Resonant power converters with switchable resonant modes

1. A system comprising:

an input port having an input voltage;

an output port having an output voltage;

a first winding in series with a power switch, wherein the power switch is connected between the first winding and a first terminal of the input port, and wherein a second terminal of the input port is connected to the first winding;

a second winding magnetically coupled to the first winding, wherein the second winding is coupled to the output port through a switch network;

a first resonant tank comprising a first resonant capacitor and a first resonant inductor comprising the first winding, wherein the first resonant capacitor is connected between the input port and the junction point of the first winding and the power switch;

a second resonant tank comprising a second resonant capacitor and a second resonant inductor comprising the second winding, wherein the second resonant capacitor is coupled between the second winding and the switch network; and

a controller configured to adjust a switching frequency or a duty cycle of the power switch.

2. The system of claim 1 , wherein the controller comprises a resonant mode selection block configured to adjust a value of a resonant component in the first resonant tank or the second resonant tank in response to a change of the input voltage, the output voltage or the switching frequency.

3. The system of claim 2 , wherein the resonant component is a switchable capacitor comprising a plurality of switch-capacitor branches.

4. The system of claim 2 , wherein the controller is configured to adjust the value of the resonant component in response to a fault in the system.

5. The system of claim 2 , wherein the switching frequency is limited within a preset range.

6. The system of claim 2 , wherein the controller is configured to adjust the value of the resonant component to achieve a soft switching for the power switch.

7. The system of claim 1 , further comprising a third resonant tank comprising a third resonant capacitor and a third resonant inductor comprising a third coil, wherein the third coil is magnetically coupled to the first coil.

8. The system of claim 1 , wherein the first winding and the second winding form a power transformer.

9. The system of claim 8 , wherein the power transformer comprises a plurality of PCBs.

10. The system of claim 1 , wherein the first resonant capacitor or the second resonant capacitor comprises a parasitic capacitance.

11. An apparatus comprising:

an input port having an input voltage;

an output port having an output voltage;

a transformer having a primary winding connected in series with a power switch and magnetically coupled to a secondary winding, wherein the power switch is connected between the primary winding and a first terminal of the input port, and wherein the primary winding is connected to a second terminal of the input port;

a rectifier circuit coupled between the secondary winding and the output port;

a primary resonant tank comprising:

a primary resonant capacitor connected between the input port and a junction point of the primary winding and the power switch; and

a primary resonant inductor comprising the primary winding;

a secondary resonant tank comprising:

a secondary resonant capacitor coupled between the secondary winding and the rectifier circuit; and

a secondary resonant inductor comprising the secondary winding;

and a control block configured to control at least one of a duty cycle and a switching frequency of the power switch.

12. The apparatus of claim 11 , wherein one of the first resonant capacitor and the second resonant capacitor is a switchable device configured to have different capacitance values in response to a change in the input voltage or in the output voltage, or the switching frequency.

13. The apparatus of claim 12 , wherein the switchable device comprises a plurality of switch-capacitor branches configured to control an operational parameter of the apparatus, and wherein a switch-capacitor branch comprises a capacitor and a switch.

14. The apparatus of claim 13 , wherein the switchable devices is configured to achieve zero voltage switching for the power switch.

15. The apparatus of claim 12 , wherein the switchable devices is configured to limit a switching frequency of the power switch within a preset range.

16. The apparatus of claim 11 , wherein the rectifier circuit comprises a half-bridge the switch network.

17. A method comprising:

configuring a power system comprising:

an input port having an input voltage;

an output port having an output voltage;

a first winding in series with a power switch, wherein the power switch is connected between the first winding and a terminal of the input port, and wherein a second terminal of the input is connected to the first winding;

a second winding magnetically coupled to the first winding, wherein the second winding is coupled to the output port through a switch network having a plurality of power switches;

configuring a first resonant tank comprising a first resonant capacitor and a first resonant inductor comprising the first winding, wherein the first resonant capacitor is connected between the input port and a junction point of the first winding and the power switch, and a second resonant tank comprising a second resonant capacitor and a second resonant inductor comprising the second winding, wherein the second resonant capacitor is coupled between the second winding and the switch network;

and

configuring a controller to adjust a switching frequency or a duty cycle of the power converter.

18. The method of claim 17 , further comprising adjusting a value of a switchable component in the first resonant tank or the second resonant tank in response to a change of the input voltage, the output voltage or the switching frequency.

19. The method of claim 18 , further comprising adjusting the value of the switchable component to maintain a zero-voltage switching of the power switch.

20. The methods of claim 17 , wherein the first winding and the second winding form a transformer.