Abstract: The present method and apparatus detects the rotor position of a brushless DC motor with an accuracy of .pi./m electrical radians (where m = the number of motor phases) within one electrical period, and provides enough information to enable starting the motor in the correct direction with certainty. After starting the motor in an open loop mode of one or two steps, a closed loop mode may be switched on, using a dynamic indirect position detection as is already well known in the technology. More specifically, the position at start is determined by the injection of short current pulses in different motor phases, each phase or pair of phases being energized first by a pulse of one polarity and of the opposite polarity. The sign of the time difference between the decay times of the induced voltages in the un-energized phase is detected.
Abstract: A method and apparatus for improving the performance of polyphase AC machines. The polyphase AC machines are excited both with a fundamental frequency and with an odd harmonic of the fundamental frequency. The fundamental flux wave and the harmonic flux wave will travel at synchronous speed in the air gap. This facilitates redistributing the flux densities in the machine and thereby increasing the total flux per pole in the machine.
July 17, 1989
Date of Patent:
February 23, 1993
Board of Regents, The University of Texas System
Abstract: A brushless motor drive circuit having a position detection output signal in the form of an m-phase sine wave with a signal composing circuit to flatten the inflection points of the sine wave by logarithmic compression. Switching elements control the rate of the current to the drive coil in response to the signal composing circuit. Simultaneously, the switching elements having the same phase are switched on to supply a resistive feedback element with reactive current during the periods when no current is to be supplied to the drive coil.
Abstract: A circuit for resynchronizing the rotor of a polyphase dc motor having "Y" connected stator coils and a moving rotor has circuitry for determining the actual instantaneous position of the rotor, and circuitry for determining a desired rotor position precedent to executing a desired commutation sequence.
Abstract: An improved regulator mechanism for a single-phase or three-phase, two-speed motor is disclosed. The regulator mechanism includes a first energizable contactor (having at least one contact) and a second energizable contactor (having five contacts) which cooperate to cycle the motor between inoperative and operative states and to configure the motor windings and power lines so as to provide first and second speed operation.
Abstract: Thers is provided a vehicle motor switching apparatus having an armature coil, a series circuit including a series coil and connecting the armature coil and a battery and a shunt coil, comprising a switch for connecting the shunt coil to the series circuit in parallel to the armature coil to set up the motor as a compound-wound motor when the shunt coil is connected to the series circuit, while set up the motor as a series motor when disconnected therefrom. The apparatus further comprises a switch for disconnecting the series coil from the series circuit to set up the motor as a shunt motor when the shunt coil is connected to the series circuit and the series circuit is disconnected therefrom.
Abstract: Disclosed is a starting current limiting device for single-phase induction motors, driven by an AC power supply, used in household electrical equipment. The device is adapted to provide, as the power switch of the induction motor is just turned on, a low and gradually increasing starting current flowing into the induction motor. The device is capable of cutting some portions of each cycle in the waveform of the AC power off such that the average voltage input to the single-phase induction motor is reduced, and/or converting some portions of each cycle to oscillate in the reverse directions such that the waveform of the AC power input to the single-phase induction motor appears to have a lower frequency. The device is provided with a switching circuit including a plurality of thyristors, which can be silicon controlled rectifiers or triacs.
July 3, 1991
Date of Patent:
November 17, 1992
Industrial Technology Research Institute
Tien-Cheng Hu, Wen-Hui Cheng, Ling-Hwei Chang, Eric Han
Abstract: A propulsion system for using a pair of electric induction motors to power a pair of vehicle drive wheels. The motors are driven by pulses of electric current from a common dc bus. The inductance of stator windings cause electric current to power the motors during the time between pulses so power from the dc bus is low. When a vehicle is making a tight turn, an inside motor provides an electric current to the dc bus to supply additional power to an outside motor. Speed and steering signals operate the electric motors and control speed of an engine and an alternator which supply power to the dc bus.
Abstract: A method and apparatus for controlling single or polyphase a.c. power controllers when controlling a.c. power controllers by means of phase angle control of semiconductor switches, the firing signals on the one hand must be long enough to guarantee a reliable firing and, on the other hand, be short enough to prevent an overloading of ignition amplifiers. According to the invention, therefore the use of firing signals with variable temporal lengths is provided, which end at least approximately at the reestablishment of the current flowing in the phase that has been fired. Moreover, devices for implementing the method are specified.
January 16, 1990
Date of Patent:
October 27, 1992
Diethard Runggaldier, B. Claus Doerwald
Abstract: A sewing machine drive apparatus having a first and second rectifying circuit connected to an AC power source, and a sewing machine control circuit for outputting a drive signal and for outputting a voltage control signal after a certain time period has elapsed from outputting said drive signal. A motor drive circuit is connected to the first rectifying circuit for driving a motor. A DC/DC converter solenoid power source circuit is connected to the second rectifying circuit for outputting a rated voltage of a solenoid, and for outputting a hold voltage to hold the solenoid in response to a voltage control signal. A solenoid drive circuit inputs the output of the DC/DC converter solenoid power circuit in response to a drive signal to drive the solenoid.
February 22, 1990
Date of Patent:
October 20, 1992
Matsushita Electric Industrial Co., Ltd.
Abstract: An electric induction motor is coupled to a source of alternating current by a thyristor switch. A control circuit triggers the thyristor switch to create conductive and non-conductive states during each cycle of the alternating current. A circuit senses the voltage across the thyristor switch during a non-conductive state. From that sensed voltage and known characteristics of the motor being controlled, the control circuit derives a measurement of the current flowing through the motor in the conductive state of the thyristor switch. One of two different derivation techniques is used depending upon the length of the non-conductive state. The control circuit includes a means for calibrating the derivation of the current measurement for a specific motor.
Abstract: A motor controller includes a set of thyristors which couple the motor to a source of alternating electricity. A detector senses when the voltage of the source makes a zero crossing. A mechanism is provided to vary the frequency of a clock signal at a rate determined by a user selectable input which represents the rate at which the motor speed is to change during starting or stopping. The clock signal is applied to a counter which produces an active trigger signal when a given number of clock signal cycles have been counted following a zero crossing of the source voltage. The active trigger signal causes a brief trigger pulse to be applied to gate electrodes of the thyristors. The varying frequency of the clock signal alters the relative times at which the thyristors are triggered to vary the amount of voltage applied to the motor. Different frequency variation functions can be stored in a memory for the starting and stopping modes.
Abstract: In an automatic winder wherein each of a plurality of winding units thereof has a traverse drum driving motor and an inverter for driving the motor, the numbers of those inverters which are to be decelerated and accelerated are controlled in such a manner that the regenerative energy generated upon deceleration of the motors and the motor driving energy may be cancel each other.
Abstract: This invention relates to an induction motor magnetic flux operation method in a vector control device in which a primary current is supplied to the induction motor in response to an excitation current command value and a torque current command value and the frequency is controlled on the basis of the magnetic flux operated from the voltage and current applied on the motor, characterized in that, when the magnetic flux is operated on the basis of the voltage, current on the motor and a magnetic flux command signal by using a primary delay circuit, the time constant of the primary delay circuit is set equal to that of the secondary circuit of the motor. According to this invention, it is possible to minimize the phase error with respect to the true secondary magnetic flux included in the secondary magnetic flux value, which leads to an accurate torque control.
Abstract: A control system for an AC excited synchronous machine for use in an electricity generator/motor system. The AC excited synchronous machine can be driven not only in a variable-speed operation based on 2-axis current control but also in a constant exciting frequency operation based on only direct-axis current component control. A phase signal is switched to drive stably the AC excited synchronoius machine in a self-excited operation or in a rotary phase modifying operation. Further, when it is desired to start pumping-up water, a synchronizing power is provided to keep constant the rotational speed of the machine at the time of establishing a desired water pressure. Because of the switching arrangement of the phase signal, the AC excited synchronous machine can be operated as an ordinary synchronous machine exhibiting ordinary synchronous characteristics, that is, self-excited operation characteristics, rotary phase modifying operation characteristics and pumping-up start characteristics.
Abstract: For operating electric drives, in particular of two-pole and multi-pole asynchronous induction motors intended for driving devices having at least two significantly different operating speeds it is proposed to operate at least one two-pole or multi-pole multi-phase asynchronous induction motor from a single-phase mains supply (L, N) by rendering conductive each of a plurality of power semiconductors (Triac T1, T2, T3) being connected in series to one of the windings (W1, W2, W3) each, only during a half wave of the single-phase supply voltage, in a manner staggered in time relative to the other series-connected semiconductor switches, and successively relative to the latter (FIG. 1).
Abstract: The present invention provides a current supply control apparatus for an inductance load which controls the energizing current of an armature coil for a specified waveform when an electric motor is rotating at high speed. Since a great inductance load requires much time for the accumulation and discharge of magnetic energy, a chopper circuit is utilized for high-response current supply control. The current supply control of the inductance load can be achieved with higher responsiveness, despite the use of a lower applied voltage, by means of a diode (6, 6a) for back flow prevention, a small-capacity capacitor (5), etc.
Abstract: The direct (d) and quadrature (q) components of flux, as sensed by flux sensors or determined from voltage and current measurements in a direct field orientation scheme, are processed rapidly and accurately to provide flux amplitude and angular position values for use by the vector rotator of a universal field-oriented (UFO) controller. Flux amplitude (linear or squared) is provided as feedback to tune the UFO controller for operation in direct and indirect field orientation modes and enables smooth transitions from one mode to the other.
Abstract: A synchronous motor is divulged whose direction of rotation may be chosen, comprising a rotor with permanent magnet and a stator with homopolar field, including a winding fed with an AC voltage. In response to a stopping order, a circuit controls the switch for opening the connection of the winding when the voltage is decreasing in absolute value or is cancelled out and stores the sign of its slope at the time of opening. The circuit controls the switch for closing the connection when the voltage is cancelled out or is increasing in absolute value, with a sign slope identical to, respectively opposite, the stored sign, in accordance with an order for setting in rotation in a direction identical to, respectively opposite, the preceding direction of rotation.
Abstract: A lock detector for a switched reluctance motor (SRM) position estimator monitors the rotor angle estimates from a SRM rotor position estimator to make sure that the estimator is accurately tracking rotor position. Phase flux and current measurements corresponding to the rotor angle estimate of the sampled phase are supplied to dividing circuitry which generates a phase inductance estimate. The phase inductance estimate is compared by logic circuitry to lower and upper inductance limits to determine whether the rotor angle estimate falls within a specified tolerance of a theoretical inductance value. Alternatively, a flux-current map is used to generate a phase flux reference for comparison to the phase flux estimate. A lock detector flip-flop is reset whenever the phase inductance estimate (or phase flux estimate) is outside the specified tolerance, and a signal is sent thereby to disable the SRM.