Method and apparatus for deriving current for control in a resonant power converter
View Patent ↗An apparatus, method, and system for measuring current within a converter. The converter including a resonant tank circuit with a capacitor, the resonant tank circuit is coupled to a DC input bridge and a first terminal of the capacitor is coupled to a ground of the DC input bridge. In addition, a voltage monitor coupled across the capacitor for measuring a voltage across the capacitor. The converter also includes a resonant current calculation module for computing a tank current value based on the voltage.
1. An apparatus for measuring current in a power converter comprising:
a resonant tank circuit with a capacitor, the resonant tank circuit is coupled to a DC input bridge and a first terminal of the capacitor is coupled to a ground of the DC input bridge;
a voltage monitor coupled across the capacitor for measuring a voltage across the capacitor; and
a resonant current calculation module for computing a tank current value, based on the voltage across the capacitor, of a tank current through the capacitor.
2. The apparatus of claim 1 , wherein the DC input bridge is a half-bridge.
3. The apparatus of claim 1 , wherein the DC input bridge is a full-bridge and coupled to a transformer with a primary winding split into sub-windings.
4. The apparatus of claim 3 , wherein the capacitor is located in an electrical center potential of the primary winding.
5. The apparatus of claim 3 , wherein the sub-windings further comprise a first and a second sub-winding equal in space, size, and number of turns.
6. The apparatus of claim 5 , wherein the transformer further comprises a secondary winding as a single winding with no sub-windings.
7. The apparatus of claim 1 , wherein the capacitor is coupled across an amplifier and a primary winding of a transformer.
8. The apparatus of claim 1 , wherein a bridge control module coupled to the resonant current calculation module operative to control switches in the DC input bridge.
9. The apparatus of claim 1 , wherein a second terminal of the capacitor is coupled to the DC input bridge through a primary winding of a transformer.
10. A system for measuring current in a power converter comprising:
at least one photovoltaic (PV) module; and
at least one power converter coupled to the PV module comprising:
a resonant tank circuit with a capacitor, the resonant tank circuit is coupled to a DC input bridge and a first terminal of the capacitor is coupled to a ground of the DC input bridge;
a voltage monitor coupled across the capacitor for measuring a voltage across the capacitor; and
a resonant current calculation module for computing a tank current value, based on the voltage across the capacitor, of a tank current through the capacitor.
11. The system of claim 10 , wherein the DC input bridge is a half-bridge.
12. The system of claim 10 , wherein the DC input bridge is a full-bridge and coupled to a transformer with a primary winding split into sub-windings.
13. The system of claim 12 , wherein the capacitor is located in an electrical center potential of the primary winding.
14. The system of claim 12 , wherein the sub-windings further comprise a first and a second sub-winding equal in space, size, and number of turns.
15. The system of claim 14 , wherein the transformer further comprises a secondary winding as a single winding with no sub-windings.
16. The system of claim 10 , wherein the capacitor is coupled across an amplifier and a primary winding of a transformer.
17. The system of claim 10 , wherein a bridge control module coupled to the resonant current calculation module operative to control switches in the DC input bridge.
18. The system of claim 10 , wherein a second terminal of the capacitor is coupled to the DC input bridge through a primary winding of a transformer.
19. A method for measuring current in a power converter comprising:
measuring a voltage across a capacitor of a resonant tank in a resonant power converter, wherein the resonant tank is coupled to a DC input bridge of the resonant power converter and wherein a terminal of the capacitor is coupled to a ground of the DC input bridge, wherein the voltage is measured by a voltage monitor coupled across the capacitor;
measuring by a resonant current calculation module, a change in the voltage over time; and
determining by the resonant current calculation module, a tank current value, based on the change in the voltage across the capacitor, of a tank current through the capacitor.
20. The method of claim 19 , further comprising adjusting a switching frequency of switches within the DC input bridge coupled to the capacitor and a transformer with a primary winding split into a first sub-winding and second sub-winding.