Inductive power transfer apparatus with AC and DC output
An inductive power transfer system (IPT) pick-up comprises: a pick-up coil capable of generating a voltage by magnetic induction from a primary conductive pathway, and a tuning capacitor associated with the pick-up coil to provide a first pick-up resonant circuit; a first output associated with a first control means to substantially control the voltage or current provided by the first output; a further resonant circuit connected in series or parallel with the first pick-up resonant circuit; and a second output associated with a second control means to control the voltage or current provided by the second output and a method of providing an additional independently controllable output from an IPT pick-up having a resonant pick-up circuit is also disclosed.
1. An inductive power transfer system (IPT) pick-up comprising:
a pick-up coil capable of generating a voltage by magnetic induction from a primary conductive pathway, and a tuning capacitor associated with the pick-up coil to provide a first pick-up resonant circuit;
a first output associated with a first control to substantially control a voltage or current provided by the first output;
a further resonant circuit connected in series or parallel with the first pick-up resonant circuit; and
a second output associated with a second control to control a voltage or current provided by the second output;
wherein the first output and second output are electrically associated with the pick-up coil, the pick-up coil generates an alternating current (AC) output, and the first output is generated from the AC output of the pick-up coil without rectification.
2. The IPT pick-up as claimed in claim 1 wherein the first output and second output are independently controllable.
3. The IPT pick-up as claimed in claim 1 wherein the first output is generated from an output of the first pick-up resonant circuit, and the second output is generated from an output of the further resonant circuit.
4. The IPT pick-up as claimed in claim 1 wherein one of the first output or the second output comprises an AC output, the other of the first output or the second output comprises a DC output, and the DC output is provided by the first or second control functioning as a buck, boost, or buck-boost converter.
5. The IPT pick-up as claimed in claim 4 wherein the AC output is provided by the first or second control introducing a phase delay.
6. A wireless power pick-up, comprising:
a pick-up coil;
at least one tuning capacitor connected to the pick-up coil to form a first resonant circuit with the pick-up coil, wherein the first resonant circuit is configured to supply power to a first electrical output of the wireless power pick-up; and
a second resonant circuit connected to the pick-up coil, wherein the second resonant circuit is configured to supply power to a second electrical output of the wireless power pick-up,
wherein the wireless power pick-up is configured to produce, without rectification, an alternating current (AC) at the first electrical output.
7. The wireless power pick-up of claim 6 , wherein the second resonant circuit comprises an LC circuit that is tuned to resonant at a same frequency as the first resonant circuit, and an inductor of the LC circuit is connected in series with the pick-up coil of the first resonant circuit.
8. The wireless power pick-up of claim 6 , wherein the first resonant circuit is a series tuned resonant circuit, the first electrical output of the wireless power pick-up is an alternating current (AC) output, and the second electrical output of the wireless power pick-up is a direct current (DC) output.
9. The wireless power pick-up of claim 6 , wherein the first resonant circuit is a series tuned resonant circuit, the first electrical output of the wireless power pick-up is an alternating current (AC) output, and the wireless power pick-up is configured to open-circuit the first electrical output for part of a resonant cycle of the first resonant circuit to control the power supplied to a load via the first electrical output, and wherein the wireless power pick-up is configured to continue to supply power to the second electrical output of the wireless power pick-up for the part of the resonant cycle that the first electrical output is open-circuit.
10. The wireless power pick-up of claim 6 , wherein the first resonant circuit is a parallel tuned resonant circuit, the first electrical output of the wireless power pick-up is an alternating current (AC) output, and the wireless power pick-up is configured to short-circuit the first electrical output for part of a resonant cycle of the first resonant circuit to control the power supplied to a load via the first electrical output.
11. The wireless power pick-up of claim 6 , wherein the wireless power pick-up comprises at least one switch connected in series or in parallel with the first resonant circuit, and wherein the wireless power pick-up is configured to operate the switch to open-circuit or short-circuit the first electrical output, and wherein the wireless power pick-up is configured to supply power to the second electrical output of the wireless power pick-up irrespective of a state of the switch.
12. An inductive power pick-up comprising at least two resonant circuits, wherein a first of the at least two resonant circuits comprises a pick-up coil and at least one tuning capacitor, and a second of the at least two resonant circuits is connected in series or in parallel with the first of the at least two resonant circuits, wherein the inductive power pick-up is configured to produce, without rectification, a controlled alternating current (AC) output from AC power received via the pick-up coil.
13. The inductive power pick-up of claim 12 , wherein the second of the at least two resonant circuits comprises at least one inductor and at least one tuning capacitor, and wherein the at least one inductor of the second of the at least two resonant circuits is connected in series with the first of the at least two resonant circuits.
14. The inductive power pick-up of claim 13 , wherein the at least one inductor of the second of the at least two resonant circuits is connected in series with the pick-up coil.
15. The inductive power pick-up of claim 12 , wherein the inductive power pick-up has at least two electrical outputs that are configured to supply power to an electrical load, wherein the first of the at least two resonant circuits produces an alternating current (AC) output for the first of the at least two electrical outputs, and the second of the at least two resonant circuits produces a direct current (DC) output for the second of the at least two electrical outputs.
16. The inductive power pick-up of claim 15 , wherein the inductive power pick-up does not have a rectifier between the first of the at least two resonant circuits and the first of the at least two electrical outputs.
17. The inductive power pick-up of claim 12 , wherein the first of the at least two resonant circuits and the second of the at least two resonant circuits are configured to resonate at the same resonant frequency.