To elucidate the principles of notable torque and flux ripple during the steady state of the conventional direct torque control （DTC） of induction machines, the factors of influence torque variation are examined. A ...To elucidate the principles of notable torque and flux ripple during the steady state of the conventional direct torque control （DTC） of induction machines, the factors of influence torque variation are examined. A new torque ripple minimization algorithm is proposed. The novel method eradicated the torque ripple by imposing the required stator voltage vector in each control cycle. The M and T axial components of the stator voltage are accomplished by measuring the stator flux error and the expected incremental value of the torque at every sampling time. The maximum angle rotation allowed is obtained. Experimental results showed that the proposed method combined with the space vector pulse width modulation （SVPWM） could be implemented in most existing digital drive controllers, offering high performance in both steady and transient states of the induction drives at full speed range. The result of the present work implies that torque fluctuation could be eliminated by imposing proper stator voltage, and the proposed scheme could not only maintain constant switching frequency for the inverter, but also solve the heating problem and current harmonics in traditional induction motor drives.展开更多
In this paper, the feasibility of embedding the direct torque control （DTC） of an induction machine into field programmable gate arrays （FPGA） is investigated. DTC of an induction machine is simulated in a MATLAB/...In this paper, the feasibility of embedding the direct torque control （DTC） of an induction machine into field programmable gate arrays （FPGA） is investigated. DTC of an induction machine is simulated in a MATLAB/Simulink environment using a Xilinx system generator. The resulting design has a flexible and modular structure where the designer can customize the hardware blocks by changing the number of inputs, outputs, and algorithm when it is compared to the designs implemented using classical microcontrollers and digital signal processors. With its flexibility, other control algorithms can easily be programmed and embedded into the FPGA. The above system has been implemented on Xilinx Spartan 3A DSP FPGA controller. Simulation and experimentation have been performed to prove the validity of the proposed methodology.展开更多
Model predictive control(MPC)has attracted widespread attention in both academic and industry communities due to its merits of intuitive concept,quick dynamic response,multi-variable control,ability to handle various ...Model predictive control(MPC)has attracted widespread attention in both academic and industry communities due to its merits of intuitive concept,quick dynamic response,multi-variable control,ability to handle various nonlinear constraints,and so on.It is considered a powerful alternative to field oriented control(FOC)and direct torque control(DTC)in high performance AC motor drives.Compared to FOC,MPC eliminates the use of internal current control loops and modulation block,hence featuring very quick dynamic response.Compared to DTC,MPC uses a cost function rather than a heuristic switching table to select the best voltage vector,producing better steady state performance.In spite of the merits above,MPC also presents some drawbacks such as high computational burden,nontrivial weighting factor tuning,high sampling frequency,variable switching frequency,model/parameter dependence and relatively high steady ripples in torque and stator flux.This paper presents the state of the art of MPC in high performance induction motor(IM)drives,and in particular the progress on solving the drawbacks of conventional MPC.Finally,one of the improved MPC is compared to FOC to validate its superiority.It is shown that the improved MPC has great potential in the future high performance AC motor drives.展开更多
基金supported by the National Natural Science Foundation of China (Grant No.2004EA105003)
文摘To elucidate the principles of notable torque and flux ripple during the steady state of the conventional direct torque control （DTC） of induction machines, the factors of influence torque variation are examined. A new torque ripple minimization algorithm is proposed. The novel method eradicated the torque ripple by imposing the required stator voltage vector in each control cycle. The M and T axial components of the stator voltage are accomplished by measuring the stator flux error and the expected incremental value of the torque at every sampling time. The maximum angle rotation allowed is obtained. Experimental results showed that the proposed method combined with the space vector pulse width modulation （SVPWM） could be implemented in most existing digital drive controllers, offering high performance in both steady and transient states of the induction drives at full speed range. The result of the present work implies that torque fluctuation could be eliminated by imposing proper stator voltage, and the proposed scheme could not only maintain constant switching frequency for the inverter, but also solve the heating problem and current harmonics in traditional induction motor drives.
文摘In this paper, the feasibility of embedding the direct torque control （DTC） of an induction machine into field programmable gate arrays （FPGA） is investigated. DTC of an induction machine is simulated in a MATLAB/Simulink environment using a Xilinx system generator. The resulting design has a flexible and modular structure where the designer can customize the hardware blocks by changing the number of inputs, outputs, and algorithm when it is compared to the designs implemented using classical microcontrollers and digital signal processors. With its flexibility, other control algorithms can easily be programmed and embedded into the FPGA. The above system has been implemented on Xilinx Spartan 3A DSP FPGA controller. Simulation and experimentation have been performed to prove the validity of the proposed methodology.
文摘Model predictive control(MPC)has attracted widespread attention in both academic and industry communities due to its merits of intuitive concept,quick dynamic response,multi-variable control,ability to handle various nonlinear constraints,and so on.It is considered a powerful alternative to field oriented control(FOC)and direct torque control(DTC)in high performance AC motor drives.Compared to FOC,MPC eliminates the use of internal current control loops and modulation block,hence featuring very quick dynamic response.Compared to DTC,MPC uses a cost function rather than a heuristic switching table to select the best voltage vector,producing better steady state performance.In spite of the merits above,MPC also presents some drawbacks such as high computational burden,nontrivial weighting factor tuning,high sampling frequency,variable switching frequency,model/parameter dependence and relatively high steady ripples in torque and stator flux.This paper presents the state of the art of MPC in high performance induction motor(IM)drives,and in particular the progress on solving the drawbacks of conventional MPC.Finally,one of the improved MPC is compared to FOC to validate its superiority.It is shown that the improved MPC has great potential in the future high performance AC motor drives.
