Transformerless Adaptive Tuning Circuit for Wireless Power Transfer
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Solution Overview
Problem
Wireless power transfer systems require adaptive tuning to match impedance between transmitter and receiver circuits, but existing solutions rely on DC bias from isolated switching mode power supplies with power transformers, adding size, weight, cost, and causing electromagnetic interference (EMI) issues.
Innovation Solution
A transformerless adaptive tuning circuit using an RC circuit with diodes and a tuning logic to control power from a supply capacitor to a tuning circuit, eliminating the need for power transformers and SMPS-related EMI, by utilizing AC energy to generate a DC bias supply for switch activation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If isolated switching mode power supply with power transformer is used for adaptive tuning, then DC bias for impedance matching is provided, but system size, weight, cost increase and electromagnetic interference occurs
Solution Approach 1:
The patent extracts and removes the power transformer and isolated switching mode power supply from the adaptive tuning circuit, replacing them with a simplified RC circuit and diode-based voltage doubler. This extraction eliminates the source of EMI and reduces system size/weight while maintaining the essential function of providing DC bias for impedance matching.
Solution Approach 2:
The tuning circuit generates its own DC bias voltage using the available AC signal from the wireless power transfer system. The voltage doubler circuit rectifies and doubles the AC voltage to create the required DC bias, making the circuit self-sufficient and eliminating the need for external power transformers or isolated power supplies.
2Reliability
If isolated switching mode power supply with power transformer is used for adaptive tuning, then DC bias for impedance matching is provided, but electromagnetic interference causes system failure
Solution Approach 1:
The patent extracts and removes the power transformer and isolated switching mode power supply from the adaptive tuning circuit, replacing them with a simplified RC circuit and diode-based voltage doubler. This extraction eliminates the source of EMI and reduces system size/weight while maintaining the essential function of providing DC bias for impedance matching.
Solution Approach 2:
The patent uses a voltage doubler circuit that copies and transforms the available AC signal into the required DC bias voltage. Instead of using a separate isolated power supply, the circuit copies the existing AC waveform and transforms it through rectification and voltage doubling to generate the necessary DC bias for the tuning transistors.
3Reliability
If power transformer is used in adaptive tuning circuit, then DC bias supply is generated, but design flexibility is reduced
Solution Approach 1:
The patent implements dynamic adaptive tuning where the RC circuit and voltage doubler provide variable DC bias to continuously adjust the resonant frequency of the transmitter coil. This dynamic adjustment capability allows the system to adapt to changing load conditions and maintain optimal power transfer efficiency, significantly improving design flexibility compared to fixed transformer-based solutions.
Solution Approach 2:
The patent changes the operating parameters of the tuning circuit by using variable capacitance in the RC circuit and controllable voltage doubling to adjust the DC bias level. This allows continuous variation of the resonant frequency and impedance matching characteristics, enabling the system to adapt to different operating conditions without requiring multiple fixed transformers.
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 enhances system efficiency, reduces size and weight, and minimizes EMI noise, providing a cost-effective and flexible design for wireless power transfer systems without the need for power transformers.
Implementation Method 1
an RC circuit comprising a resistor and a supply capacitor; a first diode configured to be forward biased when the AC power is positive for charging the supply capacitor
Implementation Method 2
a second diode configured to be forward biased when the AC power is negative for minimizing discharge from the supply capacitor
Implementation Method 3
Wireless power transfer (WPT) or wireless energy transmission is the transmission of electrical power from a power source to a receiving device without using solid wires or conductors. Generally, the term refers to a number of different power transmission technologies that use time-varying electromagnetic fields.
Data Source
AI summary
Systems, apparatuses and methods for an adaptable tuning circuit for a wireless power transfer system including an inductor and a capacitor. An input may be configured to receive alternate current (AC) power. An RC circuit may include a resistor and a supply capacitor, where a first diode is configured to be forward biased when the AC power is positive for charging the supply capacitor, and a second diode is configured to be forward biased when the AC power is negative for minimizing discharge from the supply capacitor. A tuning logic is provided for controlling power from the supply capacitor to a tuning circuit comprising a tuning capacitor and a switch arrangement, wherein the tuning circuit is configured to be parallel to the capacitor of the wireless power transfer system.