Wireless Power Reception Device Dual Rectifier Ripple Suppression
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Solution Overview
Problem
In noncontact wireless power supply systems, the rectification and smoothing circuit fails to smooth pulsating voltages accurately when the DC voltage is high, leading to significant ripple and inaccurate detection of coil positions, especially when the relay circuit is turned off.
Innovation Solution
A wireless power reception device with a dual rectification and smoothing circuit configuration, including a first and second rectifier circuit with capacitors, allows for accurate detection of the power receiving coil's position relative to the power transmitting coil by using a second voltage detecting circuit to suppress ripples and enhance voltage gain.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single rectification and smoothing circuit is used, then the device complexity is low, but the measurement precision of coil position detection deteriorates when DC voltage is high due to large ripple
Solution Approach 1:
The patent divides the single rectification and smoothing circuit into two separate parallel circuits: a first rectification and smoothing circuit for power supply and a second rectification and smoothing circuit for detection. This segmentation allows each circuit to be optimized for its specific function, with the second circuit providing clean detection signals free from the ripple affecting the first circuit.
Solution Approach 2:
The patent introduces a second rectification and smoothing circuit as an intermediary detection path that does not directly supply power to the load. This intermediary circuit provides a clean voltage signal for coil position detection, mediating between the high-power first circuit and the sensitive detection requirements.
2Device complexity
If a single rectifier circuit is used for both power supply and detection, then the device complexity is low, but the reliability of position detection deteriorates when load is disconnected
Solution Approach 1:
The patent segments the rectifier functions into two independent parallel circuits: the first rectifier circuit handles power supply to the load, while the second rectifier circuit is dedicated to detection signals. This ensures that detection reliability is independent of load connection state, as the second circuit maintains stable detection capability regardless of whether the load is connected or disconnected.
3Object-generated harmful factors
If a larger smoothing capacitor is used in the single circuit, then the ripple is reduced for power supply, but the response speed of position detection slows down
Solution Approach 1:
The patent segments the smoothing function into two separate capacitors: a first smoothing capacitor for power supply that can be large to reduce ripple, and a second smoothing capacitor for detection that can be small to maintain fast response speed. This segmentation resolves the contradiction by allowing each capacitor to be optimized for its specific requirement without compromising the other.
Solution Approach 2:
The patent applies different quality characteristics to different parts of the system: the first smoothing capacitor is designed with large capacitance for low ripple in power supply, while the second smoothing capacitor is designed with small capacitance for fast response in detection. This local differentiation of quality parameters optimizes each function for its specific performance requirements.
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 configuration enables precise detection of the power receiving coil's position irrespective of the load connection state, improving transmission efficiency and accuracy by reducing ripple effects and enhancing voltage detection.
Implementation Method 1
a power receiving coil L2 that is magnetically coupled to the power transmitting coil L1
Data Source
AI summary
A wireless power reception device includes: a power receiving coil coupled to a transmitting coil; a first rectifier circuit rectifies AC voltage supplied from the receiving coil and outputs to a load; a first capacitor connected between 11th and 12th output terminals respectively on high and low potential sides among output terminals in the first rectifier circuit and the first rectifier circuit and the load; a second rectifier circuit connected to the receiving coil parallel to the first and rectifies AC voltage supplied from the receiving coil; a second capacitor connected between 21st and 22nd output terminals respectively on the high and low potential sides among second rectifier circuit output terminals; a second voltage detecting circuit detects voltage between the 21st and 22nd output terminals; and a position detecting circuit detects the receiving coil position relative to the power transmitting coil by voltage detected by the second voltage detecting circuit.