计及换流器间动态交互的中压直流配电系统控制参数设计

由于各换流器间存在动态交互作用,使得中压直流(MVDC)配电系统的控制参数设计比单台换流器时困难得多。首先,针对系统中换流器的电流控制环、电压控制环和下垂控制环,依次分别建立了计及换流器间动态交互的开环和闭环传递函数,并且所建传递函数零极点的个数与单台换流器独立运行时完全一致。然后,提出了一种计及换流器间动态交互的MVDC配电系统控制参数设计方法,该方法能够从系统动态稳定性的角度定性定量设计控制参数。该设计方法通过部分零极点的相互抵消,利用一对共轭主导极点准确设计系统动态特性,并在较宽频率范围(如10~50 Hz)内均有效。最后,在电力电子仿真软件PLECS中对所提传递函数和控制参数设计方法进行了仿真验证。

Control Parameter Design of Medium-voltage DC Distribution System Considering Dynamic Interaction Between Converters

Due to the dynamic interaction between converters,the design of control parameters of medium-voltage DC(MVDC)distribution systems is much more complicated than that of single converter.First,for the current control loop,the voltage control loop and droop control loop of the converters in the system,the open-loop and closed-loop transfer functions considering the dynamic interaction between the converters are established respectively.In addition,the number of poles(or zeros)of the transfer function considering the dynamic interaction between converters is consistent with the single-converter situation.Then,a control parameter design method for the MVDC distribution system considering the dynamic interaction between converters is proposed.In this design method,the control parameters of all converters are designed qualitatively and quantitatively from the perspective of system dynamic stability.Through the mutual cancellation of some zeros and poles,the dynamic characteristics of the system can be designed by this method with a pair of conjugate poles.Moreover,this design method is effective in a wide oscillation frequency range(for example 10~50 Hz).Finally,the proposed transfer function and control parameter design method are simulated and verified in the power electronics simulation software PLECS.