| Wit h the development of power electronic technology,permanent magnet synchronous motor(PMSM)vector control technology has been more and more widely used in various fields of industry.PMSM positio n sensorless vector control technology can further save the posit ion sensor,reduce the weight and volume of the system,reduce the system cost,improve the system reliabilit y,and make the PMSM have a wider range of applicat ions.The PMSM speed sensorless control system usually uses mult iple current sensors to realize t he current closed-loop control.However,the highprecisio n current sensors is expensive,and t he gain error caused by mismatch of current sensors is unexpected.Therefore,reducing the number of current sensors is of great significance to broaden the applicat ion range of PMSM.This thesis analyzes the speed sensorless vector control system of PMSM based on single resistance sampling.In the applicat ion of PMSM speed sensorless control based on phase current reconstruct ion,if there is a sudden power failure,the controller will lo se control of the motor for a while,and the motor will remain in the running state.If direct ly restart the motor,it will cause a large current impact,it is necessary to obtain the posit ion and ang le of the rotor to ensure that can restart the motor smoothly.This paper first introduces the PMSM mathemat ical model and the basic principle of vector control,and then proposes a speed sensorless control algorithm based on the current model.The deviat ion value between the actual detected current value and the calculated value based on the equivalent motor model is used to correct the estimated speed,then we can obtain an accurate est imated speed,thus realizing the speed sensorless vector control of the PMSM,and the effect iveness of the proposed algorithm is verified by building a simulat ion model.Then the thesis analyzes the relationship between DC bus current and motor phase current,and introduces the basic principle of phase current reconstruct ion.In the actual control system,due to the existence of non-ideal factors,there will inevitably be blind areas of current reconstruct ion.By analyzing the characterist ics of different blind areas,the blind areas are divided into three areas: low modulat ion blind area,medium modulat ion blind area and high modulat ion blind area.The phase current reconstruct io n problem of the low modulat ion blind zone and the middle modulat ion blind zone is solved by insert ing measurement pulses in the zero voltage vector segment,and the voltage vector approximat ion method is adopted in the high modulation blind zone.At this t ime,the reference voltage vector in the high modulation blind zone becomes a fixed point.After that,the paper proposes a pulse conduct ion method of the inverter,which calculates the motor speed and the rotor posit ion at a specific point by analyzing the characterist ics of the bus current,and then realized the PMSM flying start.At the end of this paper,a permanent magnet synchronous motor drive contro l system based on phase current reconstruction is designed,which verifies the validit y and practicabilit y of the above content. |
