DC Capacitor-less Power Converters

• US 20120307531A1
• Filed: 06/01/2012
• Published: 12/06/2012
• Est. Priority Date: 06/03/2011
• Status: Active Grant

• Current Assignee: Texas A&M University System
• Original Assignee: Texas A&M University System
• Inventors: Toliyat, Hamid A., Amirabadi, Mahshid
• Granted Patent: US 8,988,900 B2
• Time in Patent Office: Days
• US Class Current: 363/36
• CPC Class Codes: H02M 5/4585 having a rectifier with controlled elements
• CPC Class Codes: Y02B 70/10 Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes

Abstract

Three resonance-based universal power converter topologies are disclosed. One includes a partially resonant parallel L-C link and incorporates intermediate cross-over switching circuits between the link stage and each of the input and output stages (which are constructed using unidirectional switches), thereby permitting the partially resonant circuit to be operated bi-directionally. A second includes a partially resonant series LC link in parallel with the input and output networks. A third includes a partially resonant series LC link in series between the input and output networks. The input and output networks can be formed from either bidirectional switches or a combination of unidirectional switches and intermediate cross-over switching circuits, permitting the partially resonant circuit to be operated bi-directionally. All embodiments permit the use of smaller reactive components in the link stage and the use of AC rather than DC capacitors, which reduces size and costs of the device while increasing the reliability.

Claims

1. A power conversion circuit comprising:

an input switch bridge stage comprising a plurality of unidirectional conducting and bidirectional blocking switching devices and configured to be coupled to a power source;

a link stage comprising at least one reactive component of a partially resonant circuit, the partially resonant circuit being configured for AC operation with no DC component;

an output switch bridge stage comprising a plurality of unidirectional conducting and bidirectional blocking switching devices and configured to be coupled to a load;

a first crossover switching circuit coupling the input switch bridge stage to the link stage, the crossover switching circuit comprising a bridge of unidirectional conducting and bidirectional blocking switching devices, wherein the first crossover switching circuit is configured to facilitate operation of the switching devices of the input switch bridge stage in cooperation with the AC operation of the link stage; and

a second crossover switching circuit coupling the link stage to the output switch bridge stage, the crossover switching circuit comprising a bridge of unidirectional conducting and bidirectional blocking switching devices, wherein the second crossover switching circuit is configured to facilitate operation of the switching devices of the output switch bridge stage in cooperation with the AC operation of the link stage.

2. The power conversion circuit of claim 1 wherein the link stage comprises at least one reactive component of a partially resonant parallel L-C circuit.

3. The power conversion circuit of claim 2 wherein the at least one reactive component of the partially resonant parallel L-C circuit comprises an inductor and wherein the partially resonant circuit is formed by inductance of the inductor together with parasitic capacitance of the inductor.

4. The power conversion circuit of claim 2 further comprising a shunt capacitor providing a low-impedance voltage source at one or more of the input and output of the circuit.

5. The power conversion circuit of claim 1 wherein the link stage comprises at least one reactive component of a partially resonant series L-C circuit connected in parallel between the first and second crossover switching circuits.

6. The power conversion circuit of claim 5 wherein the at least one reactive component comprises a capacitor and wherein the partially resonant circuit is formed by capacitance of the capacitor together with parasitic inductance of the capacitor.

7. The power conversion circuit of claim 5 further comprising a series inductor providing a high-impedance current source at one or more of the input and output of the circuit.

8. The power conversion circuit of claim 1 wherein the link stage comprises at least one reactive component of a partially series resonant L-C circuit connected in series between the first and second crossover switching circuits.

9. The power conversion circuit of claim 8 wherein the at least one reactive component comprises a capacitor and wherein the partially resonant circuit is formed by capacitance of the capacitor together with parasitic inductance of the capacitor.

10. The power conversion circuit of claim 8 further comprising a series inductor providing a high-impedance current source at one or more of the input and output of the circuit.

11. The power conversion circuit of claim 1 further comprising an additional crossover switching circuit coupling an additional input switch bridge stage or an additional output switch bridge stage to the link stage, the crossover switching circuit comprising a bridge of unidirectional conducting and bidirectional blocking switching devices and configured to facilitate operation of the switching devices of the additional input or output switch bridge stage in cooperation with the AC operation of the link stage.

12. The power conversion circuit of claim 1 wherein the at least one reactive component comprises a transformer.

13. A power conversion circuit comprising:

an input switch bridge stage comprising a plurality of bidirectional switching devices and configured to be coupled to a power source;

a link stage coupled to the input switch bridge stage and comprising at least one reactive component of a partially resonant series L-C circuit configured for AC operation with no DC component;

an output switch bridge stage comprising a plurality of bidirectional switching devices coupled to the link stage and configured to be coupled to a load;

wherein the bidirectional switching devices of the input switch bridge stage and the output switch bridge stage are configured to facilitate bidirectional operation of the link stage by driving voltage through said at least one reactive component in both directions during each cycle.

14. The power conversion circuit of claim 13 wherein the partially resonant series L-C circuit is connected in parallel with the input switch bridge stage and the output switch bridge stage.

15. The power conversion circuit of claim 13 wherein the partially resonant series L-C circuit is connected in series between the input switch bridge stage and the output switch bridge stage.

16. The power conversion circuit of claim 13 wherein the at least one reactive component of the partially resonant series L-C circuit comprises a capacitor, and wherein a parasitic inductance of the capacitor together with a capacitance of the capacitor form the partially resonant series L-C circuit.

17. The power conversion circuit of claim 13 wherein the at least one reactive component of the partially resonant series L-C circuit comprises a series combination of an inductor and a capacitor.

18. The power conversion circuit of claim 13 further comprising a series inductor providing a high-impedance current source at one or more of the input and output of the circuit.

19. The power conversion circuit of claim 13 wherein the at least one reactive component comprises a transformer.

20. A method of operating a power conversion circuit comprising at least one input stage configured to be coupled to a power source and including a switching bridge, a link stage comprising at least one reactive component of a partially resonant circuit configured for AC operation with no DC component, and at least one output stage configured to be coupled to a load and including a switching bridge, the method comprising:

operating the at least one input stage to charge a reactive component of the partially resonant circuit;

allowing the link stage partially resonant circuit to resonate, wherein the resonant circuit is configured for AC operation with no DC component; and

operating at least the output stage to discharge a reactive component of the partially resonant circuit.

21. A power conversion device comprising:

at least one input means for coupling a power source to the power conversion device;

a link means for transferring energy between an input of the power conversion device and an output of the power conversion device, said link means comprising at least one component of a reactive circuit wherein said reactive circuit is configured for AC operation with no DC component; and

at least one output means for coupling a load to the power conversion device;

wherein said input means and said output means are coupled to said link means.

22. The power conversion device of claim 21 wherein at least one of the input means or at least one of the output means comprises a crossover switching circuit coupling a respective input or output to the link means, the crossover switching circuit comprising a bridge of unidirectional conducting and bidirectional blocking switching devices, wherein the crossover switching circuit is configured to facilitate operation of a corresponding input or output means in cooperation with the AC operation of the link stage.

23. The power conversion device of claim 21 wherein at least one of the input means or at least one of the output means comprises a switch bridge stage including a plurality of bidirectional switching devices configured to be coupled to a power source corresponding to the input means or a load corresponding to an output means, wherein the bidirectional switching devices of the switch bridge stage are configured to facilitate bidirectional operation of the link stage by driving voltage through said at least one reactive component in both directions during each cycle.