The present invention relates to a bi-directional DC-DC converter comprising: a first terminal, a second terminal, a transformer circuit, a first high voltage side coupled to said first terminal, and a second low voltage side coupled to said second terminal; wherein said first high voltage side and said second low voltage side are coupled to each other by means of said transformer circuit, and said first high voltage side comprises a resonant tank circuit coupled between a first bridge circuit of said first high voltage side and a high voltage side of said transformer circuit. Furthermore, the invention also relates to a system comprising at least two such bi-directional DC-DC converters.

A drive circuit, an electronic device, and a method of controlling a drive circuit that can reduce power consumption. The drive circuit includes: a control circuit that controls application of an AC voltage to a capacitive load; an inductive element which constitutes a closed circuit along with the capacitive load; a diode , which is connected in series to the inductive element between the capacitive load and the inductive element so as to constitute the closed circuit; and a switch element, which is connected in series to the diode between the capacitive load and the inductive element so as to constitute the closed circuit.

An LLC converter includes a resonant circuit connected to a DC input voltage, a switching circuit connected to the DC input voltage, transformers each including primary windings and secondary windings, and synchronous rectifiers each connected to one secondary winding and to ground. The primary windings of the transformers include a first primary winding and a second primary winding. The first primary windings of the transformers are connected in series, and the second primary windings of each of the plurality of transformers are connected in series. The series-connected first primary windings and the series-connected second primary windings are directly connected in parallel with the resonant circuit. A first current from a first switch flows into the series-connected first primary windings, and a second current from a second switch flows into the series-connected second primary windings. Currents from each of the secondary windings are equal or substantially equal.

A direct current (DC) to DC power converter includes a first converter for converting a first DC bus voltage into a first high frequency AC voltage and a second converter for converting a second high frequency alternating current (AC) voltage into a second DC bus voltage. The DC to DC converter also includes a resonant circuit for coupling the first bus converter and the second bus converter and a controller for providing switching signals to the first converter and the second converter to operate the power converter in a soft switching mode. The resonant circuit includes a high frequency transformer coupled between the first converter and the second converter and an auxiliary converter coupled in series with a first resonant inductor and the high frequency transformer. The resonant circuit further includes second inductor coupled across a first winding of the high frequency transformer. An auxiliary voltage generated by auxiliary converter is added in series with an output voltage of the first converter.

The present invention relates to a single phase, non-insulated, miniaturized DC/AC power inverter (1) having an output power density higher than 3000 W/dm.sup.3, wherein said first (S1_H), second (S1_L), third (S2_H) and fourth (S2_L) switches are made of wide-band semiconductors and preferably of gallium nitride or GaN semiconductors; and wherein said DC/AC power inverter (1) further comprises: a ripple-compensating active filter comprising a third half-bridge (203) having a fifth switch (S3_H) in series with a sixth switch (S3_L), said fifth switch (S3_H) being connected at one end to the positive terminal (L+) of the DC input, said sixth switch (S3_L) being connected at one end to the negative terminal (L) of the DC input,the other end of the fifth switch (S3_H) being connected to the other end of the sixth switch (S3_L), defining a third common end, said third common end being connected to a first end of a LC filter, made of at least one inductor (L6) and one storage capacitor (C5), a second end of the LC filter being connected to the negative terminal (L); modulation control means of said first (S1_H), second (S1_L), third (S2_H), fourth (S2_L), fifth (S3_H) and sixth (S3_L) switches for providing a switch frequency comprised between 20 and 500 kHz and allowing variable phase shifts between any two of said first (201), second (202) and third (203) half-bridges and allowing dead time modulation of the switches of said half-bridges (201, 202, 203), so that to obtain a switching approaching ZVS switching, in particular to obtain switching when current crosses through zero and further to cancel switching losses and so that to allow high peak-to-peak voltage variations in the active filter, while storing corresponding energy in the storage capacitors (C5), wherein the Y-capacitors of the common mode noise filter (100), are referenced to a shielding being at a reference potential, said shielding being insulated from earth, said Y-capacitors having a value comprised between 100 nF and several F.

Driver circuits are disclosed having a high-side switch and a low-side switch. A pre-charging circuit is provided to pre-charge the low-side switch. In other implementations, methods are disclosed which involve precharging a low-side switch.

The present invention relates to a single phase, non-insulated, miniaturized DC/AC power inverter (1) having an output power density higher than 3000 W/dm.sup.3, wherein said first (S1_H), second (S1_L), third (S2_H) and fourth (S2_L) switches are made of wide-band semiconductors and preferably of gallium nitride or GaN semiconductors; and wherein said DC/AC power inverter (1) further comprises: a ripple-compensating active filter comprising a third half-bridge (203) having a fifth switch (S3_H) in series with a sixth switch (S3_L), said fifth switch (S3_H) being connected at one end to the positive terminal (L+) of the DC input, said sixth switch (S3_L) being connected at one end to the negative terminal (L) of the DC input,the other end of the fifth switch (S3_H) being connected to the other end of the sixth switch (S3_L), defining a third common end, said third common end being connected to a first end of a LC filter, made of at least one inductor (L6) and one storage capacitor (C5), a second end of the LC filter being connected to the negative terminal (L); modulation control means of said first (S1_H), second (S1_L), third (S2_H), fourth (S2_L), fifth (S3_H) and sixth (S3_L) switches for providing a switch frequency comprised between 20 and 500 kHz and allowing variable phase shifts between any two of said first (201), second (202) and third (203) half-bridges and allowing dead time modulation of the switches of said half-bridges (201, 202, 203), so that to obtain a switching approaching ZVS switching, in particular to obtain switching when current crosses through zero and further to cancel switching losses and so that to allow high peak-to-peak voltage variations in the active filter, while storing corresponding energy in the storage capacitors (C5), wherein the Y-capacitors of the common mode noise filter (100), are referenced to a shielding being at a reference potential, said shielding being insulated from earth, said Y-capacitors having a value comprised between 100 nF and several F.

The present invention relates to a single phase, non-insulated, miniaturized DC/AC power inverter having an output power density higher than 3000 W/dm.sup.3, wherein said power inverter is packaged in a casing made of an external electrically conductive enclosure containing a fan blowing in an axial direction to a side face of the casing and, in a stacked elevation arrangement, successively from a bottom side to a top side, a layer of active filter capacitors, a heatsink, a layer of wideband semiconductors switches connected to a PCB with thermal vias and a layer of active filtering inductors, the fan and the component stacked arrangement being designed so as, in operation, the external temperature of the casing does not overcome 60 C. in any point, for an ambient temperature of maximum 30 C. under a maximum load of 2 kVA.

A power converter system includes an auxiliary resonant commutated pole converter leg, particularly an ARCP half-bridge, having a series connection of a saturable-core inductor and at least one bi-directional auxiliary switch connected to a dc-link neutral point. An ARCP controller is provided to control turn-on of the at least one bi-directional auxiliary switch to provide an auxiliary current flowing through the saturable-core inductor, and a saturation instant detector is provided to detect a saturation instant of the saturable-core inductor due to the auxiliary current exceeding a saturation current after turn-on of the at least one bidirectional auxiliary switch. The ARCP controller is responsive the detector to continue providing the auxiliary current and thereby a boost current for a predetermined boost period after the detected saturation instant of the saturable-core inductor to achieve a desired total boost current.

Embodiments includes systems, methods, and apparatuses for determining a resonant frequency of an LLC converter via a primary side of the LLC converter. In one embodiment, a circuit comprises an LLC converter and a resonant frequency determination unit, the resonant frequency determination unit configured to monitor electrical current on the primary side of the LLC converter, isolate a portion of the electrical current, determine, based on the portion of the electrical current, a crossing point, and determine, based on the crossing point, a resonant frequency of the LLC converter.