Abstract: This patent describes embodiments of systems, apparatus and methods to provide improved control and coordination of a multiplicity of electric distribution grid-connected, energy storage units deployed over a geographically-dispersed area.

Abstract: This patent describes embodiments of systems, apparatus and methods to provide improved control and coordination of a multiplicity of electric distribution grid-connected, energy storage units deployed over a geographically-dispersed area.

Abstract: A closed loop pulse width modulator (PWM) inverter corrects for variations and distortion in the output AC voltage waveform caused by non-linearities of the switching devices or changes in the DC link voltage. A signal is generated that is a volt-seconds representation of the voltage error between a voltage command and the actual AC output voltage of the PWM inverter. The volt-seconds error signal becomes a controlling means in the closed loop of the PWM inverter to regulate the output AC voltage of the PWM inverter. Another signal that represents changes in the DC link voltage also modifies the voltage command signal. The system will compensate for the non-linear behavior of the PWM inverter due to deadtime, minimum on-times and off-times, and DC link voltage variations and voltage drops across the switching devices, and will also allow the operation of the inverter in a linear fashion for the region of operation when one or more of its phases are saturated, i.e., either full on or full off.

Abstract: A method of controlling a switched reluctance motor during high speed operation in an operational range when the counter electromotive force exceeds the available DC source voltage and, therefore, the maximum desired converter current cannot be obtained, establishes torque control in a feedforward manner by controlling current pulse position.

Abstract: A method for operating a multi-phase switched reluctance motor is a generator mode includes gating switches connected in series with selected ones of the phase windings of the motor into conduction to establish current flow in a selected one of the windings. The switches are thereafter disabled and current is forced to commutate into flyback diodes whereby the current is returned to an associated DC bus. The instant at which the conducting switches are gated out of conduction is selected or measured in angular displacement between an associated stator pole and a corresponding rotor pole by establishing a preselected magnitude of current such that when the current in the winding reaches that magnitude, the switches are disabled. The voltage at the DC bus is regulated during generator mode operation by adjusting the phase angle measured between a stator pole and a corresponding rotor pole at which the switches are gated into conduction.

Abstract: A method and apparatus for improving the operation of a switched reluctance motor at low speed incorporates an advance angle regulator which regulates the firing angle of current pulses to the switched reluctance motor so that over a wide range of speeds and levels for direct current source voltages, the winding current reaches a commanded set point at a commanded angle. The advance angle regulator may comprise a closed loop regulator which includes apparatus for detecting the actual angular position at which motor current reaches a commanded level and adjusts the turn-on angle to shift the angle at which current reaches its desired level to a desired angle. The regulator incorporates a feedforward portion and an integral portion. The feedforward portion is utilized primarily to accommodate situations in which there is no current feedback. The integral portion provides the primary regulation when current is regulated to its desired value.

Abstract: A method of developing a signal representative of the instantaneous frequency of an alternating current signal encompasses first determining the apparent frequency of the signal at the ends of sampling periods (e.g., half cycles). From successively derived apparent frequencies the rate of change in frequency is calculated. The actual frequency signal is then generated as a function of the apparent frequency and the rate of change. In a specific implementation, the method is employed to develop a signal representative of the rotational speed of a motor.

Abstract: A system for controlling the operation of an alternating current induction motor having windings supplied by electrical power from the polyphase alternating current source includes a load commutated inverter circuit which is connected between the power source and the induction motor for furnishing electrical power to the motor. Controllers responsive to a command signal and a feedback signal indicative of motor operating parameters control the operation of said load commutated inverter circuit. There is further provided a fixed capacitor circuit connected between the windings of the motor for supplying reactive volt amperes (VARs) to said load commutated inverter circuit and said motor.

Abstract: A system for controlling the operation of an alternating current induction motor having windings supplied by electrical power from the polyphase alternating current source includes a load commutated inverter circuit which is connected between the power source and the induction motor for furnishing electrical power to the motor. Controllers responsive to a command signal and a feedback signal indicative of motor operating parameters control the operation of said load commutated inverter circuit. There is further provided a fixed capacitor circuit connected between the windings of the motor for supplying reactive volt amperes (VARs) to said load commutated inverter circuit and said motor.

Abstract: A variable aspect arc chute comprises a stack of pivotally-mounted plates which are held in electrical contact along one edge thereof by means of a bias spring or other device. The arc chute may be employed in a circuit interrupter, connected in parallel arrangement across main contacts which the present invention protects from excessive arcing damage.