Abstract: An electrical machine, such as a switched reluctance motor, has a rotor and a controller arranged to energize at least one electrically energizable phase winding in dependence on the angular position of the rotor. The controller may employ a control law table derived by applying a predetermined DC link voltage to the windings. Differences between an applied DC link voltage and the predetermined DC link voltage may be compensated by applying a predetermined correction to the angular position of energization of the phase winding in dependence on the value applied DC link voltage. Such a compensation factor may be derived from a relationship held in memory.

Abstract: A method and system for starting and operating an electrically driven load, e.g. a compressor or pump, by power supply from a mechanical driver, e.g. a turbine or combustion engine, whereby the load is mechanically connected to a first electrical machine, and the mechanical driver is mechanically connected to a second electrical machine. The first electrical machine is electrically interconnected to the second electrical machine at a standstill or when the first and or second machine have low speed. In an acceleration phase, the first electrical machine is accelerated by accelerating the second electrical machine with the mechanical driver. When the first electrical machine has reached a predefined rotational speed, the first machine is synchronized with a local electrical power network and connected it to that network.

Abstract: HVAC systems implementing micro-electromechanical system based switching devices. Exemplary embodiments include a HVAC system, including a load motor, a main breaker micro electromechanical system (MEMS) switch, and a variable frequency drive (VFD) disposed between and electrically coupled to the load motor and the main breaker MEMS switch.

Abstract: A system and method for controlling a permanent magnet motor are disclosed. Briefly described, one embodiment receives a torque command and a flux command; receives information corresponding to a direct current (DC) bus voltage and a motor speed; computationally determines feedforward direct-axis current information and feedforward quadrature-axis current information from a plurality of parameters associated with the permanent magnet motor; determines a current signal (idq*) based upon at least the requested torque command, the flux command, the DC bus voltage, the motor speed, the feedforward direct-axis current information, and the feedforward quadrature-axis current information; and controls a power inverter that converts DC power into alternating current (AC) power that is supplied to the permanent magnet motor, such that the permanent magnet motor is operated in accordance with the determined idq*.

Abstract: Provided is a motor having a combination of a plurality of coil pairs and a permanent magnet, wherein these coil pairs are supplied with an excitation signal from a drive circuit so as to be excited at alternate opposite poles, and the permanent magnet is constituted such that the plurality of polar elements is disposed to become alternating opposite poles; the drive circuit is constituted to supply an excitation signal having a prescribed frequency to the coil pairs, and relatively move the coil pairs and permanent magnet with the magnetic attraction—repulsion between the coils and permanent magnet; and the drive circuit is constituted to supply to the coil pairs a waveform signal corresponding to the pattern of the back electromotive voltage to be generated in accordance with the relative movement between the coil pairs and permanent magnet.

Abstract: Indirect rotor resistance estimation for an AC induction motor is achieved by successively stepping the quadrature command to zero and the direct current command to a predetermined value causing the quadrature stator voltage to decay as a representation of rotor current decay; defining, in response to the decaying stator voltage reaching two spaced thresholds, a voltage/time difference, and retrieving from a storage device the rotor resistance associated with the voltage/time difference.

Abstract: A vector controller for a permanent magnet synchronous motor according to the present invention has a motor constant identifying unit for identifying motor constants of the permanent magnet synchronous motor, which is connected to an electric power converter in the vector controller, by using a second d-axis current command value, a second q-axis current command value, a detected output current of the electric power converter, and motor constant settings. The vector controller uses the motor constants identified by the motor constant identifying unit in vector control calculation so as to control the driving of the permanent magnet synchronous motor. Thereby, the vector controller achieves torque control with high accuracy and superior responsiveness.

Abstract: Two apparatuses are disclosed for providing a dynamically varying water surge in a salt-water reef aquarium. The first apparatus is a micro-controller based variable frequency reef surge drive 100 for an AC permanent magnet synchronous motor (PMSM) submersible aquarium pump. Drive 100 comprises voltage conversion circuitry 105, xmicro-controller 110, reef-surge generation program 115, variable frequency drive 118, mode switch 130 and tidal cycle switch 135. Three user-selectable modes of operation are provided: a random frequency mode, a fixed-program mode and a tidal mode. A second apparatus comprises a novel submersible AC PMSM pump with dual impeller assemblies and dual input and output chambers for supporting forward and reverse flow through an AC PMSM pump.

Abstract: The present invention restrains high frequency leakage current while reducing ripples of current flowing through a motor having one set and another set of independent phase windings. A plurality of inverter type drive means drives the respective phase windings and a PWM control means controls the respective inverter type drive means, by a switching sequence connecting one end of all phase windings including the other set to the negative side of the power supply when both ends of the phase winding included in one set are connected to the positive side of the power supply and connecting at least one end of all phase windings included in the other set to the positive side of the power supply when both ends of at least one phase winding included in one set are connected to the negative side of the power supply.

Abstract: A controller for a motor performs field weakening control by changing a phase difference between two rotors, which are concentrically disposed, and by accurately recognizing the phase difference.

Abstract: An electronic device is provided for controlling a motor having three phases driven by a motor driver. In one implementation, the electronic device includes a detection means and a control circuit. The detection means includes three high-gain differential amplifiers and three A/D converters. The detection means detects back EMF voltages induced by the rotation of the motor and applies corresponding signals to the control circuit. The control circuit computes and filters the position and/or the speed of the motor and then delivers the filtered values of the computed rotor position and/or speed to control the motor driver. The motor may thus be controlled even at near-zero rotational speed.

Abstract: The synchronous motor driving apparatus including position sensors provided in the synchronous motor, a current polarity detection circuit for detecting the polarities of the currents in the respective phase windings of the synchronous motor, an inverter driving the synchronous motor, a motor speed calculation unit calculating the rotational speed of the synchronous motor depending on the output signals from the position sensors, a speed control unit outputting a first voltage adjusting component (q-axis current command value Iq*) to cause the rotational speed of the synchronous motor to approach a speed command value and a phase control unit outputting a second voltage adjusting component (d-axis current command value Id*) to cause the phase differences between the phases of the position sensor signals and of the currents in the respective phase windings of the synchronous motor to become a predetermined value.

Abstract: A method for providing a correlation between a periodic analog/digital conversion and an angle-synchronous signal, in which the periodic analog/digital conversion is provided with a timing mark, which correlates with the angle-synchronous signal, and is assigned to an angular position of a device via this timing mark.

Abstract: The present invention provides a circuit for monitoring harmonic distortion in the power supply of a synchronous electrical machine with permanent magnet excitation that comprises a rotor without a damper cage, a stator with first, second, and third windings, a frequency converter, and control circuits for controlling the frequency converter.

Abstract: The invention relates to a sensorless electric motor and a method of controlling such an electric motor, which motor comprises a permanently magnetic rotor, a stator having at least one winding, and a power stage for influencing the current flowing through the winding. As a function of a predetermined commutation duration (T_K), a commutation period is defined, during which period the direction of the magnetic field generated by current flow through the winding is not modified, during which period a commutation completion operation (107) and a commutation initiation operation (109) take place, and which period starts at a first commutation instant (t_KN) and ends at a second commutation instant (t_KN+1); preferably, commutation timing is adjusted, based upon a value of induced voltage picked up at a currently non-energized one of the winding strands, during a plateau portion (108) of a winding voltage trace, located temporally between commutation instants.

Abstract: Control technique of a synchronous motor capable of suppressing rotation pulsation caused by individual difference without complicating control algorithm is provided. A pulsation generator superimposing a pulsation component anticipated in advance to a current command for the synchronous motor and a correction current generator superimposing a correction signal substantially having an average value of zero to the current command are provided in a synchronous motor control device. By this configuration, the correction signal suppressing a distortion component is superimposed to a value of the current command with a simplified control configuration. Torque pulsation is suppressed by determining the correction signal from difference between a detection current and a command current.

Abstract: To obtain an adjustment method of rotor position detection of a synchronous motor with excellent productivity. An adjustment method of rotor position detection of a synchronous motor, wherein a synchronous motor having a stator wound around a stator coil and a rotor provided with magnetic poles, and a rotational position detector having a sensor rotor fixed to the rotor and a sensor stator disposed opposite to the sensor rotor for detecting a rotational position of the rotor are provided, and wherein an amount of deviation between the rotational position of the synchronous motor determined from an output of the rotational position detector and an actual rotational position of the synchronous motor is adjusted, the method comprising: a step of detecting the amount of deviation during rotation of the synchronous motor; and a step of mechanically adjusting a relative position between the rotational position detector and the synchronous motor based on a detected value of the amount of deviation, is provided.

Abstract: A plurality of parameters of a Permanent Magnet Synchronous Motor (PMSM) is determined by a motor controller for differentiating between a plurality of PMSMs. This is achieved by first applying regulated DC motor currents at a commanded fixed rotor angle and measuring a quadrature voltage; parking the PMSM at standstill, Then, after selecting an initial set of controller parameters; applying the quadrature voltage equal to zero and measuring a time constant. Then, accelerating the PMSM with a constant torque up to a preset target speed and measuring a total acceleration time taccelerate until the preset target speed ?target is reached. After regulating a stator current at 0 value, measuring the quadrature voltage and a freewheeling motor speed ?freewheel immediately after applying the 0 stator current; and calculating an electrical constant KE of the PMSM; a load inertia J; and a set of parameters for the controller.

Abstract: A direct current motor controlling method includes a mean for transforming a duty signal to computed value by a microprocessor unit. The microprocessor unit computes the computed value and then produces a target value by executing a dichotomy method, a rotation method and a transformed function, capable of reducing executing time and executing load of the microprocessor unit and saving memory space. The microprocessor unit sends a frequency signal to a driving circuit unit according to the target value. The driving circuit unit receives the frequency signal and then provides a driving voltage to a power switch. The power switch provides a voltage to a direct current motor or not according to the driving voltage for controlling output performance of the direct current motor.

Abstract: Provided is a motor having a combination of a plurality of coil pairs and a permanent magnet, wherein these coil pairs are supplied with an excitation signal from a drive circuit so as to be excited at alternate opposite poles, and the permanent magnet is constituted such that the plurality of polar elements is disposed to become alternating opposite poles; the drive circuit is constituted to supply an excitation signal having a prescribed frequency to the coil pairs, and relatively move the coil pairs and permanent magnet with the magnetic attraction repulsion between the coils and permanent magnet; and the drive circuit is constituted to supply to the coil pairs a waveform signal corresponding to the pattern of the back electromotive voltage to be generated in accordance with the relative movement between the coil pairs and permanent magnet.

Abstract: In an apparatus for generating complementary first and second pulse width modulation signals, a signal generating circuit generates a first signal for causing the first pulse width signal to switch from an ON level to an OFF level, a second signal for causing the first pulse width signal to switch from the OFF level to the ON level, a third signal for causing the second pulse width signal to switch from the ON level to the OFF level, and a fourth signal for causing the second pulse width signal to switch from the OFF level to the ON level. A control circuit sets a first dead time between the first and fourth signals and a second time between the third and second signals individually.

Abstract: A variable reluctance electric power system which comprises an alternator and a motor having a rotor with longitudinal lobes and no windings, commutators, slip rings, magnets, or laminations. The alternator and the motor have stators which have conventional windings and laminations and a rotor which is polarized using a static field winding which surrounds but does not touch the rotor. The alternator and the motor may be coupled with current from the alternator driving the motor and solid state power devices controlling the frequency of the current to insure that the current from the alternator is always synchronized with the motor rotor.

Abstract: A frequency-variable PWM motor drive circuit includes a drive IC member, a Hall IC member, a PWM converter circuit and a compensation unit. The drive IC member electrically connects with the Hall IC member, the drive IC member further includes a pin electrically connected with the compensation unit and the PWM converter circuit. The PWM converter circuit has a PWM input pin to receive a PWM signal, and converts it into a voltage signal. The compensation unit connects between the pin of the drive IC member and the PWM converter circuit. In operation, the compensation unit can improve a waveform of the voltage signal supplied from the PWM converter circuit, and then output it to the pin of the drive IC member. Consequently, the drive IC member can be steadily operated at predetermined motor speeds under various frequencies of the PWM signals.

Abstract: An electric power converter which has improved accuracy in compensation of a dead time. A motor driving system employing the electric power converter is also provided. A power module includes a plurality of switching devices connected in series and converts DC power to AC power. A control circuit produces a voltage command value in accordance with a control command inputted from the exterior, and produces gate signals to drive the switching devices of the power module corresponding to a final voltage command value which is obtained from the voltage command value with dead time compensation. A dead time compensation logic circuit calculates a final dead time compensation voltage based on a change rate of the voltage command value, a gain (dead time compensation voltage value), and a polarity of a current, the gain being calculated from a DC voltage value supplied to the electric power converter, a dead time, and a switching frequency.

Abstract: A control circuit of rotational speed of a fan is provided, wherein by a switching of a switch unit, a PWM (Pulse Wide Modulation) unit can output a sampling pulse whose period is changing. A voltage is also changing following the period after taking a sample to an AC voltage by the control unit. The voltage after sampling serves as a working voltage of a load unit, so as to enable a fan device and a lamp device of the load unit to achieve effects of adjusting speed and brightness.

Abstract: An influence resulting from double saliency of an electric motor, i.e., an influence of a deviation of the axis of an alternating current due to a rotor magnetic pole position ? on the estimation of a magnetic pole position, is eliminated, and, in particular, the magnetic pole position of a double saliency electric motor can be estimated with high precision.

Abstract: A method and apparatus for controlling a permanent magnet synchronous motor by accurately detecting 3-phase motor currents from a DC input current in a full voltage range are provided. In the motor control apparatus for detecting the 3-phase motor currents on the basis of the value of the current detected at a DC side of a PWM inverter, when a difference width between PWM pulse signals of two of three phases of the 3-phase PWM inverter which cannot detect the motor currents is not larger than a predetermined value or when the output voltage of the 3-phase PWM inverter is low, the apparatus automatically reduce the carrier frequency of the PWM inverter.

Abstract: A motor controller for simultaneously controlling operations of at least two system motors by pulse-width modulation. The motor controller includes a pair of switches, a pair of pulse signal generators, and a phase shifter. The switches are used for supplying driving power to the two system motors. The pulse signal generators are used for generating a pair of pulse signals respectively having predetermined duty ratios at predetermined cycles, and outputting the pulse signals to the pair of switches to turn on or off the pair of switches. The phase shifter is used for inverting, with respect to the phase of one of the two pulse signals that is generated and output by one of the two pulse signal generators, the phase of the other of the two pulse signals, which is generated and output by the other of the two pulse signal generators, by 180 degrees.

Abstract: Windings of each phase in a three-phase AC motor are independent of one another. A motor control unit gives, to windings of each phase (U, V and W-phase), currents (IU, IV, IW) obtained by adding, to a fundamental sine wave current, a current having a frequency which is three times as high as that of the fundamental sine wave current. That is, IU=I·sin ?t+Ia·sin 3?t: IV=I·sin(?t+2/3?)+Ia·sin 3?t: IW=I·sin(?t+4/3?)+Ia·sin 3?t Also, amplitude Ia of a current having a frequency which is three times as high as that of the fundamental sine wave current is set to a predetermined value smaller than amplitude I of the fundamental sine wave current.

Abstract: A startup control method of a BLDC motor is disclosed. The method can control the BLDC motor to prevent the generation of a transient current such that the vibration of the BLDC motor can be reduced at the startup stage and perform a stable conversion into a sensorless operation mode such that the startup failure rate of the BLDC motor can be reduced. The startup control method includes commutating a current applied to stator windings according to a rotor position. The method of operating the BLDC motor includes a rotor position that is forcibly aligned and so that phase commutation is performed, a back-electromotive force (back-emf) is detected from a lead voltage of a phase of a voltage which is not applied thereto after performing phase commutation and a determination is performed as to whether the detected back-emf is in a rising interval.

Abstract: A motor control system comprising a plurality of motor controllers and a power source adapted to drive an electric motor. The motor control system comprises a switch that is selectively operable between at least a first position and a second position. In the first position, the power source is coupled to a first controller to provide the power to drive the electric motor. In the second position, the power source is coupled to a second controller to provide the power to drive the electric motor. The switch also electrically isolates the input and the output of the first controller from the power source when the manual bypass switch is positioned in the second position.

Abstract: A stepping motor control apparatus in accordance with the present invention comprises: a current detection unit that detects phase currents flowing into a stepping motor; an equivalent model-of-motor arithmetic unit that includes a coefficient multiplication block which performs multiplication using a coefficient ka?=Ts/? as a multiplier, a coefficient multiplication block which performs multiplication using a coefficient kb?=?/(Ts+?) as a multiplier, and a coefficient multiplication block which performs multiplication using a coefficient kg?=I0/E0 as a multiplier, and that calculates an estimated angle of excitation; a current control unit that controls an exciting current on the basis of the estimated angle of excitation, an angle command, and the phase currents detected by the current detection unit; and a variable voltage inverter that applies phase voltages to phase windings included in the stepping motor according to outputs of the current control unit.

Abstract: A system for enhancing the performance of a carrier insertion sensorless (CIS) position sensing system for a wound field synchronous machine that utilises the positively rotating components (+2?ct) of the carrier second harmonic currents that contain rotor position information before field excitation to serve as a north-south pole indicator that determines if the CIS system has locked onto the north or south pole of the rotor.

Abstract: Disclosed is a control device of a permanent magnet electric motor which makes it possible to synchronously control the permanent magnet electric motor even when the magnetic pole logarithm of the permanent magnet electric motor is not an integral multiple of the number of repeats of a rotation phase signal during one rotation.

Abstract: The present invention discloses devices and methods for improved starting and stopping of rotary motors. A rotary electrical machine (3) is supplied with a voltage from a voltage supply (10). The magnitude of a phase current is measured. The measured current value (IM) and applied voltage (U) is compared with what is expected for a predetermined target slip (ST), by means of a relation between phase current, applied voltage and slip. The comparison gives a discrepancy value, which is used to create a regulation signal (?U) to the voltage supply (10). To start and stop the machine, the target slip is increased and decreased, respectively, in a predetermined manner. The means for regulation may be provided as a separate add-on unit to existing soft starter equipment.

Abstract: A device and a method for non-contacting sensing of the rotational state of a rotor (10). The rotor has a surface divided into an electrically conductive part (1e) and a nonconductive part (1f). Three electric coils (2a, 2b, 2c) are each included in a respective parallel resonant circuit and are applied close to and with their longitudinal axes oriented towards the rotational path of the electrically conductive part of the rotor. The resonant oscillations are damped depending on the rotational position of the rotor. The rotational state is evaluated with an electronic circuit. In a liquid-flow meter, the coils may be applied in the dry part of the meter.

Abstract: The stepping motor driver comprises an inverter for feeding stepped currents to windings of a stepping motor, a position detector for obtaining a detected angle of a rotor of the stepping motor and a current controller for controlling the inverter. In a d-q rotational coordinate system in which the d-axis is in the direction of the magnetic flux of the rotor and the q-axis is in the direction perpendicular to the d-axis, an excitation angle for a winding is determined from a d-axis component and a q-axis component of a command current to the winding, a lead angle control signal is computed from the excitation angle, and a phase of an applied voltage to the stepping motor is controlled using the lead angle control signal.

Abstract: A speed-control drive circuit for a D.C. brushless fan motor includes a pulse width modulation input end for receiving an external pulse width modulation signal for controlling (and changing) the motor speed, and a motor winding drive circuit. The motor winding drive circuit and the pulse width modulation input end are connected to a set of motor windings. The pulse width modulation signal controls the motor winding drive circuit to cause excitation/unexcitation of the set of motor windings and to alternately changes a direction of current such that the set of motor windings adjusts a speed of the fan motor in response to excitation of the set of motor windings responsive to the pulse width modulation signal. The speed of the fan motor increases when an operational period of the pulse width modulation signal increases, and the speed of the fan motor decreases when the operational period of the pulse width modulation signal decreases.

Abstract: Method and system for controlling a permanent magnet machine are provided. The method provides a sensor assembly for sensing rotor sector position relative to a plurality of angular sectors. The method allows starting the machine in a brushless direct current mode of operation using a calculated initial rotor position based on angular sector position information from the sensor assembly. Upon reaching a predefined mode-crossover criterion, the method allows switching to a sinusoidal mode of operation using rotor angle position based on extrapolating angular sector position information from the sensor assembly.

Abstract: A programmable fountain controller for varying the flow rate of an AC PMSM fountain pump in a pre-determined manner so as to generate dynamically changing flow patterns. A micro-controller is provided to vary the pulse width and frequency timing over time for generating signals to an output switching circuit that drives the pump. A mode switch provides user-settable modes of operation selected from a group comprising a programmed flow control mode, a manual flow setting mode, an audio input mode and an external data input/output mode.

Abstract: A household electrical appliance for a.c. operation includes a synchronous motor, a dropping resistor, and a device for inserting the dropping resistor. The synchronous motor is rated at a first frequency. The device inserts the dropping resistor in series with the synchronous motor for operating the synchronous motor at a second frequency.

Abstract: A rotor angle detecting apparatus for a DC brushless motor is capable of detecting the angle of the rotor of the DC brushless motor with accuracy without the need for a position detecting sensor. A motor controller has a high-frequency voltage imposer, an angle detector, a U-phase current sensor, and a W-phase current sensor for detecting the rotor angle of the DC brushless motor. The angle detector detects the rotor angle &thgr; using a current value IU_s detected by the U-phase current sensor, a current value IW_s detected by the W-phase current sensor, and high-frequency components depending on high-frequency voltages vu, vv, vw, when the high-frequency voltages vu, vv, vw are imposed on command values VU_c, VV_c, VW_c for three-phase voltages by the high-frequency voltage imposer.

Abstract: The invention indicates a method for signal processing of an amplitude-modulated and/or phase-modulated high-frequency signal (RF signal), in which the RF signal is broken down into two signals (FM1 and FM2) by relative phase displacement by an angle +&bgr; and −&bgr; and the signals are amplified before they are added to form a transmission signal, and to a circuit arrangement in which the pure phase-modulated RF signal is multiplied in a first branch by cos &bgr; and in a second branch by sin &bgr; and the two signals (FM1, FM2) are obtained by respective summation and subtraction of the multiplied signals.

Abstract: There is provided a control circuit including (a) a first circuit for generating a three-phase PWM (pulse width modulation) signal, the circuit having functions of generating a PWM signal necessary for driving a three-phase invertor motor, generating interruption at a carrier period, and generating interruption at an intermediate point of a carrier period, and (b) a second circuit for generating an analog-digital start trigger in synchronization with a timing at which the PWM signal is output. For instance, the second circuit includes a first compare register having a two-staged structure, and a second compare register having a two-staged structure, and the first circuit includes a PWM timer. The first and second compare registers makes comparison with an output signal transmitted from the PWM timer to thereby generate the analog-digital start trigger.

Abstract: Axial error calculation unit is provided for estimating an axial error &Dgr;&thgr; between a d-q axis and a dc-qc axis by using Ld, Lq, Ke, Id*, Iq*, Idc and Iqc in a range of all rotational speeds except zero of a rotational speed command of a synchronous motor, Ld denoting an inductance on a magnetic pole axis d of the synchronous motor, Lq an inductance on a q axis orthogonal to the magnetic pole axis d, Ke a generated power constant of the motor, Id* a current command of the d axis, Iq* a current command on a q axis, Idc a detected current value on an assumed dc axis on control, and Iqc a detected current value on an assumed qc axis orthogonal to the assumed dc axis. Irrespective of presence of saliency, position sensorless control can be achieved in a wide range a low to high speed zone.

Abstract: A three region control strategy for a permanent magnet motor is presented. In a first control region, the permanent magnet motor is operated at, a 120° conduction square wave mode at reduced phase current, and below a no-load speed. The motor phase current commutation causes eddy current losses in the rotor magnets and core which are insignificant due to the low phase currents and relatively low rotor speed. Meanwhile, the inverter switching losses are kept low as two switches are in use (on/off) for each current commutation during the 120° conduction mode. In a second control region, the permanent magnet motor is operated at a 180° conduction sinusoidal wave mode with high phase currents. The 180° conduction sinusoidal wave mode minimizes the commutation loss. In a third control region, the permanent magnet motor is operated above its no-load speed or in a field weakening mode.

Abstract: A switched reluctance drive is supplied from a voltage source which varies from the voltage at which the control laws for the drive were determined. The control system compensates for this by modifying both the speed and torque values used to determine the correct firing angles for the demanded load. The system works over a very wide range of voltage variation and is independent of the shape of the torque/speed curve of the drive.

Abstract: A method and apparatus for controlling a permanent magnet synchronous motor (8) coupled to a turbo engine such that transient current and steady state current are minimized. The method comprises the steps of, for a given DC bus voltage, determining an acceleration profile as a function of a voltage-offset value, a low-speed rated speed value, a high-speed rated speed value, a first desired speed for warming up the turbo engine, and a second desired speed where the turbo engine has sufficient torque to accelerate to its rated speed without the aid of the permanent magnet synchronous motor (8).

Abstract: A method and apparatus for controlling a permanent magnet synchronous motor (8) coupled to a turbo engine such that transient current and steady state current are minimized. The method comprises the steps of, for a given DC bus voltage, determining an acceleration profile as a function of a voltage-offset value, a low-speed rated speed value, a high-speed rated speed value, a first desired speed for warming up the turbo engine, and a second desired speed where the turbo engine has sufficient torque to accelerate to its rated speed without the aid of the permanent magnet synchronous motor (8).

Abstract: A method for monitoring the speed of a synchronous motor, the synchronous motor having a permanent magnet rotor (3) and coils (1, 2), sinusoidal currents being applied to the coils (1, 2). Also a device for monitoring the speed of such a motor, wherein in at least one of the coils (1, 2) the power supply is disconnected and one or more voltage characteristics (U1, U2) are evaluated which are induced by the permanent magnet rotor (3) in one or more of the coils (1, 2) disconnected from the power supply, the minimum duration of the interruption of the power supply of the coils (1, 2) and the evaluation of the voltage characteristic (U1, U2) being equal to the temporal spacing between two consecutive zero crossings of the respectively induced voltage characteristics (U1, U2).