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 plurality of magnetic sensors are provided in a magneto motor to sense variations of rotating poles of rotor magnets. One of the magnetic sensors is provided to let the exciting current of stator coils and the rotating poles of the rotor interchange orthogonally, and the others are provided to let the exciting current of the stator coils and the rotating poles of the rotor interchange non-orthogonally. The magnetic sensor letting the stator coils and the rotor magnets orthogonally excite each other will let the magnetic flux density of the armature gap be highest, and the others letting the stator coils and the rotor magnets non-orthogonally excite each other will generate an effect similar to weak magnetic control.

Abstract: Method and system for controlling the start of a permanent magnet machine are provided. The method allows to assign a parameter value indicative of an estimated initial rotor position of the machine. The method further allows to energize the machine with a level of current being sufficiently high to start rotor motion in a desired direction in the event the initial rotor position estimate is sufficiently close to the actual rotor position of the machine. A sensing action allows to sense whether any incremental changes in rotor position occur in response to the energizing action. In the event no changes in rotor position are sensed, the method allows to incrementally adjust the estimated rotor position by a first set of angular values until changes in rotor position are sensed. In the event changes in rotor position are sensed, the method allows to provide a rotor alignment signal as rotor motion continues. The alignment signal allows to align the estimated rotor position relative to the actual rotor position.

Abstract: An inverter for use in a switched reluctance (SR) motor drive is provided. The inverter comprises a first and second transistor for selectively providing current to an SR motor winding. A resonant-type snubber circuit is connected to the transistors to reduce turn-off loss. The snubber circuit includes a pair of diodes, a capacitor, and an inductor. The snubber circuit is reset during switch-on time of the transistors. At transistor turn-off time, the snubber circuit uses the capacitor to effectively limit the rate of change of voltage across the transistors. This allows the transistors to turn off with lower losses, and can also reduce the acoustical noise generated by the motor drive.

Abstract: The technique of the present invention sets a torque voltage to be applied to a motor in response to a required torque and adjusts the duty of an inverter to ensure application of the torque voltage according to the observed voltage of a battery. In a motor controller constructed to attain such control, before a start-up of normal operation of the motor, a fixed duty is set for switching the inverter to apply a voltage to the motor. The value of electric current running in response to the applied voltage is measured. The mapping of the value of electric current to the source voltage in the case of switching the inverter at a fixed duty is stored in advance in the form of a table. The procedure reads the true value of the source voltage from the table and thereby specifies an offset error occurring in a voltage sensor of the battery. The procedure then corrects the observed voltage of the battery and adequately regulates the torque voltage.

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).

Abstract: A method to control a switched reluctance motor (SRM) with a first phase (1) and a second phase (2) comprises: aligning the rotor with the second phase (2); at a first time point (t1), energizing the first phase (1) with a phase voltage that is substantially constant; monitoring an increase of the phase current (I1) in the first phase (1) until the phase current reaches a maximum (302); monitoring a decrease (303) of the first current (I1) until at a second time point (t2) the phase current (I1) reaches a minimum (304) and starts to increase again (305); de-energizing the first phase (1) at a third time point (t3) that follows the second time point at (t2) at a predetermined time interval; and repeating energizing, monitoring and de-energizing for the second phase (2) instead of the first phase (1).

Abstract: A small synchronous motor with high reliability so devised that transition from start operation to synchronous operation is ensured. A microcomputer 22 switching-controls the current application range to a range where the rectified current flowing through a rectifying bridge circuit 20 and an A-coil alternately is inverted during one turn of a permanent magnet rotor 5 to suppress the input on the inverted side with respect to the non-inverted side and thereby to start a synchronous motor, turns off first to fourth transistors 16-19 when the rotational speed of the permanent magnet rotor regulated by the power source frequency and measured by a power source frequency measuring section 24, and turns on triacs SW1 and SW2, thereby making a switch to the synchronous operation circuit 21.

Abstract: A method is for decoding three logic signals produced by three Hall effect sensors installed in an electronically-switched three-phase brushless motor according to a sequence of six driving phases to be switched synchronously with a rotor position. The method includes determining a real phasing of the three Hall effect sensors at 60, 120, 300 or 240 electrical degrees. The determining is accomplished by decoding a whole set of eight possible combinations of the three logic signals produced by the three Hall effect sensors. The real phasing of the three Hall effect sensors is discriminated based upon two dissimilar combinations from among six valid combinations, the six valid combinations from among the eight possible combinations. The method further includes determining the rotor position based upon the real phasing of the three Hall effect sensors and generating logic driving signals synchronous with the rotor position.

Abstract: A permanent magnetically excited electrical rotary drive for a blood pump is proposed, comprising a permanent magnetic rotor and a stator, said stator comprising a drive winding having at least two loops for the production of a magnetic drive field which produces a torque on the rotor, with each loop belonging to a different electrical phase, furthermore comprising a setting device which supplies each loop in each case with a phase current or in each case with a phase voltage as a setting parameter, with the setting device comprising a separate power amplifier for each loop so that the setting parameter for each loop can be regulated independently of the setting parameter for the other loops.

Abstract: A method for restarting a three-phase synchronous permanent magnet motor in which the rotor is still rotating and in which the motor is connected to a drive unit having a DC-stage with voltage measuring means, a variable voltage and frequency output stage including power switching devices, and a means for determining the current in two of the output phases from the drive unit, wherein the motor with the output stage is momentarily short-circuited, the current magnitudes generated by the motor in the two output phases are measured during the short-circuiting moment, the phase angle generated by the motor during the short-circuiting moment is calculated, the rotor speed is determined, and the drive unit is synchronized with the rotor to enable restarting of the motor.

Abstract: An electrical angle detecting apparatus determines an electrical angle &thgr; from voltages Vd, Vq, and currents Id, Iq along a d-axis and a q-axis of a synchronous motor, by using the following expressions: &thgr;=&thgr;(n−1)+k1×&Dgr;Id+k2×&Sgr;(&Dgr;Id) &Dgr;Id=Id(n)−Id(n−1)−t(Vd−R×Id(n−1)+&ohgr;×Lq×Iq(n−1))/Ld; &ohgr;=(k1×&Dgr;Id+k2×&Sgr;(&Dgr;Id))/t where (n−1) indicates a value of each variable at the previous timing; (n) indicates a value at the given timing; R is the resistance of a coil; t is the determination executing period; and k1, k2 are coefficients. This determination makes it easier to set appropriate gains, so that precision improves. Furthermore, the amount of determination reduces, and the processing time shortens.

Abstract: A drive control apparatus for an electric synchronous machine is composed of armature current control means and transient operation detection means. When the synchronous machine is intended to increase power in a transient operation, the current control means supplies the armature winding with compensation current to cancel counter-electromotive force formed when field current is supplied to the field winding through a mutual inductance of the field winding and the armature winding.

Abstract: A speed control system for a brushless repulsion motor of the type including a series of armature mounted switches for shorting circumferentially spaced armature coils, said system comprising: a digital counter on the armature for creating a repetitive succession of switch activating signals in a selected sequence at a given rate determined by the counting rate of the counter; means for activating the switches with the signals in the sequence and at the rate to control the speed of the armature; and, means for directing a reference pulse signal at a reference frequency to the counter to set the counting rate of the counter.

Abstract: The conventional technique can not detect the electrical angle of a synchronous motor in a sensor-less manner when a high torque is required under the condition of a low-speed operation of the motor. The direction that passes through the axis of rotation of the motor and causes a magnetic flux to pass through a permanent magnet is defined as a d axis, whereas the direction that is electrically perpendicular to the d axis in the plane of rotation of the motor is defined as a q axis. In the case where the motor is required to output a high torque, the technique of the present invention applies a predetermined detection voltage to the q axis and determines the electrical angle based on the ratio of electric currents flowing through the d axis and the q axis. Application of a negative voltage to the q axis relieves magnetic saturation occurring on the q axis under a high torque condition and thereby allows detection of the electrical angle.

Abstract: When a required torque increases under the condition of high-speed rotation, the conventional technique can not detect an electrical angle or control a synchronous motor in a sensor-less manner. The direction that passes through the rotating axis of the motor and makes a magnetic flux run through a permanent magnet is defined as the d-axis, whereas the direction that is electrically perpendicular to the d-axis in the rotational plane of the motor is defined as the q-axis. The technique of the present invention applies voltages to the d-axis and the q-axis based on an estimated electrical angle and solves voltage equations with the observed electric currents. The technique then calculates a correction amount of the electrical angle according to errors of the arithmetic operations and controls the motor. The arithmetic operations are carried out by varying the inductance according to the required torque of the motor.

Abstract: An AC machine comprises: a motor energized by an AC source subject to irregularities of frequency and voltage; a generator driven by the motor for supplying an AC output signal of substantially constant frequency and voltage, the generator having a rotor with a layer of a re-magnetizable, relatively high coercive magnetic material on the rotor and a stator of a soft magnetic material having a pole piece and an excitation coil on the pole piece, the stator and the rotor rotating relative to one another with a clearance enabling rotor poles to be formed on the re-magnetizable layer by current energizing the excitation coil; and, a control signal generator responsive to at least one of the AC output signal and a signal representative of the current energizing the excitation coil for generating pulses of programmed wave shapes which differ in at least one of width, phase and magnitude as necessary to modify the rotor poles during the irregularities of the AC source to maintain the substantially constant frequency

Abstract: At the time of starting a synchronous motor (40), one method of the present invention assumes that the synchronous motor (40) rotates at a revolving speed of not less than a predetermined level, and detects an electrical angle of a rotor (50) according to a first detection process, which has a practical accuracy when the revolving speed of the rotor (50) is not less than the predetermined level (step S120). In case that the electrical angle has not been detected successfully, the method detects the electrical angle of the rotor (50) according to a second detection process, which has a practical accuracy when the revolving speed of the rotor (50) is less than the predetermined level (step S160). Another method first detects the revolving speed of the rotor (50).

Abstract: The prior art technique should return the voltage applied to a synchronous motor to zero in the process of measurement of an electrical angle. This causes foreign noises. The structure of the present invention utilizes the fact that the electrical angle of a three-phase synchronous motor 40 depends upon the inter-coil inductances. The procedure of the present invention applies a predetermined voltage for measurement to each combination of coils, and measures variations in electric currents flowing through the respective coils. The electric current flowing through each coil is attenuated in the presence of a driving current in the three-phase synchronous motor 40, compared with the case in the absence of a driving current. The procedure of the present invention accordingly refers to a table 122A to correct the observed values of electric currents based on the variations in electric currents, and refers to another table 122B to read the electrical angle .pi.

Abstract: In a driving system comprising a permanent magnet type synchronous machine, an electric power converter for the synchronous machine and a driving controller for driving the electric power converter, the driving controller comprises a current command generator for generating a d-axis current command and a q-axis current command of the synchronous machine, a d, q-axis current control uni for generating AC voltage command values Vu*, Vv* and Vw* based on the d-, q-axis currents from the synchronous machines, and a PWM control unit for generating driving signals for the electric power converter based on the AC voltage command values. A phase generator generates a phase signal from zero-cross point information of the AC voltage command values and a phase difference angle .delta. between induced voltage and terminal voltage of the synchronous machine; and a magnet temperature compensating unit generates a phase signal from zero-cross point information of the AC voltage command values and a phase difference angle .

Abstract: An inverter(3) for driving a motor(4) of an electric automobile(20) produces a three-phase PWM current. When the torque reference is zero, alternatively or when the torque reference is zero and motor speed is no higher than a predetermined value, the inverter(3) is controlled to be cut off so that current from a main power battery(9) is suspended or stopped.

Abstract: The disclosure relates to a synchronous permanent-magnet electric motor and a vehicle driven by such a motor. The electric motor has a leakage inductance whose value is at least about 10% of the value of its effective inductance. In this way, the total inductance of the motor is maximized so as to optimize the effect of the variation of the phase of the stator current on the variation of the voltage at the terminals of the motor. The invention is notably applicable to an electric vehicle.

Abstract: A polyphase dynamoelectric machine (10) such as a switched reluctance motor has a stator assembly (12) and a rotor assembly (14). The rotor assembly is movable with respect to the stator assembly. The stator assembly includes a stator (16) having a plurality of stator poles (18). The rotor assembly includes a rotor (20) having a plurality of rotor poles (22). The stator assembly further includes a plurality of separately energizable stator windings (24) associated with the respective machine phases. These stator windings are energized and de-energized in a predetermined sequential manner to sequentially activate and deactivate the machine phases. Energization and de-energization of the respective stator windings is at least partially determined as a function of the machine's instantaneous rotor position. The machine includes a processor (26) for determining the rotor position.

Abstract: Power is provided to the stator windings of an AC machine which includes a component at the fundamental drive frequency for the machine and a superimposed signal component which is at a substantially higher frequency than the drive power. The rotor has saliencies which result in a change in impedance as seen at the stator windings to the high frequency excitation signal as a periodic function of rotor rotational position. Such saliencies are inherent in some permanent magnet synchronous and all synchronous reluctance machines, and may be provided by appropriate modification of the rotor of induction machines. The stator response at the signal frequency is then detected to provide a correlation between the response at the signal frequency and the rotor position.

Abstract: The method and the apparatus are for starting up a synchronous machine having a rotor and a stator provided with a winding. The rotor has an initial position with respect to the stator.

Abstract: A compact, high efficiency non-interruptive motor generator power system for generating and supplying to a load A.C. of a substantially constant frequency and of a substantially constant voltage, the motor thereof being a synchronous A.C. motor energizable from a source of irregular and interruptible A.C. line power, the generator being capable of converting its rotational energy into the A.C. output for many seconds after interruption of the A.C. line power. The power system comprises a high efficiency, synchronous permanent magnet A.C. motor and an A.C. generator coupled to and driven by the motor. Both the motor and generator have a high rotational enertia common rotor wherein an outer cylindrical shell contains motor and generator rotor elements of high permeability soft magnetic material with a surface layer of magnetizable permanent magnetic material, and in each stator is an excitation coil, energizable with A.C.

Abstract: A synchronous A.C. electrical motor comprising (A) a stator having a body of slotted, soft ferromagnetic, low eddy current loss material, the slots having A.C. power windings to produce a rotating magnetic field, an excitation coil energizable with single phase A.C. located in two adjacent slots with a pole piece between them, and feedback windings located in slots such that when A.C. potential therefrom is conveyed to the excitation coil the excitation A.C.

Abstract: Control system for driving a synchronous motor at a speed greater than a rated speed with a rotational speed detector for the rotor mounted on the motor, rotational position detector for detecting the rotational position of the field pole of the motor, an error signal generator which produces the difference between a desired speed signal and an actual rotational speed signal, and a calculating device for calculating armature current component values Id, Iq and power-factor .phi..

Abstract: This invention is directed to a controllable infinitely variable speed A.C. electrical motor, comprising a rotor having a core of soft magnetic material carrying a peripheral layer of magnetizable permanent magnet material, which layer is magnetized by a stationary excitation coil energized with A.C. potential so that the peripheral layer assumes a selected configuration of north and south magnetic poles as the rotor revolves; A.C. potential is also applied to windings in slots in the stator core to provide a plurality of magnetic poles in the stator coacting magnetically with the configuration of north and south magnetic poles in the layer of magnetic material in the rotor, whereby to cause the rotor to revolve. Phase shifting means are provided in the circuit leading to the excitation coil to enable the phase of the A.C. current being supplied thereto to be shifted with respect to the phases of the A.C.