摘要
以往,对单相逆变器的研究都是基于静止坐标系的,其若采用传统PI控制器,则无法实现精准控制;而采用比例谐振调节器控制,则既复杂繁琐又存在很多限制条件。此外,在静止坐标系下,单相逆变器孤网/并网的切换较难实现。基于此,文章借鉴三相逆变系统在旋转坐标系下的控制方法,首先建立单相逆变器在旋转坐标系下的数学模型,然后给出其在dq坐标系下孤网运行、并网预同步和并网运行的控制策略,并通过dq坐标变换将变化的交流量变成恒定不变的直流量。这样,单相逆变器采用PI控制器便可以实现无差控制,而无需设计复杂的控制器,从而大大简化了单相逆变器的各种控制策略。最后,在dq旋转坐标系下对所提控制策略进行仿真及试验验证,结果显示,单相逆变器工作在孤网模式时,可输出50 Hz标准正弦波;当电网满足并网条件时,逆变器输出电压与电网电压可实现相位同步,为并网做准备;当并网运行时,逆变器从V/f控制转为PQ控制。该结果验证了所提方法的可行性和正确性。
Single-phase inverters have been extensively researched in static coordinate systems;however,traditional PI controllers cannot achieve accurate control,and proportional resonant regulators are not only complex to operate but also constrained by various conditions.Additionally,it is also difficult to switch single-phase inverters between island operation and grid-connected operation in stationary coordinate systems.This paper aims to addresses these issues.Drawing on the control methods of three-phase inverters in rotating coordinate systems,a mathematical model was established for single-phase inverters in these systems.Their control strategies were defined respectively for island operation,pre-synchronization operation,and grid-connected operation in dq coordinate systems.Through coordinate transformation,varying AC quantities were converted into constant DC quantities in dq coordinate systems,enabling the use of PI controllers for single-phase inverters to achieve deviation-free control,without the need to design complex controllers.This approach greatly simplifies the implementation of various control strategies for single-phase inverters.These control strategies were verified through both simulations and experiments in dq rotating coordinate systems.The results showed that the single-phase inverter achieved standard sine wave output up to 50 Hz in island operation mode.Under grid conditions suitable for connection,the inverter's output voltage realized phase synchronization with the grid voltage in preparation for grid connection.Furthermore,under grid-connected operation conditions,it transitions from a V/f control strategy to a PQ control strategy.The experimental results have verified the feasibility and correctness of the proposed method.
作者
马龙
苏文胜
蒋超
MA Long;SU Wensheng;JIANG Chao(Jiangsu Special Equipment Safety Supervision and Inspection Research Institute,Nanjing,Jiangsu 210036,China)
出处
《控制与信息技术》
2024年第5期18-24,共7页
CONTROL AND INFORMATION TECHNOLOGY
基金
江苏省特检院科技项目(KJ(Y)2023035)。
关键词
单相逆变器
dq坐标系
控制器
控制策略
single-phase inverter
dq coordinate system
controller
control strategy