Constant Current Source for Inductive Vehicle Charging
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Solution Overview
Problem
Current systems for transferring electromagnetic energy to vehicles, such as trams and buses, face inefficiencies and high manufacturing costs due to the need for heavy components like inductances to maintain constant current, which also produce significant reactive power.
Innovation Solution
The system employs a constant current source with a T-network configuration, utilizing the inherent inductance of the segments to minimize reactive power, and connects segments in parallel to a common current supply, reducing the number of discrete components and installation effort.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If heavy inductance components are used to maintain constant current, then constant current operation is achieved, but device complexity and manufacturing costs increase
Solution Approach 1:
The patent combines multiple discrete inductance components into a single common inductance that serves multiple segments simultaneously. This merging approach maintains constant current operation for each segment while reducing the total number of discrete components and simplifying the overall device structure.
Solution Approach 2:
The common inductance component performs multiple functions by serving several segments at once. It provides the necessary inductance for constant current operation across multiple segments, eliminating the need for separate inductance components for each segment and thereby reducing device complexity.
2Reliability
If heavy inductance components are used to maintain constant current, then constant current operation is achieved, but manufacturing costs increase
Solution Approach 1:
By merging multiple inductance functions into a single common inductance component, the patent reduces the total component count, simplifies manufacturing processes, and lowers overall manufacturing costs while maintaining reliable constant current operation.
Solution Approach 2:
The universal common inductance component serves multiple segments, reducing the bill of materials and manufacturing complexity, thereby decreasing production costs while ensuring constant current operation is maintained.
3Ease of manufacture
If segments are connected in parallel to common current supply, then installation effort is reduced, but current distribution control becomes difficult
Solution Approach 1:
The patent employs feedback mechanisms where the common inductance and associated control systems monitor and adjust current distribution to each segment. This feedback ensures that while segments are conveniently connected in parallel, the current distribution remains controlled and optimized for each individual segment's requirements.
4Loss of energy
If constant current operation is implemented, then efficiency is improved, but reactive power production increases
Solution Approach 1:
By merging the inductance resources into a common component, the patent optimizes the magnetic circuit utilization, reducing redundant reactive power generation while maintaining the constant current operation that ensures efficient energy transfer.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enhances efficiency, reduces manufacturing and installation costs, and allows for flexible operation by maintaining constant current independently of the power transferred to vehicles, while minimizing reactive power production.
Implementation Method 1
an electric conductor arrangement for producing an alternating electromagnetic field and for thereby transferring electromagnetic energy to the vehicle
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
The invention relates to a system for transferring electric energy to a vehicle (81; 91), in particular to a track bound vehicle (81) such as a light rail vehicle or to a road automobile (91) such as a bus, wherein - the system comprises an electric conductor arrangement (3, T) for producing an alternating electromagnetic field and for thereby transferring electromagnetic energy to the vehicle, - the conductor arrangement (3, T) comprises a plurality of segments (T1, T2, T3, T4, T5, T6), wherein each segment (T1, T2, T3, T4, T5, T6) extends along a section of the path of travel of the vehicle, - each segment comprises one line for each phase of an alternating current which is to be carried by the segment in order to produce the electromagnetic field, - the system comprises a current supply (3) for conducting electric energy to the plurality of the segments (T1, T2, T3, T4, T5, T6), wherein the segments (T1, T2, T3, T4, T5, T6) are electrically connected in parallel to each other with the current supply (3), - at least one of the segments (T1, T2, T3, T4, T5, T6) is coupled to the current supply (3) via an associated constant current source (12) adapted to keep the electric current through the segment (T1, T2, T3, T4, T5, T6) constant - while the segment (T1, T2, T3, T4, T5, T6) is operated - independently of the electric power which is transferred to one or more vehicles travelling along the segment (T1, T2, T3, T4, T5, T6), - each constant current source (12) comprises a first inductance (L6P1) and optionally more than one inductances and comprises a first capacitance (C6P) and optionally more than one capacitances, the inductances and the capacitances being adapted to each other and to the voltage at the input side of the constant current source so that a desired constant current is output to the output side, i.e. the side of the segment, - the first inductance (L6P1) is arranged in a line (100) of the constant current source (12) which connects the input side with the output side and at least one junction of the line (100) is connected with the first capacitance(C6P), - the first inductance (L6P1) and the first capacitance (C6P) as well as a second inductance (L6P2), which is formed at least partly by the inherent inductance (LT) of the segment (T), are adapted to each other and to any additional capacitance in the segment can be operated at a corresponding resonance frequency and the reactive power produced by the segment (T) is essentially zero.