Digital control method for DC (Direct Current)-DC converter based on LQR (Linear Quadratic Regulator) optimum control

Abstract

The invention discloses a digital control method for a DC (Direct Current)-DC converter based on LQR (Linear Quadratic Regulator) optimum control. The digital control method comprises manual / automatic control mode switching design, state observer design, an LQR optimal controller with integral control and considering of tracking performance of reference input voltage, and the design of a method for resisting integral saturation. According to the digital control method disclosed by the invention, the LQR optimal controller with the integral control is designed, the output residual error of the DC-DC converter is effectively eliminated, and the tracking performance of the reference input voltage is considered, so that output voltage of the DC-DC converter can be used for better tracking the change of the reference input voltage in real time; the method for resisting the integral saturation is adopted for processing the control variable duty cycle output, and the problem that the controller is failed as the duty cycle is saturated for a long time caused by wide-range change of loads and the like in the actual engineering application is avoided; a switch is adopted for controlling the manual / automatic control mode to be switched, so that smooth switching of two operating modes is guaranteed. Shown by the actual engineering application, the digital control method disclosed by the invention has good control precision and robustness.

Description

technical field [0001] The invention belongs to the technical field of switching power supply control, and in particular relates to a digital control method of a DC-DC converter based on LQR (linear quadratic regulator) optimal control. Background technique [0002] In recent years, the digital control of high-frequency DC-DC converters has attracted more and more attention from the international academic and engineering circles. With the continuous in-depth research and development of digital control systems, digital control methods are more and more widely used in high-frequency Frequency and small and medium power switching power converter control. The programmability of digital control makes up for the shortcomings of traditional analog compensation control methods, and can design more advanced and complex control algorithms and apply them in engineering. [0003] At present, in practical engineering applications, compared with the trial-and-error design method of the t...

AI Technical Summary

Problems solved by technology

Therefore, there are more and more digital discretization methods for traditional analog control methods. Although the conversion from analog to digital can achieve better control effects, the neglect of parameters and the delay of the zero-order keeper in the discretization process will cause problems. Cause certain adverse effects, and whether the selection of the zero pole of the compensation network is appropriate greatly affects the control performance of the system, because of this, the design of the compensation network needs to go through the process of repeated trial and verification

[0004] Digital control theory proposes the use of state feedback optimal control to automatically optimize the zero-pole placement method, H.S Bae in [H.S.Bae, J.H.Yang, J.H.Lee, B.H.Cho, "Digital state feedback current control using the pole placement technique," Journal of Power Electronics, 2007, Vol.7, No.3, pp:213-221] proposed to use digital state feedback method to control the current control DC-DC converter, but the above method assumes that all states are measurable and the feedback The selection of proportional gain is also obtained by empirical method, and this algorithm does not consider the tracking performance of the voltage setting value, so the performance in practical applications has a large gap compared with the analog compensation network

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