US 12,445,078 B2
Managing regenerative energy of rod pump system without dynamic braking resistor
Mohammed S. Arefeen, Houston, TX (US)
Assigned to Weatherford Technology Holdings, LLC, Houston, TX (US)
Filed by Weatherford Technology Holdings, LLC, Houston, TX (US)
Filed on Nov. 29, 2023, as Appl. No. 18/522,707.
Claims priority of provisional application 63/603,747, filed on Nov. 29, 2023.
Prior Publication US 2025/0175109 A1, May 29, 2025
Int. Cl. H02P 27/08 (2006.01); F04B 47/02 (2006.01); H02P 25/032 (2016.01)
CPC H02P 27/08 (2013.01) [F04B 47/022 (2013.01); H02P 25/032 (2016.02)] 23 Claims
OG exemplary drawing
 
1. A variable-frequency drive for use with an alternating current (AC) power source and an electric motor of a reciprocating load device, the variable-frequency drive comprising:
an input being configured to connect to the AC power source;
an output being configured to connect to the electric motor;
a rectifier stage connected to the input and being configured to convert AC power from the AC power source to direct current (DC) power on a DC bus;
a DC bus filter connected between the DC bus and being configured to filter the DC power of the DC bus;
an inverter stage connected to the DC bus and being configured to convert the DC power to three-phase AC power for the output to the electric motor;
a DC capacitor bank having one or more capacitors connected to the DC bus, the DC capacitor bank being configured to store regenerative power on the DC bus from the inverter stage as stored DC power, the DC capacitor bank being configured to supply the stored DC power to the DC bus for conversion to the three-phase AC power to drive the electric motor; and
control circuitry being configured to pre-charge the one or more capacitors of the DC capacitor bank from the AC power of the AC power source, the control circuitry being configured to monitor one or more parameters of the variable-frequency drive and being configured to detect one or more fault conditions associated with the one or more parameters.