微网中电池储能系统控制策略的研究

发布时间：2018-04-14 22:20

本文选题：微网 + 电池储能系统　；参考：《天津大学》2014年博士论文

【摘要】：在含有大量光伏、风电等可再生能源的微网中，电池储能系统是其重要组成部分。论文针对提高电网接纳可再生能源发电能力和增强微网供电可靠性的需要，围绕电池储能系统的控制方法，研究了可以有效地抑制可再生能源输出功率波动的电池储能系统并网时的控制策略和可以提高微网供电可靠性的电池储能系统离网时的下垂控制策略，并进行了相应的仿真验证。论文具体工作如下：（1）针对光伏、风电等可再生能源输出功率波动性大且随机性强的特点，在计及电池使用寿命等约束基础上，提出了一种基于实测电池荷电状态（State ofCharge，SOC）的可变平滑控制时间常数储能控制方法。该方法通过实时调节储能系统的输出功率，对可再生能源输出功率中某一特定频段的波动成分进行补偿，同时根据电池的SOC值，对平滑控制时间常数进行调节，从而使电池的SOC值稳定在一定的范围内，避免了电池的过充过放。（2）提出了一种基于平滑控制的超级电容与电池混合储能系统的能量管理方法。该方法分别利用超级电容与电池补偿可再生能源输出功率波动的高频分量和中低频分量，并在传统限值管理的基础上引入了超级电容端电压预先控制，根据超级电容的剩余容量与充放电状态对超级电容与电池的输出功率进行修正，可有效防止超级电容因端电压达到上下限而停止工作。（3）分析了线路阻抗对电池储能系统离网下垂控制的影响并提出了一种改进策略。该控制策略采用基于线路压降差补偿的改进下垂控制方法，根据测量得到的线路阻抗参数和逆变器出口功率信息，实时补偿由线路阻抗差异导致的压降差，从而使储能逆变器能够精确地均分有无功负荷。（4）推导了包含多储能逆变器、线路和负荷的微网整体小信号模型，并通过特征值分析确定了影响微网稳定的关键参数。揭示了储能逆变器产生正阻尼的机理，提出了增加储能逆变器正阻尼的改进下垂控制策略。该方法基于储能逆变器动态频率特性的概念，根据其产生正阻尼作用的相位条件和幅值条件，在传统下垂控制中加入了附加阻尼控制环节。此改进方法可以在不影响系统稳态频率和储能逆变器输出功率的前提下，，有效地增加系统的阻尼并抑制储能逆变器输出功率的振荡，增强系统的稳定性。
[Abstract]:The battery energy storage system is an important part of the microgrid which contains lots of renewable energy sources such as photovoltaic, wind power and so on.This paper focuses on the control method of battery energy storage system in order to improve the power generation capacity of renewable energy and enhance the reliability of microgrid power supply.The control strategy of the battery energy storage system when connected to the grid and the droop control strategy of the battery energy storage system when it can improve the reliability of the microgrid power supply are studied, which can effectively restrain the fluctuation of the renewable energy output power.And the corresponding simulation verification is carried out.The specific work of the thesis is as follows:1) in view of the high volatility and randomness of the output power of renewable energy, such as photovoltaic and wind power, and taking into account the constraints of battery life,A variable smooth control time constant control method for energy storage is proposed based on the measured state of state of charge SOC.By adjusting the output power of the energy storage system in real time, this method compensates the fluctuating components of a certain frequency band in the output power of renewable energy, and adjusts the smooth control time constant according to the SOC value of the battery.Thus, the SOC value of the battery is stabilized in a certain range, and the overcharge and overdischarge of the battery are avoided.(2) an energy management method based on smooth control for hybrid energy storage system of super capacitor and battery is proposed.The method uses super capacitor and battery to compensate the high frequency component and middle low frequency component of the renewable energy output power fluctuation, and introduces the super capacitor terminal voltage pre-control based on the traditional limit value management.According to the residual capacity and charge-discharge state of the super capacitor, the super capacitor and the output power of the battery can be corrected, which can effectively prevent the super capacitor from working because the terminal voltage reaches the upper and lower limit.The influence of line impedance on the droop control of battery energy storage system is analyzed and an improved strategy is proposed.This control strategy adopts an improved droop control method based on line voltage drop compensation. According to the measured line impedance parameters and inverter outlet power information, the voltage drop caused by line impedance difference is compensated in real time.So that the energy storage inverter can accurately divide the reactive load.(4) the integral small-signal model of microgrid including multi-energy storage inverter, circuit and load is derived, and the key parameters that affect the stability of microgrid are determined by eigenvalue analysis.The mechanism of positive damping of energy storage inverter is revealed, and an improved droop control strategy is proposed to increase the positive damping of energy storage inverter.This method is based on the concept of dynamic frequency characteristics of energy storage inverter. According to the phase condition and amplitude condition of the positive damping effect, the additional damping control link is added to the traditional sag control.This improved method can effectively increase the damping of the system, suppress the oscillation of the output power of the energy storage inverter and enhance the stability of the system without affecting the steady-state frequency of the system and the output power of the energy storage inverter.
【学位授予单位】：天津大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：TM91

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