Research On Control Technology For Open Winding PMSM With Z-source Inverter

Open-winding permanent magnet synchronous motor(OW-PMSM)is widely used in electric vehicles,wind power generation and other fields due to its high power density,high efficiency,reliable operation performance and it is suitable for high-voltage and high-power applications.The Z-source inverter has attracted extensive attention and research due to its flexible buck-boost characteristics.Applying the Z-source inverter to the OW-PMSM system can further increase the operating speed of the OW-PMSM under the condition of limited DC bus voltage.Therefore,the control technology for OW-PMSM based on Z-source inverter is studied in this paper:(1)For the OW-PMSM system supplied by the Z-source and voltage source integrated inverters with isolated dc bus,mathematical models are established under the three-phase coordinate system and the synchronous rotation coordinate system.The equivalent d-axis and q-axis circuit models are analyzed.The control strategy based on vector control is adopted,and an experimental platform is built,and the effectiveness of the system and its control strategy is verified experimentally.(2)Z-source inverter is applied to OW-PMSM system with common DC bus in this part.For the OW-PMSM system supplied by the Z-source and voltage source integrated inverters with common dc bus,the mathematical model of the system is established.The zero-sequence voltage loop model and the cause of zero-sequence current are analyzed.The system control strategy and zero-sequence current suppression strategy based on PI-R controller and zero-sequence voltage redistribution are employed.The results show that the zero sequence current suppression strategy can effectively eliminate the DC component and the three harmonic component in the three-phase current.(3)For the OW-PMSM system supplied by the Z-source dual-inverters with common DC bus,the system control strategy and zero-sequence current suppression strategy based on PI-R controller and zero-sequence voltage redistribution are adopted,and a cooperative SVPWM strategy of Z-source dual-inverters is proposed to avoid the influence of the shoot-through state.The effectiveness of the modulation strategy is verified by experiments.The experimental results show that the above three OW-PMSM systems based on Z-source inverter,compared with the traditional OW-PMSM,can effectively improve the speed range of the motor,and achieve good performance.