Publication:
Direct Torque Control of Permanent Magnet Motors (1996)
Author(s): PP Acarnley CD French
- : Direct Torque Control of Permanent Magnet Motors
Abstract: Many permanent magnet motor drives use an open loop form of torque control, based on the assumption that output torque is proportional to applied current. In a practical motor this assumption may not always be correct, due to sub-optimal alignment of magnets, non-uniformity of magnetic material, current sensor non-linearities and current controller limitations. These factors, together with non-optimised current references, can lead to undesirable levels of torque ripple and copper loss. This paper describes a method of estimating the electro-magnetic torque from the rate of change of co-energy with respect to position, thus taking account of mutual torque, reluctance torque and saturation effects. The paper shows how the estimater can be used in a direct torque control scheme. The direct torque controller maximises the torque : copper loss ratio. Implementation of the direct torque controller in a DSP based drive system is described, with steady-state and transient experimental results illustrating the effectiveness of the direct torque control scheme.
- Short Title: Direct Torque Control of Permanent Magnet Motors
- Date: Sept
- Journal: IEEE Industrial Applications Transactions
- Volume: 32
- Issue: 5
- Pages: 1080 1088
- Publication type: Article
- Bibliographic status: Published
