US 7,607,896 B2 · Systems and methods for power ride-through in variable speed drives

Abstract

Systems and methods for providing ride-through for interruptions in the power supplied to drives that are used to control equipment such as downhole submersible pumps. In one embodiment, a variable speed drive includes converter and inverter sections, a capacitor bank and a control system. The drive shuts down the converter section upon detecting a disruption in the AC input power and continues to generate output power by drawing on the energy stored in the capacitor bank. When the AC input power returns (or begins to return) to normal, the drive resumes operation of the converter section in a controlled manner (e.g., by presetting the firing angle of the SCR's in the converter to match the voltage across the capacitor bank.) The drive thereby limits the current that recharges the capacitor bank and prevents sudden inrushes of current that could damage the drive.

Claims16

Dependent claims

A method implemented in a drive for electrical equipment, the drive having a converter section, a capacitor bank and an inverter section, the method comprising:

detecting a beginning of a ride-through event;
disabling the converter section of the drive in response to detecting the beginning of the ride-through event, wherein disabling the converter section comprises actively controlling the converter section to prevent the converter section from converting an AC voltage on an input line to a DC voltage at the capacitor bank;
drawing power from the capacitor bank during the ride-through event to maintain operation of the inverter section;
detecting an end of the ride-through event;
and
resuming operation of the converter section of the drive in response to detecting the end of the ride-through event, wherein resuming operation of the converter section comprises actively controlling the converter section to cause the converter section to convert the AC voltage on the input line to the DC voltage at the capacitor bank and to limit current flowing to the capacitor bank.

3 more elements

A drive system for powering electrical equipment, the system comprising:

a converter section;
a capacitor bank;
an inverter section;
and
a control system configured to
detect a beginning of a ride-through event,
disable the converter section in response to detecting the beginning of the ride-through event, wherein the control system is configured to disable the converter section by actively controlling the converter section to prevent the converter section from converting an AC voltage on an input line to a DC voltage at the capacitor bank,
draw power from the capacitor bank during the ride-through event to maintain operation of the inverter section,
detect an end of the ride-through event, and
resume operation of the converter section of the drive in response to detecting the end of the ride-through event, wherein the control system is configured to resume operation of the converter section by actively controlling the converter section to cause the converter section to convert the AC voltage on the input line to the DC voltage at the capacitor bank and to limit current flowing to the capacitor bank.

7 more elements

Dependencies are inferred from the claim text.

Systems and methods for power ride-through in variable speed drives

Life of this patent

Systems and methods for power ride-through in variable speed drives

Life of this patent

Abstract

Claims16