Three-Phase Wireless Power Coupling Without a DC Link
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Solution Overview
Problem
Conventional wireless energy transfer systems for electric vehicle charging suffer from inefficiencies due to reliance on DC link platforms and bulky capacitors, and existing AC-to-AC converter topologies often result in poor power quality and high voltage/current stresses.
Innovation Solution
A method and system for wirelessly providing AC power to electric vehicles using a modulated high-frequency voltage signal with an AC-to-AC bidirectional converter, which includes half-bridges and coupling capacitors to convert grid voltage to a high-frequency carrier signal, reducing the need for bulky capacitors and improving power factor and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional AC-to-DC stage with DC link platform is used, then power factor correction and DC voltage stabilization are achieved, but larger bulky capacitors are required and system complexity increases
Solution Approach 1:
The patent extracts and eliminates the DC link platform and bulky capacitors from the conventional wireless power transfer system. By using direct AC-to-AC conversion with three-phase coupled inductors, the system removes the intermediate DC conversion stage and associated large capacitors, achieving power factor correction and voltage stabilization without the problematic DC link components.
Solution Approach 2:
The patent merges the AC-to-DC and DC-to-AC conversion stages into a single AC-to-AC conversion stage. By combining these functions into one integrated converter with three-phase coupled inductors, the system achieves both power factor correction and voltage stabilization in a single unified structure, eliminating the need for separate DC link components.
2Loss of energy
If direct AC-to-AC converter with energy injection control is used, then switching losses are reduced, but input current THD becomes too high for continuous operation
Solution Approach 1:
The patent changes the operating parameters of the converter by using three-phase coupled inductors with specific coupling coefficients and operating at optimized switching frequencies. This allows the system to achieve low switching losses while maintaining low input current THD through proper parameter selection and control strategies.
Solution Approach 2:
The patent implements feedback control mechanisms that monitor input current quality and adjust switching patterns in real-time. This feedback system ensures that energy injection control maintains low THD while minimizing switching losses, enabling continuous operation with high power quality.
3Ease of manufacture
If conventional single stage AC-to-DC PFC and DC-to-DC conversion is used, then system cost is reduced, but voltage and current stresses require additional commutation or compensation circuits
Solution Approach 1:
The patent introduces three-phase coupled inductors as intermediary components that mediate between the AC input and the wireless power transfer stage. These coupled inductors act as natural commutation devices, reducing voltage and current stresses on switching devices without requiring additional commutation circuits, thereby maintaining cost-effectiveness while managing stress levels.
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
The solution enables efficient wireless AC power transfer with reduced system complexity and cost, eliminating the need for bulky capacitors and improving power quality by using a modulated high-frequency voltage signal with an AC-to-AC bidirectional converter.
Implementation Method 1
producing a modulated high-frequency voltage signal that includes a high-frequency carrier signal having an envelope corresponding to the grid-voltage signal, and wirelessly transmitting the modulated high-frequency voltage signal
Implementation Method 2
at an on-board module spaced apart from, and electromagnetically coupled with, the off-board module, wirelessly receiving the modulated high-frequency voltage signal
Data Source
AI summary
A system and method for wirelessly or conductively (non-wireless) providing power. A three-phase coupling transmitter may be provided to wirelessly transmit modulated high-frequency voltage signals to a receiver, which may supply the received power to a load.