values by proportional control and proportional integral control based on the dq-axis reference current values, the dq-axis detected current values, a rotation angular speed of the AC motor, and a motor parameter setting value, wherein the integration controller provides an initial voltage value to an integrator before switching to the proportional integral control, and wherein the initial voltage value is based on the dq-axis reference current values, the dq-axis detected current values, the rotation angular speed, the motor parameter setting value, and one of a proportional gain and the dq-axis reference voltage

Abstract: A method (400) of determining equivalent circuit parameters of a three phase induction motor is provided. The method (400) comprises applying (410) a current to a stator winding (362) of an induction motor (360), and varying (420) a voltage applied to the stator winding to regulate the applied current to be a constant current. Application of the current is terminated (430) when the applied voltage has reached a constant voltage. The equivalent circuit parameters are determined (440) from the value of the constant current, the values of the applied voltage, and a time period until the applied voltage attains the constant voltage. The method may provide values for a resistance (210) of the stator winding, a resistance (250) of a rotor winding (364), a magnetizing inductance (230), and a total inductance leakage value (220, 240) for the stator winding and the rotor winding.

Abstract: The power transmission mechanism abnormality diagnostic device includes a monitoring diagnosis unit for performing determination as to abnormality of a power transmission mechanism, and a current detector connected to a power supply of an electric motor, wherein the monitoring diagnosis unit includes an analysis unit for analyzing current transmitted from the current detector and an abnormality determination unit for performing determination as to abnormality of the power transmission mechanism on the basis of a result of analysis by the analysis unit.

Abstract: Disclosed is a device for detecting a phase loss in an output current in an inverter. The device includes: an output current detection unit for detecting two phases output currents from two signals output from two shunt-resistors connected to two phases legs respectively; an output current calculation unit for calculating an output current of one remaining phase using the detected two phases output currents; and an output phase loss detection unit configured for detecting an output phase loss when the calculated output current is within a current band corresponding to the output phase loss or when the calculated output current has a magnitude equal to and a sign opposite to one of the detected two phases output currents.

Abstract: A system for controlling an AC motor is provided. The system comprises an electrical connection path for connecting an electrical input of the AC motor to a first phase of alternating current from an electric power supply. The system also comprises two or more motor controllers, each motor controller is located on the electrical connection path between the electric power supply and the AC motor and is operable to regulate current of the first phase passing through it. Each motor controller is connected in parallel, relative to the other motor controllers, to the electrical connection path. At least one processor is configured to control the motor controllers to repeatedly change which of the motor controllers current of the first phase passes through, such that at any given time current of the first phase only passes through one of the motor controllers. A corresponding method is also provided.

Abstract: A control system controls a machine according to a control policy parameterized on a lifted state space of the machine having an unknown onto mapping to a state space of the machine. The control system accepts measurements of state variables that form a portion of the state of the machine and determines a derivative of at least one measured state variable using values of the state variable measured for multiple time instances, such that a combination of the measured state variables and the derivative of the at least one measured state variable defines the lifted state for the time instance. The control system updates the control policy by evaluating a value function of the control policy using the lifted states, such that a control input to the machine is determined using the lifted state and the updated control policy.

Abstract: Operating an asynchronous machine includes: closed loop control of a first and a second three-phase winding by a first and a second closed loop control method, respectively. The second closed loop control method supplies a voltage vector to a second inverter device, and changes from the first closed loop control method to a first open loop control method. The first open loop control method includes supplying a first reference current vector to a first filter device, supplying a filtered first reference current vector to a calculation device for calculating an electrical angle, supplying the electrical angle to a first transformation device for transforming a first open loop control deviation vector, transforming a first open loop control deviation vector into a third voltage vector, and supplying the third voltage vector to the first inverter device for the operation of the first three-phase winding.

Abstract: In one embodiment, a system includes a drive train starter system. The drive train starter system includes a generator mechanically coupled to a drive train of a gas turbine system and an exciter system electrically coupled to the generator and configured to provide a magnetic field. The drive train starter system additionally includes a load commutated inverter (LCI) electrically coupled to the generator and configured to provide electrical power to the generator and a controller communicatively coupled to the generator, the exciter system, and the LCI. The controller is configured to start up the drive train via the LCI and the generator up to less than a drive train operating speed, wherein the generator is converting electricity into mechanical motion; drive the drive train via a gas turbine up to the drive train operating speed; and to drive the drive train via the generator at the drive train operating speed.

Abstract: A method for identifying the discrete instantaneous angular speed of electromechanical systems in which electrical rotating machinery is used and in which at least one electrical signal is measured during an operation of the electromechanical system. The method includes measuring analog stator current signals and analog stator voltage signals for at least one phase A, B, C, converting the measurements into a digital discrete form, transmitting the digital discrete signals to a computer device wherein data analysis is performed in a processor unit on the basis of a simplified mathematical model of the dynamics of the motor or generator. During the data analysis an average rotor time constant is calculated, an average supply frequency value is identified, an average angular speed is obtained, and an instantaneous phase difference between the discrete stator current signals and the discrete stator voltage signals is determined.

Abstract: In this rotating electrical machine, each of coil centers of a first concentric coil and a third concentric coil is located on one side in a circumferential direction with respect to a center of a magnetic pole, and each of coil centers of a second concentric coil and a fourth concentric coil is located on the other side in the circumferential direction with respect to the center of the magnetic pole.

Abstract: A closed-loop control device includes a target value entrance for inputting a target value for at least one control value, an actual value entrance for inputting an actual value for the at least one control value, wherein the actual value is determined based on the at least one measuring value, a calculation unit for calculating the actuation value based on a deviation of the actual value from the target value in such a way that the actual value follows the target value, and a control exit for outputting the actuation value for an actuator of the at least one tempering circle. The calculation unit is configured in such a way that the actuation value is calculated based on the present operating point or in a manner adapted to the present operating point.

Abstract: A power conversion apparatus having a converter, an inverter controlled by inverter controller, and an input power source fluctuation detecting and controlling circuit is proposed. The input power source fluctuation detecting and controlling circuit includes an input power source fluctuation detector and a converter failure detector to detect overcurrent and/or overvoltage of the converter. When both of the input power source fluctuation and the converter failure are detected, the converter is gate blocked, and the inverter continues its operation, and when the DC voltage become lower than a threshold voltage during the converter is gate blocking, the input power source fluctuation detecting and controlling circuit outputs an inverter control changeover flag to the inverter controller for switching a contents of inverter control.

Abstract: Provided is a wire connecting structure of coils of a three-phase motor, a wire connecting method and three-phase motor, which is capable of reducing a size of a short circuit terminal for a neutral point. The wire connecting structure is a wire connecting structure of coils which are wound to each salient-pole in a three-phase motor having respective salient-pole of a U phase, a V phase and a W phase, the coils of the salient-poles belonging to any two phases among the U phase, the V phase and the W phase are formed by a single continuous first conducting wire, and the coil of the salient-pole belonging to the rest one phase is formed by a single continuous second conducting wire.

Abstract: Provided is a device for estimating a rotor angle in a motor. The device includes a sensor configured to measure a rotation angle “?in” of a motor including a pulsation, a D-Q converter configured to convert the rotation angle “?in” into a D-axis conversion angle, and a phase-locked loop (PLL) block configured to perform proportional integral control on the D-axis conversion angle according to a PLL algorithm to estimate a rotation angle “?out” from which the pulsation has been removed.

Abstract: A method for operating an unbalanced load manager for a three-phase induction motor or heater, includes receiving, by a load manager, values representative of current flow sensed by current sensors and voltages sensed by voltage taps corresponding to phases of a three-phase power system providing power to the motor or heater. The method includes detecting, by the load manager, a transition from positive or negative to zero current, to measure a phase shift between line-to-line and current. The method further includes synchronizing, by the load manager, firing from line-to-line signal to line-to-neutral signal of phases of the three-phase power system, using the measured phase shift between line-to-line and current.

Abstract: An initial position estimating apparatus for estimating an initial position of a rotor of a motor includes: a signal processor for outputting an angular error component from a change amount of a q-axis current in an estimated rotor reference frame; a position estimator for estimating an electrical position of the rotor from the angular error component; a magnetic pole determination portion for outputting magnetic pole determination information according to a sign of a magnetic pole determination signal determined based on a change amount of a d-axis current in the estimated rotor reference frame and based on a d-axis voltage; and a first addition portion for outputting an initial position of the rotor by adding the magnetic pole determination information to the electrical position.

Abstract: Methods and apparatus to control a three-phase BLDC motor using phase current and phase voltage at zero current detection and a driving current derived from a bus current, for example. The driving current can be combined with a difference angle with an output provided to a controller to control a speed of the motor.

Abstract: Implementations of methods for sensing rotor positions of a motor may include coupling a controller with a PMSM and applying, using the controller, a plurality of vectors to the PMSM, the plurality of vectors including a plurality of dummy vectors and a plurality of measured vectors, wherein at least one measured vector is applied quadrature to a dummy vector from the plurality of dummy vectors immediately preceding each measured vector. The method may also include measuring, with a measurement circuit, a plurality of values from a three-phase inverter coupled with the PMSM, each value of the plurality of values corresponding with one of the plurality of measured vectors, and calculating, with one or more logic elements coupled with the PMSM, based on the plurality of values and using one or more position algorithms, a position of a rotor of the PMSM relative to a stator of the PMSM.

Abstract: In a method for reducing noise of a motor fed by a converter, a magnetic flux in the motor is changed for reducing a fundamental oscillation and a harmonic oscillation of the magnetic flux, and a degree of control and/or a pulse frequency of the converter is changed so as to change a harmonic oscillation of the magnetic flux.

Abstract: A detection device and a detection method of a rotor position of three-phase motor are disclosed which measure induced voltages under different voltage vectors and calculate an induced voltage relationship among the different induced voltages. Then the detection device and the detection method find out the rotor position suitable for the induced voltage relationship according to a rotor position table. Therefore, the detection device and the detection method can accurately detect the rotor position in a standstill state to prevent the three-phase motor from operating abnormally and burning out.

Abstract: A controller includes a torque command value calculation module configured to calculate a torque command based on a speed command of the motor, an output voltage controlling module configured to control an output voltage of the power converter based on the torque command calculated by the torque command value calculation module, a voltage command value correcting module configured to correct a voltage command to the power converter based on a measured output voltage from the power converter, a flux estimation module configured to estimate stator flux and rotor flux of the motor in a subsequent control period based on the voltage command by the voltage command value correcting module and a measured current of the stator and a motor speed estimation module configured to estimate a speed of the motor in a subsequent control period based on the flux estimated by the flux estimation module.

Abstract: A power supply system for an electric vehicle includes a battery, an inverter configured to supply alternating-current electric power to a motor for traveling, a first voltage converter connected between the battery and the inverter, a second voltage converter connected in parallel with the first voltage converter, a temperature acquisition unit configured to acquire a temperature of the first voltage converter, a current acquisition unit configured to acquire magnitude of a current flowing in the second voltage converter, and a controller. Each of the first voltage converter and the second voltage converter includes two switching elements, two diodes, and a reactor.

Abstract: An energization control system includes a sensor unit including a magnetic detection portion detecting a magnetic flux density of a magnetic flux generated at a surrounding of a conductor in response to a current flowing in the conductor of an electrical apparatus, a temperature detection portion detecting a temperature level within a package in which the magnetic detection portion is disposed, a correction portion correcting a temperature characteristic of a detection result of the magnetic detection portion based on the detected temperature level, and an output portion outputting temperature information indicating the detected temperature level. The energization control system further includes a control unit including a control portion controlling a current flowing in a heating element of the electrical apparatus based on the temperature information.

Abstract: A first-stage phase compensator, a second-stage phase compensator, and a third-stage phase compensator are configured in such a way that a frequency at which a phase calculated through the transfer function of the first-stage phase compensator becomes maximal and a frequency at which a phase calculated through a transfer function of the first-stage phase compensator and the third-stage phase compensator becomes maximal coincide with each other; a motor for generating assist torque is controlled, based on a torque signal to which the first-stage phase compensator, the second-stage phase compensator, and the third-stage phase compensator have applied phase compensation.

Abstract: A motor control apparatus that performs a drive control of a motor includes a current detector configured to detect a driving current flowing in a winding of the motor, a calculator configured to calculate an estimated value indicating a rotational position of a rotor of the motor by an estimation computation based on a value of the driving current detected by the current detector, and a corrector configured to correct the estimated value of the rotational position based on a rotation amount of the rotor in a predetermined period from a start of the estimation computation by the calculator until completion of the estimation computation. In addition, a controller controls the driving current flowing in the winding of the motor so that a deviation between the estimated value corrected by the corrector and an instructed value indicating a target position of the rotor is reduced.

Abstract: A method is provided to control the output voltage across an unbalanced load connected to a three-phase inverter, The method includes transformation of a set of three-phase voltage signals to a dq-coordinate system. Based on the transformation, a set of d-axis and a set of q-axis positive, negative and a set of zero sequence signals are generated. The method includes phase shifting of each of the zero sequence signals to generate 120 degrees and 240 degrees phase shifted zero sequence signals. Each of the zero sequence signals, the 120 degrees and the 240 degrees phase shifted zero sequence signals are transformed to a set of d-axis and q-axis zero sequence signals. A set of error signals, calculated based on the set of d-axis and q-axis zero, positive and negative sequence signals, are minimized and transformed to abc-coordinate system to obtain a three-phase control voltage signal.

Abstract: A motor controller that is configured to switch power supply phases of the motor, to perform a limit-position abutment control by rotating the motor to a movable limit of a movable range of the rotation object to learn a reference position of the motor, perform a power-saving return control afterwards, in which a power supply to the motor is stopped, thereby returning a rotation position of the motor toward a target rotation position, and stop the rotation of the motor by simultaneously supplying power to a preset phase of the motor, when the rotation position of the motor reaches the target rotation position. In such manner, the power consumption as well as the heat generation of the motor are reduced for returning the rotation position of the motor to a preset rotation position after the abutment control of the motor.

Abstract: A control device capable of suppressing electromagnetic force applied to a motor has a harmonic current calculation section and an operation section. The harmonic current calculation section calculates amplitude and phase of each of harmonic currents to be superimposed over a fundamental current which flows in phase windings of a stator of the motor based on conditions relating to load change of the motor. The operation section generates and transmits instruction signals to an inverter so that the calculated superimposed harmonic currents flow in the phase windings of the stator.

Abstract: In an embodiment, an offset voltage generator includes a first limiter configured to compare a first phase-voltage signal with a maximum limit value and a minimum limit value to output a first limit-voltage signal; a second limiter configured to compare a second phase-voltage signal with the maximum limit value and the minimum limit value to output a second limit-voltage signal; a third limiter configured to compare a third phase-voltage signal with the maximum limit value and the minimum limit value to output a third limit-voltage signal; and a summer configured to add a difference between the first phase-voltage signal and the first limit-voltage signal, a difference between the second phase-voltage signal and the second limit-voltage signal, and a difference between the third phase-voltage signal and the third limit-voltage signal, to output an offset voltage.

Abstract: In some embodiments, a system of controlling an induction electric motor, includes a command voltage output unit for generating a command voltage for operating an inverter according to a command speed and outputting the generated command voltage to the inverter; a control unit for controlling the command voltage output unit such that the command voltage output to the inverter is compared with an operation limiting voltage and the command voltage is corrected to fall within the operation limiting voltage; and the inverter for controlling the induction electric motor depending on the corrected command voltage. Thus, it is possible to precisely control the induction electric motor even in a high speed operation region by regulating the magnitude of the command voltage applied to the induction electric motor by means of dynamic modulation strategies without the magnetic flux controller.

Abstract: A magnetoelectric device capable of storing usable electrical energy includes an inductive servo control unit and a motor. The motor includes a rotor and three ferromagnetic-core coils disposed around the rotor. The inductive servo control unit executes individual phase control on the three-phase induction motor to magnetize the ferromagnetic-core coils with respective phases. When each of the ferromagnetic-core coils is demagnetized, it generates a current due to counter-electromotive force to charge a damping capacitor.