Enhanced power factor correction for welding and cutting power supplies
AssigneeIllinois Tool Works Inc.
InventorsSteven J. Geissler, Todd G. Batzler, Michael D. Madsen
Life of this patent
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Abstract
Enhanced power factor correction for a welding-based power supply includes a controller that tracks a rectified input voltage waveform and detects zero-crossing events therein. The controller generates an ideal sinusoidal current reference signal synchronized by expected zero-crossings in the supplied power. The reference signal is used in a current control loop within the controller to control the power electronics such that the waveform of the current drawn by the power supply matches the waveform of the input voltage. The frequency of the supplied power may be calculated using the expected zero-crossings and used to adjust the expected zero-crossings.
Claims20
A welding-type power supply comprising:
- an input rectifier configured to receive a supplied AC power and convert the supplied AC power to a DC power having a rectified voltage waveform;
- a power conditioner configured to receive the DC power from the rectifier and condition the DC power to have characteristics within a predefined set of thresholds;
- an inverter configured to receive the conditioned power from the power conditioner and convert the conditioned power to AC power;
- an output rectifier configured to convert the AC power to DC welding-type power to drive a welding-type process;
- and
- a controller configured to:
- monitor the rectified voltage waveform;
- calculate expected zero crossings of the supplied AC power based on the rectified voltage waveform;
- generate a sinusoidal reference signal based on the expected zero crossings;
- and
- adjust a current drawn by the power supply based on the sinusoidal reference signal to improve a power factor of the power supply.
A method of correcting a power factor of a welding-type device comprising:
- rectifying power from a power supply, the rectified power supplied to the welding-type device to create a rectified voltage waveform;
- tracking the rectified voltage waveform;
- determining expected zero crossings in the supplied power;
- generating a sinusoidal current reference using ideal sine wave values synchronized with the expected zero crossings;
- and
- controlling a current drawn by the power supply with the generated current reference to improve the power factor of the power supply.
Dependencies are inferred from the claim text.