System and method for transferring electric energy to a vehicle using constant current operation of segments of a conductor arrangement
A system for transferring electric energy to a vehicle such as a track bound vehicle or road automobile. The system includes an electric conductor arrangement which produces an alternating electromagnetic field, transfers electromagnetic energy to the vehicle and includes a plurality of segments. Each segment extends along the vehicle path of travel and includes one line for each phase of alternating current carried by the segment. The system includes a current supply for conducting electric energy to the segments which are electrically connected in parallel. At least one segment is coupled to the current supply via a constant current source. Each constant current source includes one or more inductances and one or more capacitances, the inductances and capacitances being adapted to each other and the input side of the constant current source so that a constant current is output to the output side.
1. A system for transferring electric energy to a vehicle, comprising:
an electric conductor arrangement for producing an alternating electromagnetic field and for thereby transferring electromagnetic energy to the vehicle,
wherein, the conductor arrangement comprises:
a plurality of segments electrically connected in parallel to each other and to a current supply, wherein the segments extend in a direction of travel of the vehicle and at least one of the segments is coupled to the current supply via an associated constant current source to keep an alternating electric current through the segment constant,
wherein, each constant current source comprises at least a first inductance and at least a first capacitance, the inductance and the capacitance being adapted to each other and to a voltage at an input side of the constant current source so that a desired constant current is output to an output side of the constant current source,
wherein, the first inductance is arranged in a line of the constant current source which connects the input side with the output side and at least one junction of the line is connected with the first capacitance, and
the first inductance and the first capacitance as well as a second inductance, which is formed at least partly by an inherent inductance of the segment, are adapted to each other and to any additional capacitance in the segment so that the segment can be operated at a corresponding resonance frequency and the reactive power produced by the segment is essentially zero.
2. The system of claim 1 , wherein the first inductance and the first capacitance are parts of a common module which is electrically connected to the segment.
3. The system of claim 1 , wherein the at least one segment comprises a plurality of electric lines connected to a corresponding line of the constant current source, wherein
each series connection of a line of the segment and of a line of the constant current source is adapted to carry a different phase of a multi-phase alternating current,
each line of the constant current source comprises an inductor or an arrangement of inductors forming the first inductance and comprises a capacitor or an arrangement of capacitors forming the first capacitance which is connected to the line via a junction and
for each of the series connections, the first inductance and the first capacitance as well as a second inductance, which is formed at least partly by the inherent inductance of a corresponding line of the segment, are adapted to each other and to any additional capacitance in the segment so that the segment can be operated at a corresponding resonance frequency and the reactive power produced by the segment is essentially zero.
4. The system of claim 1 , wherein the second inductance is completely formed by the inherent inductance of the segment or of a corresponding line of the segment.
5. The system of claim 4 , wherein the segment does not comprise an additional capacitance which compensates the inherent inductance(s) of the segment in order avoid a production of reactive power by the segment.
6. The system of claim 1 , wherein the constant current source is connected to the current supply via a transformer adapted to produce an input voltage to be input to the constant current source so that the desired constant current is produced by the constant current source.
7. The system of claim 6 , wherein the second inductance is completely formed by the inherent inductance of the segment.
8. The system of claim 7 , wherein a stray inductance of the transformer acts as the first inductance of the constant current source.
9. A method of manufacturing a system for transferring electric energy to a vehicle, comprising the steps of:
providing an electric conductor arrangement for producing an alternating electromagnetic field and for thereby transferring electromagnetic energy to the vehicle,
providing a plurality of segments as part of the conductor arrangement, electrically connected in parallel to each other and to a current supply, so that the segments extend in a direction of travel of the vehicle,
coupling at least one of the segments to the current supply via an associated constant current source to keep an alternating electric current through the segment constant,
equipping each constant current source with at least a first inductance and at least a first capacitance, wherein the inductance and the capacitance are adapted to each other and to a voltage at an input side of the constant current source so that a desired constant current is output to an output side of the constant current source,
placing the first inductance in a line of the constant current source which connects the input side with the output side and connecting at least one junction of the line to the first capacitance, and
dimensioning the first inductance and the first capacitance as well as a second inductance which is formed at least partly by an inherent inductance of the segment, so that the segment can be operated at a corresponding resonance frequency and the reactive power produced by the segment is essentially zero.
10. The system for transferring electric energy to a vehicle as in claim 1 , wherein the vehicle is a track bound vehicle or a road vehicle.