基于虚拟同步电机技术的VSC-HVDC整流侧建模及参数设计

Modeling and Parameters Design for Rectifier Side of VSC-HVDC Based on Virtual Synchronous Machine Technology

在传统控制方式下,柔性直流输电(voltage source converter based high voltage direct current,VSC-HVDC)系统换流站难以有效参与电网动态调节,而虚拟同步电机技术通过合适的控制设计使得换流器单元能够为系统提供惯性支撑,已引起广泛关注。首先结合VSC-HVDC系统数学模型,分析换流站等效为同步电机的可行性,给出基于虚拟同步电机技术的换流站控制方案。其次,针对整流侧换流站,在动态过程中将逆变侧等效为一个恒功率负载,建立虚拟同步电机内环和电压外环的小信号数学模型,分析并给出一种系统化的控制参数设计方法。最后,通过仿真分析验证文中理论分析的正确性和参数设计方法的有效性。

With the traditional control strategies, voltage source converter based high voltage direct current（VSC-HVDC） system is hard to be involved in the dynamic regulation of the power system effectively. However, the noticeably new technology of virtual synchronous machine（VSM） enables converter units to provide inertial support to power system according to proper control design. Firstly, the mathematical model of a VSC-HVDC system was provided to analyze the equivalent relationship between converter station and synchronous machine, which leads to a new control scheme of VSC-HVDC system based on virtual synchronous machine technology. Secondly, by considering the inverter station as a constant power load, the small signal model of rectifier station was proposed, which consists of the inner VSM loop and outer voltage loop. Based on the proposed model, a systematic design method for control parameters was presented and analyzed. Finally, simulations were performed to verify the feasibility of the theoretical analysis and the effectiveness of the design method for control parameters.