Induction type wireless power supply system double-closed-loop constant output current control method

Abstract

Provided is an induction type wireless power supply system double-closed-loop constant output current control method. The method comprises outer-loop controlling and inner-loop controlling. The outer-loop controlling comprises the steps that based on a short time fourier transformation method, real-time processing is carried out on output voltage and output current signals of a primary side high-frequency inverter, an equivalent impedance of a resonance circuit is calculated, it is judged whether an impedance phase-angle is in a threshold value range or not, if the impedance phase-angle exceeds a threshold value, an automatic frequency adjusting module is started, calculation is repeated, and the equivalent impedance of the primary side resonance circuit is judged until a system works in a resonance state. The inner-loop control comprises the steps that an input voltage theoretical value of the high-frequency inverter is calculated and corrected, and is used as an input voltage reference value of the inner-loop controlling. According to deviation of the input voltage reference value and a measuring value (actual input voltage of the high-frequency inverter), real-time calculation is carried out, a duty ratio of a switch signal of the deviation is removed, and a corresponding switch pulse signal is output. According to double-closed-loop constant output current controlling, energy output of an induction type wireless power supply system can be effectively controlled, and the wireless electric energy transmission quality is improved.

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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