Wireless power transmission system for online load identification and load identification method

Abstract

The invention discloses a wireless power transmission system for online load identification and a load identification method suitable for use in the field of wireless charging. The wireless power transmission system comprises a high-frequency inverter, a primary-side fundamental wave energy transmission module, a primary-side harmonic energy transmission module, a secondary-side energy receiving module, a system load, a secondary-side signal processing and transmitting module, a primary-side signal receiving and processing module and a selector switch. When the system normally outputs power, the selector switch is turned off and is cut off the primary-side harmonic energy transmission module, energy from the primary-side fundamental wave energy transmission module is received through a secondary-side magnetic energy pick-up coil in the secondary-side energy receiving module and transferred to the load; and when dynamic load identification needs to be carried out, the selector switch is turned on and cut in the primary-side harmonic energy transmission module, a fundamental wave in load current of the system and the content and the size of harmonic current are extracted and detected, and an equation set for load resistance and reactance is built according to a superposition theorem, thereby dynamically identifying the property and the size of the load. Load identification is carried out by adopting a harmonic wave, the steps are simple, the energy utilization rate is high, energy transmission of the system is not affected by the load identification process and the load identification accuracy is high.

Description

technical field [0001] The invention relates to a wireless power transmission system, and is especially suitable for a wireless power transmission system and a load recognition method for online load recognition used in the field of wireless charging. Background technique [0002] The traditional way of power transmission is to transmit power from the grid to electrical equipment through connecting devices such as cables. Traditional power transmission requires a direct physical connection between power supply equipment and electrical equipment, and this connection will cause sparks or damage due to frequent friction and exposure, which not only greatly shortens the service life of electrical equipment, And it seriously threatens the safety of power supply, especially in coal mines, underwater and other occasions with harsh electrical environments, and may even cause major safety accidents. Therefore, under such market demand, wireless power transmission technology emerges ...

AI Technical Summary

Problems solved by technology

However, since the current research on power, efficiency, system stability, and system modeling in the field of wireless power transfer is based on known loads, not all system loads are known, and wireless power The load of the transmission system has variable and unknown characteristics. The change of the load will cause the operating frequency of the system to drift, deviate from the resonant frequency range of the system, and make the stability of the system worse, thus causing certain difficulties to the research of the ICPT system.

[0003] In order to solve this problem, the methods currently used are mostly based on the law of energy conservation, and the load size is obtained from the energy formula of the primary and secondary sides. However, due to the invisibility of energy and many factors ignored by this method, the calculated by this method Load values ​​are not very precise

For example, the document "Inductive Power Transfer System Parameter Identification and Constant Current Control" measures the zero-crossing point of the system's primary side resonant voltage and current waveform, and mea

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