Five-phase permanent-magnet synchronous motors(PMSMs)offer high fault tolerance,low torque ripple,and high torque density.An open-circuit fault results in an asymmetric motor model,which causes direct current(DC)bias ...Five-phase permanent-magnet synchronous motors(PMSMs)offer high fault tolerance,low torque ripple,and high torque density.An open-circuit fault results in an asymmetric motor model,which causes direct current(DC)bias and harmonics,thus affecting operational performance with sensorless control under fault-tolerant conditions.To improve operational performance,this study proposes a novel sliding mode observer(SMO)based on an enhanced adaptive complex-coefficient filter(EACCF)for the sensorless vector-control strategy of a five-phase PMSM with an open-circuit fault.The novelty of the proposed strategy is the development of the EACCF,which is characterized by an effective DC bias and harmonic-attenuation capability.Additionally,the fundamental back electromotive force can be estimated without phase lag or amplitude attenuation using the SMO.By incorporating a phase-locked loop,the accuracy of position estimation can be improved under both healthy and open-circuit fault conditions.The sensorless control can not only restrain the fluctuating torque caused by open-circuit faults but also offers good steady-state and dynamic performances under healthy and open-circuit fault conditions.Experimental results are presented to demonstrate the feasibility of the proposed method.展开更多
Current quality is one of the most important issues for operating three-phase grid-connected inverter in distributed generation systems. In practice, the grid current quality is degraded in case of non-ideal utility v...Current quality is one of the most important issues for operating three-phase grid-connected inverter in distributed generation systems. In practice, the grid current quality is degraded in case of non-ideal utility voltage. A new control strategy is proposed for the three-phase gridconnected inverter. Different from the traditional method,our proposal utilizes the unique abc-frame complex-coefficient filter and controller to achieve the balanced, sinusoidal grid current. The main feature of the proposed method is simple and easy to implement without any frame transformation. The theoretical analysis and experimental test are presented. The experimental results verify the effectiveness of the proposed control strategy.展开更多
A generalized ionospheric dispersion simulation method is presented to verify and test wideband satellite-ground-link radio systems for dispersion robustness. In the method, ionospheric dispersive effects on wideband ...A generalized ionospheric dispersion simulation method is presented to verify and test wideband satellite-ground-link radio systems for dispersion robustness. In the method, ionospheric dispersive effects on wideband radio waves are modeled as an allpass nonlinear phase system, thus greatly decreasing the need for signal priori information. To accurately simulate the ionospheric dis- persion and reduce the implementation complexity, the system is decomposed into three new allpass subsystems： with a linear phase passing through zero frequency, a constant phase, and a nonlinear phase with zero-offset and quasi-parabolic form respectively. The three subsystems are implemented respectively by the combination of integer-interval delay and fractional delay filter, digital shifting phase and the complex-coefficient finite impulse response （ FIR ） filter. The ionospheric dispersion simulation can be achieved by cascading the three subsystems in a complex baseband and converting the frequency to a radio frequency. Simulation results show that the method has the ability to accu- rately simulate the ionospheric dispersion characteristics without knowing the signal priori informa- tion and has a low implementation complexity.展开更多
基金Supported by the National Natural Science Foundation of China(52277052).
文摘Five-phase permanent-magnet synchronous motors(PMSMs)offer high fault tolerance,low torque ripple,and high torque density.An open-circuit fault results in an asymmetric motor model,which causes direct current(DC)bias and harmonics,thus affecting operational performance with sensorless control under fault-tolerant conditions.To improve operational performance,this study proposes a novel sliding mode observer(SMO)based on an enhanced adaptive complex-coefficient filter(EACCF)for the sensorless vector-control strategy of a five-phase PMSM with an open-circuit fault.The novelty of the proposed strategy is the development of the EACCF,which is characterized by an effective DC bias and harmonic-attenuation capability.Additionally,the fundamental back electromotive force can be estimated without phase lag or amplitude attenuation using the SMO.By incorporating a phase-locked loop,the accuracy of position estimation can be improved under both healthy and open-circuit fault conditions.The sensorless control can not only restrain the fluctuating torque caused by open-circuit faults but also offers good steady-state and dynamic performances under healthy and open-circuit fault conditions.Experimental results are presented to demonstrate the feasibility of the proposed method.
基金supported by the National Natural Science Foundation of China(No.51307149)
文摘Current quality is one of the most important issues for operating three-phase grid-connected inverter in distributed generation systems. In practice, the grid current quality is degraded in case of non-ideal utility voltage. A new control strategy is proposed for the three-phase gridconnected inverter. Different from the traditional method,our proposal utilizes the unique abc-frame complex-coefficient filter and controller to achieve the balanced, sinusoidal grid current. The main feature of the proposed method is simple and easy to implement without any frame transformation. The theoretical analysis and experimental test are presented. The experimental results verify the effectiveness of the proposed control strategy.
基金Supported by the Foundation of Shanghai Aerospace Science and Technology(20120541088)China Postdoctoral Science Foundation(2015M580997)
文摘A generalized ionospheric dispersion simulation method is presented to verify and test wideband satellite-ground-link radio systems for dispersion robustness. In the method, ionospheric dispersive effects on wideband radio waves are modeled as an allpass nonlinear phase system, thus greatly decreasing the need for signal priori information. To accurately simulate the ionospheric dis- persion and reduce the implementation complexity, the system is decomposed into three new allpass subsystems： with a linear phase passing through zero frequency, a constant phase, and a nonlinear phase with zero-offset and quasi-parabolic form respectively. The three subsystems are implemented respectively by the combination of integer-interval delay and fractional delay filter, digital shifting phase and the complex-coefficient finite impulse response （ FIR ） filter. The ionospheric dispersion simulation can be achieved by cascading the three subsystems in a complex baseband and converting the frequency to a radio frequency. Simulation results show that the method has the ability to accu- rately simulate the ionospheric dispersion characteristics without knowing the signal priori informa- tion and has a low implementation complexity.
