Abstract: A wireless communication system includes a first coupler having a first pair of electrodes and second coupler having a second pair of electrodes that at least partially oppose the first pair of electrodes. A transmission circuit applies a differential signal to the first coupler. A reception circuit receives a differential signal output from the second coupler based on electromagnetic coupling between the first coupler and the second coupler. A distance between centroids of the first pair of electrodes differs from a distance between centroids of the second pair of electrodes.

Abstract: An example vehicle comprises: (i) at least one electric generator that can be electronically-commutated or passively rectified, (ii) at least one electronically-commutated electric motor configured to drive a wheel of the vehicle, (iii) a voltage bus connecting the electric generator with the electronically-commutated electric motor, and (iv) means of controlling voltage level of the voltage bus.

Abstract: An electric machine, in particular an electric motor and/or generator, has a stator and a rotor which is designed to be permanently magnetic or to be energized in particular. The machine has at least two sub-machines. Each of the sub-machines has the same number of phases. The machine has a power output stage for each sub-machine, and the machine also has at least one control unit which is connected to the power output stages. The control unit is designed to generate a pulse width-modulated signal for actuating the power output stages. The control unit is designed to generate the PWM signal for the sub-machines such that an ascending or descending side of a PWM pulse for one sub-machine, said side representing a switching time in each case, and a pulse center of a PWM pulse for another sub-machine of the sub-machines are delayed relative to each other.

Abstract: According to an example aspect of the present invention, there is provided an apparatus for magnetically attaching to a load comprising: a direct current power source; an electromagnet comprising a coil connectable to the direct current power source for feeding current to the coil for attaching to a load by a magnetic force; a current measurement device connected to the coil; a user interface for displaying information indicating a load capacity of the apparatus; and a controller operatively connected to the direct current power source, the coil, the current measurement device and the user interface to cause: connecting the direct current power source to the coil; measuring current of the coil; determining a rise time of the current to a nominal value of current of the coil, when the load is attached to the apparatus; determining a load capacity and/or usage level of the load capacity of the apparatus based on the rise time of the current to the nominal value; and displaying the load capacity on the user inte

Abstract: A driver circuit for generating a sequence of pulses of a drive voltage from a supply voltage is described. The drive voltage is used for operating an electrical actuator, such as an electrical engine or machine. The driver circuit comprises means for providing an amplitude indication of an amplitude of the supply voltage, which is used for generating a first pulse of the sequence of pulses. Furthermore, the driver circuit comprises an integration unit configured to integrate the amplitude indication for a duration of the first pulse, thereby generating an integrated voltage. In addition, the driver circuit comprises a comparator configured to compare the integrated voltage with a reference voltage, thereby generating a comparator signal. Furthermore, the driver circuit comprises a control unit configured to terminate the first pulse in dependence of the comparator signal.

Abstract: Systems and methods for monitoring excitation of a generator based on a faulty status of a generator breaker are provided. According to one embodiment, a system may include a controller and a processor communicatively coupled to the controller. The processor may be configured to receive, from a contact associated with a generator breaker, a reported status of the generator breaker, receive operational data associated with one or more parameters of a generator associated with the generator breaker, and correlate the reported status of the generator breaker and the operational data. Based on the correlation, the processor may establish an actual status of the generator breaker, and, based on the actual status, selectively modify a mode of excitation of the generator.

Abstract: A generator protection device is provided. The generator protection device includes a safety factor estimation module configured to estimate a safety factor as a function of a terminal voltage (VS) of a source-end generator, and a swing center voltage (SCV) between the source-end generator and a receiving-end generator. The system further includes a comparison module configured to compare the estimated safety factor with a defined safety threshold limit, and a decision module configured to trigger an alarm or a generator circuit breaker trip action or both, based on the comparison between the estimated safety factor and the defined safety threshold limit.

Abstract: A system and method for efficiently regulating the fuel consumption of a variable speed combustion engine used to control loads such as a hoist motor in a mobile gantry crane based on load motor speed commands issued by a crane operator. The system and method can rely on a programmable logic controller to issue engine fuel commands to regulate engine speed based on interpolations derived from data representing the relationship between load motor voltage and engine speed and data representing the relationship between engine speed and engine power capacity. The method may also be used in modified form by combustion engines which need digital fixed speed commands.

Abstract: An electric drive system includes a prime mover connected to a generator, which is controlled in part by an excitation current. The generator makes electrical power available on a dc link. A method of load demand and power generation balancing within the electric drive system includes determining a voltage of the dc link and determining a torque command by an operator of the system. A speed for each of one or more drive motors receiving power from the dc link is determined and normalized to derive an average motor speed. A mechanical power being commanded is derived based on the average motor speed and the torque command. A predicted excitation current that is required to achieve the derived mechanical power is determined and an actual excitation current is determined based on the predicted excitation current. The actual excitation current is then applied to the generator.

Abstract: A system and method are provided for controlling the speed of a motor driving a load that is electrically connected to a generator driven by an engine, through use of a first control feedback loop configured to control the rotor flux of the motor by controlling the field excitation of the generator, and a second control feedback loop configured to control the speed of the motor by controlling the throttle position of the engine.

Abstract: A method of controlling a hybrid vehicle with an engine, a battery, and at least one motor generator. System efficiencies of each of several candidate driving states are calculated. Calculating efficiency when the battery is discharged uses power of the engine Pfuel, power drawn from the battery Pb,out, and required driving power Pdemand. Calculating efficiency when the battery is charged uses Pfuel, Pdemand, and power charged to the battery Pb,in. Pb,out is calculated using a real battery discharge power Pb,out,real, a battery discharge energy efficiency ?bd, a historic efficiency ?b,pwr of energy loss when the battery is charged, and a correction coefficient SOCcorrection for controlling the battery charge amount. Pb,in is calculated using real battery charge power Pb,in,real, battery charge energy efficiency ?bc, ?bd, and efficiency ?in,pwr when power is consumed in the future. The driving state with the highest efficiency is then selected.

Abstract: A control system and method for a hybrid electric vehicle. One example control system includes a current calculating module to calculate a current, the current being at least one of a current to drive a motor of the vehicle and a current generated by the motor, and a feed controller to selectively implement a first mode when the calculated current is below a predetermined current value and to selectively implement a second mode when the calculated current is more than the predetermined current value, wherein either the first feed circuit or the second feed circuit is used in the first mode and both the first feed circuit and the second feed circuit are used in the second mode.

Abstract: A method and apparatus for moving magnetic material includes an electromagnet for attaching and detaching the magnetic material where upon release of the magnetic material, the residual magnetic flux of the released magnetic material is reduced. The apparatus includes a generator coupled to the electromagnet. The generator includes a control input and an armature having a voltage output. A controller has an output coupled to the generator's control input and an input coupled to the armature voltage output, whereupon receiving a lift or release material signal from an operator interface panel to lift or release the magnetic material from the electromagnet, the controller transmits a control signal that is at least partially responsive to the voltage output of the armature to effectively maintain the voltage output of the armature to a set-point value.

Abstract: A method and apparatus for moving magnetic material includes an electromagnet for lifting the magnetic material where upon its release, the residual magnetic flux of the lifted magnetic material is reduced. The apparatus includes a generator coupled to the electromagnet. The generator includes a control input and an armature having a voltage output. A controller has an output coupled to the generator's control input and armature voltage output, whereupon receiving a release material signal from an operator interface panel to release the magnetic material from the electromagnet, the controller transmits a plurality of control signals, one of which is at least partially dependent upon the duration of a previously transmitted control signal, to effectively alternate the polarity and reduce the magnitude of the magnetizing force of the electromagnet.

Abstract: A method of coupling a mechanical power source through an electrical power generator to an electrical load is disclosed. A characteristic of an electrical output is measured from the electrical power generator produced during a power generation cycle during which there is a coupling of the mechanical power source through the electrical power generator to the electrical load. The coupling of the mechanical power source is adjusted through the electrical power generator to the electrical load during a subsequent power generation cycle based at least in part on the measured characteristic of the electrical output.

Abstract: A vehicular generator-motor control apparatus wherein a winding field type salient-pole generator-motor 1 (in FIG. 1) for a vehicle is subjected to a conduction control by a DC-AC converter 2, characterized in that a stator 1A of the vehicular winding field type salient-pole generator-motor 1 is energized by rectangular wave voltages at those conduction start angles ? of respective phases of the stator 1A which are shifted a predetermined angle relative to a rotor position, and that the conduction start angles ? of the respective phases change substantially continuously in accordance with an input voltage of the DC-AC converter 2 and a revolution speed of the generator-motor 2.

Abstract: According to the invention, there is provided a control apparatus for a motor generator of a hybrid vehicle. The control apparatus includes a determiner, a comparator, and a controller. The determiner works to determine values of a first and a second parameter, which are defined in the same unit and respectively representative of economic benefits obtainable by operating the motor generator in generator and motor modes. The comparator works to compare the determined values of the first and second parameters. The controller works to control the motor generator to operate in the generator mode when the value of the first parameter is greater than that of the second parameter and in the motor mode when the value of the second parameter is greater than that of the first parameter. With such a configuration, the control apparatus can economically shift operation of the motor generator between the generator and motor modes.

Abstract: A control and power module for a rotating electrical machine comprising a power circuit containing a number of branches, and a control circuit designed for controlling the power circuit when the machine operates in a nominal mode. The inventive module is characterized in that the control circuit is also designed for monitoring an output voltage from the power circuit and blocking at least one branch of the power circuit in a conduction state when the output voltage reaches an at least first threshold value so that the machine functions in a degraded mode. The invention is for use in an alternator starter.

Abstract: Systems and methods are provided for charging energy sources with a rectifier using a double-ended inverter system. An apparatus is provided for an electric drive system for a vehicle. The electric drive system comprises an electric motor configured to provide traction power to the vehicle. A first inverter is coupled to the electric motor and is configured to provide alternating current to the electric motor. A first energy source is coupled to the first inverter, wherein the first inverter is configured to provide power flow between the first energy source and the electric motor. A second inverter is coupled to the electric motor and is configured to provide alternating current to the electric motor. A rectifier is coupled to the second inverter and configured to produce a direct current output. The second inverter is configured to provide power from the rectifier to the electric motor.

Abstract: A rotor is provided with slits each of which serves as a flux barrier blocking a magnetic flux. A direction shown by an arrow is a forward direction along which the rotor rotates when a vehicle moves forward. Each of the slits has a width tapering down from a trailing position toward a leading position with respect to the forward direction. The rotation in a reverse direction opposite to the forward direction shown by the arrow causes larger magnetic flux linkage than the rotation in the forward direction, and hence generates high torque and high counterelectromotive force. Therefore, in the reverse direction, the rotor cannot serve as a motor to produce an output unless high voltage is applied thereto. Accordingly, the torque generated in the reverse direction is used for regenerative operation. It is thereby possible to provide a vehicle drive system capable of exhibiting performance in a well-balanced manner between power running and regenerative operation, and a vehicle provided with the same.

Abstract: An electric motor control system including a generator, an AC motor, a power converter for driving the AC motor using a DC output voltage of the generator, and an electric motor controller for controlling the power converter. The electric motor controller controls the power converter by predicting a change in the DC voltage.

Abstract: The invention relates to a method and a device for switching on a power switch (S1, S2) arranged between capacitive elements (C1, DLC, B36) a choke (L) being connected in parallel to the switching contacts of the still open power switch (S1, S2). Said choke enables compensating currents to flow between the elements (C1, B36, DLC) to be interconnected and to decay before the power switch (S1, S2) is then closed in a de-energized manner.

Abstract: In a motor-generator control system for controlling a motor-generator, first and second sets of multiphase windings of a motor-generator are arranged to be spatially shifted in phase from each other. An allocating unit is configured to, upon input of workload request for the motor-generator, determine a first torque to be allocated to the first set of multiphase windings and a second torque to be allocated to the second set of multiphase windings. A resultant torque of the first torque and second torque meets the input workload request for the motor-generator. An energizing unit is configured to energize the first set of multiphase windings to create the first torque and energize the second set of multiphase windings to create the second torque.

Abstract: A power generation and/or storage device utilizes human motion inputs or other power sources (i.e. hydraulics, pneumatics or explosive gases) to create mechanical kinetic energy that is stored (preferably in springs) and later released on demand to rotate a generator to produce electricity.

Abstract: A battery pack of a series combination of cell units is connected with a motor drive control circuit to drive a traction motor for a vehicle. A current sensor senses a discharge/charge current of the battery pack, and a voltage detecting circuit senses a voltage between two separate points in the series combination of the battery pack. A memory section stores a reference voltage drop quantity representing a decrease in voltage during a predetermined time interval between the two separate points. An offset detecting section compares an actual voltage drop quantity sensed by the voltage detecting circuit, with the reference voltage drop quantity, thereby detects a non-discharge/charge-current state of the current sensor, and reserves an output of the current sensor, as an offset quantity upon the detection. A correcting section corrects a sensed value of the discharge/charge current with the reserved offset quantity.

Abstract: A transient response system includes a power source operable to generate a power output and a transmission operatively coupled to the power source. The transient response system also includes a generator operatively coupled to the power source and a controller in communication with the generator and at least one of the power source and the transmission. The controller is operable to receive at least one input having a value indicative of a change in load on the power source and operable to cause the generator to remove power from the power output at a rate corresponding to the value of the at least one input.

Abstract: A power generation and/or storage device utilizes human motion inputs or other power sources (i.e. hydraulics, pneumatics or explosive gases) to create mechanical kinetic energy that is stored (preferably in springs) and later released on demand to rotate a generator to produce electricity.

Abstract: An engine start/stop control system for preventing an engine from stopping when a vehicle is traveling. The system includes an IG1 driver circuit arranged between a power supply control unit and an IG1 relay. The IG1 driver circuit is activated in accordance with an activation signal from the power supply control unit or an output signal of a latch circuit and includes an FET for activating a relay. The latch circuit keeps the FET ON and the relay activated unless the vehicle stops traveling and a start/stop switch is pushed.

Abstract: A starting system and method for a gas turbine engine includes a controlled starter system and a controlled fuel system. The controlled starter motor is accelerated along an acceleration profile to a dwelling point. Concurrently with the starter motor spinning up the gas turbine engine rotor, the fuel system controller commands the pump motor to drive the fuel pump at a speed which fills the fuel line volumes and establishes adequate pressure for fuel atomization at light off. As the fuel pump motor and starter motor are independently controlled and coordinated the starter motor maintains the gas turbine engine at the predetermined dwelling point until ignition occurs. The starter motor also provides a controlled amount of assisting torque during acceleration of the gas turbine to minimize thermal transients which thereby increased the gas turbine engine operational life.

Abstract: An exciter assembly for supplying power to a superconducting load, such as a superconducting field coil, disposed within a cryogenic region of a rotating machine. The exciter assembly provides an efficient and reliable approach for transferring the electrical power energy across a rotating interface and for controlling the ramp up and regulation of field excitation current in the field coil. In particular, the invention provides a controlled recirculation path for current flowing through the field coil. The exciter assembly includes a transformer having a primary winding and a secondary winding, a sensor which provides a control signal indicative of the flow of field excitation current to the superconducting load; and a current regulator which is disposed in the rotating reference frame and, on the basis of the control signal, regulates the field excitation current to a predetermined set.

Abstract: An electrical charge assembly 10 for use within a vehicle 12 having a transmission 20, a starter assembly 16, and an engine 14. The assembly 10 includes a capacitor assembly 34 which selectively provides electrical charge to the starter assembly 16, effective to allow the engine 14 to be activated. The starter 16 may be selectively coupled to the transmission 20, effective to increase the torque produced by the transmission 20 and may selectively provide electrical charge to the capacitor assembly 34.

Abstract: A conventional motor controlling circuit is adapted to control an inverter that drives a permanent magnet generator as a motor to spin an engine to a speed sufficient to permit the engine to start. The commutation frequency is adjusted as a function of speed utilizing an automatic commutation frequency adjustment circuit. This circuit has multiple commutation frequency ranges that overcome a large initial bearing drag during low speed operation while still permitting high speed operation. The automatic commutation frequency adjustment circuit preferably generates first and second voltage ramps that overcome the initial bearing drag and accelerate the generator at a rate fast enough for sufficient back EMF to be generated for a closed-loop commutation phase. A speedup circuit operates during the closed-loop commutation phase to achieve the high speeds typically necessary for engine starting. The inventive circuits even permit a turbine type engine to be successfully started.

Abstract: To obtain a control apparatus for a Diesel-electric locomotive that harmonizes an engine power with a torque command of an induction motor, which is a load of an engine, in the Diesel-electric locomotive and avoids an overload of the engine.A cooperative controller 15 is provided, the controller 15 which receives a notch signal N, an engine speed command value n* corresponding to the notch signal N, an engine speed n, and rotating speed fr of an induction motor 17, calculates a torque command value Tp corresponding to the engine speed n from torque command values before and after the notch signal changing during response time for control of the engine speed if the notch signal N changes, and calculates the torque command value Tp corresponding to the notch signal N after a notch is changed, except the case thereof. Furthermore, the torque command value Tp is outputted to an inverter controller 20.

Abstract: A D.C. motor-generator and an electric double layer capacitor are fixedly connected directly to each other and a rotary shaft of the motor-generator is rotated in one direction by an external force to generate D.C. electric energy which is stored in the electric double layer capacitor. By supplying the electric energy from the electric double layer capacitor to the D.C. motor-generator, the stored electric energy can be discharged as mechanical rotation energy. By deriving the stored energy as electric energy, an emergency power source can be provided.

Abstract: An apparatus and method for controlling a lifting magnet (12) of a materials handling machine (10) to eliminate arcing between contacts (70-80) within the magnet controller (26) as is well as is large voltage spikes. The controller (26) selectively excites the shunt field windings (66,68) of a direct current generator (22). The magnitude and direction of the current passing through the shunt field windings (66,68) is varied by the magnet controller (26) to control the magnitude and polarity of the voltage at the generator output (23). The armature (60) of the generator (22) is rotatably driven by a hydraulic motor at an essentially constant speed to minimize voltage variations at the output (23) of the generator (22). At least the drop cycle is controlled through use of a current transducer (200) that senses current flowing to the lifting magnet so that the electronic controller is able to control the flow of current to the lifting magnet based upon the sensed current in the magnet circuit.

Abstract: A hydraulic circuit (124) is defined in a manifold (130) which may be aluminum, steel, or any other suitable material. The circuit (124) regulates the flow of hydraulic fluid to the hydraulic motor (120) and thus ensures that the motor rotates at an essentially constant speed, independent of the speed of the hydraulic pump (122) supplying the circuit. The circuit includes a pressure compensated flow control valve assembly (140) with an adjustable flow control valve (142) that regulates the flow of hydraulic fluid to the motor (120). The assembly (140) also includes a balanced piston-type pressure compensator (144) that ensures a select pressure differential across the flow control valve (142) such that the flow through the valve (142) remains at least essentially constant. This constant flow through the pressure compensated flow control valve assembly (140) ensures an essentially constant rotational speed of the motor (120).

Abstract: A battery charging apparatus for a vehicle having a vehicle propulsion mechanism, vehicle accelerator mechanism, a vehicle drive train mechanism and a vehicle electrical system includes a vehicle battery, including an electric generator having a generator output shaft drivably connected to the vehicle drive train mechanism, a generator disengagement switch, a generator circuit electrically connecting the generator to the generator disengagement switch and to the vehicle battery, a mechanism for connecting the generator disengagement switch to the vehicle accelerator mechanism so that the disengagement switch opens the generator circuit during operation of the vehicle accelerator mechanism, and so that the disengagement switch closes the generator circuit during non-operation of the vehicle accelerator mechanism to prevent loss of vehicle kinetic energy to the generator during vehicle deceleration.

Abstract: An apparatus and method for controlling a lifting magnet (12) of a materials handling machine (10) to eliminate arcing between contacts (70-80) within the magnet controller (26) as well as large voltage spikes. The controller (26) selectively excites the shunt field windings (66,68) of a direct current generator (22). The magnitude and direction of the current passing through the shunt field windings (66,68) is varied by the magnet controller (26) to control the magnitude and polarity of the voltage at the generator output (23). The armature (60) of the generator (22) is rotatably driven by a hydraulic motor at an essentially constant speed to minimize voltage variations at the output (23) of the generator (22). The magnet controller (26) includes a programmable logic controller (40) which selectively opens and closes the contactors (70-80) within the controller (26).

Abstract: A control system controls a hybrid vehicle having an engine for rotating a drive axle, an electric motor for assisting the engine in rotating the drive axle, and electric energy storage unit for supplying electric energy to the electric motor.

Abstract: A motor generator system in accordance with the invention includes a prime mover (21) for driving an output shaft (18); a main motor generator (16, 105), having a rotor driven by the output shaft, for producing electrical power on a plurality of stator phase windings (36a-36c) in response to the prime mover rotating the output shaft and for driving the output shaft in response to operation as a motor, an exciter (14, 102), having a rotor driven by the output shaft, for applying excitation to a field winding (34) of the main motor generator during operation for producing electrical power on the plurality of phase windings and for applying current to the field winding of the main motor generator to produce a magnetic field in the field winding during operation of the main motor generator as a motor, a time varying signal source (200) for applying a time varying signal having a fundamental frequency 202 to a field winding (28) of the exciter, a main inverter (114), responsive to signal (302) representing a rotar

Abstract: A control circuit of the current to the secondary and a control circuit of the voltage to the secondary are such that the current for charging the battery and the current for starting will each have a defined maximum value, and such that the voltage at the battery terminals will have a predetermined maximum value.

Abstract: A control system for a vehicular drive unit that includes an engine, a motor-generator connected to the output shaft of the engine and which acts as both a motor and a generator, a battery for storing the energy recovered by the motor-generator as electric power and for feeding electric power to drive the motor-generator, a first clutch for connecting the motor-generator and the wheels, a stop state detector for detecting the stopped state of the vehicle, and a controller for controlling the engine, the motor-generator and the first clutch. When the stopped state is detected by the stop state detector, the controller releases the first clutch, interrupts the feed of fuel to the engine, and feeds electric power to the motor-generator to drive the motor-generator to thereby hold the rotation of the engine substantially at an idling RPM.

Abstract: A conventional full wave diode bridge of an alternator is replaced with a full wave controlled rectifier bridge having controlled switches in place of diodes and the rectifier bridge is controlled in response to a third harmonic of the voltage generated by the alternator to synchronize the rectifier bridge with the alternator and to increase output power from the alternator. The alternator includes a rotor having a field winding receiving a field current which is controlled up to a maximum field current for partial control of the output power produced by the alternator. Power produced by the alternator is also controlled by introducing a phase angle between the phase voltages at the three output connections of the stator winding and the third harmonic up to a maximum or optimum phase angle. To increase power output from the alternator, preferably the field current is increased up to a maximum before any phase angle is introduced between the phase voltages and the third harmonic.

Abstract: A generator is controlled by a controller to generate power sufficient to a battery quickly in addition to power which is required by a wheel-drive motor for a while after a car is started and until a battery charging ratio becomes higher than a first predetermined ratio, between 80% and 100% for example. When the battery charging ratio becomes higher than the first predetermined ratio, the generator is controlled to generate a regulated power which is obtained by adding a constant power to the mean value of the power required by the wheel-drive motor to prevent the battery from generating gases due to overcharging. When the battery-charging ratio further increases and becomes higher than a second predetermined ratio, 120% for example, the generator is controlled to generate less power than the requirement of the wheel-drive-motor.

Abstract: When a target generated output established for a generator by a target generated output setting unit depending on an operating condition of a hybrid vehicle varies, an intake air control valve control unit starts varying the opening of an intake air control valve of an engine in order to equalize the power output of the engine to a new varied target generated output. A delay time estimating unit estimates a delay time after the opening of the intake air control valve has started to vary until the engine eventually produces a power output corresponding to the new target generated output according to a preset correlation based on the present rotational speed of the engine. Upon elapse of the estimated delay time after the opening of the intake air control valve has started to vary, a generator controller increases or reduces the generated output of the generator into agreement with the target generated output.

Abstract: An electric drive propulsion system is composed of one or more series motor coupled directly to drive individual wheel axles of a vehicle, the motors being electrically connected directly to the output of a generator driven by the vehicle engine. A power switch is operated by the vehicle brake pedal to disconnect and connect excitation current to the generator to initiate and stop propulsion. Speed of propulsion is controlled by the accelerator pedal of the vehicle engine, the generator driven thereby providing the sole source of energy for the propulsion motors.

Abstract: A generator driving apparatus is provided with a thyristor driving device for driving a motor-generator, and the thyristor driving device always controls the driving of the motor-generator regardless of the number of rotations thereof. Also, when the motor-generator is coming to a stop, energy conserved in the motor-generator is regenerated to an electric power system through the thyristor driving device.

Abstract: This invention is directed to a digital feedback control system. The control system includes a controlled device which generates an output signal representative of the operation of that device, with that output signal being a relatively high frequency carrier signal having a relatively slowly varying (compared to the carrier signal) envelope. The control system further includes a difference network for generating an error signal representative of the difference between an input command signal and a sensor signal derived from the output signal of the controlled device. A feedback network is responsive to the output signal to provide the sensor signal. The feedback network includes a selectively operative integrator which generates an integrated signal representative of the integral of the output signal. The feedback system further includes a selectively operable network for resetting the integrator.

Abstract: A Ward-Leonard drive system for a dragline excavator includes a feedback circuit which connects to the motor-generator armature loop to sense a signal proportional to motor armature counter emf and rate of change of armature current. The feedback circuit takes the second derivative of this signal and applies it to a circuit which controls motor speed and torque. The feedback circuit alters the response of the drive system to sudden increases in motor load caused by rough digging and thereby reduces transient loading on the mechanical elements of the drive system.