Novel multi-terminal flexible DC power distribution system coordination control method

Abstract

The invention belongs to the field of power electronic converter control, and particularly relates to a novel multi-terminal flexible DC power distribution system coordination control method. On the basis of analyzing the advantages and disadvantages of traditional double-closed-loop PI control, a novel URC controller is provided, different working modes are set in the controller according to different parameter matrix values, multi-mode smooth switching of a multi-terminal flexible DC power distribution system is realized, the dynamic responsiveness and power fluctuation of a multi-terminal high-voltage DC power grid can be improved, and the stability and robustness of the system are improved.

Description

technical field [0001] The invention belongs to the field of power electronic converter control, and in particular relates to a novel multi-terminal flexible direct current power distribution system coordination control method. Background technique [0002] With the rapid development of social economy, high-reliability power supply and high-proportion clean energy-friendly access put forward higher requirements for power transmission technology of distribution network. The traditional contact switch of the distribution network only has two states of on and off, and problems such as short-circuit current increase, electromagnetic ring network, and circulating power are prone to occur during operation. Therefore, the concept of a multi-port flexible DC power distribution system is proposed. The multi-terminal flexible DC power distribution system is a new type of system based on power electronics technology. It decouples and interconnects the AC system in the form of "AC-DC-AC...

AI Technical Summary

Problems solved by technology

However, the voltage outer loop has nonlinear characteristics. Disturbances such as port power mutations and AC voltage fluctuations will cause voltage fluctuations on the DC side and affect the normal operation of the system.

In order to control the voltage stability, PI control has been used in existing research, but there are many PI controllers in the multi-terminal flexible straight system, the parameter setting is difficult, the control accuracy is not high, and the anti-interference ability is poor

There are also studies based on model prediction to design the inner loop current controller, which improves the dynamic response speed of the system, but does not consider the integral saturation and low voltage stability of the outer loop PI controller, which is not conducive to the safe and stable operation of the system.

Foreign studies have used reverse push control to design the controller, which effectively improved the problem of large voltage fluctuations during the system mode switching process, but it required multiple derivations of the virtual control quantity, which increased the amount of control calculations and increased the complexity of system control.

Images