Urban rail vehicle DC power supply low-voltage protection circuit

Abstract

The invention provides a low-voltage protection circuit of an urban rail vehicle direct-current power source. The anode of a storage battery is connected to one end of a turnoff button through a reverse current protection diode D3, and the other end of the turnoff button is connected to the positive terminal of a turnoff keeping contactor coil. The positive terminal of the turnoff keeping contactor coil is further connected to the cathode of the reverse current protection diode D3, the negative terminal of the turnoff keeping contactor coil is connected to the cathode of the storage battery, one end of a turnoff keeping contactor normally open contact is connected to the anode of the storage battery, and the other end of the turnoff keeping contactor normally open contact is connected to a load through a reverse current protection diode D2. A low-voltage protection relay coil is connected with the turnoff keeping contactor coil in parallel, and a low-voltage protection relay normally open contact is connected between the cathode of the reverse current protection diode D3 and the positive terminal of the turnoff keeping contactor coil and the positive terminal of the low-voltage protection relay coil in series. When the voltage of the storage battery is lower than a set value of a low-voltage protection relay, the turnoff button is pressed, the low-voltage protection relay coil is not powered on, and low-voltage protection is achieved for the storage battery.

Description

technical field [0001] The invention relates to a low-voltage protection circuit for a DC power supply of an urban rail vehicle, belonging to the technical field of urban rail vehicle manufacturing. Background technique [0002] In subway vehicles, the DC110V power supply supplies power to almost all vehicle electrical control devices. Whether the working state of the power supply is safe and stable directly determines whether the subway vehicles can operate normally. The DC110V power supply of the prior art subway vehicles mainly adopts the parallel connection of two power storage groups arranged on the head car and the tail car, and prevents the generation of reverse current by setting a diode at the positive end of the battery group. Although this solution can realize the DC110V power supply for subway vehicles, in some extreme cases, such as long-term high-current discharge of the battery, or long-term storage without use, the battery will be short of power after self-di...

AI Technical Summary

Problems solved by technology

Although this solution can realize the DC110V power supply for subway vehicles, in some extreme cases, such as long-term high-current discharge of the battery, or long-term storage without use, the battery will be short of power after self-discharge, and the power supply lacks low-voltage protection. Serious damage to the battery

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