An overvoltage protection device for a converter of a wind power generating set

Abstract

The invention discloses an overvoltage protection device of a wind driven generator set converter, wherein the overvoltage protection device consists of a precision resistor voltage division circuit, an independent reference source circuit, a voltage hysteresis comparison circuit, a high-low voltage isolating circuit, a failure warning circuit, a DC / DC (direct current / direct current) power supply and an LDO (low dropout regulator) module circuit. Through the precision resistor voltage division circuit, after a high voltage is changed into a low voltage through voltage division, the low voltage and the reference source circuit are compared, if the low voltage is higher than the reference source voltage, a low level is output through the voltage hysteresis comparison circuit, and if the low voltage is lower than the reference source voltage, a high level is output through the voltage hysteresis comparison circuit; and a failure signal is transferred to a main control system of a wind driven generator set through the high-low voltage isolating circuit and the failure warning circuit, and the main control system determines whether a converter bus voltage is overhigh through reading the failure signal.

Description

[0001] Technical field: [0002] The invention relates to an overvoltage protection device for a converter, in particular to an overvoltage protection device for a converter of a wind power generating set above the megawatt level. [0003] Background technique: [0004] At present, wind power generating units can be roughly divided into the following types: direct-drive inverter units and double-fed units. Of the five largest wind turbine manufacturers in China, three of them produce direct drive variable frequency wind turbines. Whether it is a doubly-fed unit or a direct-drive inverter unit, the converter is an important component. [0005] The main function of the converter is to convert the electric energy generated by the wind turbine: AC-DC-AC, so that the frequency of the electric energy finally connected to the national grid meets the requirements of the national grid. At present, the cost of the converter in a single unit can account for about 30% - 40%. Therefore, ...

AI Technical Summary

Problems solved by technology

So easy to burn the inverter

In the case of previous contact, the largest manufacturer of direct drive fans in China once had dozens of converters burnt out due to the protection value being set too high

[0007] The accuracy of the existing converter overvoltage protection device to detect the DC bus voltage is not high enough, and the response speed of the subsequent processing circuit is not fast enough, which may easily cause the converter module to burn out. Therefore, when protecting the converter, it is necessary to consider: The protection voltage value of the current transformer should be accurate, the protection method should be scientific, the response speed should be fast, and the circuit should have strong electrical isolation function, etc.

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