Isolation Transformer Damping Circuit for Wireless Power Resonance
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Solution Overview
Problem
Wireless energy transmission systems face energy loss due to low magnetic coupling and parasitic resonances, leading to inefficiency and electromagnetic pollution, with existing common-mode chokes being only partially effective.
Innovation Solution
An isolating transformer with an input winding, output winding, and a third winding connected in series with a capacitive and resistive element forms a damping circuit, reducing unwanted resonances by dissipating parasitic power through electrical resistance, tuned to the operating frequency or harmonics, thereby enhancing coupling efficiency and reducing environmental interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a common-mode choke is used to reduce common-mode noise, then common-mode interference is suppressed, but the device complexity increases and differential-mode resonances are only partially suppressed
Solution Approach 1:
The patent combines common-mode noise suppression and differential-mode resonance suppression into a single integrated isolation transformer structure. The third winding is incorporated directly into the transformer core, creating a unified component that addresses both interference types simultaneously, rather than requiring separate common-mode chokes and resonance suppression circuits.
Solution Approach 2:
The isolation transformer with the third winding serves multiple functions: it provides galvanic isolation between primary and secondary sides, suppresses common-mode interference through the third winding's connection to ground, and damps differential-mode resonances through the capacitive and resistive elements connected to the third winding. This multi-functional design eliminates the need for separate interference suppression components.
2Reliability
If parasitic inductive and capacitive elements are present in the energy path, then resonances are formed at operating frequency and harmonics, but energy efficiency is reduced due to energy loss
Solution Approach 1:
The patent converts the harmful parasitic capacitive elements into useful components of the resonance suppression circuit. The capacitive element connected to the third winding works in conjunction with the inductive element to create a tuned circuit that specifically targets and dampens resonances at the operating frequency and harmonics, transforming what was previously a source of energy loss into a mechanism for controlling and eliminating unwanted resonances.
Solution Approach 2:
The patent introduces capacitive and resistive elements with specifically selected parameter values to tune the resonance suppression circuit. By carefully selecting the capacitance value and resistance value, the circuit is optimized to dampen resonances at specific frequencies (operating frequency and harmonics) while minimizing energy loss in the power transmission path.
3Productivity
If electrical power is emitted but not absorbed by the receiving coil, then energy transmission efficiency is reduced, but electromagnetic pollution of the environment increases
Solution Approach 1:
The isolation transformer with the third winding provides a feedback mechanism for suppressing unwanted electromagnetic emissions. The capacitive and resistive elements connected to the third winding create a damping circuit that actively suppresses resonances and reduces electromagnetic pollution generated by reflected or unabsorbed energy, thereby improving overall system efficiency and reducing environmental electromagnetic interference.
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 increases the coupling factor of the power transmission system, reduces resonance formation at operating frequencies, and minimizes environmental interference, resulting in higher energy transmission efficiency and reduced emissions.
Implementation Method 1
the capacitive element and the resistive element and the third winding are connected in series... the inductance of the third winding and the capacitance of the capacitive element can form a resonant circuit whose resonant frequency is tuned to the operating frequency of the isolation transformer or to a higher harmonic thereof. Parasitic power can then be dissipated in a targeted manner through the electrical resistance of the resistive element.
Implementation Method 2
The input winding, the output winding and the third winding are magnetically coupled... An isolating transformer has an input winding, an output winding and a third winding... The input winding, the output winding and the third winding are wound on the transformer core.
Data Source
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AI summary
The invention relates to an isolation transformer which is particularly suited for use in an energy transfer device and reduces unwanted resonances. The isolation transformer has an input winding, an output winding and a third winding, and also a capacitive element and a resistive element. The third winding is magnetically coupled to the input winding and to the output winding and forms a damping circuit for reducing the unwanted resonances together with the capacitive element and the resistive element.