Research On Speed Sensor-less Vector Control Of Asynchronous Motor Based On Model-based Design

As one of the key components of the electric vehicle drive system,the motor and controller are one of the current research cores in this field.High-performance asynchronous motor control technology needs to provide a motor speed signal,but the installation of a speed sensor,such as an encoder,can not only increase the cost but also reduce the reliability.The control code of asynchronous motor DSP mostly uses the manual handwriting method,after successful simulate of the algorithm model,manually configure register operations.In the case where the size of the control code is increasing,this method is not only inefficient,but also poor portability,and errors are inevitable.These two problems will restrict the rapidly development of the electric vehicle industry.In view of the above issues,this paper will study the speed sensor-less technology and automatic code generation technology based on model-based design.Based on the equations of the asynchronous motor obtained from the coordinate transformation in the synchronous rotating coordinate system,the vector control algorithm based on rotor field orientation is studied.Based on this,the parameters of PI regulator are designed.And because the modulation algorithm of the triangle connected asynchronous motor used here is different from the traditional star connected asynchronous motor,the SVPWM technology of triangle connected asynchronous motor is deduced in detail,and its dead-zone effect is analyzed and a new dead zone compensation strategy is proposed.In this strategy,the dead zone is eliminated in the non-zero-crossing area of the line current using single-arm drive method.In the line current zero-crossing area,the normal drive method is used.The dead-zone compensation is performed according to pulse equivalent time compensation method.Based on the analysis of the current flux and speed estimation of speed sensor-less technology,the full-order state observer algorithm based on the stator current error is introduced in detail.In terms of the feedback gain matrix for this algorithm contains the rotational speed and the expression is complex,when it is actually used,it needs a large number of calculations and it is difficult to achieve.This paper proposes a simplified algorithm to convert the gain matrix into a constant to reduce the amount of calculation.A simulation model was built on the MATLAB/Simulink platform.Simulation results show that the simplified algorithm has good performance such as fast response and good tracking ability,and can fully meet the system control requirements.And experiment is conducted on the motor control platform.The experimental results show that the simplified algorithm is correct.This paper uses a method of model-based design,a code model of the vector control of the asynchronous motor is established on the MATLAB/Simulink platform based on the hardware system of the motor controller and the simulation model.Design Verifier and Model Advisor tools are used to perform multiple test verifications on the code model,ensure that the code model complied with the safety standards of the automotive industry,such as ISO 26262 and MISRA C:2012.Finally,the product-level motor controller embedded code is generated directly from the code model and verified on the motor control experiment platform.The experimental results show that the correctness of the established code model and code generated based on the model-based design fully meets the needs of the electric vehicle motor control system.