Abstract: A motor system includes an air core motor having a rotor with opposed permanent magnet poles defining therebetween a magnetic airgap and driving magnetic flux across the magnetic airgap. A stationary armature with air core windings is located within the magnetic airgap. The permanent magnet poles produce a magnetic flux density through the air core windings to produce a back emf in the windings comparable to the voltage of the line power when the rotation of the permanent magnet poles is synchronous with the line power. A electronic variable speed drive coupled by a switch to the air core windings ramps up the frequency of power to the air core windings for accelerating the rotor to near line synchronous speed. When the frequency of the back emf approaches the frequency of the line power, the switch decouples the electronic variable speed drive and couples the air core windings to the line power for synchronous operation.

Abstract: A method and system for adaptively controlling a hybrid vehicle comprises a recorder for recording a historical load or duty cycle of vehicle during or after operation of the vehicle. A classifier classifies the historical load in accordance with a load category. A controller assigns at least one of a current control curve and a slew rate control curve associated with the load category for a defined time period after the recording of the historical load or if the vehicle is presently operating generally consistent with the load category. At least one of the current control curve and the slew rate control curve, or data representative thereof, are used to control an operation of an electric drive motor of the vehicle for the defined time period.

Abstract: A field-winding type of synchronous machine comprises a stator with an armature winding wound phase by phase, a rotor having a rotor core with a field winding wound, and a circuit enabling an armature current to pass the armature winding, the armature current corresponding to a synchronous current producing a rotation field rotating at an electrical-angle rotation speed agreeing to a rotation speed of the rotor. The synchronous machine further comprises a current suppressor and a current supplier. The current suppressor is connected to the field winging and suppresses, into a unidirectional current, an induced alternating current induced through the field winding in response to the armature current passing the armature winding. The current supplier supplies, phase by phase, to the armature winding a rotor exciting current whose waveform is different from the synchronous current only during a predetermined period of time shorter than one cycle of the synchronous current.

Abstract: A magnetic pole position in a synchronous motor having salient poles is estimated from an instructed voltage applied to the motor, a current generated from the instructed voltage and parameters. To estimate the position substantially matching with a true magnetic pole position, a phase matching voltage having a phase matching with the estimated magnetic pole position previously obtained is applied to the motor. The phase matching voltage has a harmonic frequency higher than that of the instructed voltage. A phase matching current generated from the phase matching voltage is detected from the motor. A value of at least one of the parameters is corrected such that a difference in phase between the phase matching voltage and the phase matching current substantially becomes zero. An estimated magnetic pole position is calculated from the instructed voltage, the generated current and the parameter having the corrected value.

Abstract: A rotary sensor that outputs two analog signals, such as one sine wave and one cosine wave and has multiple periods within one period of the electrical angle of a motor is employed. The motor is energized at each position for a specified length of time upon its startup by using multiple electrical angles corresponding to the multiple candidate absolute angles obtained from the rotary sensor signal as the initial position of the motor, and the electrical angle at which the motor acceleration becomes maximum is determined as the absolute angle. While the motor drive is in operation, on the other hand, the phase difference ?? between the phase of the motor at the counter electromotive voltage and the control phase is directly computed from the parameters of the motor, sensed current, voltage command and angle speed so as to correct the shifted position.

Abstract: A synchronous motor driving apparatus having a power converter which applies AC variable voltages having variable frequency to a synchronous motor includes a pulsating current application unit for applying pulsating current to the synchronous motor and a magnetic pole position presumption unit. The magnetic pole position presumption unit detects two current values ?Idcp1 and ?Idcp2 on the positive side and two current values ?Idcn1 and ?Idcn2 on the negative side of the pulsating current and presumes the magnetic pole position of the synchronous motor on the basis of difference between change rates of ?Idcp1??Idcp2 and ?Idcp1??Idcp2.

Abstract: A desired q-axis current is determined based on a desired torque, and a desired d-axis current is determined based on the rotating speed of a synchronous motor when the terminal voltage of the synchronous motor coincides with a predetermined maximum permissible voltage to weaken a magnetic field created by the synchronous motor equivalently and to prevent the drop of the output torque of the synchronous motor. The desired d-axis current is determined based on the desired torque and the rotating speed. Therefore, the desired d-axis current can be reduced when a high torque is not necessary and undesired increase of the desired d-axis current can be prevented. Thus the synchronous motor operates efficiently, heat generation of the synchronous motor is prevented and power factor is improved.

Abstract: A method of controlling a power converter (258) of a synchronous machine drive system (100) determines position and speed of a rotor (350) of the synchronous machine (300); regulates a current vector relative to a reference frame, having a direct-axis component and a quadrature-axis component, the regulating step selectively causing the current vector to lag a quadrature axis of the machine (300); and outputs a command signal to the power converter (258) as a function of the regulating step. According to one implementation, this process creates higher total torque and maintains supply voltage within a maximum level during a high speed range of the machine.

Abstract: A system for controlling a permanent magnet synchronous motor calculates fundamental a d-axis (or q-axis) voltage command based on a difference between a d-axis (or q-axis) current command and a d-axis (or q-axis) current feedback signal, calculates a harmonic suppression d-axis (or q-axis) voltage command used to suppress at least one higher-order harmonic current component included in a harmonic current component which is calculated based on the differences between the current feedback signals and the current commands, and calculates a d-axis (or q-axis) voltage command by adding the fundamental d-axis (or q-axis) voltage command and the harmonic suppression d-axis (or q-axis) voltage command. The d-axis and q-axis voltage commands are transformed into three-phase voltage commands, which are converted into a drive voltage for driving the permanent magnet synchronous motor. As a result, the harmonic current components are significantly suppressed and the motor's overall performance is improved.

Abstract: A synchronous machine with 3-phase sensors set 120° apart and 90° advanced is used to provide commutation from a direct current source. A time delay circuit with an electronically implemented algorithm controls torque by delaying the 90° advance. This delay is controlled by a linear voltage, independent of frequency, and can be used to control position, speed, or acceleration. A delay beyond 90° advance causes commutation to cease, and the alternating current machine switches to a generator, indicative of motive power being applied. If motive power ceases, the alternating current machine switches to a motor. Controlled switching can be less than half of one hertz.

Abstract: A position sensing apparatus (300) derives rotor position of a synchronous machine (200) from signals output from the machine (200). In one embodiment, the position sensing apparatus (300) comprises: a bandpass filter (322) that filters phase voltage signals output from main stator windings (216) of the synchronous machine (200) during AC excitation, thereby extracting a rotor position-indicating component from the phase voltage signals; a converter (324) that converts the filtered phase voltages into balanced two-phase quadrature signals, the balanced two-phase quadrature signals indicating positioning of the rotor (212); and an excitation controller (204) for controlling AC excitation frequency as a function of rotor speed.

Abstract: A carrier injection sensorless (CIS) starting control system that is capable of determining the angular position and velocity of a rotor for a wound field synchronous machine at or near rest and comprises north-south pole determination and a variable or dual frequency carrier signal for improved performance throughout the start sequence for the machine.

Abstract: A drive system includes a central power supply with a line-commutated converter and a DC/DC converter connected downstream of the line-commutated converter, and a plurality of inverters, each inverter having an output connected a load, for example a motor, and a DC input connected to a regulated DC voltage output of the central power supply. Buffer capacitors are connected across the respective input and output of the DC/DC converter. The drive system further includes an energy recovery device with an input connected to the controlled voltage output of the central power supply and an output connected to at least two input terminals of the line-commutated converter. This type of drive system eliminates a bulky brake circuit.

Abstract: A synchronous machine control device includes a flux command generator, a magnetic flux estimator, a divider, a flux controller and ?- and ?-axis armature current controllers. The flux command generator produces a flux command from the synchronous machine turning speed. The magnetic flux estimator calculates the magnitude and phase of armature flux linkage from armature currents and field current taking into consideration magnetic fluxes produced by permanent magnets. The divider produces an armature current command by dividing a torque command by the armature flux linkage. The flux controller determines a field current command based on an error of the magnitude of the armature flux linkage from the flux command.

Abstract: A method and apparatus for use with a controller for controlling a machine wherein a torque reference value is provided, the method for identifying an error representative of the difference between the torque reference value and the torque applied to the machine and using the error value to modify machine operation, the method comprising the steps of obtaining feedback current values corresponding to the currents provided to the machine, mathematically combining the feedback current values to generate an error value, mathematically combining the error value and the torque reference value to generate a torque command value and using the torque command value to control the machine.

Abstract: Reactive power (VAR) consumption in a power plant or facility having synchronous machines is adaptively controlled in an automated manner. Electrical parameters of the plant are dynamically monitored during plant operation, and the overall plant power system is brought to an optimum operating point under control of a microprocessor-based power measurement system. The microprocessor-based power measurement system adaptively changes the excitation system of synchronous machines in the plant based on results of monitoring. The excitation systems of the synchronous machines may be adjusted to be constant bus voltage, constant reactive power, or constant power factor, according to optimum system performance requirements. The power measurement system also assists in avoiding problems in voltage regulation during increased load demand conditions, such as when starting large electrical motors or energizing large transformers in the system.

Abstract: An excitation controller controls excitation of a synchronous machine, which is connected to a power transmission system through a transformer, so that a high-side voltage of the transformer is maintained at a target voltage with high accuracy. An output terminal target voltage of the synchronous machine is set to precisely compensate for a voltage drop in the transformer, corresponding to the transformer phase angle variation. To achieve this result, the excitation controller detects an output terminal voltage and an output current of the synchronous machine and calculates active and reactive currents of the output current, sets the output terminal target voltage of the synchronous machine from the active and reactive currents, the high-side voltage of the transformer, and the reactance of the transformer, and controls excitation of the synchronous machine to compensate for the voltage drop in the transformer corresponding to phase angle variation of the transformer.

Abstract: A method in connection with a synchronous machine, the method comprising the steps of determining phase currents (iu, iv, iw) of a stator in the synchronous machine, determining phase voltages (uu, uv, uw) of a stator in the synchronous machine and estimating a position angle (&ggr;). The method also comprises the steps of generating estimates for stator flux vector components (&psgr;i&agr;, &psgr;i&bgr;) of the determined phase currents (iu, iv, iw) of the stator and the estimated rotor angle (&ggr;) using a current model (2) of the synchronous machine, generating estimates for the stator flux vector components (&psgr;i&agr;, &psgr;i&bgr;), comparing the generated stator flux vector estimates (&psgr;i&agr;, &psgr;i&bgr;; &psgr;&agr;, &psgr;&bgr;) with the phase difference of the estimates in order to achieve a proportional quantity, and adjusting the estimate (&ggr;) of the rotor position angle on the basis of the quantity proportional to the phase difference.

Abstract: A device and method for driving a concentrated winding synchronous motor which, upon supply of a given electric current to a stator coil of the motor, generates an increased torque. Periodical corrections are executed to the waveform of the current to be supplied to the coils of each phase of the stator and corrections are executed to decrease the alternating current supplied to the coil of any tooth at which a portion of a magnetic field generated, with respect to the pole of the closest rotor, is in a direction reverse to a rotation of the rotor.

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: An electronic control system for regulating the amount of torque applied by a starter/generator to a gas turbine engine during startup. The control system senses engine speed, compares the engine's actual acceleration with a predetermined acceleration, and adjusts the torque to the engine so that the engine accelerates along the predetermined schedule. The predetermined schedule is a function of the engine's speed or time, inlet conditions and oil temperature.

Abstract: A method and apparatus for cranking of an internal combustion engine in an AC electric traction motor propelled vehicle using inverters normally coupled to supply power to each of a plurality of AC motors. The inverters have DC input terminals connected between a relatively positive DC bus and a relatively negative DC bus and the DC buses are connected to DC output terminals of a rectifier. The rectifier has AC input terminals connected to stator terminals of a synchronous generator. The generator includes a field winding and a rotor connected in driving relationship to a crank shaft of the engine.

Abstract: To provide a control system for a permanent magnet synchronous motor which can ensure stability of the current control system, even if the revolution frequency of the motor becomes higher and the terminal voltage of the motor exceeds the inverter maximum output voltage. In this method, when the revolution frequency of the motor exceeds a specified value, the size of the voltage vector is made a specified voltage vector, and a modulation factor based on its value is obtained. At the same time, a magnetic flux direction current correction value is found based on the size of a voltage vector from a polarity coordinates conversion unit and the above specified voltage vector size. Then, the magnetic flux direction current instruction is corrected by that value.

Abstract: An induction synchronous motor comprises: a unitary rotor having a first and a second rotor core; a first and a second stator mounted surroundingly facing the first and the second rotor core; a voltage phase shifting means for producing a first and a second phase differences; a static magnetic field around each of the first and second rotor cores; and a rotor magnetizing means having diodes for rectifying alternating voltages and for having the resultant direct current produce magnetic poles in the first and second rotor cores. The motor is caused to initiate its operation as an induction motor based on the first phase difference produced by the voltage phase shifting means, to have the first phase difference shifted to the second phase difference produced by the phase shifting means operated, and to have the first and second rotor cores produce the magnetic poles attracted by the rotating magnetic field produced by the first and second stators, resulting in the synchronous operation of the motor.

Abstract: In a novel method and apparatus for controlling a synchronous motor, an angular position transducer, in whose output winding three-phase voltages with amplitude variations of N (N: an integer of 1 or more) cycles per revolution is induced, is directly coupled to a synchronous motor with 2N poles so that the demodulated a-phase voltage of the transducer has its positive peak value multiplied by the cosine of a selected angle as MMF phase angle when a direct axis of the motor is located in the position of its a-phase winding axis. The instructions to control three-phase currents of an inverter feeding the motor are produced by multiplying the current phase instructions by the amplitude instruction. The former is directly obtained using the three-phase voltages demodulated from the output of the transducer and the latter is derived from the detected speed deviation or torque instruction.

Abstract: The present invention provides a digital circuit for controlling application of DC excitation to the rotor field winding of a synchronous electric motor. The circuit detects the analog slip frequency of the motor and converts the analog signal to a digital signal. A digital timer produces a timing signal after a predetermined time interval. After the frequency of the slip signal has slowed sufficiently, as indicated by the timing signal, a control signal is supplied to a thyristor to gate the thyristor and provide DC excitation to the rotor field winding.

Abstract: A converter for synchronous motor starting rectifies the input voltage from a polyphase input power source to develop a starting current having a substantial DC component. The starting current is then sequentially applied to each of the phase windings in the synchronous motor, with the sequential rate of application occurring at a continuously increasing frequency. The angular velocity of the motor synchronously increases with the increasing frequency of the sequential rate of application of the starting current to the phase windings. By application of the starting current at an increasing frequency, the synchronous motor operates in a forced commutation mode. The starting current is removed when the angular velocity of the motor is synchronous with the constant frequency of the polyphase input power source. When the starting current is removed, and the motor is synchronous with the input power, the input power may then be applied directly to the motor in a natural commutation mode.

Abstract: A controller of a synchronous motor for stably controlling the synchronous motor from a low speed to a high speed. The controller includes a multi-phase synchronous motor, a multi-phase square wave oscillator circuit, a magnetic pole position detection unit for detecting a position of the magnetic pole of a rotor of the multi-phase synchronous motor, and a unit for calculating a detection period of the magnetic pole position of the rotor by the magnetic pole position detection unit. The controller further includes a unit for dividing multi-phase square waves for each phase generated from the multi-phase square wave oscillator circuit into a plurality of pulses for each period to produce the divided square pulses. The controller also includes an excitation current control unit for controlling the divided square pulses for each phase in accordance with the detection period to supply the pulses to stator coils of the motor.

Abstract: During the run-up of high-power synchronous machines (6), such as those used in pumped storage plants, in gas turbines sets and so forth, unwanted alternating currents with slip frequencies between those of the phase swings and the nominal frequency (50 Hz) of the synchronous machine (6) can also occur in the disturbed condition in addition to low-frequency plant-specific phase swings. These alternating currents are induced in the field windings of the synchronous machine (6) as a consequence of an unwanted asynchronous starting and can lead to inadmissible heating of the synchronous machine and to overvoltages in the field circuit. Alternating voltages (U1) associated with the slip frequencies are detected from use of a sensing resistor (4) in the exciter current (i.sub.

Abstract: In a brushless synchronous motor in which a short-circuited protective winding (9) is associated with the field winding (2) of the rotor the starting conditions are improved in that the protective winding (9) consists of two winding sections (10, 11), which have different numbers of turns and are either wound in mutually opposite senses or are wound in the same sense but connected in opposition.

Abstract: A brushless exciter is provided for controlling excitation of a synchronous motor. The brushless exciter uses a center tapped rotating transformer, a discharge resistor, a field winding which has one end coupled to the ends of the rotating transformer and the other end connected to the discharge resistor and center tap of the rotating transformer. Four power SCR's are used in the brushless exciter. The electronics for controllably firing the SCR's and applying and removing the field are arranged in modules. A field current regulator module is located externally of the rotating apparatus for external control and contains circuitry for field forcing. The circuitry controls the application of field current and the level of excitation. The circuitry monitors the presence, frequency and phase angle of the discharge current and determines the time for field application and removal.

Abstract: For starting a rotatable 3-phase a-c electrical machine of the synchronous type, the stator windings of the machine are connected to an electric storage battery via a controllable electric power converter, and the d-c field winding is connected in series with the stator windings by inserting it in the load current path between the converter and battery. Field weakening resistance is connected in parallel with the field winding. The converter includes a plurality of electric valves (thyristors) that are cyclically turned on in a predetermined sequence in synchronism with alternating voltages developed at the line terminals of the stator windings.

Abstract: An electric synchronous machine is excited via rotating rectifiers by an exciter machine. To this end, the three-phase winding of the exciter machine is connected to two Y-connected rectifiers having different current conduction directions. One end of the field winding of the synchronous machine is connected to the central point of the three-phase winding. In addition, there is provided between the Y-point of the rectifiers and the other end of the field winding one thyristor each, to the control electrodes of which a parallel-connected voltage sensitive firing device is coupled. Furthermore, stationary electrical elements are connected to the exciter device via switches and auxiliary slip rings and liftable brushes.

Abstract: In a current-fed static controlled synchronous motor drive which includes a ramp logic for establishing the desired firing retardation for the naturally commutated thyristors, an optical encoder provides a position signal and a velocity signal, while the ramp counting the velocity pulses is automatically aligned with the position signal by means of a phase detector causing either to add pulses from a local oscillator or to inhibit velocity pulses so as to compensate for a phase error in either direction. Alignment is also provided within 60.degree. initially by presetting the ramp counting in relation to a digital representation of sine 60.degree. time intervals over a fundamental cycle.

Abstract: A rotatable transformer field excitation system for an armature converter-fed variable speed self-controlled brushless polyphase synchronous motor wherein the armature converter is energized from an alternating current voltage source having one or more phases, and wherein the motor includes a rotor having a wound field winding and a rectifier circuit mounted on the rotor and rotatable therewith to energize the field winding with direct current from the rectifier circuit, and wherein the rotatable transformer includes a primary winding having a number of phases equal to the phases of the alternating current voltage source and having a plurality of coils located in slots on the inner periphery of and defining at least two poles of a rotatable transformer stator, the slots being spaced a predetermined distance from the center of the rotor axis, and a separate rotatable secondary winding, the number of phases of which equals the phases of the rotatable transformer, the secondary winding being formed by a pluralit