Double-differentiation channel PID control algorithm for pumping energy storage machine unit speed regulating device

Abstract

The invention relates to a PID control algorithm for double differential passages for a speed regulator of a water pumping and energy storing unit. The PID control algorithm comprises two differential passages with same structures. The sampling period of a first differential passage is comparatively short, while the sampling period of a second differential passage is comparatively long. The algorithm treats a quick change part and a slow change part of frequency separately, namely, adopting the first differential passage at the quick change part and adopting the second differential passage at the slow change part, so that a differential link functions within a wider regulating range all the time, and the rotating speed of the unit can have less fluctuation nearby a network frequency value. The PID control algorithm for the double differential passages effectively solves the problem that the prior PID control algorithm has larger differential dead area after discretization and the problem of effectively regulating narrow bandwidth, improves stability of the water pumping and energy storing unit during idle running at low water head, reduces influence of S-shaped characteristics to stable running of the water pumping and energy storing unit, and improves high-frequency interference inhibiting capability of the speed regulator of the water pumping and energy storing unit at the same time.

Description

technical field [0001] The invention relates to a dual differential channel PID control algorithm for the governor of a pumped-storage unit, which optimizes the control process of the governor of the pumped-storage unit. Background technique [0002] The full characteristic curve of the pump turbine ( figure 1 ) in the elliptical area, there are three different flow rates on an equal opening line, corresponding to the working condition of the turbine, the working condition of the turbine and the working condition of the reverse pump respectively. This area constitutes the “S” shape characteristic area of ​​the pump turbine. The pump-turbine operates erratically in this area. The unit speed of the pump turbine is: n N =nD / H 1 / 2 , where n is the rotational speed, D is the nominal diameter of the turbine, and H is the head. When starting operation under low water head, the unit speed of the unit is relatively large at no-load, and the unit is easily affected by the "S" shap...

AI Technical Summary

Problems solved by technology

However, the differential action is very sensitive to interference, which reduces the ability of the system to suppress interference; and in the digital PID control algorithm, the differential can be replaced by the differential, that is can be discretized as e(k) is the input deviation. Since the sampling period is very short, when the deviation changes slowly, e(k) and e(k-1) are almost equal in value, so [e(k)-e(k- 1)] is basically 0, which causes the differential action in the PID control algorithm to have a large differential dead zone after discretization, and the actual adjustment range of the differential action is small, which affects the adjustment effect

Therefore, the traditional parallel PID adjustment algorithm cannot solve the influence of the "S" shape characteristic on the stable operation of the pumped storage unit.

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