On-board charger and its pre-charging circuit and electric vehicle

Abstract

The invention discloses an on-board charger, its pre-charging circuit and an electric vehicle, wherein the on-board charger includes a pre-charging capacitor and an AC / DC converter, and the pre-charging circuit includes: a first pre-charging resistor and a second pre-charging resistor Charging resistance, one end of the first pre-charging resistor is connected to one end of the AC power supply, the other end is connected to one end of the pre-charging capacitor, one end of the second pre-charging resistor is connected to the other end of the AC power source, and the other end is connected to the other end of the pre-charging capacitor One end is connected; the first controllable switch and the second controllable switch, one end of the first controllable switch is used to connect one end of the AC power supply, the other end is connected to one end of the pre-charged capacitor, and one end of the second controllable switch is used to connect The other end of the AC power supply is connected to the other end of the pre-charged capacitor; among them, the front and rear ends of the first controllable switch and the second controllable switch form a circuit network to facilitate the port withstand voltage test, so as to ensure The withstand voltage requirements of the on-board charger.

Description

technical field [0001] The invention relates to the technical field of electric vehicles, in particular to a precharging circuit of a vehicle charger, a vehicle charger and an electric vehicle. Background technique [0002] The input terminal of the car charger is connected to the L and N lines of the AC power supply AC, and the AC / DC converter is connected to the power battery to convert the AC power into DC power to charge the power battery. Due to the need for control and protection, such as figure 1 As shown, relays k2 and k3 are generally added on the input side to disconnect ports and internal circuits. Since there is a capacitive load c1 at the back end of the relays k2 and k3, the current of the relays k2 and k3 is too large at the moment of closing, which is easy to impact the on-board charging system and damage the electronic devices. Therefore, it is necessary to increase the pre-charging circuit. [0003] Such as figure 1 As shown, in the related art, the pre-...

AI Technical Summary

Problems solved by technology

However, the commonly used relay contact gap is very small, usually only about 2mm, and cannot withstand the test voltage above 1000VAC, and the relay with a large contact gap will have a large volume and power, and is not suitable for pre-charging circuits.

[0005] As a result, it will lead to the problem that the relay back-end circuit cannot be tested when the on-board charger is performing a withstand voltage test, and it is impossible to detect whether the on-board charger has insufficient withstand voltage.

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