Voltage stabilization control method for three-phase AC power spring

Abstract

The invention relates to a voltage stabilization control method for a three-phase AC power spring, which includes the following steps: S1, designing an outer energy loop based on differential smoothing control: obtaining an expression of smooth output variables from the smooth output variables, state variables and control variables of a three-phase AC power spring, acquiring a differential smoothing control law, and obtaining an outer loop reference value by calculation; S2, designing an inner current loop based on PI control: calculating the difference between the actual value of PI control current and the outer loop reference value, inputting the difference to a PI controller, and outputting a dq modulation signal; and S3, carrying out dq-abc conversion on the dq modulation signal to obtain an SPWM modulation signal, and controlling the working state of the three-phase AC power spring according to the SPWM modulation signal, so as to achieve stable output of key load voltages. Compared with the prior art, the reference trajectory can be tracked quickly to realize global stability, and the method has the advantages of fast dynamic response and strong robustness.

Description

technical field [0001] The invention relates to the field of power system operation and control, in particular to a method for voltage stability control of a three-phase AC power spring. Background technique [0002] The electric spring technology is to directly connect the power electronic converter to the electric load, and automatically generate or consume reactive power according to the actual situation, so as to stabilize the voltage. With the increasing penetration of renewable energy such as solar energy and wind energy The higher the value, the intermittent and unpredictability of the microgrid will cause problems such as power imbalance and voltage fluctuation on the supply and demand side, which will seriously affect the power quality on the user side. At this time, the electric spring can be connected in series with the non-critical load to ensure the stability of the critical load voltage, and at the same time automatically adjust the power consumption of the non...

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Problems solved by technology

[0003] On the user side of the current micro-grid, different loads connected to the user have different voltage requirements. In order to meet the voltage regulation requirements of the entire micro-grid, it is necessary to use three-phase AC power springs to solve the problem of micro-grid voltage stability. The existing The three-phase AC power spring control method is mostly based on the vector control method, using the traditional linear PI controller or PR controller, usually a linear control design around a specific operating point, so it can only ensure local stability near the operating point, and the stability domain is narrow. The robustness is not strong. When the microgrid voltage fluctuates sharply and rapidly or the circuit parameters change, the control performance is difficult to guarantee. In addition, because the three-phase AC power spring itself is a nonlinear system with multiple nonlinear components, traditional PI control or PR control Small-signal disturbance linearization approximation is often used, but the nonlinear component cannot be directly compensated, which is not conducive to the stable output of the key load voltage

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