摘要
微电网系统可以实现分布式电源、储能和负载的灵活接入,目前受到了广泛关注。建模仿真方法是微电网系统分析和设计的基础工具。但是,由于微电网系统往往含有多种直流、交流电源以及大量的电力电子装置,对系统进行准确解算耗时很长,仿真速度慢已成为系统分析设计的瓶颈问题之一。离散状态事件驱动(DSED)方法能够针对大规模电力电子变换器进行高效的解算,具备在微电网系统仿真中应用的潜力,但是由于建模解算均基于线性状态方程,该方法目前无法求解电励磁同步电机这一微电网系统中的非线性基本元件。该文提出了基于DSED方法的电励磁同步电机建模解算方法——状态变量接口解耦解算方法,使得DSED方法能够对包含电励磁同步电机的非线性微电网系统进行高效解算,从而提高仿真效率。在微电网系统算例研究中,与商业仿真软件相比,基于该文所提方法可以在相同精度下提高解算速度40余倍,从而可以为包含非线性旋转设备的大规模微电网系统准确高效的分析和设计提供仿真工具。
Microgrids can realize the flexible access of distributed generations,energy storages,and loads.A typical microgrid system often contains various DC and AC power supplies and many power electronic devices,challenging conventional simulation tools.Recently,the discrete state event-driven(DSED)approach has been proposed and can efficiently solve large-scale power electronic converters.This method models power electronic converters as piecewise linear(PWL)state equations and consists of a flexible,adaptive integration method based on the Taylor series.It can solve PWL systems but cannot solve the system containing electrically excited synchronous machines.Therefore,this paper proposes a state-variable-interfaced decoupling strategy based on the DSED approach.The state-variable-interfaced decoupling strategy can decouple the electrically excited synchronous machine from the whole system.The electrically excited synchronous machine and the other part systems exchange high-order time derivatives of interface variables to assure the simulation accuracy.In addition,a method for simplifying the time derivative calculation of electrically excited synchronous machines’state variables is proposed.The time derivatives can be obtained recursively,and the complicated and troublesome high-order derivative expressions can be avoided.The numerical errors introduced by the simplifying method are analyzed and can be well controlled using the proposed error equations.In the case study of a microgrid system,compared with commercial simulation software,the proposed method can improve the calculation speed by more than 40 times with the same accuracy.The simulated microgrid system consists of two distributed synchronous machines as AC generations and three DC generations with inverters.The simulated working conditions are as follows:initially,only DC power supplies are available,and the microgrid is connected to the power grid;At 0.2 s,put AC power into operation,that is,electrically excited synchronous machines;At 0.4 s,the microgrid is disconnected from the power grid,and the AC power supply supports the line voltage and frequency.The simulated results show good agreement with the commercial simulation software.The improvement of computing efficiency mainly benefits from two aspects.The single-step computational cost of the adaptive integration method is lower than that of the commonly used explicit Runge-Kutta method under the same order.The DSED method considers events and uses an event-driven strategy to conduct numerical integration of continuous state variables between event points,reducing the number of calculation points.The following conclusions can be drawn from the simulation analysis:(1)When adopting the ideal switched model,power electronic systems contain discrete switch events and continuous state events.The DSED method adopts a flexible,adaptive Taylor series-based integration method to adapt to this hybrid nature and achieve high simulation efficiency.(2)The proposed state-variable-interfaced decoupling strategy makes the DSED method efficiently solve the microgrid with electrically excited synchronous machines.(3)The proposed method has the potential to be transferred to solve systems containing other motors,such as induction motors.
作者
许涵
赵争鸣
施博辰
鞠佳禾
虞竹珺
Xu Han;Zhao Zhengming;Shi Bochen;Ju Jiahe;Yu Zhujun(State Key Laboratory of Control and Simulation of Power Systems and Generation Equipments Department of Electrical Engineering Tsinghua University,Beijing 100084 China)
出处
《电工技术学报》
EI
CSCD
北大核心
2023年第10期2602-2612,共11页
Transactions of China Electrotechnical Society
基金
“台达电力电子科教发展计划”资助项目。
关键词
离散状态事件驱动
电励磁同步电机
电力电子系统仿真
微电网
Discrete state event-driven approach
electrically excited synchronous machine
power electronic system simulation
microgrid
作者简介
通信作者:许涵,男,1999年生,硕士研究生,研究方向电力电子系统建模仿真。E-mail:xuhan21@mails.tsinghua.edu.cn;赵争鸣,男,1959年生,教授,博士生导师,研究方向为大容量电力电子变换器、太阳能光伏发电系统。E-mail:zhaozm@mail.tsinghua.edu.cn。
