Modified Cascaded Boundary-Deadbeat Control for a Virtually-Grounded Three-Phase Grid-Connected Inverter With LCL Filter
Modified Cascaded Boundary-Deadbeat Control for a Virtually-Grounded Three-Phase Grid-Connected Inverter With LCL Filter
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DOI：
10.1109/tpel.2016.2637078
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发表时间：
2017-10
影响因子：
6.7
通讯作者：
Yuanbin He;H. Chung;C. N. Ho;Weimin Wu
中科院分区：
文献类型：
--
作者：
Yuanbin He;H. Chung;C. N. Ho;Weimin Wu
级联边界无差拍控制器是一种有效的单相LCL输出滤波器并网逆变器控制方法。这种结构减轻了滤波器共振，并在硬电网和弱电网条件下提供了良好的稳定性。然而，它的优点是需要许多传感器，专用的控制回路来调节工作频率，以及高精度的电路变量周期内信息来指示开关的状态。针对一种带LCL滤波器的虚拟接地三相并网逆变器，提出了一种改进的减少电流传感器数量、利用电流带调节工作频率的级联边界无差拍控制律，以及滤波电容电压的周期内信息恢复机制。它继承了使逆变器具有快速动态响应和减轻滤波器谐振的优点。恢复滤波电容电压的污染周期内信息，从而准确地估计和预测状态轨迹。在此基础上，提出了一种减少电压传感器数量的直流母线电压前馈注入方案。它利用栅极信号的占空比信息来补偿直流母线电容电压不平衡对调制饱和和电流畸变的影响。研究参数变化下的系统特性。已经建造了一个3千瓦的原型，并在硬网和弱网条件下进行了评估。
Cascaded boundary-deadbeat controller has been proven to be effective in controlling single-phase grid-connected inverter with LCL output filter. Such architecture mitigates filter resonance and offers good stability under stiff- and weak-grid conditions. However, its merits are offset by requiring many sensors, dedicated control loop to regulate the operating frequency, and high-precision intracycle information of the circuit variables to dictate the states of the switches. A modified cascaded boundary-deadbeat control law with reduced number of current sensors, the use of current band to regulate the operating frequency, and intracycle information recovery mechanism of the filter capacitor voltage for a virtually-grounded three-phase grid-connected inverter with LCL filter is presented. It inherits the merits of allowing the inverter to exhibit fast dynamic response and mitigating filter resonance. The contaminated intracycle information of the filter capacitor voltage is recovered so as to estimate and predict state trajectories accurately. Furthermore, a dc bus voltage feedforward injection scheme with reduced number of voltage sensor is proposed. It utilizes the duty cycle information of the gate signals to compensate the effect of the unbalanced dc bus capacitor voltages on causing modulation saturation and current distortion. The system characteristics under parametric variations will be studied. A 3-kW prototype has been built and evaluated under stiff- and weak-grid conditions.