System and method for managing a cumulative DC offset in a magnetizable material. A primary driving AC voltage and a magnetic flux sensor. The flux sensor output is continuously received into memory while the the flux sensor output for each phase half-cycle is processed to continuously compute and re-compute in real time a flux-second integral for each half-cycle. The two half-cycle flux-second integrals are compared to each other for a DC offset value and the offset value drives a slow loop DC compensation circuit to steer a PWM control.

A digital power supply protection circuit includes: a signal preprocessing circuit, configured to receive an overcurrent signal and a first inceptive impulse clock timing, and perform preprocessing on the overcurrent signal according to the first inceptive impulse clock timing so as to obtain a first reference signal a signal generation circuit, configured to receive the first inceptive impulse clock timing, count time duration between a rising edge of the first inceptive impulse clock timing and a rising edge of the first reference signal so as to obtain a first time duration, and upon the first time duration is greater than a second time duration, generate a first disabling signal by delaying the rising edge of the first inceptive impulse clock timing for the second time duration; and a clock timing adjustment circuit, configured to adjust the first inceptive impulse clock timing according to the first disabling signal.

A power converter comprising an inverter for receiving a supply power and providing an alternating output. An output rectifier receives the alternating output and provides a rectified output to a load. An output winding receives the rectified output, and a sensing winding is inductively coupled to the output winding and provides a sensing output. A controller receives the sensing output and provides a control signal to the inverter for controlling the alternating output. A related method of converting power is also provided.

A switching voltage converter using an isolated topology includes a transformer for coupling power from an input source to an output load. The transformer must be protected to prevent saturation of its core due to excessive magnetic flux density as the transformer transfers power from its primary side to its secondary side. The magnetic flux is estimated using a voltage measured on the primary or secondary side of the transformer, wherein the secondary-side voltage may be a rectified voltage. If the estimated magnetic flux is detected as approaching a saturation level of the transformer core, any power being input to the transformer is curtailed. This may be accomplished by modifying pulse-width modulated (PWM) waveforms controlling power switches that control the input power transferred to the transformer. Using these techniques, transformer saturation may be avoided without requiring a significantly oversized transformer within the voltage converter.

A welding-type power supply includes a controller, a preregulator, a preregulator bus, and an output converter. The controller has a preregulator control output and an output converter control output. The controller has a converter control output connected to the control input, and a flux balancing module. The converter control output is responsive to the flux balancing module such that the flux in the transformer remains balanced.

Magnetic saturation detectors for power converters are presented herein. An energy transfer element has an input power winding wrapped around a center post. Single or multiple transverse windings are positioned perpendicular to the input power winding and coupled to receive a transverse current that provides a transverse magnetic flux density within the energy transfer element. The transverse magnetic flux density produces a transverse voltage waveform. A voltage detection circuit is configured to receive the transverse voltage waveform and detect a change in the sign of the slope of the transverse voltage waveform. The change in the sign of the slope indicates magnetic saturation. The voltage detection circuit is configured to detect an occurrence of an extremum in the transverse voltage waveform. The extremum indicates the change in the sign of the slope.

In this power conversion device, first three-phase AC voltages generated by an inverter and an AC filter are divided by first to third voltage dividers to generate second three-phase AC voltages, and third three-phase AC voltages that are line-to-line voltages of the second three-phase AC voltages and a neutral point voltage of the first three-phase AC voltages are detected. Then, DC components of the third three-phase AC voltages resulting from errors of voltage ratios of the first to third voltage dividers are obtained based on the detection results and contents in a storage unit, the DC components are removed from the third three-phase AC voltages to generate fourth three-phase AC voltages, and the inverter is controlled such that DC components of the fourth three-phase AC voltages are eliminated.

The present invention is concerned with pre-magnetizing a Modular Multilevel power Converters connected transformer in order to moderate inrush currents upon connecting the transformer to an electric grid. The invention takes advantage of the high amount of stored energy in MMC converters as compared to other converter types. This stored energy is used to pre-magnetize the converter-connected transformer, therefore no additional or dedicated pre-magnetizing hardware is required in addition to the charging hardware provided to charge the converter capacitors. As the transformer pre-magnetizing takes place subsequent to the converter charging, the converter charging circuit is not used to, and therefore does not need to be designed to, directly magnetize the transformer.

A switching power converter includes an integrated transformer and coupled inductor, first and second primary switching circuits, and a master controller. The integrated transformer and coupled inductor includes (a) first and second primary windings electrically coupled in series and (b) first and second secondary windings. The first and second primary switching circuits are electrically coupled to an end of the first primary winding and an end of the second primary winding, respectively. The master controller is configured to determine a magnitude of magnetizing current of the integrated transformer and coupled inductor from a difference between magnitude of current flowing through the first secondary winding and magnitude of current flowing through the second secondary winding, when the first and second primary switching circuits are in their respective off-states.

A switching power converter includes an integrated transformer and coupled inductor, first and second primary switching circuits, and a master controller. The integrated transformer and coupled inductor includes (a) first and second primary windings electrically coupled in series and (b) first and second secondary windings. The first and second primary switching circuits are electrically coupled to an end of the first primary winding and an end of the second primary winding, respectively. The master controller is configured to determine a magnitude of magnetizing current of the integrated transformer and coupled inductor from a difference between magnitude of current flowing through the first secondary winding and magnitude of current flowing through the second secondary winding, when the first and second primary switching circuits are in their respective off-states.