SAR satellite power supply Buck converter three-domain control system

Abstract

The invention discloses a three-domain control system of an SAR satellite power supply Buck converter. The three-domain control system comprises a control domain I unit (linear domain), a control domain II unit (nonlinear multi-threshold hysteresis domain) and a control domain III unit (nonlinear slamming domain). The three control domains are selected according to the output voltage value. The control domain I unit adjusts the output voltage when the output voltage is near the steady-state value. And when the output voltage exceeds the steady-state amplitude limit, a control domain II unit adjusts the output voltage. And when the output voltage reaches the maximum allowable range, a control domain III unit adjusts the output voltage. The three-domain control combines the advantages of linear control and nonlinear control. According to the method, the optimization of steady-state precision and dynamic response of the Buck converter in the SAR satellite is achieved through the cooperation of the three control domains, high control precision is achieved in the steady state, and rapid dynamic response is achieved when the load dynamically changes in a large range.

Description

technical field [0001] The invention relates to the technical field of SAR satellite power supply control, in particular to a three-domain control system for a SAR satellite power supply Buck converter. Background technique [0002] Synthetic Aperture Radar (SAR) satellites have all-weather and all-weather high-resolution and large-scale earth observation capabilities, making them widely used in many fields, and have advantages that optical remote sensing satellites cannot match. SAR is a kind of pulse-type load. It works in pulse mode. At the moment when the power of high-power pulse load changes, the current input by the DC bus will reach hundreds of amperes or even greater, which is very similar to the characteristics of short-circuit current and will cause A series of power quality problems, such as the output load changes rapidly and the load current is large, it is a very big challenge to ensure that the output voltage is within the specified range. In the spacecraft ...

AI Technical Summary

Problems solved by technology

The traditional SAR load power supply converter adopts a proportional-integral (PI) controller, which applies a linear control strategy based on a small-signal model, and has good control performance near the steady-state point, but when the load changes in a large range, the DC stability The operating point range of the state is wide, and the performance of the PI controller is limited

When the load changes step by step, the frequency spectrum of the step change signal will exceed the control bandwidth. At this time, the only way to meet the requirements of the output voltage change range is to increase the size of the capacitor.

Increasing the capacitance will cause the system dynamic performance to deteriorate and the power density to decrease

In addition, for spacecraft power supplies, the size limit is very strict, and increasing the size of the capacitor will also cause a significant increase in cost

In order to improve the dynamic performance of the converter, nonlinear control strategies such as hysteresis control are also applied, but the nonlinear control has poor steady-state accuracy, and the switching frequency is not fixed, and the electromagnetic compatibility (EMC) performance is poor.

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