Weatherford Technology Holdings, LLC

The University of Texas System

Mohammed S Arefeen

Thomas Anthony Lipo

Mehrdad Ehsani

A variable-frequency drive includes a rectifier, a filter, an inverter, a capacitor bank, and control circuitry. The rectifier converts AC power from a power source to DC power on a DC bus for filtering by the filter. The inverter converts the DC power to three-phase AC power for output to the electric motor. The capacitor bank has one or more capacitors connected to the DC bus. The capacitor bank can store regenerative power on the DC bus from the inverter and can supply the stored DC power to the DC bus for conversion to the three-phase AC power to drive the electric motor. The control circuitry pre-charges the capacitor bank from the AC power of the power source. The control circuitry monitors one or more parameters of the variable-frequency drive and detects one or more fault conditions associated with the one or more monitored parameters.

Managing regenerative energy of rod pump system without dynamic braking resistor

An electrical ride-through (ERT) unit is configured to apply a voltage to a drive circuit during disruptions of line voltage to the drive circuit. The ERT unit includes a capacitor on an ERT circuit that is prevented from applying the voltage to the drive circuit during normal operation of the drive circuit and applies the voltage to the drive circuit during a voltage drop on the drive circuit.

Method and apparatus for riding through power disruptions of a drive circuit

An electrical ride-through (ERT) unit is configured to apply a voltage to a drive circuit during disruptions of line voltage to the drive circuit. The ERT unit includes a capacitor on an ERT circuit that is prevented from applying the voltage to the drive circuit during normal operation of the drive circuit, and applies the voltage to the drive circuit during a voltage drop on the drive circuit.

A discrete position sensor elimination technique for a sinusoidally wound synchronous reluctance motor drive uses induced voltage, phase currents, and excitation frequency to estimate rotor position at all speeds, including zero speed.

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Houston, TX, United States of America

Mohammed S Arefeen