Hybrid Control Apparatus for Wireless Power Transfer Efficiency
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Solution Overview
Problem
High power density and high efficiency wireless power transfer systems face challenges in achieving efficient power transfer under varying loading conditions, particularly at higher frequencies, and struggle with low electromagnetic interference (EMI).
Innovation Solution
A hybrid control method is implemented in a wireless power transfer system, where a power converter is configured to align the turn-on time of its power switch with the transmitter's switches, and operates in different modes based on load currents, using a high-side and low-side switch configuration with an inductor and a full-bridge converter to manage voltage and reduce EMI.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If resonant converter based wireless power transfer systems are used to achieve high efficiency through zero voltage switching and zero current switching, then power losses are reduced, but achieving high efficiency under different loading conditions at higher frequencies becomes difficult
Solution Approach 1:
The patent implements dynamic switching between two control modes: phase-shift control for light loading conditions and frequency control for heavy loading conditions. This dynamic adaptation allows the system to maintain high efficiency across the entire loading range by selecting the optimal control strategy based on real-time load conditions, resolving the contradiction between achieving low power losses and maintaining adaptability to different loading conditions.
2Power
If the frequency of the wireless power transfer system is increased to achieve higher power density, then power transfer capability is improved, but maintaining high efficiency under varying loading conditions becomes more challenging
Solution Approach 1:
The system dynamically adjusts its operating frequency and control mode based on loading conditions. At higher frequencies, the system switches between phase-shift control (for light loads) and frequency control (for heavy loads), enabling it to maintain high power density while adapting efficiently to varying loading conditions throughout the operating range.
3Loss of energy
If a power converter is added to regulate voltage under light load conditions, then efficiency is improved, but system complexity increases
Solution Approach 1:
The power converter is designed to perform multiple functions: it regulates voltage under light load conditions using phase-shift control, and operates as a standard power conversion stage under heavy load conditions using frequency control. This multi-functionality allows a single device to handle both efficiency optimization and power conversion requirements without requiring separate dedicated components for each function.
4Object-generated harmful factors
If alignment of turn-on time instants between power converter and transmitter switches is implemented, then electromagnetic interference is reduced, but control complexity increases
Solution Approach 1:
The system pre-synchronizes the turn-on time instants of the power converter switches with those of the transmitter switches through coordinated control signaling. This preliminary alignment of switching events prevents EMI-generating transient overlaps, and the synchronization is maintained through the existing control infrastructure without requiring additional complex control mechanisms.
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 and reduces electromagnetic interference across different loading conditions, achieving high power transfer efficiency and minimizing EMI, thereby improving system performance.
Implementation Method 1
The primary side transmitter is magnetically coupled to the secondary side receiver through a magnetic coupling. The magnetic coupling may be implemented as a loosely coupled transformer having a primary side coil formed in the primary side transmitter and a secondary side coil formed in the secondary side receiver.
Implementation Method 2
a transmitter coil coupled to the full-bridge through a resonant capacitor
Data Source
AI summary
An apparatus comprises a power converter connected between a power source and a wireless power transfer system, wherein a power switch of the power converter is configured such that a turn-on time instant of the power switch is aligned with a turn-on time instant of at least one of switches of a transmitter of the wireless power transfer system.