Overvoltage protection method and device for trolley bus

Abstract

The invention relates to a non-track electric vehicle over-potential protecting method and relative device, which arranges a composite electric vehicle over-potential protector in present protecting circuit, that uses a protective lock and a chopper control to protect, and uses brake chopper, hardware controlled chopper and protective lock to realize three-stage over-potential protection. The first stage is brake chopper protection, the second stage is hardware controlled chopper protection and the third stage is protective lock protection. The electric vehicle over-potential protective main circuit is connected with a chopper tube controlled by an inverter control system in the main circuit, while the cathode of the chopper tube is serially connected with a brake resistance, and the inverter control system and the anode of chopper tube are serially connected with a protective lock control system serially connected on the anode circuit between a potential sensitive resistance and a capacitor.

Description

technical field [0001] The present invention is a circuit control method and device, specifically an overvoltage protection method and device, especially a trolleybus overvoltage protection method and device. technical background [0002] The trolley bus is used as a city bus, and its biggest advantages are no exhaust and low noise pollution, but in stormy weather conditions, the overhead wires of the trolley bus will be overvoltage, in this case, the electronic device of the trolley bus must be Can be protected from being affected, otherwise the electronic device of the trolley bus will be severely damaged and the vehicle will not be able to operate normally. Existing overvoltage protection technology usually adopts the method of adding varistor and line reactor at the front end to suppress overvoltage. There are certain defects and deficiencies in this method, mainly in the following two points: (1) The voltage action value of the varistor has a certain dispersion, and it...

AI Technical Summary

Problems solved by technology

There are certain defects and deficiencies in this method, mainly in the following two points: (1) There is a certain dispersion in the voltage action value of the varistor, and its parameter selection should not be too low, and it is often higher than the supporting capacitance of the drive converter The nominal voltage of

If the overvoltage does not reach the action value of the varistor but lasts long enough, it may still exceed the voltage that the supporting capacitor of the converter can withstand after passing through the line reactor, causing capacitor breakdown, resulting in major faults and damage

(2) The varistor has a certain capacity limit. If the overvoltage energy is large enough, the varistor may be burned and opened. This is because the varistor loses its ability to absorb overvoltage, resulting in overvoltage of subsequent components. to press

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