Composite power control method for high-robustness self-stabilization hybrid energy storage system

Abstract

The invention discloses a composite power control method for a high-robustness self-stabilization hybrid energy storage system. In the current sampling period, the expected current ibatt req of a storage battery and the expected current icap req of a super capacitor in the next sampling period respectively pass through a second-order tracking smooth preprocessor to obtain a tracking value vx1 anda tracking trend vx2 of the expected current of the storage battery or the super capacitor; a sensorless state observer is used for obtaining a feedback value zx1, a change trend zx2 and a corresponding relation between system disturbance zx3 and a controlled quantity ux of actual current ix in a current sampling period of the storage battery and the super capacitor, and then a progressive robuststate function sx based on deviation ex1 and differential deviation ex2 is used for rapidly converging and solving the controlled quantity ux of the converter; and finally, a DC / DC converter is controlled according to the control quantity ux to output the actual current ix of the next sampling period, so that the actual total current itotal of the next sampling period is close to the expected current itotal req; andthe control process is carried out based on the condition that the state of charge of the storage battery is normal, so the problems that traditional control is poor in robustness,prone to oscillation and saturated in controlled quantity are solved.

Description

technical field [0001] The invention relates to the field of direct current power distribution network control, in particular to a compound power control method for a highly robust self-stabilizing hybrid energy storage system. Background technique [0002] Due to the increasing shortage of non-renewable energy such as oil and coal, people are paying more and more attention to the development of renewable energy, and more and more distributed power supply technologies have emerged one after another. The performance of the composite power control method of the hybrid energy storage system directly affects the operating characteristics of the DC microgrid, which makes the composite power control method of the hybrid energy storage system one of the current research focuses and hotspots. Model predictive control (Model Predictive Control, MPC) is a nonlinear optimal control method, which has the characteristics of good control effect and strong robustness. At present, the curr...

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Problems solved by technology

[0004] In order to solve the above problems, the present invention discloses a compound power control method of a highly robust self-stabilizing hybrid energy storage system, through the expected current i of the storage battery in the next sampling period battreq and the expected current i of the supercapacitor in the next sampling period capreq Obtain the tracking value v of the expected current of the battery or supercapacitor in the next sampling period through a second-order tracking smoothing preprocessor respectively x1 and track trends v x2 , through the sensorless state observer SLESO to obtain the actual current i of the battery and supercapacitor in the current sampling period x The feedback value z x1 , change trend z x2 and system disturbance z x3 and control quantity u x The corresponding relationship, and then use the deviation based on e x1 and differential deviation e x2 The asymptotically robust state function s of x Fast convergence to solve the converter control variable u of the battery and supercapacitor x , and finally according to the control quantity u x Control the DC / DC converter to output the actual current i of the next sampling period x , realizing the actual total current i total Approximate desired current i totalreq , the above control process is based on the condition that the state of charge of the battery is normal, which solves the problems of poor robustness, easy oscillation and saturation of the control amount of the traditional control

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