Motor target prediction torque obtaining method and motor control system

Abstract

The invention discloses a motor target prediction torque obtaining method. The method comprises calibrating an A / B corresponding relation table and a motor efficiency table; calculating according to the motor predicted voltage uppred and the motor predicted current ipred to obtain motor predicted power Ppred, and checking a motor efficiency table according to the motor predicted power Ppred and the motor rotating speed n to obtain motor predicted efficiency eta pred; obtaining a motor table prediction torque Tqpred, map according to the motor prediction power Ppred, the motor rotation speed n and the motor prediction efficiency eta pred; calculating to obtain A according to the motor predicted current ipred and the motor actual current iact; checking an A / B corresponding relation table according to A to obtain B; and according to the predicted torque Tqpred, map of the motor table and the actual torque Tqact, A and B of the motor, obtaining the target predicted torque Tqpred of the motor, nammely Tqpred = Tqpred, map * B + A * Tqact * (1-B). The invention further discloses a motor control system. The precision of the target prediction torque Tqpred of the motor is improved, meanwhile, the calculation amount is reduced, the calculation space of the controller is saved, and it is avoided that the service life of the battery is shortened due to over-current of the battery.

Description

technical field [0001] The invention relates to new energy vehicle technology, in particular to a method for obtaining a motor target predicted torque and a motor control system. Background technique [0002] The 48V micro-hybrid system, as a more realistic and feasible energy-saving and emission-reduction method, has been highly praised by car companies and parts manufacturers in the past two years. [0003] According to the position of the motor in the power vehicle system, the 48V micro-hybrid system can be divided into P0, P1, P2, P2.5, P3, P4, EV and other configurations. [0004] The 48V P0 system belongs to the basic scheme of the 48V system, which is simple to implement and low in cost. The system mainly reduces fuel consumption through idling start-stop and braking energy recovery. The power improvement is achieved through the 48V motor assist. The realized functions are mainly as follows: [0005] (1) Idling start-stop function --- The stop condition is met, an...

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Problems solved by technology

The accuracy of this scheme to calculate the predicted torque of the motor is limited due to errors in linear interpolation

[0013] (2) In actual work, the motor supplier may not be able to provide an accurate efficiency table considering different factors, and the accuracy of the motor's predicted torque will be greatly reduced under the premise of inaccurate efficiency calculations

Even if the accuracy of the motor efficiency meter can be guaranteed, it is only the result of static measurement on the bench, and the motor working mode and working environment in the 48V system are constantly changing, and there are certain errors in the sensor signal, and these errors add up. It will have a considerable impact on the final torque prediction value calculation results

Although the predicted torque has been adjusted through closed-loop control, the phenomenon of battery overcurrent in a short period of time is still unavoidable, and the cumulative effect over a period of time will affect battery life.

[0014] (3) The method of interpolation after looking up the table is more complicated, such as 4 different temperatures, 4 different voltages, and the motor is working in two modes of power generation and driving, then there are 4*4*2=32 efficiency tables, which not only takes up a lot ECU resources also increase the difficulty of calibration

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