Protection circuit of DC motor

Abstract

The invention discloses a protection circuit of a DC motor. The protection circuit comprises a sampling unit, a comparison processing unit and a control unit, wherein the sampling unit is configured to sample a current flowing through the DC motor, acquire a sampled voltage value and output the sampled voltage value to the comparison processing unit; the comparison processing unit is configured tocompare the sampled voltage value and a set reference voltage value, and output a comparison result to the control unit; the control unit is configured to output a first control signal to control theDC motor to turn off when the sampled voltage value is higher than the reference voltage value for a first preset time, and output a second control signal to control the DC motor to reboot when the DC motor is controlled to turn off for a second preset time; and the first preset time is set by means of a first capacitor module, the second preset time is set by means of a second capacitor module,and the first capacitor module and the second capacitor module in the control unit are independent of each other in the control unit and can be adjusted separately without influencing each other.

Description

technical field [0001] The invention relates to the technical field of circuit design, in particular to a protection circuit of a DC motor. Background technique [0002] The greater the power of the DC motor, the smaller the internal resistance of its windings. When the motor is blocked by resistance, the large current flowing through the windings will cause it to heat up violently, and it is easy to burn the motor windings. In order to ensure the safety of the motor when it is stalled and avoid overheating of the motor, it is necessary to design a stall protection circuit. [0003] At present, there are roughly two types of motor stall protection circuits, self-locking and hiccupping. The design of the self-locking protection circuit is simple and convenient. It closes and locks the motor after the rotor is blocked, but the motor cannot be restarted after the protection, which is inconvenient to use. The hiccup protection circuit cuts off the power supply after detecting ...

AI Technical Summary

Problems solved by technology

[0004] The starting time of motors with different powers is different. If the protection delay time of the stall protection circuit is too short, it is easy to cause malfunction during the motor starting process. If the time is too long, it will be difficult to protect; if the hiccup restart time is too short, it will Make the motor restart frequently and cause the winding to overheat. If the time is too long, it will not be able to restart in time after the fault is eliminated.

[0005] Therefore, it is necessary to design a DC motor protection circuit to control the hiccup protection process of the motor to avoid overheating and damage to the motor due to faults such as stalled rotor or short circuit

Images