Protective device and protective method for automotive direct current brush motor of current-free sensor

Abstract

The invention relates to a protective device and a protective method for an automotive direct current brush motor of a current-free sensor. Two input ends of a current acquisition circuit of the device are respectively connected with a drain electrode and a source electrode of a field effect tube switch T1 in a motor H-bridge control circuit, the output of the current acquisition circuit is connected with the input of an isolating amplifier circuit, the output of the isolating amplifier circuit is connected with the input of a motor control and protection circuit, and the output of the motor control and protection circuit is connected to a grid electrode of the field effect tube switch T1. The protective device acquires voltages at two ends of the field effect tube to amplify, process and calculate the current to make a motor protecting model, a feedback temperature model calculates field effect tube switch junction temperature and rating data is used for judging the process difference so as to amend current, an AMT system in a short-circuit condition can be protected, the performance and the stability of the AMT can be improved, and the protective device has simple circuits and is fast in speed response and strong in reliability, not only can protect the motor quickly, but also can be prevented from generating harmful and mistaken response in emergency.

Description

technical field [0001] The invention relates to a DC brushed motor protection device and method for a vehicle without a current sensor, and is especially suitable for a control system driven by an AMT transmission motor of a car and a mini-car. Background technique [0002] At present, the safety protection measures of the control system motor mainly include: (1) the hardware circuit has a current sensor to collect the output current of the motor; (2) calculate the output current of the motor according to the output command of the control and the control situation of the target. Both of the above two methods have certain advantages and disadvantages. The first method is more accurate in collecting information, but increases the cost of hardware, increases the difficulty of production technology and increases the risk of failure; the second method is low in cost, but the calculation of current is inaccurate. The current value cannot be calculated accurately in real time. [...

AI Technical Summary

Problems solved by technology

These circuits and methods are for the protection of the motor body, and no protection is proposed for the circuit and wiring harness of the controller.

Images