Permanent magnet synchronous motor output torque on-line calculating method

Abstract

The invention relates to a permanent magnet synchronous motor output torque on-line calculating method. The method is characterized in that an entire vehicle control unit is configured to send an active short-circuit control instruction to an active short-circuit control unit according to the entire vehicle operation mode; the active short-circuit control unit determines whether the active short-circuit control needs to be implemented according to the active short-circuit control instruction sent by the entire vehicle control unit and the rotational speed signal output by a position and rotation speed processing unit, when the active short-circuit control instruction output by the entire vehicle control unit is 1 and the motor mechanical speed exceeds the turning point speed omega g, in the case of the two conditions are met, the active short-circuit PWM signal is output to an inversion switching circuit, if the conditions are not met, the active short-circuit PWM signal is not output. By measuring the active short-circuit current, the influence of the temperature on the permanent magnet flux linkage can be compensated, and the output torque calculation accuracy of the permanent magnet synchronous motor can be improved.

Description

technical field [0001] The invention relates to an online calculation method for the output torque of a permanent magnet synchronous motor, which belongs to the technical field of motor drive control. Background technique [0002] In general, new energy vehicles are driven by multiple power sources. The power sources include motors and engines. The motors can be driven simultaneously with the engine or independently to complete various vehicle working modes. The motors in the vehicle mostly adopt the torque control mode, but the working environment temperature range of most automotive motors is between -40°C and 150°C. For permanent magnet synchronous motors, within this temperature range, the torque output will decrease with the increase of temperature, resulting in insufficient output power of the whole vehicle. In order to achieve torque safety, one method is to add a torque sensor on the output shaft of the motor to monitor the output torque in real time to ensure syste...

AI Technical Summary

Problems solved by technology

The patent obtains the d-axis and q-axis current commands Id*, Iq* through the torque command T* look-up table, and does not consider the influence of temperature on torque

[0005] In summary, the above torque estimation methods do not consider the influence of permanent magnet temperature, and all depend on the L of the permanent magnet synchronous motor body d , L q and R s and other parameters, and the time-varying characteristics of these parameters limit the accuracy of torque estimation

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