| With the wide application of AC speed regulation of asynchronous motor,high performance motor control system has been paid more and more attention.As an important index to improve performance,accurate speed identification has become one of the research hotspots.In order to achieve low cost,strong adaptability and good coaxiality in speed estimation,it is of practical significance to adopt speed sensorless vector control.At present,the speed of motor is estimated with high precision at medium and high speed,and the speed identification technology is quite mature.However,at low speed or even zero speed,the error of speed estimation is large,so it is very important to study the low speed performance,especially to identify the low speedIn the traditional adaptive speed identification algorithm,the flux error is not considered,and the speed following error is large when the speed is low.In order to reduce the error of low speed identification and improve the low speed performance of the system,first of all,the three-level SVPWM algorithm is adopted in the modulation strategy.In addition,flux error and feedback gain matrix G are considered based on the traditional adaptive speed identification algorithm.The estimation error of low speed can be reduced by adding two adaptive coefficients and reasonable adjustment of Mi and M2.And the stability of the system for low speed identification can be improved by properly designing the feedback gain matrix G.Then,the effect of replacing the high precision encoder at low speed can be achieved and the hardware costs can be reducedFinally,the feasibility of the three-level SVPWM modulation algorithm and the improved low speed estimation method of the adaptive flux observer are verified by the Matlab/Simulink simulation experiment and the hardware system with TMS320F2812 DSP as the control chip.And the way for further research on the improvement of low speed performance of asynchronous motors has been paved. |
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