Power smooth control method applied to adaptive adjustment of energy storage

Abstract

The invention relates to a power smooth control method applied to the adaptive adjustment of energy storage. According to the method, a power outer loop, a voltage control loop and a current control loop are comprised, and a direct current energy storage DC-DC measures the output power Pesdc in real time, passes a filter with a filter coefficient of Tf and then enters a control system. By the power reference values Pes and ref of a power control loop, the steady-state power output of an energy storage system is controlled, and the transient power output of the energy storage system is controlled through a proportional parameter Ddc and an integral parameter Tdc of the power control loop. The method for adaptively adjusting the proportional parameters of the power loop comprises the following steps of when the energy storage system outputs the transient power, obtaining the direct-current bus voltage change rate information z according to the change of the direct-current bus voltage ubus and through a filter, a differential link and an absolute value link, and adjusting the parameter z through an amplification coefficient K and a natural index to obtain a proportionality coefficientDdc, so that the daptive control is realized.

Description

technical field [0001] The invention belongs to the control field of energy storage converters, and relates to a power smoothing control method applied to self-adaptive regulation of energy storage. Background technique [0002] With the rapid increase of new energy power generation and DC load capacity, the DC system is showing advantages such as low construction and transformation costs, large capacity, low loss, and convenient access to new energy [1]. Large-scale new energy power generation and DC loads can be connected to the DC bus through DC-AC or DC-DC, and then connected to the AC grid through grid-connected DC-AC. Frequent switching will bring certain threats to the stable operation of DC voltage. [0003] In order to solve the above problems, one idea is to use the energy storage system to temporarily stabilize the unbalanced power, stabilize the DC voltage, and reduce the speed requirements of the power output of the GCC [2-3]. In the control application of ene...

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Problems solved by technology

In the control application of energy storage, the existing conventional power or constant current control methods cannot achieve power disturbance stabilization in dealing with power disturbances. Conventional droop control or its improved forms are mostly aimed at the distribution of steady-state power, which cannot realize It can only support the transient power; in the literature [4-6], the sub-band control of the hybrid energy storage is proposed, both of which use the energy-type energy storage to stabilize the low-frequency power, and the power-type energy storage to stabilize the high-frequency power, and [7 Integral droop control proposed in ] to simulate the characteristics of capacitance to realize fast charging and discharging of power

Although the above energy storage control method can stabilize the transient power, the method is limited to the energy storage system, and mainly focuses on the sharing of the transient power, and cannot realize the adjustment of the steady-state power. At the same time, when the above method cooperates with GCC, The response characteristics of the energy storage control method to the transient power and the influence on the stability of the DC voltage are to be explored; another point is that in the transient process, if the response peak value of the energy storage power is large, there will be some problems in the process of restoring the steady state. May cause problems with too little damping

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