AC envelope modulation based wireless electric power transmission system

Abstract

The invention belongs to the technical field of wireless electric power transmission, and provides an AC envelope modulation based wireless electric power transmission system. The AC envelope modulation based wireless electric power transmission system comprises a primary circuit and a secondary circuit; the primary circuit comprises an AC electric power input module, a high-frequency envelope electric power conversion module and a primary high-frequency resonant link; the secondary circuit comprises a secondary high-frequency resonant link, a high-frequency envelope electric power demodulation module and an AC electric power output module; and the high-frequency envelope electric power demodulation module comprises a secondary inversion circuit, a secondary current sampling circuit, a Butterworth electronic filter, a current zero-crossing detection circuit, a logic circuit and a driving circuit. As a secondary rectification circuit is removed, and the Butterworth electronic filter is adopted to process secondary pickup resonant current, a soft driving signal for polarity switching is provided for the secondary inversion circuit, and the secondary control is enabled to be independent and simple; and the AC envelope modulation based wireless electric power transmission system in such structure greatly reduces the overall volume and cost of the system, and increases the transmission efficiency and an input power factor.

Description

technical field [0001] The invention belongs to the technical field of wireless power transmission, and in particular relates to a wireless power transmission system based on AC envelope modulation. Background technique [0002] Traditional wireless power transfer technology often takes DC load as the research object. For the application of AC load, it usually adopts AC / DC / AC mode or AC / AC mode. In the research and application, it is found that the traditional transmission under the condition of AC load mode wireless power transfer system [such as figure 1 (a)] A number of problems remain. Mainly manifested in: 1. Low efficiency. In order to convert AC to DC, there are AC / DC rectification, large electrolytic filter links and DC / DC voltage regulation links in the primary and secondary stages, and the switching loss and harmonic content are large; 2. The control is complicated , the system order is high and the inertia is large, and both the primary and secondary stages have...

AI Technical Summary

Problems solved by technology

Mainly manifested in: 1. Low efficiency. In order to convert AC to DC, there are AC / DC rectification, large electrolytic filter links and DC / DC voltage regulation links in the primary and secondary stages, and the switching loss and harmonic content are large; 2. The control is complicated , the system order is high and the inertia is large, and both the primary and secondary stages have relatively complex control loops; 3. The power factor and power density are low, and the large electrolytic capacitors in the primary and secondary energy conversion circuits reduce the power factor and power density. Source power factor correction inevitably increases system scale and cascading links, reducing power density; 4. High cost and bulky

The above shortcomings seriously hinder the development of wireless power transmission technology and limit the application range of wireless power transmission technology

For wireless power transmission systems with direct AC / AC structure, matrix converters and complex control modes are usually used, which increases the cost and control difficulty of the system to a certain extent.

[0003] While the traditional envelope modulation wireless power transfer system [such as image 3 (a)] Compared with the traditional transmission mode wireless power transfer system [such as figure 1 (a)], although the cascading link of the system is reduced to a certain extent and the density is improved, the disadvantage is that there is still a rectifier bridge at the secondary pickup end, which cannot avoid the conduction loss under high current and the reverse osmosis current under high frequency conditions. In addition, it also increases the cost and volume of the system. At the same time, due to the characteristics of large inertia and large delay of the wireless power transmission system, the secondary polarity switching is also a very difficult problem, and there is no better structural solution yet.

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