A low-voltage DC bus bridge arm short-circuit fault protection circuit

Abstract

The invention discloses a low-voltage direct-current bus bridge arm short-circuit fault protection circuit. The low-voltage direct-current bus bridge arm short-circuit fault protection circuit comprises a bus current detection and over-current fault judgment unit, a protection and release delay control unit and an over-current protection unit. In the bus current detection and over-current fault judgment unit, a bus current detection resistor is connected to an incoming line at the positive end of a bus in series; a current is converted into voltage drop signals at the two ends of the resistor;through a voltage division and filter circuit, voltages, relative to signal ground, at the two ends of the bus current detection circuit are converted into non-inverting and inverting input voltagesof a comparison circuit; an over-current judgment level signal is output by a hysteresis comparison circuit; the over-current judgment level signal is sent to the protection and release delay controlunit, and an over-current protection level signal is generated; and the over-current protection level signal is sent to a driving stage of a switching tube of a bridge arm, and the driving pulse levelof the switching tube can be blocked when a bus over-current fault occurs, so that the over-current protection effect is achieved. A simple and reliable discrete component is adopted for collecting acurrent signal at the positive input end of the low-voltage direct-current bus; and through reasonable protection and release delay control, the problem of damage failure of the switching tube of thebridge arm of a low-voltage drive circuit due to short circuit or over-current faults can be effectively solved.

Description

technical field [0001] The invention relates to a bus short-circuit fault protection circuit, which belongs to the field of low-voltage servo control and is suitable for servo drive controllers such as spacecraft actuators that need to work for a long time in harsh environments such as irradiation. Background technique [0002] In the existing motor power drive circuit, one of the following three methods is mainly used to realize short-circuit or over-current fault protection: [0003] (1) Power devices such as MOSFETs use a dedicated integrated drive and protection module. The short-circuit or over-current fault protection circuit used in the module generally detects when the switching device is in the on state, its collector-emitter (or: drain- Source) to indirectly obtain the amplitude information of the current flowing through the device, and judge whether the device is in a normal working state, or has been in a short circuit or overcurrent fault state based on the volt...

AI Technical Summary

Problems solved by technology

However, compared with discrete devices such as resistors, capacitors, and diodes, current Hall sensors have no advantages in terms of cost, reliability, temperature, irradiation, and mechanical condition adaptability in applications in harsh environments such as space environments.

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