Abstract: A drive circuit includes an internal oscillator and a pre-drive controller coupled to the internal oscillator. The pre-drive controller can have a switch control output configured to be coupled to a switch input. The pre-drive controller can receive switch control data, receive a clock signal, receive a synchronization signal, synchronize the internal oscillator based on the clock signal and the synchronization signal, and generate a pulse modulated switching signal at the switch control output based on the switch control data and the internal oscillator.

Abstract: According to one aspect, a system for testing an engine includes a dynamometer coupled to the engine. The dynamometer is responsive to a control signal. The system further includes a controller that derives the control signal from an engine operation parameter.

Abstract: In accordance with one embodiment, a voltage control apparatus comprises a pulse width control section, a pulse width modulation wave generation section, a variable amplifier control section and a variable amplifier. The pulse width control section specifies the pulse width of the pulse width modulation wave. The pulse width modulation wave generation section generates a pulse width modulation wave having the pulse width specified by the pulse width control section. The variable amplifier control section generates a GAIN signal for scaling up/down the pulse width modulation wave generated by the pulse width modulation wave generation section. The variable amplifier scales up/down the pulse width modulation wave generated by the pulse width modulation wave generation section according to the GAIN signal generated by the variable amplifier control section and outputs the scaled up/down the pulse width modulation wave.

Abstract: A motor drive control system connected to an alternating current/direct current conversion circuit which converts alternating-current voltage or alternating current to direct-current voltage or direct current are provided. A control circuit controls supply or stop of the supply of the direct-current voltage or direct current from the alternating current/direct current conversion circuit to the first number of first direct current/alternating current conversion circuits and the second number of second direct current/alternating current conversion circuits while maintaining the total of the outputs of the first number of motors and the outputs of the second number of motors at a certain power not more than power which can be supplied from the alternating current/direct current conversion circuit.

Abstract: A method and apparatus for anti-islanding of distributed power generation systems having an inverter comprising a phase locked loop (PLL), a phase shift generator for injecting a phase shift into the PLL during at least one sample period, and a phase error signature monitor for monitoring at least one phase error response of the PLL during the at least one sample period.

Abstract: A motor controlling apparatus having a controller for controlling a plurality of inverters correspondingly provided to each of a plurality of alternating-current motors is reduced in size, mass, and cost by effectively grouping operations performed by each calculation unit included in the controller. This controller for controlling the inverters includes: a first common calculation unit and a second common calculation unit that calculate and output control signals that are common to each of the inverters; individual calculation units that individually calculate and output a control signal related to each of the inverters; and a common logic calculation unit 60 that outputs a gate signal for controlling switching of each of the inverters based on the signals received from the first common calculation unit, the second common calculation unit, and the individual calculation units.

Abstract: A method and assembly for synchronizing machine operations, the assembly comprising a reference generator for generating a speed reference signal and a position reference signal, a plurality of slave units, each slave unit including, a mechanical device, a separate motor linked to and driving the mechanical device and a separate unit controller for controlling the unit motor, the unit controller receiving and using the reference signals to control motor operation and a synchronizer receiving the reference signals from the control signal source and simultaneously providing the reference signals to each of the slave unit controllers for use in controlling operation of the motors in a synchronized fashion.

Abstract: Steering apparatus includes at least one motor for generating a steering assisting force in a direction to steer a steerable wheel, two drive circuits having respective switching elements for PWM-controlling the motor, and a controller for differentiating, between the drive circuits, a control frequency at which the switching element is switched on and off. The differentiated PWM switching timing can effectively reduce switching noise and magnetostrictive sound of the motor.

Abstract: A method and a system for controlling parallel-connected frequency converters or inverter units feeding an alternating-current motor (MOTOR1) provided with parallel windings or separate parallel motors having their shafts mechanically coupled together via a load, in which method the current supplied to the motor is measured. The frequency converters/inverter units are connected to each other via a data bus, e.g. a fast serial bus, and one of the frequency converters/inverter units (FCON1 or INU1) functions as a master device in such manner that it sends to the other device/devices (FCON2 or INU2) information over the data bus regarding the instantaneous value of the current (IW1) fed by it to the motor, said other devices functioning as follower devices so that they adjust their own current (IW2) on the basis of the current of the master device.

Abstract: An airflow blockage detection apparatus for a permanent split-capacitor single-phase cooling fan motor measures and compares electrical currents in main and auxiliary windings of the motor to detect airflow blockage. Main and auxiliary current sensors detect AC currents in the main and auxiliary windings, respectively, and a blockage detection circuit forms a difference between the detected currents. An airflow blockage alarm is activated when the current difference exceeds a specified setpoint indicative of abnormally low airflow.

Abstract: A dual motor configuration 10 is provided for driving two fans for moving air to cool an engine. The dual motor configuration includes a primary brushless motor 18 constructed and arranged to be electronically controlled to drive a first fan 16 over a range of speeds. A secondary brush motor 24 is constructed and arranged to be electronically controlled to drive a second fan 22 over a range of speeds. The secondary brush motor includes an electronic switching device 26 associated therewith for receiving a pulse width modulated signal for controlling speed of the secondary brush motor. Thus, different combinations of speeds of the first and second motors can be selectively chosen to meet cooling requirements.

Abstract: A cooling system includes multiple cooling fans, each driven by a corresponding fan motor controller. Each fan motor controller includes electronic commutation circuitry that is responsive to a modulated signal to control the speed of the associated motor and fan. The controller for one motor includes a microcontroller that receives a single control signal from an external control unit and translates that control signal into the modulated signals provided to all of the other motor controllers. In one embodiment, the microcontroller can adjust the duty cycle of the modulated control signals, and can stagger the on-off times of the signals to minimize conducted RFI emissions.

Abstract: An AC motor control based on an iterative computation of the motor load and method of accurately determining motor load. At the initiation of motor operation, the load term (%LOAD) is initialized to zero, and the motor is energized in accordance with a predetermined voltage and frequency schedule for producing motor rotation. During the starting interval the power loss term LOSSES and the load term (%LOAD) are iteratively computed as a function of the input voltage and current (V.sub.bus, I.sub.bus) and the motor inverter frequency (IF). When a predetermined motor speed has been achieved, the run mode is initiated. At this point, the load is known based on the iterative load calculations performed during starting, and the motor voltage and inverter frequency are scheduled as a function of motor speed and load. The iterative computation of losses and load continue during the run mode so that changes in the motor load are taken into account.

Abstract: To regulate the speed of a plurality of asynchronous motors fed by a converter having a variable output frequency and output voltage and having a load-dependent slip, particularly asynchronous motors for driving spindles of a textile machine, the rotational frequency of several selected asynchronous motors is measured by means of respective digital frequency indicators. This measurement takes place in continuous repetition, always beginning simultaneously. The pulses of the frequency indicators are counted by means of respective first counters (1-6), all of which release a pulse when they reach the same counter condition. An OR circuit (13-17) connects the counter outputs with a second pulse counter (18) in such a manner that this condition is reached first by the output pulse released by the highest rotational frequency and then by the output pulses released by the second-highest rotational frequency, etc.

Abstract: A DC voltage on an electric car stringing is supplied to a variable voltage and variable frequency PWM inverter so as to be converted into a three-phase alternating current which is supplied to a plurality of three-phase induction motors. The motors are connected to different wheels to drive an electric car. The inverter is controlled on the basis of an operating frequency command determined by adding or subtracting a slip frequency command to or from a motor speed and a voltage command proportional to the operating frequency command. On the other hand, a motor current command is set and compared with a maximum current value of currents of the plurality of motors, and the slip frequency command is corrected in accordance with a difference therebetween.

Abstract: Protection for D.C. electrical circuit branches against incipient overloads comprises the use of semiconductor devices known as intelligent switches. An intelligent switch comprises a main controlled conduction path whose conductivity is controlled by an external control input. The semiconductor architecture is configured to possess internal self-protection for the main controlled conduction path against incipient current and/or temperature rises exceeding the device's rating by rendering the main controlled conduction path non-conductive when such incipient conditions are sensed. The invention, recognizing that this internal self-protection attribute can be used also to provide protection for external circuit components connected to the switch in the branch, further comprises the elimination of external protective devices from the branch such that the intelligent switch itself provides the entire overload protection within the branch.

Abstract: A rotation control apparatus for a differential actuator includes two induction motors and a differential mechanism for producing a constant torque on its output shaft based on the differential speed of the induction motors. The appartus includes two inverters each located between one of the induction motors and a common power source for the induction motors and having individual voltage/frequency output characteristics. The inverters set separately the voltage/frequency output characteristics of power supplied to the induction motors so as to control the speed of the induction motors separately, thereby controlling the output torque on the output shaft of the differential actuator. And the output shaft of the differential actuator is controlled to constant speeds regardless of the load torque on the shaft based on the difference of setting frequencies on both inverters.

Abstract: A device for controlling plural loads with phase locked loop control method by means of reference signals of different phases in order to avoid peak in electric power consumption.

Abstract: An emergency battery power supply for a ring-spinning or ring-twisting frame can be brought into operation by an automatic circuit to bridge brief power failures and effect programmed shutdown of the motors upon longer power failures, with the speed ratios between the motors being maintained substantially to standstill to avoid yarn breakage during shutdown.

Abstract: A method for optimizing the power input to a plurality of parallel connected hysteresis motors wherein a three phase alternating voltage source jointly supplies the motors with an adjustable operating voltage. The method includes measuring, during the operation of each motor, the phase angle difference between motor voltage and motor current and determining the power factor therefrom for each motor. The effective current value of each motor is measured during operation and is combined with the power factor to obtain the active current for each motor. An active current limit value at which each motor transitions from synchronous to asynchronous operation is measured once and stored for each motor prior to commencement of continuous synchronous operation.

Abstract: A control system is provided in which a signal proportional to the actual rotor speed of an induction motor is coupled to a variable gain amplifier. Changes in the commanded gain of the amplifier electronically control the ratio between rotor speed and the output signal amplitude of the variable gain amplifier. The output of the variable gain amplifier determines the commanded stator frequency. Disks optically encoded with a PWM pattern are driven at a speed which corresponds to the commanded stator frequency. Optical sensors read the pattern and provide switching signals to an inverter coupled to an induction motor.

Abstract: The exact shaft angle position synchronization of two or more ordinary synchronous induction motors is provided. One motor, serving as the master, is powered directly from a source of alternating current. Each additional motor, which may be of a different size or type, is slaved to the intrinsic rotational speed of the master through the inherent electrical speed synchronization wrought by being excited by a common alternating current power source. Each slave motor is further synchronized by this invention to attain, and subsequently hold, an exact angular shaft position relative to the master. The position of the master and each slave motor shaft position is constantly measured, thereby producing several trains of electrical pulses which are compared. When an error exists, an electrical signal is produced which acts with the a.c.

Abstract: The operation of a first motor and a second motor generates first and second frequency signals, respectively, which are fed to a phase lock loop (59) for phase comparison. A tri-level detection circuit (61) develops an output signal in response to the phase relationship between the first and second frequency signals. The first frequency signal is converted to a voltage signal by a converter (63) which is fed to an amplifier (64). A feedback circuit (66) is connected across the amplifier and includes several selectable levels of impedance. A switching network (62) responds to the output signal of the detection circuit (61), and thereby in response to the phase relationship between the first and second frequency signals, to connect one of the impedance levels of the feedback circuit (66) across the amplifier circuit (64).

Abstract: A device for controlling the phase of an output pulse sequence relative to an input pulse train of the same frequency comprises a multiplier receiving the pulse train from a frequency generator and emitting to a divider a rectangular waveform having a frequency m times that of the pulse train. The divider is controlled by a comparator to divide the frequency of the rectangular waveform by a factor of m.div.1, m-1, or m, depending on whether the actual phase difference between the pulse train and the sequence is less than, greater than, or equal to a predetermined phase angle, the actual phase difference being communicated to the comparator by a counter registering during each cycle of the pulse train a number of pulses proportional to the phase difference.

Abstract: A radio control driving circuit device used for a model device having a radio control system comprising a d-c power supply, two electric motors and a receiver, characterized in that two transistors of the same type, instead of the conventional complementary type, are used as two transistors each connected in series to the right and left motors for separately driving each of the motors, and a common power supply is used for driving the motors to permit control signals from the receiver to be introduced via a phase division circuit.

Abstract: A web fed press has at least one press unit including a first web driving means driven by a first motor. Downstream from the press unit is a second web driving means, such as nip rolls, driven by a second motor. Encoders are associated with the motors to produce pulse trains which are compared for motor speed relationship. If the relationship is not correct, the energization of the second motor is varied to correct the error. The relative web speed at the two locations is adjusted by effectively varying the number of pulses per revolution produced by the encoder for the second motor.

Abstract: This invention concerns a method for the synchronization of a gear machining instrument that works according to the hobbing method. It has different drives for the tool and the work-piece. In the process, a series of pulses are produced, dependent upon the rotational speed of each drive. The occurrence of the pulses are compared digitally resulting in an analog control signal for the adjustment of the work-piece drive.

Abstract: There is disclosed apparatus suitable for use in conjunction with film editing tables or other devices requiring precise control over shaft rotation speed, that is, apparatus for interlocking two or more shaft rotating systems to rotate one or more slave shafts in precise speed synchronism with one remote master shaft. For each slave shaft to be controlled, there is provided a differential amplifier connected in a velocity servo loop designed to force the slave shaft to rotate in precise speed synchronism with a remote or line master shaft. The primary feedback loop comprises means for generating trains of pulses having a characteristic representative of each of the rotational speeds and for deriving from these pulse trains analog voltages which are applied to a differential amplifier to produce an error signal to be driven to zero for controlling the speed of the slave shaft.

Abstract: The invention relates to a control circuit for controlling the speed ratio of a lead motor and a follower motor. The outputs of pulse generators driven by the motors are compared by being fed the positive and negative inputs of a bidirectional counter which outputs a positive or negative value indicative of the sensed speed ratio. A digital/analog converter driven by the counter effectively controls the speed of the follower motor pursuant to the sensed speed ratio.

Abstract: Apparatus for controlling the rotational speed of a polygonal mirror adapted to scan a reflected light beam over a desired scanning area as each facet of the mirror is rotated into the path of an incident light beam. The apparatus comprises a poly-phase motor coupled to the mirror for driving same. The motor has a plurality of input terminals and a plurality of motor windings connected to the input terminals. First means responds to the reflected light beam for generating a first clock signal having a frequency proportional to the actual rotational speed of the mirror. Second means generates a second clock signal having a frequency proportional to a desired rotational speed of said mirror. Third means coupled to the first and second means responds to the first and second clock signals for generating a third clock signal having a frequency representative of the difference in phase or frequency between the first and second clock signals.

Abstract: A pulse controller for controlling the current supply to a plurality of d.c. loads through a respective main thyristor for each load is provided with digital circuitry operable to maintain the mark-space ratios of voltage applied to the loads in a relationship to one another which is set by a differential control circuit while the mark-space ratios are simultaneously varied in response to a drive control circuit. The controller may be used to control two d.c. motors respectively driving right-hand and left-hand traction wheels of a battery-electric vehicle, to provide differential drive when the vehicle negotiates a curve.

Abstract: Long and short term variations in the speed at which a magnetic tape is moved with respect to a read and/or write head are minimized by maintaining the product of the speed of the tape payout and take-up reels constant. In accordance with a preferred embodiment the rotational speed of the payout reel and the rotational speed of the take-up reel are sensed and effectively multiplied to derive a signal which is compared with a predetermined constant magnitude reference signal. The result of the comparison is an error voltage which is employed to energize and thus control the speed of the drive motor for the take-up reel.

Abstract: The separate motors of the single facer and double facer machines of a corrugator are controlled in response to separate digital set point signals. Each set point signal is generated by a counter in response to a pulse generator. In a RUN mode, the counter automatically generates a preselected set point signal indicative of a preselected minimum speed and the motor speed is brought up to the preselected minimum speed. The pulse generator and counter are free-running until a digital detector senses the preselected set point signal and inhibits the pulse generator. In FAST and SLOW modes, the pulse generator is selectively steered by the operator to cause the counter to generate selective set point signals indicative of selective set point speeds and the motor speed is varied to the set point speeds.