Position Sensorless Control Strategy Of Five-phase Pmsm Based On High Frequency Injection Method

Compared with three-phase motor,Five-Phase Permanent Magnet Synchronous Motor(Five-Phase PMSM)has the advantages of small torque ripple,high power density and strong fault-tolerant control performance.It is widely used in aerospace,electric vehicle,track traction,ship propulsion and so on.In this paper,the rotor position identification technology at low speed range is studied so as to further improve the reliability of Five-Phase motor drive system.First of all,taking the third harmonic air gap magnetic flux density into account,by maintaining the fundamental and the third harmonic stator magnetic flux circular rotation,Clarke and Park matrix can be applied to Five-Phase motor,and further realize the decoupling of Five-Phase motor model in the synchronous rotating coordinate system.The simulation model of Five-Phase motor is considered,and the correctness and validity of Five-Phase motor vector control are verified by simulation.Secondly,the topology and mathematical model of Five-Phase half-bridge inverter are studied,and the adjacent four-vector SVPWM modulation strategy for the Five-Phase motor drive system is deduced.The method of determining the sector of the space voltage vector,the calculation of the time and the equivalent of the switching action time are analyzed and calculated theoretically.The correctness and validity of the adjacent four-vector SVPWM modulation strategy used in this paper are verified by simulation.Then,in order to realize the rotor position identif ication at low speed,a high-frequency mathematical model of Five-Phase PMSM in rotating coordinate system is established.Considering the complexity of Five-Phase motor drive system and the weakly polarized characteristics of Five-Phase motor studied,combined with the specificity of the fundamental and harmonic subspace of Five-Phase motor,this paper proposes Five-Phase motor rotor position identification.After comparing the simulation,this paper chooses the fundamental wave high frequency pulse current injection method,and uses the proportional resonance regulator to realize the accurate tracking of the high frequency current signal to reduce the low frequency filter in the analog conditioning circuit to the high frequency current.And the demodulation and observation of the rotor position are proposed to improve the control performance of rotor position identification technology of weakly polarized polar motor.Finally,the hardware structure and control algorithm of the drive system are introduced.The correctness and validity of the Five-Phase motor vector control,the adjacent four-vector SVPWM modulation strategy and the rotor position identification and related control technology suitable for operation in low speed region are experimented.