Abstract: A submersible pumping system which, in one embodiment, includes a motor, a pump and a control circuit, or unit, coupled to the motor for controlling the operation of the motor is described. Using motor and sensor signals, the control unit detects various conditions within the pumping system and alters motor operation. In an exemplary embodiment, the control unit initiates an oscillation sequence of applying a forward torque for a first preselected period of time, applying a reverse torque for a second preselected period of time, and then repeating the torque applying steps a selected number of times to eliminate an obstruction from the pump.

Abstract: A method and apparatus for detecting the presence of a ground leakage path in an electric motor system including an alternating current (ac) electric motor coupled for receiving electric power from a switching inverter of the type having, for each phase of the motor, a pair of serially connected electronic switching devices connected between relatively positive and negative direct current (dc) voltage buses with the switching devices being alternately gated into and out of conduction for providing switched electric power to the motor. The inverter includes a current detector for detecting current in the relatively negative voltage bus. The method comprises initially applying a gating pulse each time the motor is energized to the switching device of each phase connected to the negative voltage bus and identifying a ground leakage path when such gating pulse produces current at the current detector.

Abstract: A power control system in combination with a three-phase AC motor coupled to a water pump enables the operation of the motor at speeds up to 10,800 RPM so as to provide improved pumping capacity with a smaller motor and smaller pump. The control system supplies AC power to the motor with a frequency of the power being increased at a first high rate up to a frequency at which pump pressure is about equal to a value at which water is being pumped from the outlet pipe of the pump. Thereafter, AC power frequency is increased to the second, slower rate up to a maximum operating frequency of the motor. During the time that frequency of the AC power is being increased, motor current is continuously monitored and compared to a maximum allowable current. If monitored current exceeds allowable current, the frequency of operation is decreased until monitored current is less than the allowable current. Thereafter, frequency is again increased so long as monitored current is less than allowable current.

Abstract: A scheme for optimizing the efficiency of an AC motor drive operated in a pulse-width-modulated mode provides that the modulation frequency of the power furnished to the motor is a function of commanded motor torque and is higher at lower torque requirements than at higher torque requirements.

Abstract: An electric vehicle drive train includes an electric motor and an associated speed sensor, a transmission operable in a speed reduction mode or a direct coupled mode, and a controller responsive to the speed sensor for operating the transmission in the speed reduction mode when the motor is below a predetermined value, and for operating the motor in the direct coupled mode when the motor speed is above a predetermined value. The controller reduces the speed of the motor, such as by regeneratively braking the motor, when changing from the speed reduction mode to the direct coupled mode. The motor speed may be increased when changing from the direct coupled mode to the speed reduction mode. The transmission is preferably a single stage planetary gearbox.

Abstract: An electric vehicle drive train includes a controller for detecting and compensating for vehicle rollback, as when the vehicle is started upward on an incline. The vehicle includes an electric motor rotatable in opposite directions corresponding to opposite directions of vehicle movement. A gear selector permits the driver to select an intended or desired direction of vehicle movement. If a speed and rotational sensor associated with the motor indicates vehicle movement opposite to the intended direction of vehicle movement, the motor is driven to a torque output magnitude as a nonconstant function of the rollback speed to counteract the vehicle rollback. The torque function may be either a linear function of speed or a function of the speed squared.

Abstract: A drive train for an electric vehicle includes a traction battery, a power drive circuit, a main contactor for connecting and disconnecting the traction battery and the power drive circuit, a voltage detector across contacts of the main contactor, and a controller for controlling the main contactor to prevent movement of its contacts to the closed position when the voltage across the contacts exceeds a predetermined threshold, to thereby protect the contacts of the contactor. The power drive circuit includes an electric traction motor and a DC-to-AC inverter with a capacitive input filter. The controller also inhibits the power drive circuit from driving the motor and thereby discharging the input capacitor if the contacts are inadvertently opened during motoring. A precharging contactor is controlled to charge the input filter capacitor prior to closing the main contactor to further protect the contacts of the main contactor.

Abstract: A scheme for optimizing the efficiency of an AC motor drive operated in a pulse-width-modulated mode provides that the modulation frequency of the power furnished to the motor is a function of commanded motor torque and is higher at lower torque requirements than at higher torque requirements.

Abstract: A battery powered traction vehicle propulsion system uses an alternating current (AC) adjustable speed electric traction motor to propel the vehicle. The motor is connected to a source of controllable AC power that is responsive to a control signal for setting the value of power applied to the motor. A function generator produces the control signal in response to a command signal and limits the rate of change of the control signal and its minimum and maximum values. The minimum and maximum values are varied in response to preselected operating characteristics of the propulsion system, such as, for example, battery voltage, motor temperature, motor and vehicle speed and control system temperature.

Abstract: The invention disclosed provides an intelligent input/output system for a programmable controller and includes a plurality of input/output (I/O) modules, each of which may be located in proximity to the process being controlled. Each module is interconnected, via a communications link, to a central processor unit (CPU) through an I/O controller. Each module is made up of a plurality of input/output circuits and each may be selectively operated as an input circuit or as an output circuit. The selection is preferably under control of the CPU. Each I/O module includes an operations control unit for controlling each I/O circuit and for providing an exchange of diagnostic and control signals between each I/O circuit and the I/O controller and CPU. Communications between the operations control unit and each I/O circuit is preferably carried out via a pair of conductors, one conductor of which conveys a set of recurring control signals (e.g.

Abstract: An intelligent input/output system for a programmable controller includes a plurality of input/output (I/O) modules, each of which may be located in proximity to the process being controlled. Each module is interconnected, via a communications link, to a central processor unit (CPU) through an I/O controller. Each module is made up of a plurality of input/output circuits and each may be selectively operated as an input circuit or as an output circuit. The selection is preferably under control of the CPU. Each I/O module includes an operations control unit for controlling each I/O circuit and for providing an exchange of diagnostic and control signals between each I/O circuit and the I/O controller and CPU. Communications between the operations control unit and each I/O circuit is preferably carried out via a pair of conductors, one conductor of which conveys a set of recurring control signals (e.g., in signal frames) and the other of which conveys encoded diagnostic signals.

Abstract: The invention disclosed provides circuitry which is selectively operable either as an input point or as an output point in a programmable controller having multiple input and output points for exchanging signals between a central processing unit (CPU) of the controller and a process being controlled. Preferably, operation as an input point or as an output point is under control of the CPU. The invention includes a common input/output terminal for terminating both input and output devices; an input return terminal for terminating a return conductor from the input device; an output return terminal for terminating a return conductor from the output device; a preload resistor connected between the input/output terminal and the output return terminal so that a status signal is developed across the preload resistor indicating the status (generally, open or closed) of the input device; and an insulated gate transistor (IGT) connected between the input/output terminal and the input return terminal.

Abstract: The invention disclosed provides a control system for an electric vehicle which automatically slows the vehicle during a turn and causes it to be increasingly slowed as the sharpness of the turn increases. The invention includes means for regulating the field excitation in accordance with a field regulating signal; means providing an armature current indicative signal; means providing a turning angle signal which is indicative of the turning angle of the vehicle; and a field excitation selector which receives the armature current indicative signal and the turning angle signal and then selects one or the other or a minimum reference value as the field regulating signal. The signal which produces the maximum field excitation is thus automatically selected. If a turning maneuver is being carried out, the turning angle signal increases until, at some point, the field excitation becomes a function of the steering angle and the vehicle is then automatically slowed as a function of the sharpness of the turn.

Abstract: The invention disclosed is a control system for controlling a pair of separately excited motors arranged such that each motor of the pair drives a separate wheel on a common axle of an electrically powered vehicle. The control system continuously and individually adjusts the field excitation of the drive motors so that torque and speed of the separate wheels are apportioned to the wheels as a function of the steering angle of the vehicle.

Abstract: A plug current regulator for a dc electric traction motor propelled vehicle, implemented using a microcomputer for controlling a time-ratio switching regulator, provides a substantially smooth electrical braking function by applying relatively short time duration current pulses to build up braking current, followed by a relatively long time duration in which current pulses are inhibited. Current regulation is provided by comparing motor current to a desired braking current and generating an update signal when actual current drops below desired current. Filtering is minimized by sampling motor current at a time interval occurring relatively long after a current pulse is supplied to the motor.

Abstract: A transistor fault indicator circuit monitors the conduction state of a transistor and compares that state to a commanded state. Differences in states are treated as faults and actuate an alarm or shut down the system including the transistor. In systems in which the transistor may be operated in a continuous conduction mode for long time periods, a control circuit is provided to periodically short circuit the base-emitter bias of the transistor to force a momentary period of nonconduction during which time the proper operation of the transistor can be verified.

Abstract: A fault detection and inhibit circuit for a power control unit in an electric traction motor propelled vehicle of the type wherein the power control unit includes a chopper circuit and a bypass contactor for shunting the chopper circuit when its percent conduction exceeds a relatively high value and a main contactor for connecting the chopper circuit and motor to a power source. The circuit assures that neither the main contactor, the bypass contactor nor the chopper circuit are in a shorted condition before permitting the application of power to the system. In the event of a running failure, the circuit prevents restarting until the failed condition has recovered.

Abstract: For protection against commutation failures in a motor control circuit, there is provided a method and apparatus by which the charge on a commutating capacitor is made to track the armature current of a separately excited motor regardless of the operating mode of the motor. In preferred form, a commutating network is provided having a commutating capacitor, a charge reversal thyristor, and a commutating thyristor configured to cause commutation of a main, control thyristor upon sequentially gating the charge reversal thyristor and the commutating thyristor with charge of sufficient magnitude stored on the capacitor. The thyristors of the commutating network are gated according to the operating mode of the motor; thus, there is included a means, or step, for sensing the motor operating mode.

Abstract: A current regulator for a dc electric traction motor propelled vehicle, implemented using a microcomputer, incorporates an accelerator response characteristics of an accelerator in an internal combustion engine powered vehicle. The regulator uses a current feedback loop to regulate motor torque to the value called for by the accelerator. However, of the magnitude of voltage as a percentage of available source voltage required to generate the desired current exceeds the percentage displacement of the accelerator, the applied voltage is limited to the percent accelerator displacement.

Abstract: A control system for a separately excited DC electric traction motor in an electrically powered vehicle incorporates a plurality of current limit functions designed to protect both the motor and control electronics. A time dependent current limit is utilized to permit overcurrent conditions for limited time intervals such that additional power can be obtained for sudden torque requirements without having to design the motor or control electronics to function under continuous high torque conditions. The continuous current limit values based on percent conduction time of a thyristor chopper circuit in the control system is modified in response to overheating of the motor and the main switching thyristor, to overvoltage on the thyristor commutating capacitor and to available voltage for powering the motor.