A double-closed-loop constant output current control method for an inductive wireless power supply system

Abstract

A double-closed-loop constant output current control method for an inductive wireless power supply system, the steps of which are: outer loop control: based on the short-time Fourier transform method to process the output voltage and output current signals of the primary high-frequency inverter in real time, and calculate the resonance The equivalent impedance of the circuit and judge whether the impedance phase angle is within the threshold range. If it exceeds the threshold, the automatic frequency modulation module is started, and the equivalent impedance of the primary side resonant circuit is repeatedly calculated and judged until the system works in a resonant state. Inner loop control: Calculate the theoretical value of the input voltage of the high frequency inverter and correct it as the input voltage reference value of the inner loop control; according to the difference between the reference value of the input voltage and the measured value (the actual input voltage of the high frequency inverter) The deviation between them is calculated in real time to eliminate the duty cycle of the switching signal, and the corresponding switching pulse signal is output. The double closed-loop constant output current control can effectively control the energy output of the inductive wireless power supply system and improve the quality of wireless power transmission.

Description

technical field [0001] The invention relates to a double closed-loop constant output current control method for an inductive wireless power supply system. Background technique [0002] Inductive wireless power transfer technology is a technology based on the principle of electromagnetic field near-field induction, which comprehensively utilizes power electronic conversion technology, magnetic field coupling technology and control theory, and realizes that electrical equipment obtains energy from the power grid in a non-wire contact manner. The basic principle is to use a resonant converter to convert power frequency alternating current or direct current into high frequency alternating current, inject it into an energy emitting mechanism (such as a coil), and combine it with the principle of electromagnetic induction to excite a high frequency alternating magnetic field with the same frequency in space, so that The high-frequency electromotive force is induced in the pick-up ...

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Problems solved by technology

[0004] However, due to the problem of parameter selection, there is often a certain deviation between the expected output voltage of the Buck DC converter (the product of the input voltage and the duty cycle of the switching signal) and the actual output voltage, resulting in an increase in the overshoot of the constant current control process and The increase in adjustment time may also introduce serious input voltage fluctuations to the inductive wireless power transfer system, affecting the power transmission quality of the entire system

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