Abnormal working condition control method for super capacitor of variable pitch system

Abstract

The invention discloses an abnormal working condition control method for a super capacitor of a variable pitch system, and belongs to the technical field of wind power generation. The method comprises the following steps: 301, detecting the voltage of the super capacitor by a variable pitch driver in the variable pitch system, calculating a variance value, and preliminarily judging whether the voltage of the super capacitor fluctuates or not through the variance value; 302, and enabling the variable pitch driver to detect the minimum value of the voltage of the super-capacitor, and to further determine whether the voltage of the super-capacitor fluctuates or not. In the operation process of a variable pitch system, especially in the pitch collecting process, a charger directly provides electric energy for a variable pitch motor, power consumption of a super capacitor is reduced, the abnormal working condition of the super capacitor is monitored through the current value of the variable pitch motor, and due to the fact that in the normal pitch changing process of blades, fluctuation of the current value of the variable pitch motor is small, and fluctuation of the voltage of the super capacitor is frequent, the current value of the variable-pitch motor can be detected more easily, the control precision is higher, and the reliability degree is higher.

Description

technical field [0001] The invention relates to the technical field of wind power generation, and more specifically, to a method for controlling abnormal working conditions of a supercapacitor of a pitch control system. Background technique [0002] In the pitch system of wind turbines, the role of supercapacitors as backup power is: when the power grid fails (such as power failure or low-voltage ride-through), the pitch system needs a backup power supply to supply power for the operation of retracting the propeller. To prevent major accidents, it is crucial to strictly monitor the performance of the backup power supply. very important and necessary. There are several main reasons for the abnormal voltage value of the supercapacitor: [0003] (1) Shell damage [0004] The aging of supercapacitors is partly due to the physical structure, such as the accumulation of internal pressure due to the accumulation of gas due to water decomposition in the closed case, and in extrem...

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Problems solved by technology

[0004] The aging of supercapacitors is partly due to the physical structure, such as the accumulation of gas due to water decomposition in the closed case, which causes the internal pressure to accumulate, and in extreme cases, the structure of the supercapacitor case is damaged.

This aging can be avoided by improving the material of the container and adding a decompression device. However, the capacity drop and ESR increase rate of the supercapacitor equipped with a pressure valve will increase significantly after the pressure valve is opened, and the leakage current may increase by an order of magnitude. At the same time, the boiling point is low. The electrolyte will also accelerate volatilization at higher temperatures

[0005] (2) Electrode deterioration or loose wiring

However, this situation has a hysteresis, that is, the abnormality is triggered first, or even causes the blade to be stuck before it can be replaced; while the biggest safety threat of the wind turbine is the blade stuck, if the abnormality of the super capacitor is detected, the blade will be temporarily stopped Pitch adjustment also has a greater risk; the reason is that the blades corresponding to the abnormal capacitance may be random; especially at present, the operation time of the fans in most wind farms is close to 10 years, and 10 years is the theoretical life of super capacitors , so if you stop propeller adjustment actively after an abnormality occurs, it is very likely that more than one blade will have a supercapacitor voltage fluctuation. big security risk

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