Abstract: A method and apparatus to provide estimates of electrical parameters for line-connected induction motors during either steady-state or dynamic motor operations. The electrical parameters are calculated from the motor nameplate data and voltage and current measurements. No speed sensors or electronic injection circuits are needed. The method can be divided into 4 major steps. First, complex space vectors are synthesized from voltage and current measurements. Second, the instantaneous rotor speed is detected by calculating the rotational speed of a single rotor slot harmonic component with respect to the rotational speed of the fundamental frequency component. Third, the positive sequence fundamental frequency components are extracted from complex space vectors. Finally, least-squares estimates of the electrical parameters are determined from a dynamic induction motor equivalent circuit model.

Abstract: An inverter device driving an induction motor including main and auxiliary windings both having different winding specifications includes a three-arm inverter circuit having phase output terminals connected to the main winding, the auxiliary winding and a neutral winding of the induction motor respectively and converting a DC power supply to two-phase substantially sinusoidal PWM voltage, a current detector detecting currents of the respective main and auxiliary windings from a DC power supply current, a vector control computing unit obtaining balanced inductance values and resistance values from inductance values and resistance values of the respective main and auxiliary windings, determining a two-phase voltage to be supplied to the induction motor by vector control computing based on the balanced inductance values and resistance values, and a PWM signal forming unit forming a PWM signal controlling the inverter circuit according to the two-phase voltage.

Abstract: A motor control device performing vector control for a motor that drives a load whose load torque varies periodically. The motor control device has: a motor speed deriving portion estimating or detecting a motor speed; a speed controller producing a specified torque current value such that the motor speed is made to follow a specified motor speed value fed from outside; a resonance filter producing a corrected torque current value by receiving a control value that varies with variations in the load torque and emphasizing a periodic variation component of the control value; a torque current corrector producing a specified superimposed torque current value by superimposing the corrected torque current value on the specified torque current value; and an adjusting portion adjusting, based on the specified superimposed torque current value, a degree of emphasis placed on the variation component by the resonance filter. The vector control is performed according to the specified superimposed torque current value.

Abstract: A dead-time compensation method is applied to a PWM inverter, which is provided to drive an induction motor using a constant V/f control. The method first calculates a root-mean-square current of the output instantaneous current of the inverter. Afterward, a lookup table of the root-mean-square current is used to obtain a dead-time compensation base voltage and a dead-time compensation per-unit voltage. Finally, the dead-time compensation base voltage is multiplied by the dead-time compensation per-unit voltage to produce a dead-time compensation voltage of the PWM inverter. Accordingly, the method reduces complexity of converting the current to the voltage to reach a faster real-time response. Furthermore, a more accurate dead-time compensation voltage is obtained without increasing hardware costs and the efficiency of operating the induction motor is improved at low speed and light load condition.

Abstract: An electric power supply driver executes duty control of turning on and off of a selected switching element to supply electric power to a corresponding stator coil in a case where an actual rotational direction and a target rotational direction of a motor shaft coincide with each other. Furthermore, the driver sets an on-duty ratio of the selected switching element below a lower limit value, which is at least required to rotate the motor shaft through the power supply to each corresponding stator coil in a case where the actual rotational direction and the target rotational direction do not coincide with each other.

Abstract: A powertrain system is operative to transfer power between an input member and a plurality of power actuators and an output member to generate an output torque. The power actuators are connected to an energy storage device. A method for controlling the powertrain system includes monitoring operating conditions of the powertrain system, determining an electric power limit for output power of the energy storage device, selectively enabling electric power boost based upon the operating conditions of the powertrain system, and increasing the electric power limit when electric power boost is enabled.

Abstract: Control systems, methods and power conversion systems are presented for controlling harmonic distortion, in which multi-sampling space vector modulation (SVM) is employed for controlling power converter switching devices, with a reference vector being sampled two or more times during each SVM period to update the SVM dwell times more than once during each SVM cycle.

Abstract: The single-phase brushless motor according to one aspect of the present invention includes a coil array having a plurality of magnetic coils 11-14; a magnet array having a plurality of permanent magnets 31-34; a magnetic sensor 40 for detecting relative position of the magnet array and the coil array; and a drive control circuit that, utilizing the output signal SSA of the magnetic sensor, generates application voltage for driving the coil array with a single-phase drive signal. The coil array includes a magnetic member 20. This magnetic member 20 is constituted such that, with the single-phase brushless motor at a stop, the centers of the permanent magnets 31-34 come to a stop at locations offsetted from the centers of the magnetic coils 11-14, due to attraction of the magnetic member 20 by the magnet array.

Abstract: A method of determining a slip estimate associated with an induction motor through analysis of voltage and current signals. A fundamental frequency is calculated from a representation (e.g., complex representation) of the voltage signal, and a saliency frequency is calculated from a representation of the current signal. An estimation of slip quantity is calculated according to a slip estimation function that includes the saliency frequency, a saliency order, the fundamental frequency, a quantity of rotor slots, and a quantity of poles of the motor.

Abstract: Disclosed is an assembly encompassing a three-phase machine and a frequency converter. Said assembly has the following characteristics: the three-phase machine comprises a stator and a rotor; at least the three circuits of the stator and/or the rotor can be operated in an insulated manner relative to each other for the three phases of the rotary current while being connectable to one separate terminal point of the frequency converter, respectively, so as to be insulated relative to each other; and the frequency converter is embodied with a D.C. link having a grounded neutral in such a way that a voltage or current which is symmetric regarding the potential to ground can be output at any moment between the two associated terminal points of each circuit.

Abstract: An induction motor control device includes an inverter circuit for driving an induction motor by outputting a command voltage, a current detector for detecting an output current, a magnetic flux estimation observer for generating an estimated magnetic flux, an estimated current, and a phase command for the motor using the command voltage and the output current, a primary angular speed estimator for estimating a primary angular speed using the estimated magnetic flux, a slip compensator for calculating a slip angular frequency using the output current, a first angular speed estimator for estimating a first angular speed using the primary angular speed and the output current, a second angular speed estimator for estimating a second angular speed using the output current, the estimated magnetic flux, and the estimated current, and a resistance estimator for estimating a secondary resistance value of the motor using the first and second angular speeds.

Abstract: An electronically commutated asynchronous motor (12) features a stator (202), a short-circuit rotor (204), a controller (FOR 20) for field-oriented regulation of the motor (12), a sensor magnet (274) in thermally conductive connection with the short-circuit rotor (204), a rotor position sensor (14A; 18; 18?) arranged at a predetermined distance (d) from the sensor magnet (274) to generate an output signal (HALL, U, U1, U2) that is dependent upon the spatial orientation of the sensor magnet (274), and a temperature evaluation apparatus (CALC_T 44) configured to ascertain, during operation, from the sensor output signal (HALL, U, U1, U2), a temperature value (T) that characterizes a temperature (T_SM, T_S) in the motor (12).

Abstract: The control apparatus for a power conversion apparatus having chopper circuits and a capacitor, each of which includes a switching circuit and a coil, the switching circuit being on/off-controlled in accordance with specific timings determined in accordance with a current flowing through the coil to create required voltage in the capacitor, includes a function of evenly dividing an interval between adjacent specific timings of one of the chopper circuits to produce divided timings to be allocated to the other chopper circuits, and a function of setting, for each of the other chopper circuits, an on-time period of the switching circuit such that, when the interval varies as a result of which the specific timing of each of the other chopper circuits deviates from a corresponding one of the divided timings, an interval between adjacent specific timings of each of the other chopper circuits is varied to reduce the deviation.

Abstract: Methods and apparatus are provided for startup of a permanent magnet alternating current (AC) motor. The method comprises the steps of detecting startup of the permanent magnet AC motor; detecting a mechanical oscillation of the permanent magnet AC motor when startup of the permanent magnet AC motor is detected; and, in response to detection of the mechanical oscillation of the permanent magnet AC motor when startup is detected, suppressing the mechanical oscillation of the permanent magnet AC motor.

Abstract: A motor drive for conditioning power to be delivered to a non-motor load includes a voltage feedback circuit that monitors a DC bus voltage and, based on changes in the DC bus voltage, adjusts a power conditioning scheme such that near steady-state load conditions are maintained in response to a transient load condition. The voltage feedback circuit has a voltage sensor that provides voltage feedback to a controller that determines what changes in power conditioning are needed in response to a transient load condition that manifests itself in a change in DC bus voltage.

Abstract: In a system for controlling rotation of a rotor of a multiphase rotary electric machine in relation to a stator thereof, a superimposing unit superimposes a first frequency signal on the input signal to the multiphase rotary electric machine. The first frequency signal has a first phase and a first period, and the first period is different from a period of rotation of the rotor. An amplitude detector detects an amplitude of a second frequency signal. The second frequency signal is actually propagated in the multiphase rotary electric machine with a second phase based on the superimposed first frequency signal. A rotation angle determiner determines a rotation angle of the rotor so as to eliminate a difference between the detected amplitude of the second frequency signal and a predetermined target amplitude thereof.

Abstract: A control device of a vehicle motor includes a temperature sensor that detects a temperature of each coil, each coil supplying an alternating current to a corresponding phase of the motor and a controller that controls a torque of the vehicle motor; detects a stalled state of a vehicle; detects a current phase angle of the vehicle motor; and selects one of the temperatures detected by the temperature sensor based on a detected current phase angle, wherein the torque of the vehicle motor is reduced when the stalled state of the vehicle is detected and when a selected temperature exceeds a restrictive temperature.

Abstract: An overmodulation PWM controller includes a voltage instruction calculation unit which calculates a d axis voltage instruction and a q axis voltage instruction in which a voltage amplitude exceeds a peak value of a triangular wave carrier; a voltage instruction correction unit which corrects the d axis voltage instruction and the q axis voltage instruction so that a pulse width modulation voltage applied to an AC motor has a fundamental wave amplitude corresponding to the voltage instruction amplitude, according to the synchronization value K which is the number of the triangular carriers per one cycle of the phase voltage instruction; and a voltage instruction conversion unit which converts the corrected d axis voltage instruction and the q axis voltage instruction into a phase voltage instruction. The pulse width modulation voltage is controlled according to the result of comparison between the phase voltage instruction and the triangular wave carrier.

Abstract: An induction motor drive includes a plurality of inverters, a changeover switch which changes over outputs of the plurality of inverters to be supplied to one induction motor and a changeover controller which controls the changeover switch on the basis of a failure detection signal of one inverter to change over from the one inverter to another inverter to start the other inverter so that the induction motor is driven. The changeover controller includes a frequency/phase detector which always detects a frequency and a phase of a terminal voltage of the induction motor and a starting frequency/phase setting device which controls a frequency and a phase at starting of the other inverter in accordance with detected values of the frequency/phase detector when the failure signal is inputted.

Abstract: A boost converter boosts a DC voltage of a DC power supply. An inverter converts the output voltage of the boost converter into an AC voltage. A control device that controls the boost converter reduces an output voltage instruction value of the boost converter when the rotation speed of the AC motor decreases and an absolute value of a variation rate of the rotation speed is not less than a predetermined value. The inverter is controlled in the control mode selected from a plurality of control modes including three modes of a sine wave PWM control mode, an overmodulation PWM control mode and a rectangular wave control mode. The control device of the boost converter reduces the output voltage instruction value of the boost converter only when the control mode of the inverter is the rectangular wave control mode or the overmodulation control mode.

Abstract: After an AC motor generates a three-phase current, modulate the three-phase current to generate an original voltage space vector, and add three detecting vectors with a sum of zero after the original voltage space vector. While adding the three detecting vectors, sample the current to generate a sampling result. Then adjust the width of pulses generated by a pulse width modulator according to the sampling result.

Abstract: A method and circuit arrangement for determining position of the rotor of an electronically commutated motor, wherein the rotor has magnetic axes having different permeances. Voltage is applied to stator phases, and resultant phase currents are monitored for purpose of determining rotor position in the standstill state of the motor. First and second rise times of phase currents are determined until predetermined limit values are reached in unsaturated state. The assignment of a magnetic axis to a stator phase is determined from first rise times of the currents in unsaturated state of the rotor core, and the polarization of the rotor is determined from second rise times of currents upon energization with saturation effects. After run-up of the motor, initial energization of the stator can be determined comparing levels of the magnet wheel voltages and corrected by changing the commutation of stator energization.

Abstract: Systems, apparatus, and methods for operating inductors in a Z-source inverter in a continuous current mode are provided. One system includes an AC motor, a Z-source inverter, and a processor. The inverter is configured to provide current and reactive power to the AC motor. The processor is configured to monitor the current and instruct the inverter to provide a greater amount of reactive power to the AC motor if the current is below/equal to a threshold amount. An apparatus includes means for determining if current produced by the inverter is below/equal to a threshold amount, and means for altering voltage commands supplied to the inverter so that an AC motor is induced to draw additional reactive power. One method includes determining if a plurality of inductors are providing a threshold current amount, and inducing a motor to draw more reactive power if the current is below/equal to the threshold amount.

Abstract: A controller of an electric motor for improving operation efficiency in performing electric conducting control of the electric motor of an axial air-gap type is provided.

Abstract: An excitation current processor of a current controller processes the excitation current corresponding to the magnetic flux instruction from the magnetic flux instruction processor. It multiplies this excitation current with a boost coefficient to obtain an excitation current instruction. Here, the boost coefficient is determined based on the difference obtained by subtracting the magnetic flux estimation value processed by the magnetic flux processor based on the excitation current feedback from the voltage conversion device from the magnetic flux instruction input from the magnetic flux instruction processor. Further, the boost coefficient can be found from the function of time from the start of the rise of the magnetic flux.

Abstract: A motor controller system comprises solid state switches for connection between a single phase to three phase static converter and motor terminals for controlling application of three phase power to the motor. Sensors sense power from the static converter. A control is connected to the sensors and the solid state switches for controlling operation of the solid state switches to run the motor. The controller includes a three phase detection scheme for preventing operation of the solid state switches in the absence of desired three phase power from the static converter. A motor start scheme disables the three phase detection scheme for a select time after a motor run signal.

Abstract: For mutually cross-interlocked multiple asynchronous AC induction electrical machines of the present invention, wherein the applicable operating characteristic curves of the asynchronous AC induction electrical machines include the asynchronous AC induction electrical machine of various operating characteristics, wherein when they are provided for the individual operation in different loading conditions, it is characterized that the cross interlocked electrical machine can be used to increase or decrease the rotational speed of the individual operation.

Abstract: A voltage control circuit is disclosed. A power factor corrector may utilize the control circuit to provide power factor correction for an AC induction motor. An AC induction motor system may combine the power factor correct with an AC induction motor.

Abstract: Systems and/or methods that facilitate efficiently controlling speed of an induction motor are presented. An optimized control component controls respective switching of an auxiliary switch component associated with an auxiliary winding of the motor, a main switch component associated with a main winding of the motor, and a capacitance adjuster switch component that facilitates adjusting the amount of capacitance associated with the auxiliary winding. The timing of switching on the auxiliary switch component and main switch component can be controlled such that there can be a time difference between the respective switching on of the auxiliary switch component and main switch component to produce additional phase shift to facilitate improving motor efficiency. The capacitance adjuster switch component can be switched on when motor speed is below a predetermined low speed threshold to facilitate increasing the amount of capacitance associated with the auxiliary winding to improve motor efficiency.

Abstract: A method and system for a control scheme for linear induction machines. The control scheme includes a maximum energy conversion ratio and a maximum acceleration and deceleration for linear induction machines.

Abstract: It is determined which of six continuous sections having different magnitude correlation of signal amplitude of each phase of an input three-phase signal a section is. Predetermined subtraction is performed between respective phases in the section, to obtain a normalized amplitude value normalized in the section, using the subtraction result. The normalized amplitude value is converted to a vector phase for one cycle based on a predetermined phase and output corresponding to the determined section.

Abstract: A system and method for starting and regulating a wound rotor motor (120) including a phase-controlled SCR converter (150) and a drive circuit (130, 140) having a voltage source inverter (140) and a voltage source converter (130). The SCR converter (150) regulates power transmitted to the drive circuit from the rotor of the motor (120) so that the ratings of the drive circuit are not exceeded.

Abstract: Let an axis parallel to a magnetic flux produced by a permanent magnet provided on a rotor of a motor be called a d-axis, let an axis leading the d-axis by an electrical angle of 90 degrees be called a q-axis, and let control axes corresponding to the d-axis and the q-axis be called a ?-axis and a ?-axis, respectively. Then, a motor control device performs vector control of the motor with the ?-axis and the ?-axis made different from the d-axis and the q-axis, respectively, and with a motor current passing through the motor broken down into a ?-axis current on the ?-axis and a ?-axis current on the ?-axis.

Abstract: A power conversion device includes a converter that converts AC power to DC power, a converter controller that controls an output voltage of the converter, an inverter that converts the DC power to AC power at a variable frequency, an inverter controller that controls an output frequency of the inverter, and a current detector that detects an AC current on an input side of the converter. It is configured in such a manner that the inverter controller adjusts a slip frequency of the induction motor in response to a fluctuation of the AC current on the input side of the converter detected by the current detector. It thus becomes possible to suppress a beat current in an output current of the inverter at the occurrence of a load fluctuation as well as a power supply voltage fluctuation.

Abstract: A motor control apparatus which controls an output voltage reference for an inverter driving a permanent magnet synchronous motor based on d-axis and q-axis current references, d-axis and q-axis current detected values, and a computed frequency value. When a torque reference specifying torque greater than maximum torque that the motor can output is input, a limit value for a phase angle that is a deviation between a rotation phase reference of control and a rotation phase value of the motor is varied depending on a quantity of the predetermined state.

Abstract: An exciting coil of a motor is formed to be controlled by using an analog timer, to thus control an excitation control circuit of a motor control apparatus, whereby an excitation control circuit which excites the exciting coil of a motor control apparatus can be simplified and complexity can be reduced by simplifying a circuit construction of an excitation controller. The apparatus includes an auxiliary winding (sub-coil) and a main winding (main coil), and an exciting device electrically connected with the auxiliary winding and the main winding, determines an excitation application time and an excitation time and generates an excitation current according to the determined excitation application time and the excitation time.

Abstract: An energy saving service includes: a service contract conclusion step in which a service contract is concluded with a customer who has purchased or will purchase a product with a permanent magnet motor; a driving device provision step in which a driving device which can drive a permanent magnet motor with any specifications is provided on the basis of the service contract; and a product upgrade step in which the driving device drives the permanent magnet motor so as to improve the performance of the product with the permanent magnet motor, thereby upgrading the product with the permanent magnet motor.

Abstract: A method of controlling the speed of an electric motor, said method being a digital method designed to control the speed of an induction motor that is powered by a triac device to a preset speed, in which the speed of the motor is measured and a digital numerical value representative of the mathematical first derivative of motor speed is calculated. A determination is made of the digital numerical value of the motor speed first derivative relative to a range, or band, of values. An error signal also is computed that is proportional to the error between the measured current motor speed and the preset speed and a determination is made of the digital numerical value of this error signal relative to a range, or band, of values that includes a value corresponding to that of the motor operating at the preset speed.

Abstract: In an embodiment of a method, the method includes measuring currents and voltages that are coupled to a motor that includes an internal permanent magnet and determining a reactive power in response to the measured currents and voltages. The method further includes estimating a first flux orthogonal to an axis of the internal permanent motor and estimating a second flux aligned with the axis of the internal permanent motor. Additionally, the method includes estimating a torque in response to the measured currents and the first and second fluxes.

Abstract: The motor controller drives an electric motor including a rotor as a field magnet and stator coils of U-phase, V-phase and W-phase. The motor controller includes an exploration voltage application unit for applying an exploration voltage to the stator coils of U-phase, V-phase and W-phase such that a voltage vector expressed by the voltage applied to the stator coils rotates in a predetermined cycle with maintaining a constant magnitude, an electric current detection unit for detecting an electric current flowing through the electric motor during the period in which the exploration voltage is applied by the exploration voltage application unit, and a rotor rotation angle estimation unit for estimating a rotation angle of the rotor based on a phase of the voltage vector when a magnitude of the electric current detected by the electric current detection unit takes a local maximum value.

Abstract: A motor controller for correcting offset of a drive current of a motor. An offset amount calculating section (14) calculates offset amounts (Iuofs, Ivofs, Iwofs) of the drive currents (Iu, Iv, Iw) when the motor is being driven. A drive signal correcting section (18) corrects offset of the drive currents (Iu, Iv, Iw) by correcting the duty ratios of drive signals (Suo, Svo, Swo) based on the offset amounts (Iuofs, Ivofs, Iwofs).

Abstract: A method and apparatus to provide continuous and reliable rotor temperature estimates for line-connected induction motors during steady-state and/or dynamic motor operations. Rotor temperature is calculated from voltage and current measurements without any temperature or speed sensors. First, complex space vectors are synthesized from voltage and current measurements. Second, the instantaneous rotor speed is detected by calculating the rotational speed of a single rotor slot harmonic component with respect to the rotational speed of the fundamental frequency component. Third, the positive sequence fundamental frequency components are extracted from complex space vectors. Fourth, the rotor time constant is estimated in a model-reference adaptive system based on a dynamic induction motor equivalent circuit model. Finally, the rotor temperature is calculated according to the linear relationship between the rotor temperature and the estimated rotor time constant.

Abstract: A method for sensorless estimation of rotor speed and position of a permanent magnet synchronous machine, when the permanent magnet synchronous machine is fed with a frequency converter, the method comprising the steps of forming a stator voltage reference for the permanent magnet synchronous machine, injecting a high frequency signal (uc) into the stator voltage reference, measuring a DC-link current (idc) of the frequency converter when the permanent magnet synchronous machine (4) is fed with a voltage (us,ref) corresponding to a sum of the stator voltage reference and the injected signal, calculating a stator current estimate (îs), calculating a current error (?s) as a difference between the stator current estimate and the measured DC-link current, and estimating a rotor speed ({circumflex over (?)}m) and position ({circumflex over (?)}m) of the permanent synchronous machine based on the current error.

Abstract: A system and method of determining the temperature of a rotating electromagnetic machine, such as an electric motor or generator. A temperature calibration parameter is calculated based on the temperature of an object situated close to the motor, such as a motor drive connected to the motor, and a first resistance value of the winding. In exemplary embodiments, the motor drive and first resistance value are determined only after the motor has been idle for some predetermined time period. Once the calibration parameter is calculated, the processor uses it along with subsequent resistance measurements to calculate the temperature of the motor.

Abstract: Method and system are provided for controlling an alternating current (AC) motor via an inverter. The method includes selecting a pulse sequencing method based on a modulation index of the inverter, and providing a voltage to the AC motor based on the pulse sequencing method. The system includes an inverter having a modulation index (Mi) and a controller coupled to the inverter. The controller selects a pulse sequencing method based on Mi and produces a signal based on the pulse sequencing method. The inverter includes a switch network producing a voltage in response to the signal, and the voltage drives the AC motor.

Abstract: A system and method of determining the temperature of a rotating electromagnetic machine, such as an electric motor or generator. A temperature calibration parameter is calculated based on the temperature of an object situated close to the motor, such as a motor drive connected to the motor, and a first resistance value of the winding. In exemplary embodiments, the motor drive and first resistance value are determined only after the motor has been idle for some predetermined time period. Once the calibration parameter is calculated, the processor uses it along with subsequent resistance measurements to calculate the temperature of the motor.

Abstract: A field weakening control system for use with an induction motor is disclosed. The field weakening control system has a sensing device configured to generate a signal indicative of a speed of the induction motor and a controller. The controller is configured to determine an initial voltage command based on the signal and determine an acceleration of the induction motor based on the signal. The controller is also configured to generate a desired voltage command based on at least one of the initial voltage command and the acceleration.

Abstract: In a motor driving apparatus, a control unit detects a rotation frequency of a motor to be driven and generates a control voltage Vcnt in a manner such that the rotation frequency thereof is brought close to a desired rotation frequency. A clamping circuit sets an upper limit Vcu and a lower limit Vcl of the control voltage Vcnt. A drive unit drives the motor based on the control voltage Vcnt generated by the control unit. A start circuit fixes the control voltage Vcnt to a predetermined initial voltage Vinit at the start of driving the motor.

Abstract: The present invention provides an induction motor controller which includes: a circuit for generating a d-axis current reference signal from a d-axis current command value and a periodically varying periodic signal; a d-axis current controller for controlling a d-axis motor current flowing through an induction motor to be controlled to match the d-axis current reference signal; parameter determining means for calculating and determining a motor parameter of the induction motor based on a deviation of the d-axis motor current from the d-axis current reference signal, and controlling a voltage applied to the induction motor using a compensation voltage calculated from the calculated and determined motor parameter, in which a control parameter for controlling the induction motor is set based on the calculated and determined motor parameter.

Abstract: Systems and methods for controlling a rotating electromagnetic machine. The rotating machine, such as a permanent magnet motor or hybrid switched reluctance motor, includes a stator having a plurality of phase windings and a rotor that rotates relative to the stator. A drive is connected to the phase windings for energizing the windings. A controller outputs a control signal to the drive in response to inputs of demanded torque, rotor position and/or speed. Control methods include calculating a scaled torque demand from the received torque demand to obtain substantially constant torque over a range of motor speeds, calculating an optimal dr-axis injection current using a cost function and a starting method that switches from speed control mode to torque control mode at a predetermined rotor speed or at predetermined start-up timing intervals.