A nonlinear differential smoothing control method for distributed optical-storage DC power supply system

Abstract

The invention relates to a nonlinear differential flatness control method for a distributed type light storage direct-current power supply system. The method includes the following steps of obtaining the difference between the direct-current bus reference energy EBusref and the direct-current bus energy EBus, inputting the difference into an energy ring PI controller, making a controller output a direct-current bus power reference value, inputting the direct-current bus power reference value, power pPVo output to a direct-current bus by a photovoltaic battery, direct-current load power pLoad and energy-storage storage battery output power pBat into a power ring nonlinear differential flatness controller, making the controller output storage battery reference output power pBatref, obtaining direct-current bus reference current through storage battery reference output power pBatref and direct-current bus voltage vBus, conducting overcurrent hysteresis control, obtaining a switch signal of a three-phase staggered bidirectional converter, and conducting flatness control. Compared with the prior art, the method has the advantages of being simple in algorithm, wide in freedom degree, high in robustness and the like.

Description

technical field [0001] The invention relates to a control method for a distributed optical-storage DC power supply system, in particular to a nonlinear differential smoothing control method for a distributed optical-storage DC power supply system. Background technique [0002] Distributed photovoltaic power generation has problems such as large output voltage fluctuations and poor system stability. The distributed photovoltaic storage DC power supply system combined with energy storage technology has been widely used due to its high-quality and high-reliability power supply capabilities. The stable control of DC bus voltage is a practical application However, the reasonable design of the topology and control algorithm of the converter device is a feasible solution to realize the stable control of the DC bus voltage of the optical storage DC power supply. [0003] In terms of converter topology, photovoltaic converters usually use Boost circuits, and energy storage converters...

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Problems solved by technology

[0004] In terms of the control algorithm of interleaved parallel converters, the PI controller is widely used in engineering at present. Its design process is clear and can meet the general performance requirements of power converters. The PI control of point design is difficult to ensure the large-signal stability of the interleaved parallel converter system

In view of the nonlinear characteristics of the interleaved parallel converter itself, although there are many nonlinear control algorithms such as sliding mode control and feedback linearization control, these algorithms overcome the shortcomings of the narrow stability domain of PI control, but the calculation is complex and realizes engineering applications. There is a bottleneck

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