The stator flux and electromagnetic torque observation is the basis of direct torque controlled permanent magnet synchronous motor( PMSM) drive system. However,the traditional stator flux observer based on voltage mod...The stator flux and electromagnetic torque observation is the basis of direct torque controlled permanent magnet synchronous motor( PMSM) drive system. However,the traditional stator flux observer based on voltage model is affected by integral initial values and integral drift,that based on current model is affected by the parameters of PMSM,so a new stator flux observation method is proposed based on an improved secondorder generalized integrator( SOGI). Compared to the stator flux observation method based on the conventional SOGI,the proposed method can not only overcome the influence of integral initial values and integral drift,but also completely eliminate the DC offset's influence. Therefore,the observation accuracy of stator flux is further improved. The simulation and experimental results both show that the proposed method has a higher stator flux and electromagnetic torque observation precision.展开更多
An observing method for stator flux and rotor flux is presented. Based on the proposed flux observing method, a novel speed estimator has been designed. At last, the speed estimator combined with the flux observing is...An observing method for stator flux and rotor flux is presented. Based on the proposed flux observing method, a novel speed estimator has been designed. At last, the speed estimator combined with the flux observing is applied in the direct torque control system without speed sensor. The simulation results show that these methods can improve the accuracy of speed observing and the low speed performance of direct torque control system, and strengthen the robustness of system.展开更多
The mathematic model of direct torque control (DTC) was deduced. Two simulating models based on the MATLAB & SIMULINK were established. The emphasis is focused on study of the performance difference of the DTC sys...The mathematic model of direct torque control (DTC) was deduced. Two simulating models based on the MATLAB & SIMULINK were established. The emphasis is focused on study of the performance difference of the DTC system with stator flux hexagon and circle trajectories. The simulation waveforms of flux, torque and current characters with two flux trajectories were given. Experiments were carried out in an AC drive system based on induction motor and two-level inverter. A dual-CPU structure was used and the communication with two CPUs was obtained by a dual-port RAM in this system.展开更多
In this paper,ferrites are applied in a partitioned stator wound field switched flux(PS-WFSF)machine to increase the air-gap flux density,and hence,the average electromagnetic torque and overload capability.Introducin...In this paper,ferrites are applied in a partitioned stator wound field switched flux(PS-WFSF)machine to increase the air-gap flux density,and hence,the average electromagnetic torque and overload capability.Introducing short-circuited ferrites in the inner stator in the PS-WFSF machine can increase the open-circuit phase fundamental back-EMF and average electromagnetic torque at a 60 W copper loss by 2.33%and 3.77%,respectively.Moreover,the proposed PS-WFSF machine with ferrites can exhibit a better overload capability than conventional PS-WFSF machines without ferrites,e.g.,a 7.36%torque increment can be achieved when the copper loss is 120 W.The torque increment mechanism is analyzed and verified using finite element(FE)analysis.Moreover,the demagnetization of the ferrites in the proposed machine under rated on-load and overload conditions is investigated.Both prototypes of the proposed PS-WFSF machine with ferrites and a conventional one without ferrite are built and tested to validate the analytical and FE analyses.展开更多
基金Sponsored by the National Natural Science Foundation of China(Grant No.51377041)
文摘The stator flux and electromagnetic torque observation is the basis of direct torque controlled permanent magnet synchronous motor( PMSM) drive system. However,the traditional stator flux observer based on voltage model is affected by integral initial values and integral drift,that based on current model is affected by the parameters of PMSM,so a new stator flux observation method is proposed based on an improved secondorder generalized integrator( SOGI). Compared to the stator flux observation method based on the conventional SOGI,the proposed method can not only overcome the influence of integral initial values and integral drift,but also completely eliminate the DC offset's influence. Therefore,the observation accuracy of stator flux is further improved. The simulation and experimental results both show that the proposed method has a higher stator flux and electromagnetic torque observation precision.
文摘An observing method for stator flux and rotor flux is presented. Based on the proposed flux observing method, a novel speed estimator has been designed. At last, the speed estimator combined with the flux observing is applied in the direct torque control system without speed sensor. The simulation results show that these methods can improve the accuracy of speed observing and the low speed performance of direct torque control system, and strengthen the robustness of system.
文摘The mathematic model of direct torque control (DTC) was deduced. Two simulating models based on the MATLAB & SIMULINK were established. The emphasis is focused on study of the performance difference of the DTC system with stator flux hexagon and circle trajectories. The simulation waveforms of flux, torque and current characters with two flux trajectories were given. Experiments were carried out in an AC drive system based on induction motor and two-level inverter. A dual-CPU structure was used and the communication with two CPUs was obtained by a dual-port RAM in this system.
文摘In this paper,ferrites are applied in a partitioned stator wound field switched flux(PS-WFSF)machine to increase the air-gap flux density,and hence,the average electromagnetic torque and overload capability.Introducing short-circuited ferrites in the inner stator in the PS-WFSF machine can increase the open-circuit phase fundamental back-EMF and average electromagnetic torque at a 60 W copper loss by 2.33%and 3.77%,respectively.Moreover,the proposed PS-WFSF machine with ferrites can exhibit a better overload capability than conventional PS-WFSF machines without ferrites,e.g.,a 7.36%torque increment can be achieved when the copper loss is 120 W.The torque increment mechanism is analyzed and verified using finite element(FE)analysis.Moreover,the demagnetization of the ferrites in the proposed machine under rated on-load and overload conditions is investigated.Both prototypes of the proposed PS-WFSF machine with ferrites and a conventional one without ferrite are built and tested to validate the analytical and FE analyses.
