Conventional fractional slot concentrated winding three-phase axial flux permanent magnet machines have an abundance of armature reaction magnetic field harmonics which deteriorate the torque performance of the machin...Conventional fractional slot concentrated winding three-phase axial flux permanent magnet machines have an abundance of armature reaction magnetic field harmonics which deteriorate the torque performance of the machine.This paper presents a double-stator dislocated axial flux permanent magnet machine with combined wye-delta winding.A wye-delta(Y-△)winding connection method is designed to eliminate the 6 th ripple torque generated by air gap magnetic field harmonics.Then,the accurate subdomain method is adopted to acquire the no-load and armature magnetic fields of the machine,respectively,and the magnetic field harmonics and torque performance of the designed machine are analyzed.Finally,a 6 k W,4000 r/min,18-slot/16-pole axial flux permanent magnet machine is designed.The finite element simulation results show that the proposed machine can effectively eliminate the 6 th ripple torque and greatly reduce the torque ripple while the average torque is essentially identical to that of the conventional three-phase machines with wye-winding connection.展开更多
Compared with changing the structure of a motor that has been manufactured,changing the type of stator winding is an economical and time-saving method to reduce the vibration and noise.Thus,a concentric single-double-...Compared with changing the structure of a motor that has been manufactured,changing the type of stator winding is an economical and time-saving method to reduce the vibration and noise.Thus,a concentric single-double-layer star-delta(CSDLSD)winding for an induction motor is described in this paper with the aim of reducing the noise of the motor.By planning the turns relationship between the two parts of the winding,the harmonic component of the air-gap magnetic field can be decreased.Besides this,through adjusting the turns ratio in each slot of concentric winding per phase respectively,the waveform of the air-gap magnetic field becomes closer to a sinusoidal type.Three motors equipped with the CSDLSD winding and another two types of stator winding were analyzed.The theoretical analysis and the two-dimensional finite element method(2D-FEM)were combined to study the relationship between the harmonics of the air-gap magnetic field and the stator winding.Finally,a 2D fast Fourier transformation(2D-FFT)method was used to obtain the time-frequency spectrum of the air-gap flux density and electromagnetic excitation force,and compared with a natural vibration wave.The noise distribution was obtained using the harmonic response.The results of the theoretical analysis,2D-FEM,2D-FFT,and harmonic response corroborate each other such that the motor applying CSDLSD winding could reduce both the vibration and noise.展开更多
This study proposes a control algorithm based on synchronous reference frame theory with unit templates instead of a phase locked loop for grid-connected photovoltaic(PV)solar system,comprising solar PV panels,DC-DC c...This study proposes a control algorithm based on synchronous reference frame theory with unit templates instead of a phase locked loop for grid-connected photovoltaic(PV)solar system,comprising solar PV panels,DC-DC converter,controller for maximum power point tracking,resistance capacitance ripple filter,insulated-gate bipolar transistor based controller,interfacing inductor,linear and nonlinear loads.The dynamic performance of the grid connected solar system depends on the effect operation of the control algorithm,comprising two proportional-integral controllers.These controllers estimate the reference solar-grid currents,which in turn generate pulses for the three-leg voltage source converter.The grey wolf optimization algorithm is used to optimize the controller gains of the proportional-integral controllers,resulting in excellent performance compared to that of existing optimization algorithms.The compensation for neutral current is provided by a star-delta transformer(non-isolated),and the proposed solar PV grid system provides zero voltage regulation and eliminates harmonics,in addition to load balancing.Maximum power extraction from the solar panel is achieved using the incremental conductance algorithm for the DC-DC converter supplying solar power to the DC bus capacitor,which in turn supplies this power to the grid with improved dynamics and quality.The solar system along with the control algorithm and controller is modeled using Simulink in Matlab 2019.展开更多
基金supported in part by the National Natural Science Foundation of China Grant No.51877139。
文摘Conventional fractional slot concentrated winding three-phase axial flux permanent magnet machines have an abundance of armature reaction magnetic field harmonics which deteriorate the torque performance of the machine.This paper presents a double-stator dislocated axial flux permanent magnet machine with combined wye-delta winding.A wye-delta(Y-△)winding connection method is designed to eliminate the 6 th ripple torque generated by air gap magnetic field harmonics.Then,the accurate subdomain method is adopted to acquire the no-load and armature magnetic fields of the machine,respectively,and the magnetic field harmonics and torque performance of the designed machine are analyzed.Finally,a 6 k W,4000 r/min,18-slot/16-pole axial flux permanent magnet machine is designed.The finite element simulation results show that the proposed machine can effectively eliminate the 6 th ripple torque and greatly reduce the torque ripple while the average torque is essentially identical to that of the conventional three-phase machines with wye-winding connection.
基金National Natural Science Foundation of China under Grant 51677051.
文摘Compared with changing the structure of a motor that has been manufactured,changing the type of stator winding is an economical and time-saving method to reduce the vibration and noise.Thus,a concentric single-double-layer star-delta(CSDLSD)winding for an induction motor is described in this paper with the aim of reducing the noise of the motor.By planning the turns relationship between the two parts of the winding,the harmonic component of the air-gap magnetic field can be decreased.Besides this,through adjusting the turns ratio in each slot of concentric winding per phase respectively,the waveform of the air-gap magnetic field becomes closer to a sinusoidal type.Three motors equipped with the CSDLSD winding and another two types of stator winding were analyzed.The theoretical analysis and the two-dimensional finite element method(2D-FEM)were combined to study the relationship between the harmonics of the air-gap magnetic field and the stator winding.Finally,a 2D fast Fourier transformation(2D-FFT)method was used to obtain the time-frequency spectrum of the air-gap flux density and electromagnetic excitation force,and compared with a natural vibration wave.The noise distribution was obtained using the harmonic response.The results of the theoretical analysis,2D-FEM,2D-FFT,and harmonic response corroborate each other such that the motor applying CSDLSD winding could reduce both the vibration and noise.
文摘This study proposes a control algorithm based on synchronous reference frame theory with unit templates instead of a phase locked loop for grid-connected photovoltaic(PV)solar system,comprising solar PV panels,DC-DC converter,controller for maximum power point tracking,resistance capacitance ripple filter,insulated-gate bipolar transistor based controller,interfacing inductor,linear and nonlinear loads.The dynamic performance of the grid connected solar system depends on the effect operation of the control algorithm,comprising two proportional-integral controllers.These controllers estimate the reference solar-grid currents,which in turn generate pulses for the three-leg voltage source converter.The grey wolf optimization algorithm is used to optimize the controller gains of the proportional-integral controllers,resulting in excellent performance compared to that of existing optimization algorithms.The compensation for neutral current is provided by a star-delta transformer(non-isolated),and the proposed solar PV grid system provides zero voltage regulation and eliminates harmonics,in addition to load balancing.Maximum power extraction from the solar panel is achieved using the incremental conductance algorithm for the DC-DC converter supplying solar power to the DC bus capacitor,which in turn supplies this power to the grid with improved dynamics and quality.The solar system along with the control algorithm and controller is modeled using Simulink in Matlab 2019.
