Non-contact Power Transmitter Harmonic Suppression
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Solution Overview
Problem
Existing high-frequency power sources used in non-contact power transmission systems generate square wave signals with numerous harmonics, leading to unnecessary radiation, particularly exceeding radiation limits in designated frequency bands like the ISM band, and lack the ability to selectively suppress specific harmonic components.
Innovation Solution
A high-frequency power source employing a switching system to generate a first high-frequency signal with adjustable pulse width and a second high-frequency signal with a specific harmonic component and phase difference, which are differentially driven to create a composite signal that offsets or reduces the specific harmonic component, thereby reducing radiation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a square wave signal is generated using a switching system (half-bridge inverter, full-bridge inverter, or Class-E amplifier), then high power exchange efficiency is achieved, but numerous harmonic components are produced causing unnecessary radiation
Solution Approach 1:
The patent converts the harmful harmonic components into a beneficial cancellation mechanism by generating a second signal specifically containing the unwanted harmonic at 180 degrees phase difference, then subtracting it from the first signal. This transforms the harmful radiation problem into a solution where harmonics are deliberately generated and then canceled through differential driving, achieving harmonic suppression while maintaining switching system efficiency
Solution Approach 2:
The patent applies preliminary anti-action by generating the second signal with the specific harmonic component at 180 degrees phase difference before the harmful radiation occurs. This pre-prepared counter-signal is then combined with the first signal through differential driving to cancel out the unwanted harmonics in advance, preventing rather than correcting the radiation problem
2Power
If conventional high-frequency power sources are used, then high output power is achieved, but selective suppression of specific harmonic components is not possible
Solution Approach 1:
The patent segments the signal generation into two independent parts: a first signal generating unit that produces the main high-frequency signal, and a second signal generating unit that produces a signal containing only the specific unwanted harmonic component. This segmentation allows independent control and manipulation of each signal, enabling selective suppression of particular harmonics while preserving the main signal and other beneficial frequency components
Solution Approach 2:
The patent employs parameter changes by adjusting the pulse width and phase of the second signal to precisely control which harmonic component is generated and at what amplitude. By varying these parameters, the system can selectively target and suppress different harmonic orders (3rd, 5th, 7th, etc.) while maintaining the fundamental frequency and other desired components, providing adaptability across different operating conditions
Data Source
AI summary
A power transmitting device includes a resonance circuit, a first signal generating unit, and a second signal generating unit. The resonance circuit is used in non-contact power transmission. The first signal generating unit is connected to one end of the resonance circuit, and generates, with the use of a switching system, a first high-frequency signal including one or more harmonic components. The second signal generating unit is connected to an other end of the resonance circuit, and generates, with the use of a switching system, a second high-frequency signal including a specific harmonic component. The first high-frequency signal is adjusted in pulse width and input to the one end of the resonance circuit, and the second high-frequency signal is adjusted in pulse width and phase difference from the first high-frequency signal and input to the other end of the resonance circuit.