Direct current bus quick discharge circuit of explosion-proof converter

Abstract

The invention relates to a direct current bus quick discharge circuit of an explosion-proof converter. The circuit comprises a control power supply, a controllable switch type device, a power discharge resistor and an RCD (Residual Current Device) resistance-capacitance absorbing loop, wherein the control power supply is connected with the control end of the controllable switch type device; the power discharge resistor is connected in series with a contact switch of the controllable switch type device and then is connected to the positive end and the negative end of a direct current bus pole plate which is required to be discharged and comprises a high capacitance support; and the RCD resistance-capacitance absorbing loop is connected in parallel to two ends of the contact switch of the controllable switch type device. After a system is powered down, on and off of the contact switch of the controllable switch type device are controlled by controlling power-on and power-down of the control end of the controllable switch type device, so that quick discharge of a direct current bus capacitor is realized. The circuit has the advantages that energy stored by the direct current bus capacitor can be quickly reduced to below 0.2mJ in 15 minutes; the system has high working stability, reliability and safety; the maintenance efficiency and the repair efficiency of the system are increased; the volume of the equipment is reduced; and the system cost is reduced.

Description

technical field [0001] The invention relates to the technical field of direct current discharge after the equipment is powered off, and relates to a fast discharge circuit for a direct current bus of an explosion-proof converter. Background technique [0002] After the traditional explosion-proof converter is powered off, the DC bus voltage is discharged by the voltage equalizing resistor or the low-resistance circuit on the auxiliary power supply board. Because the impedance of the discharge circuit is large, the discharge time will be very long, which often affects the equipment. The maintenance time cannot meet the site requirements. Moreover, since the resistor is always connected in parallel to both ends of the DC bus, the resistor is large in size and generates a large amount of heat, which brings inconvenience to the installation and heat dissipation of the system, especially in the underground environment of coal mines. The stored energy drops below 0.2mJ within 15 ...

AI Technical Summary

Problems solved by technology

[0002] After the traditional explosion-proof converter is powered off, the DC bus voltage is discharged by the voltage equalizing resistor or the low-resistance circuit on the auxiliary power supply board. Because the impedance of the discharge circuit is large, the discharge time will be very long, which often affects the equipment. The maintenance time cannot meet the site requirements

Moreover, since the resistor is always connected in parallel to both ends of the DC bus, the resistor is large in size and generates a large amount of heat, which brings inconvenience to the installation and heat dissipation of the system, especially in the underground environment of coal mines. The stored energy drops below 0.2mJ within 15 minutes

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