| In recent years,with the emergence of environmental pollution and energy crisis,human environmental awareness has gradually increased,and energy conservation and emission reduction have become the focus of attention.The countries of the world spare no effort to encourage and develop new energy industries.As an important part of energy conservation and emission reduction,new energy vehicles have an irreplaceable position in dealing with energy crisis and environmental pollution.Research on new energy vehicle driving has also become a recent issue.Hotspots in academic research.Because of its simple structure,high efficiency,high torque and high power density,permanent magnet synchronous motor(PMSM)has received increasing attention and has gradually become the mainstream of new energy vehicle drive motors.The traditional mechanical sensors used to detect the position information of the rotor flux linkage have the defects of complicated installation,low reliability and poor environmental adaptability,which makes the position observation and position sensorless control technology the key to the performance improvement of the electric drive system.In response to the above requirements,the work carried out in this paper mainly includes the following aspects.1)Based on the rotating high-frequency injection method,an improved rotor position demodulation method is proposed.By multiplying the d-axis and q-axis current signals to obtain the rotor position error signal,the synchronous frame high-pass filter(SFF)and the heterodyne are avoided.Complex operations of the difference method.2)Based on the pulsed high frequency injection method,an improved rotor position demodulation algorithm is proposed,which uses the d-axis current signal to demodulate the position information in the q-axis current signal.Compared with the sinusoidal signal,the d-axis current signal contains important information such as stator resistance,system delay,and back electromotive force to compensate for the position estimation deviation and improve the estimation accuracy.3)Analyze the influence of stator resistance,system delay,filter and other factors on the position estimation of the two algorithms,and verify the simulation.4)The delayed signal cancellation(DSC)replaces the conventional low-pass filter(LPF)to eliminate high-frequency noise,which not only avoids signal delay,but also improves demodulation accuracy and enhances dynamic performance.5)Based on dual inverter driven open-winding permanent magnet synchronous motor,a zero-sequence current based position sensorless control solution is proposed.The adjacent four vector modulation enhancement is introduced to control the zero sequence signal,which fits the zero sequence path of the open winding motor.The sensorless control algorithm is used to extract the rotor position from the motor zero sequence signal and achieve the purpose of suppressing the zero sequence current.6)Set up an experimental platform and perform comparative experimental verification of two improved algorithms.Due to the coupling problem of the fundamental motor model,the method of extracting the position based on the three-phase fundamental current signal is inevitably affected by this,and if the position signal is observed based on the third harmonic in the zerosequence signal,it can be better.Avoid coupling effects.At the same time,the advantages of open-loop(OEW)drive topology in terms of voltage utilization,multi-level output characteristics,fault-tolerant characteristics,and multi-source hybrid drive have gradually drawn attention to the new energy vehicle electric drive converter topology.This topology also provides the conditions for position demodulation based on zero sequence current.Therefore,based on the dual-inverter-driven open-winding permanent magnet synchronous motor,a zero-sequence current-based position sensorless control solution is proposed.The design of the open-winding drive system control scheme is completed and verified by experiments. |
PDF Full Text Request