Motor position sensorless control method and device

Abstract

The invention discloses a motor position sensorless control method and device. The method includes: step 1: setting the initial motor phase current peak value; step 2: scanning to obtain the orthogonal axis within the preset current angle range under the phase current peak value Current; determine the orthogonal axis current that satisfies the constraint relationship between the direct axis inductance and the quadrature axis inductance, and use the orthogonal axis current corresponding to the maximum torque as the fitting point; Step 3: If the peak value of the phase current does not reach the phase current limit value, then increase the current step value at the peak value of the phase current as the new peak value of the phase current, repeat step 2; if reached, go to the next step; step 4: obtain the maximum torque-current ratio curve by fitting points, and Applied to motor control. Using the above scheme, in the case of no position sensor, considering the high-frequency change of the inductance, establish and apply a new maximum torque-current ratio curve to ensure the convergence of the motor closed-loop control, and the system is still closed-loop stable even in the case of high output torque.

Description

technical field [0001] The invention relates to the field of motor control, in particular to a method and device for controlling a motor without a position sensor. Background technique [0002] When the electric vehicle encounters the position sensor failure, it will use the position sensorless control technology scheme to continue to control the motor operation. In the zero-speed and low-speed operation stages of the motor, the pulse-vibration high-frequency voltage injection scheme can track the rotor position very well. [0003] In the pulse vibration high-frequency voltage injection scheme adopted in the prior art, the inductances used in the equations used to describe the motor model are all constants, so there is only a current differential term in the equation, and the inductance differential term is not considered (the high-frequency variation of the inductance is not considered. ), the real characteristics of the inductance under high frequency current cannot be ex...

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Problems solved by technology

[0003] In the pulse vibration high-frequency voltage injection scheme adopted in the prior art, the inductance used in the equations used to describe the motor model are all constants, so only the current differential term is used in the equation, and the inductance differential term is not considered (the high-frequency change of the inductance is not considered ), it is impossible to express the true characteristics of the inductance under high-frequency current, but due to the influence of the inductance saturation effect, the high-frequency change of the inductance value of the motor under high-frequency current cannot be ignored. If the maximum torque-current ratio curve obtained from this is used (MTPA, Maximum Torque Per Ampere) load, causing the motor to control divergence under high torque

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