Torque Ripple Minimization for Induction Motor Drives with Direct Torque Control

Direct torque control (DTC) schemes can produce quick and robust responses, but they usually behave like hysteresis controllers. Consequently, there are similar problems like non-constant switching frequencies and high torque ripple, especially when operation conditions result in low switching frequencies. In this article, the basic concept of DTC will be improved by modifying the conventional method. Problems that arise when using standard DTC methods are explained and improvements are derived to overcome these problems. Two theoretical approaches are verified and compared with standard DTC by measurements and experiments. The proposed methods provide a constant switching frequency and solve the starting problem without dither signal. Further results are a reduction of torque pulsations, as well as a new method for stator flux estimation.

[1]  J. Holtz,et al.  Sensorless vector control of induction motors at very low speed using a nonlinear inverter model and parameter identification , 2001, Conference Record of the 2001 IEEE Industry Applications Conference. 36th IAS Annual Meeting (Cat. No.01CH37248).

[2]  Hamid A. Toliyat,et al.  A novel direct torque control (DTC) method for five-phase induction machines , 2000, APEC 2000. Fifteenth Annual IEEE Applied Power Electronics Conference and Exposition (Cat. No.00CH37058).

[3]  Dong-Seok Hyun,et al.  Direct Torque Control of induction motor with reduction of torque ripple , 2000, 2000 26th Annual Conference of the IEEE Industrial Electronics Society. IECON 2000. 2000 IEEE International Conference on Industrial Electronics, Control and Instrumentation. 21st Century Technologies.

[4]  Seiji Kondo,et al.  Enlarging switching frequency in direct torque-controlled inverter by means of dithering , 1999 .

[5]  M. P. Kazmierkowski,et al.  Improved direct torque and flux vector control of PWM inverter-fed induction motor drives , 1995, IEEE Trans. Ind. Electron..

[6]  S. Sul,et al.  New direct torque control of induction motor for minimum torque ripple and constant switching frequency , 1999 .

[7]  Peter Mutschler,et al.  Direct mean torque control of an induction motor , 1997 .

[8]  Nik Rumzi Nik Idris,et al.  Direct torque control of induction machines with constant switching frequency and improved stator flux estimation , 2001, IECON'01. 27th Annual Conference of the IEEE Industrial Electronics Society (Cat. No.37243).

[9]  M. Depenbrock,et al.  Direct self-control (DSC) of inverter fed induktion machine , 1987, IEEE Power Electronics Specialists Conference.

[10]  M. Depenbrock,et al.  Direct self-control (DSC) of inverter-fed induction machine , 1988 .

[11]  Toshihiko Noguchi,et al.  A New Quick-Response and High-Efficiency Control Strategy of an Induction Motor , 1986, IEEE Transactions on Industry Applications.

[12]  S. Mahmoud,et al.  Improved direct torque control for induction motor drives with rapid prototyping system , 2006 .

[13]  J. Holtz,et al.  Pulsewidth modulation for electronic power conversion , 1994, Proc. IEEE.

[14]  L.M. Tolbert,et al.  Direct torque control of induction machines using space vector modulation , 1991, Conference Record of the 1991 IEEE Industry Applications Society Annual Meeting.