Motor abnormity protection circuit

Abstract

The invention discloses a motor abnormality protection circuit, and belongs to the field of emergency protection circuits. The circuit comprises a drive axle module, a drive output module, a function control module and a voltage monitoring module, the drive axle module comprises a discharge control unit which is set to receive a discharge voltage and enable a motor winding to be grounded, and the drive output module is connected with the drive axle module and is set to input the discharge voltage to the drive axle module. The function control module is connected with the drive output module and is set to limit the drive output module to input the discharge voltage to the drive axle module, and the voltage monitoring module is used for monitoring the voltage of a bus and is separately connected with the drive output module and the function control module. By adding the voltage monitoring module, the bus voltage can be detected by using circuit hardware when the control system fails, and the generated current is actively guided and discharged to the ground by using a method of performing active discharging by driving the output module, so that the abnormal rise of the bus voltage is prevented.

Description

technical field [0001] The invention belongs to the field of emergency protection circuits, in particular to a motor abnormality protection circuit. Background technique [0002] With the maturity of electronic power assist system technology, taking into account factors such as cost, space, weight, and performance, not only electric vehicles, but also more and more fuel vehicles use braking systems integrated with electronic power assist functions. The core of the electronic booster part in the braking system is a three-phase brushless motor. By controlling the rotation of the brushless motor and cooperating with the opening and closing of the solenoid valve, the brake fluid is delivered from the master cylinder to the wheel cylinder to provide the required power to the wheel cylinder. brake pressure. [0003] During the braking process, the motor pushes the piston to compress the brake fluid, and the pressure of the brake fluid increases continuously, which exerts a revers...

AI Technical Summary

Problems solved by technology

However, if abnormal working conditions such as power failure of the braking system occur, the software control function of the control system of the braking system will also fail due to power failure, and the high-pressure brake fluid will push the motor to reverse rapidly. So it becomes a generator, high-speed reverse power generation, the current will charge the capacitor in the motor bus power network through the body diode of the upper arm of the drive bridge, because of the single-phase conductivity of the body diode, the bus voltage will continue to rise after charging, over High voltage can damage electronic components and even burn the motor

[0004] The traditional solution is as figure 2 As shown, components such as high-power electronic voltage regulator tubes are used as passive energy absorbing devices to suppress the high voltage generated by motor reversal. When the bus voltage is too high, the voltage regulator components break down and conduct and discharge energy. However, this scheme has the following A few questions: A. High-power passive components are large in size and high in price, which has a great negative impact on system volume and cost

[0006] C. High-power passive components are affected by current impact loss, their own life, and differences in process consistency. There is a risk of random failure and fatigue failure, resulting in a decrease in protection effect or even a complete loss, especially when the battery is not firmly connected and the contact is poor. When, multiple strong current discharges will accelerate the aging and failure of components

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