Resonance enhanced wireless power transmission structure with high resonance frequency stability

Abstract

The invention discloses a resonance enhanced wireless power transmission structure with high resonance frequency stability, and relates to the technical field of wireless power transmission. According to the wireless power transmission structure provided by the invention, the change of a coupling coefficient and a load cannot influence the resonance frequency, the primary side works at a constant frequency, the voltage and the current are same in phase, and the design of an absorption circuit and a soft switch is easily realized; due to a secondary-side impedance adjusting circuit, on one hand, the whole back-stage omega 0 frequency component of a rectifier bridge is purely resistive and the load change is guaranteed not to influence the resonance frequency, and on the other hand, the output voltage is stable and the power supply demand of the back-stage load is met; meanwhile, compared with an existing secondary-side wireless power transmission structure, the secondary-side structure proposed by the invention has relatively high resonance value Q, so that the resonance is enhanced, the transmission power under the weak coupling condition is increased, and the transmission efficiency under the weak coupling condition is improved. The resonance enhanced wireless power transmission structure is suitable for wireless power transmission occasions.

Description

technical field [0001] The invention relates to the technical field of wireless power transmission. Background technique [0002] For the wireless power transmission system, the increase of the transmission distance or the side shift will lead to the decrease of the coupling coefficient, thereby reducing the transmission efficiency and power. At the same time, the change of the coupling coefficient will cause the reflection impedance to change, resulting in system detuning. On the other hand, changes in the nature of the load on the secondary side, as well as non-linear loads (such as rectifier bridges, nonlinear components, etc.) will lead to a decrease in the power factor of the secondary side, detuning the system, and affecting the transmission effect. [0003] Existing technical solutions: In order to solve the problem of system detuning caused by coupling coefficient or load changes, the publication number is CN103151853A, which discloses a wireless power transmission i...

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Problems solved by technology

[0004] The publication number is CN103746462A, which discloses a bilateral LCC compensation network and its tuning method for wireless power transmission. Through the selection of corresponding rules, the resonance frequency of the system can be independent of the relative position of the coil and the load condition, but its secondary side is Current source characteristics, the stability of the system is poor when it is no-load, and when the primary side is excited by a square wave voltage, the harmonic distortion of the current output by the inverter circuit is serious, making it difficult to operate stably and reliably

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