US 9,853,587 B2 · System for operating a three-phase variable frequency drive from an unbalanced three-phase or single-phase AC source

Abstract

A variable frequency motor drive comprises a converter including a rectifier having an input for connection to an AC power source and converting the AC power to DC power. A DC bus is connected to the rectifier circuit. At least one bus capacitor is across the DC bus. An inverter receives DC power from the DC bus and converts the DC power to AC power to drive a motor. A controller is operatively connected to the converter. The controller comprises a speed control controlling the inverter responsive to a speed command to maintain a desired motor speed. A speed foldback control measures DC bus ripple voltage and regulates the speed command responsive to the measured DC bus ripple voltage.

Claims20

Dependent claims

A variable frequency motor drive comprising:

a converter including a rectifier having an input for connection to an AC power source and converting the AC power to DC power, a DC bus connected to the rectifier circuit, and at least one bus capacitor across the DC bus, and an inverter for receiving DC power from the DC bus and converting the DC power to AC power to drive a motor;
and
a controller operatively connected to the converter, the controller comprising a speed control controlling the inverter responsive to a speed command, and a speed foldback control measuring a torque producing component of VFD output current and folding back the speed command responsive to the torque producing component of the VFD output current exceeding a specified activation level.

Dependencies are inferred from the claim text.

Facts

Application

14/259,385Filed 23 Apr 2014

Published

US 2015/0311853 A129 Oct 2015

Granted

26 Dec 2017

Term ends

Not estimatedThe source records don’t support an estimate.

Classification12 codes

H02P 27/047
Using variable-frequency supply voltage, e.g. inverter or converter supply voltage: v/F converter, wherein the voltage is controlled…
H02M 1/15
Arrangements for reducing ripples from DC input or output: using active elements
H02M 5/458
Using devices of a triode or transistor type requiring continuous application of a control signal: using semiconductor devices only
H02M 7/53875
With automatic control of output voltage or current: with analogue control of three-phase output

System for operating a three-phase variable frequency drive from an unbalanced three-phase or single-phase AC source

Life of this patent

System for operating a three-phase variable frequency drive from an unbalanced three-phase or single-phase AC source

Life of this patent

Abstract

Claims20