Inductive Power Transfer Coupler Array Shared Switch Topology
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Solution Overview
Problem
Lumped dynamic inductive power transfer systems for electric vehicles face challenges in efficiency and cost due to the need for multiple independently energized coupler modules, with existing solutions often requiring complex control methods and increased voltage stress on switches.
Innovation Solution
A low-cost converter topology using a current-sourced push-pull converter or half-bridge topology, where each coupler module is energized independently by a shared semiconductor switch, reducing current stress and eliminating the need for bi-directional AC switches, and allowing for simultaneous energization of multiple modules without proportional increase in switch current stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a separate power converter and associated circuitry is used to energize each coupler module independently, then each coupler module can be energized independently when in the vicinity of the pick-up coupler, but the system complexity and cost increase significantly
Solution Approach 1:
Multiple separate power converters are merged into a single shared power converter that can independently energize multiple coupler modules. The patent uses one power converter with multiple output channels, each channel capable of independently driving a coupler module through shared switching elements, thereby reducing system complexity while maintaining independent energization capability.
Solution Approach 2:
A single power converter is designed to perform multiple functions by serving multiple coupler modules simultaneously or sequentially. The converter incorporates multiple output channels that can be independently controlled, allowing one device to replace what would traditionally require multiple separate converters.
2Power
If a common inverter is used to drive multiple coupler modules, then the cost and size of the inverter must be increased to handle the maximum number of modules, but using multiple inverters increases system complexity
Solution Approach 1:
The inverter is segmented into multiple independent output channels, each capable of driving a coupler module independently. This allows the inverter to be sized appropriately for individual module requirements rather than requiring excessive capacity to drive all modules simultaneously at maximum power, reducing both size and cost while maintaining flexibility.
3Adaptability or versatility
If bi-directional AC switches are used to connect each coupler with a common inverter, then the switching capability is enhanced, but complex control methods are required to ensure zero current switching or zero voltage switching
Solution Approach 1:
The patent replaces complex bi-directional AC switches with simpler, lower-cost switching elements that are optimized for unidirectional operation. By using standard semiconductor switches designed for specific current directions, the system achieves the required switching capability without the need for complex bi-directional switch control methods, reducing both component cost and control complexity.
4Ease of operation
If a series capacitor is placed in series with the DC blocking capacitor to activate and deactivate a segment, then the switching control is simplified, but the voltage stress across the switch increases to at least twice the DC-link voltage
Solution Approach 1:
The patent extracts and eliminates the series capacitor from the circuit configuration. By removing this component, the voltage stress on the switching elements is reduced to the DC-link voltage level rather than twice that voltage, while the switching control remains effective through the simplified topology that directly connects switches to the DC-link through the DC blocking capacitor.
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 enables efficient and cost-effective operation of large-scale IPT systems by allowing any number of coupler modules to be energized simultaneously with reduced switch current stress, improving system efficiency and reliability.
Implementation Method 1
Inductive power transfer (IPT), also referred to as wireless power transfer (WPT) is gaining popularity as a means of transferring electrical power between two systems without any physical contact
Implementation Method 2
each of the plurality of coupler modules comprises a resonant circuit including at least one transmitter coil and a capacitive element
Data Source
AI summary
An inductive or wireless power transfer coupler array has at least two coupler modules connected in parallel to a common power source. Each coupler module comprisesa resonant circuit, including at least one transmitter coil and a capacitive element. Each of the coupler modules is connected to a second terminal of the power source across the respective resonant circuit by a corresponding pair of switching elements,and each coupler module is linked with at least one other coupler module at a shared one switching element of the corresponding pair of switching elements. A control module is configured to effect control between the active state and the passive state by controlling the phase angle of the corresponding pair of switching elements.