Impedance matching method based on circuit duty ratio

Abstract

The invention provides an impedance matching method based on circuit duty ratio. The method comprises the following steps: using a Boost impedance transformer, changing duty ratio of the Boost impedance transformer to realize impedance matching, and determining a relation between an equivalent load and the duty ratio of the Boost impedance transformer; regulating the duty ratio of the Boost impedance transformer, enabling the equivalent load to be maintained around an optimal load, and realizing maximal-efficiency transmission of a WPT system. By regulation of the duty ratio, the equivalent load is enabled to be maintained around the optimal load, and consequently, maximal-efficiency transmission is realized. By regulating the duty ratio a of a MOS tube in the Boost impedance transformer,R2 can be maintained to be almost unchanged, and consequently, transmission power and efficiency of the system are stabilized. But if power change is needed for the load, the load power can be changedthrough changing input voltage Vin. So, with the Boost impedance transformer, impedance matching is realized through changing the duty ratio of the Boost impedance transformer, the transmission efficiency of the WPT system can be stabilized, and the method is suitable for application occasions where the load has high voltage, low current and relatively high equivalent impedance value.

Description

technical field [0001] The invention belongs to the field of circuits, in particular to an impedance matching method based on a circuit duty ratio. Background technique [0002] During the charging process of the battery load by the WPT system, the equivalent load of the battery will change. The charging process of the battery can be divided into several constant current charging stages. In each constant current charging stage, the voltage at both ends of the battery rises in a curve, so as the charging process progresses, the equivalent load RL of the battery continues to rise, so that the equivalent load of the system deviates from the optimal load, resulting in a decrease in the transmission efficiency of the system . Therefore, when the equivalent load at both ends of the battery changes dynamically, impedance matching must be adopted to maintain efficient power transmission of the WPT system. [0003] In order to keep the equivalent load value on the secondary side u...

AI Technical Summary

Problems solved by technology

In each constant current charging stage, the voltage at both ends of the battery rises in a curve, so as the charging process progresses, the equivalent load RL of the battery continues to rise, so that the equivalent load of the system deviates from the optimal load, resulting in a decrease in the transmission efficiency of the system

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