Wireless Power Receiver Active Rectifier Efficiency
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Solution Overview
Problem
Conventional wireless power transfer systems for electric vehicles face efficiency variations due to changing coupling factors between charging coils, requiring additional converters that increase complexity and cost.
Innovation Solution
A wireless power receiver with a synchronous active rectifier and a DC voltage suppression control loop, which dynamically sets the equivalent resistance to optimize power transfer efficiency independently of the charging station, using a controller to manage the phase angle and waveform of the rectifier.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional wireless power transfer systems use additional converters to maintain efficiency, then power transfer efficiency is improved, but device complexity increases
Solution Approach 1:
The patent extracts the voltage regulation function from the transmitter side and implements it independently at the receiver side using a synchronous rectifier with controlled switching. This eliminates the need for complex additional converters while maintaining power transfer efficiency, as the synchronous rectifier with duty cycle control can independently regulate voltage without requiring extra conversion stages.
Solution Approach 2:
The patent employs dynamic control of the synchronous rectifier switching duty cycle to adapt to varying coupling conditions between transmitter and receiver coils. By dynamically adjusting the duty cycle, the system maintains optimal power transfer efficiency across different positional relationships without requiring fixed additional converters, thus reducing overall device complexity while preserving efficiency.
2Manufacturing precision
If conventional systems use additional converters for voltage regulation, then voltage regulation capability is improved, but manufacturing cost increases
Solution Approach 1:
The synchronous rectifier in the patent performs multiple functions: it rectifies the AC voltage from the receiver coil, regulates the output voltage through duty cycle control, and provides overcharge protection. This multi-functionality eliminates the need for separate additional converters, reducing component count and manufacturing cost while maintaining excellent voltage regulation capability.
Solution Approach 2:
The patent changes the operating parameters of the synchronous rectifier, specifically the switching duty cycle, to achieve voltage regulation. By varying the duty cycle parameter, the system can regulate output voltage without requiring additional conversion hardware, thereby reducing manufacturing complexity and cost while preserving precise voltage control capability.
3Device complexity
If the receiver uses a reduced number of components, then device complexity is reduced, but power conversion efficiency may worsen
Solution Approach 1:
The patent incorporates feedback control through the synchronous rectifier's duty cycle adjustment mechanism. The controller monitors the output voltage and battery charging status, and dynamically adjusts the rectifier duty cycle to maintain optimal power conversion efficiency. This feedback mechanism ensures that even with a reduced component count, the system achieves high efficiency by adaptively optimizing the rectifier operation.
Solution Approach 2:
The synchronous rectifier with duty cycle control performs self-regulation of power conversion efficiency. By autonomously adjusting its switching parameters based on load conditions and coupling variations, the rectifier maintains high conversion efficiency without requiring additional complex conversion components, thus achieving both reduced complexity and preserved efficiency.
4Adaptability or versatility
If the system operates with varying coupling factors, then adaptability to different positions is improved, but power transfer efficiency varies
Solution Approach 1:
The patent implements dynamic adaptation to varying coupling factors through real-time adjustment of the synchronous rectifier's duty cycle. As the coupling factor changes with positional relationship between coils, the controller dynamically modifies the duty cycle to compensate for efficiency variations, maintaining stable power transfer across different positions without sacrificing adaptability.
Solution Approach 2:
The system uses feedback from power transfer monitoring to dynamically adjust the rectifier duty cycle in response to coupling factor variations. This feedback mechanism enables the system to adapt to different positional configurations while maintaining consistent power transfer efficiency, resolving the contradiction between adaptability and efficiency stability.
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 solution improves power transfer and conversion efficiency, reduces component count, and simplifies the receiver design, allowing for independent voltage and current regulation, thus enhancing safety and reducing manufacturing costs.
Implementation Method 1
Wireless power transfer systems supply electric power using electromagnetic induction, between a power-transmitting coil of a power transmitter and a power-receiving coil of a receiver. In such systems, magnetic flux generated by the power-transmitting coil is induced at the power-receiving coil when the two coils are magnetically coupled, thereby electric power is transmitted between the coils.
Implementation Method 2
The receiver (2) has a power-receiving coil (Rx-coil (L s )) and a rectifier (7), such that the power-receiving coil (Rx-coil (L s )) is connected at the input (a1-a2) of the rectifier (7). The alternating current and voltage waveforms that reach the receiver (2), are converted by the rectifier (7) into a DC power suitable to charge the batteries of a vehicle.
Data Source
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AI summary
The present invention refers to a wireless power receiver (2) adapted to be installed in an electric vehicle, for wirelessly receiving power from the power transmitter (1) of a charging station to recharge the vehicle batteries. The receiver (2) comprises a power-receiving coil (Ls) connected at the input of a full bridge active rectifier (4), which is adapted to be connected with a battery of an electric vehicle. The controller, based on an input current (is) through the rectifier (4), operates the full bridge active rectifier (4) to set an equivalent resistance (Req) that is a close as possible to an optimum equivalent resistance of the receiver. The invention provides a power receiver (2) that optimizes power transfer and power conversion, and that performs voltage and current regulation independently from the transmitter (1) of the charging station.