Method and device for optimizing instantaneous dynamic of LLC resonant converter load

Abstract

The invention discloses a method and device for optimizing the instantaneous dynamic state of an LLC resonant converter load. Firstly, an actual test of a specific point is carried out on the LLC resonant converter; discrete points related to the LLC switching frequency, the input voltage, the output voltage and the output current are obtained; and fitting is carried out to obtain an optimal objective function of the LLC switching frequency, and then through dynamic load switching judgment, a final output PID result of the voltage loop controller linearly approaches an expected output value ofthe optimal objective function when a load suddenly changes. An effective LLC switching frequency target function is obtained through a simple fitting mode, and the PID output result of the voltage controller linearly approaches the expected value of the LLC switching frequency during dynamic load switching. According to the method, the calculation deviation and a large quantity of calculation caused by LLC small signal model modeling are avoided, and the change speed of the LLC switching frequency is increased, so that the dynamic response speed of the LLC is increased under the condition that the hardware cost of the system is not increased.

Description

technical field [0001] The invention relates to the field of LLC resonant converters, in particular to a method and device for optimizing instantaneous load dynamics of LLC resonant converters. Background technique [0002] Among the currently used dynamic control strategies for LLC resonant converters, such as the application number CN201810372510.X, the title of the invention is "A Method for Parameter Optimization Design of LLC Resonant Converter Based on Minimum Loss", all of which adopt optimal trajectory control. In the trajectory control strategy, the controller judges whether a load mutation occurs by changing the output current. Once the load mutation occurs, the controller calculates the driving cycle change amount according to the output current before the load mutation and the output current after the mutation, and superimposes it to the linear In the controller, quick adjustment is realized. However, this strategy requires accurate modeling of the LLC, and the ...

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Problems solved by technology

However, this strategy requires accurate modeling of the LLC, and the switching cycle needs to be calculated cycle by cycle, the control speed is extremely fast, and the controller has high requirements

That is to say, it has the following defects: the optimal trajectory control requires a high processing speed of the controller; the average current control only has better dynamic characteristics at the resonance point; the peak current control needs to increase the more complex peak current sampling circuit

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