Circuit and a method for driving electrical loads
A circuit and a corresponding method for driving one or more electric loads are described, comprising: a generator ( 110 ) of an electric current waveform, and a passive filter ( 150 ) connected in input to the generator ( 110 ) and in output to each electric load ( 105 ) to be driven, wherein the passive filter ( 150 ) is tuned for generating an electric current waveform resulting from a conditioning of one or more harmonics of the electric current waveform in input.
1. An electrical circuit ( 100 ), comprising at least:
an electric load to be driven ( 105 )
a generator ( 110 ) of an electric current waveform, and
a passive filter ( 150 ) connected in input to the generator ( 110 ) and in output to the electric load ( 105 ) to be driven, wherein the passive filter ( 150 ) is tuned for generating an electric current waveform resulting from a conditioning of one or more harmonics of the electric current waveforms in input,
wherein the load ( 105 ) to be driven comprises a drive terminal of an active switch, and
wherein the passive filter ( 150 ) is a resonant reactive filter comprising inductors and capacitors,
characterized in that the passive filter ( 150 ) is tuned for amplifying the first harmonic of the electric current waveform with a multiplication factor, completely or nearly completely damping the second harmonic, and amplifying the third harmonic with an amplification factor equal to one third of the multiplication factor of the first harmonic,
wherein the generator ( 110 ) of the current waveform comprises:
a generator ( 115 ) of direct electric current,
a switching circuit ( 125 ) able to convert the direct electric current into an electric current waveform,
wherein the switching circuit ( 125 ) comprises at least:
an active switch ( 135 )
a driver ( 140 ) for generating an electrical driver signal able to switch the active switch ( 135 ) on and off,
wherein the switching circuit ( 125 ) comprises an inductance ( 130 ) connected in series between the generator ( 115 ) of direct electric current and the active switch ( 135 ), the passive filter ( 150 ) having an input terminal connected with an electrical node interposed between the inductance ( 130 ) and the active switch ( 135 ), and
wherein the passive filter ( 150 ) comprises a plurality of electrical modules ( 195 ) including at least a first electrical module and a second electrical module, wherein the first electrical module comprises at least:
a first electric branch ( 200 ) branching from the input terminal,
a second electric branch ( 205 ) connecting an output terminal of the first electric branch ( 200 ) with a reference potential,
a capacitance ( 225 ) comprised in the second electric branch ( 205 ),
an inductance ( 215 ) comprised in the first electric branch ( 200 ), and
an inductance ( 230 ) comprised in the second electric branch ( 205 ), and wherein the second electrical module comprises at least:
a first electric branch ( 200 ) connected to the output terminal of the first electric branch ( 200 ) of the first electrical module,
a second electric branch ( 205 ) connecting an output terminal of the first electric branch ( 200 ) of the second electrical module with a reference potential,
a capacitance ( 225 ) comprised in the second electric branch ( 205 ) of the second electrical module, and
an inductance ( 215 ) comprised in the first electric branch ( 200 ) of the second electric module, and
an inductance ( 230 ) comprised in the second electric branch ( 205 ) of the second electric module.
2. The circuit ( 100 ) of claim 1 , wherein each electrical module ( 195 ) comprises a first inductance ( 215 ) comprised in the first electric branch ( 200 ) and a second inductance ( 230 ) arranged in series with the capacitance ( 225 ) in the second electric branch ( 205 ).
3. The circuit ( 100 ) of claim 1 , wherein each electrical module ( 195 ) comprises a capacitance ( 220 ) connected in parallel to the inductance ( 215 ) of the first electric branch ( 200 ).
4. The circuit ( 100 ) of claim 1 , wherein each electrical module ( 195 ) comprises a further capacitance ( 210 ) comprised in the first electric branch ( 200 ).
5. The circuit ( 100 ) of claim 1 , wherein the electrical load to be driven ( 105 ) is connected to the output terminal of the first electric branch ( 200 ) of the first electrical module ( 195 ) of the passive filter ( 150 ).
6. The circuit ( 100 ) of claim 1 , comprising a regulatable reactive load ( 155 ) connected to the output of the passive filter ( 150 ).
7. The circuit ( 100 ) of claim 6 , wherein the regulatable reactive load ( 155 ) comprises at least one electric branch ( 180 ) connecting the output of the passive filter ( 150 ) with a reference potential and comprising at least a reactance ( 185 ) and at least a switch ( 190 ) connected in series with the reactance ( 185 ).
8. The circuit ( 100 ) of claim 6 , wherein the regulatable reactive load ( 155 ) comprises at least an electric branch ( 180 ) connecting the output of the passive filter ( 150 ) with a reference potential and comprising at least a reactance ( 185 ), at least a diode ( 300 ), a further electric branch ( 305 ) connected to a node of the electric branch ( 180 ) comprised between the reactance ( 185 ) and the diode ( 300 ), and a digital signal applied to the further electric branch ( 305 ).
9. The circuit ( 100 ) of claim 8 , wherein a resistance ( 310 ) and an inductance ( 315 ) are arranged in series on the further electric branch ( 305 ).
10. The circuit ( 100 ) of claim 6 , wherein the regulatable reactive load ( 155 ) comprises at least an electric branch ( 180 ) connecting the output of the passive filter ( 150 ) with a reference potential and comprising two varicap diodes ( 320 ) located on the electric branch ( 180 ) with the respective cathodes connected together, and a direct current generator ( 325 ) for applying a regulatable tuning current to the cathodes of the varicap diodes ( 320 ).