A power converter includes: input terminals for inputting a DC voltage; output terminals for outputting an AC voltage; a switch; a first resonant capacitance connected between both ends of the switch; a first LC resonance circuit connected in series with the switch between the output terminals; and a second LC resonance circuit connected between the input terminals and the switch. The first LC resonance circuit includes an inductance and a capacitance in series. When the input terminals are shorted, frequency characteristics of an impedance of the second LC resonance circuit include first to fourth resonant frequencies. The first resonant frequency is higher than a switching frequency of the switch. The second and fourth resonant frequencies are around double and four times the switching frequency. The impedance has local maxima at the first and third resonant frequencies and local minima at the second and fourth resonant frequencies.

A power converter includes: input terminals for inputting a DC voltage; output terminals for outputting an AC voltage; a switch; a first resonant capacitance connected between both ends of the switch; a first LC resonance circuit connected in series with the switch between the output terminals; and a second LC resonance circuit connected between the input terminals and the switch. The first LC resonance circuit includes an inductance and a capacitance in series. When the input terminals are shorted, frequency characteristics of an impedance of the second LC resonance circuit include first to fourth resonant frequencies. The first resonant frequency is higher than a switching frequency of the switch. The second and fourth resonant frequencies are around double and four times the switching frequency. The impedance has local maxima at the first and third resonant frequencies and local minima at the second and fourth resonant frequencies.

A power supply, including a primary pre-converter, coupled to supplying mains, configured to receive an AC voltage at low frequency and output a high DC voltage, and further configured to receive the high DC voltage and to output the alternating current; a primary converter, disposed on a primary side of the power supply, coupled to the high DC voltage from the primary pre-converter; an isolating transformer to receive the high frequency AC voltage and output a high frequency secondary AC voltage, and to receive a high frequency secondary AC current and to output primary high frequency AC current; and an output converter, on a secondary side of the power supply, wherein the output converter is configured to receive high frequency AC voltage from the isolating transformer and to output a DC voltage of a first or second polarity to an output, and wherein the output converter is configured to receive DC current of a first or second direction from the output and to output a high frequency AC current to the isolating transformer.

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 (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 (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 (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.

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.

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.

An electrical motor system and a method for operating the electrical motor system are disclosed. The electrical motor system comprises a direct current (DC) source, a filter connected in parallel with the DC source and an electric motor with at least two sets of windings. A voltage signal is provided from the DC source to the inverter circuit where the signal is modulated. The modulated signal is then supplied from the inverter circuit to each set of windings with a respective time offset between each set of windings respectively, providing a very efficient DC bus ripple reduction. Hereby, it is e.g. possible to use small filter capacitors/capacitor banks in electrical motor systems.