摘要
为满足光伏逆变器并网要求,针对电网电压在对称跌落和不对称跌落情况,分别采用不同的低电压穿越控制策略。当发生对称跌落时,封锁电压外环,电流内环给定指定值;当发生不对称跌落时,采用电压前馈算法有效抑制跌落瞬间的电流冲击;快速的正负序分量提取和精确的电网电压同步信号,保证控制信号提取的实时性;抑制负序电流分量,保持三相电流平衡并动态调节无功电流输出,满足无功支撑要求;有源阻尼控制将保证系统的稳定运行。基于10 k W三电平光伏并网逆变器,进行Matlab/Simulink仿真和现场实验。结果表明,控制策略能有效抑制并网电流的瞬间冲击并具有较高的正弦度,从而保证在电网发生跌落期间的安全穿越。
In order to meet the grid-connected technical specification of photovoltaic （PV） inverter, a control strategy based on three-phase grid-connected voltage symmetrical and unsymmetrical sags for low voltage ride through （LVRT） was proposed. The voltage outer-loop was blocked and the current inner-loop of the specified value was given when three phase symmetrical voltage sag. The grid-connected voltage feed-forward control was adopted to suppress the current impact at the moment of voltage sags. Combining with fast extraction of positive-sequence and negative-sequence components of current and accurate synchronization signal of grid-connected voltage to ensure real-time control of the acquired signal, and take maintaining the balance among three-phase currents by suppressing negative-sequence current component, and adjust reactive current output to meet the reactive power support requirements. Finally, Matlab/simulink simulation and field experiments were completed based on 10 kW grid-connected PV inverter, the results showed that the control strategy can effectively suppress the grid-connected current impact at the moment of voltage sags, and keep a high degree of sinusoidal current, which could be achieving security ride through during voltage sags.
出处
《太阳能学报》
EI
CAS
CSCD
北大核心
2016年第7期1788-1796,共9页
Acta Energiae Solaris Sinica
基金
国家自然科学基金(51205018)
关键词
并网
对称跌落
不对称跌落
低电压穿越
有源阻尼
grid-connected
symmetrical sags
unsymmetrical sags
low voltage ride through （LVRT）
active damping
