Resonant power converter for wide voltage switching

1. A resonant converter device for varying resonant impedance, comprising:

a selectable primary winding comprising a plurality of circuit legs, the selectable primary winding comprising one or more of a tapped primary winding or a plurality of switchable primary windings;

at least one secondary winding coupled to the selectable primary winding to form a resonant transformer, the at least one secondary winding comprising at least a second circuit leg;

at least one resonant inductor coupled to at least one of the plurality of circuit legs or coupled to the second circuit leg;

a plurality of resonant capacitors, each circuit leg of the plurality of circuit legs comprising at least a respective one of the plurality of resonant capacitors coupled within the each circuit leg, and at least a second resonant capacitor of the plurality of resonant capacitors coupled within the second circuit leg; and

one or more switching devices connected to the resonant transformer and configured to selectively vary a resonant impedance of the resonant converter device when a voltage inputted to the resonant converter device varies.

2. The resonant converter device of claim 1 , wherein the selectable primary winding comprises a first number of turns, wherein the at least one secondary winding comprises a second number of turns, and wherein the first number of turns differs from the second number of turns so as to induce a resonant inductance in the resonant transformer.

3. The resonant converter device of claim 1 , wherein the at least one resonant inductor is configured to receive variable inductances, and wherein, when the one or more switching devices switch to connect to the resonant transformer, a predetermined magnetizing inductance to leakage inductance ratio is maintained.

4. The resonant converter device of claim 1 , wherein the plurality of resonant capacitors are configured to receive one of a single phase current or a three phase current, and wherein the one or more switching devices are configured to selectively connect to the resonant transformer to maintain a predetermined resonant frequency.

5. The resonant converter device of claim 1 , wherein the selectable primary winding comprises the plurality of switchable primary windings, and wherein the plurality of switchable primary windings are configured with at least one of the one or more switching devices to connect serially or alternatively to form the resonant transformer.

6. The resonant converter device of claim 1 , wherein the selectable primary winding comprises the at least one tapped primary winding comprising a plurality of windings divided by at least a first tap, and wherein a first number of windings on a first side of the first tap is not equal to a second number of windings on a second side of the first tap.

7. The resonant converter device of claim 1 , wherein the at least one secondary winding comprises a tapped secondary winding.

8. The resonant converter device of claim 1 , wherein the at least one secondary winding comprises a plurality of switchable secondary windings, and wherein the plurality of switchable secondary windings are configured with at least one of the one or more switching devices to connect serially or alternatively to form the resonant transformer.

9. The resonant converter device of claim 1 , wherein the one or more switching devices are configured to selectively connect the selectable primary winding to operate the resonant transformer near a resonant frequency of the resonant converter device.

10. The resonant converter device of claim 1 , wherein the switching devices are connected to operate the resonant converter to switch among the plurality of resonant capacitors to maintain the resonant converter at or near unity gain when the voltage inputted to the resonant converter device varies.

11. The resonant converter device of claim 1 , wherein the one or more switching devices are configured to selectively switch among the plurality of circuit legs to vary the resonant impedance of the resonant converter device to maintain a predetermined resonant frequency when a voltage inputted to the resonant converter device varies.

12. The resonant converter device of claim 1 , wherein the plurality of switching devices comprise one or both of one or more relays and a plurality of metal-oxide-semiconductor field-effect transistors (“MOSFETs”).

13. The resonant converter device of claim 1 , further comprising a capacitor bank comprising at least one bank capacitor, one or both of a single phase input and a three phase input, and bank switches configured to couple the one or both single phase input and three phase input to the plurality of switching devices through the at least one bank capacitor.

14. The resonant converter device of claim 13 , further comprising a bank relay coupled to the at least one bank capacitor, and wherein the at least one bank capacitor comprises a high side capacitor on a first side of the bank relay and a low side capacitor on a second side of the bank relay.

15. The resonant converter device of claim 13 , further configured as an on board charger and comprising a first battery circuit and a second battery circuit coupled to the resonant transformer, wherein the first battery circuit operates at a higher voltage than the second battery circuit.

16. An on board charger comprising the resonant converter device of claim 1 , comprising a first battery circuit and a second battery circuit coupled to the resonant transformer, wherein the first battery circuit operates at a higher voltage than the second battery circuit.

17. The resonant converter device of claim 1 , comprising a tapped or split inductor array connected on a side of the resonant transformer comprising the selectable primary winding.