Comparison of DTC implementations for synchronous machines

Direct-torque-control (DTC) is nowadays a classical technique for variable speed control of induction machines. Many implementations have been presented in literature DTC algorithm requires velocity for some parts and flexibility for other parts. Digital-signal-processors (DSP) have been used for flexibility, but field-programmable-gate-arrays (FPGA) have been preferred for velocity. Using one device (DSP or FPGA) for DTC implementation has been reported as not optimal. Codesign appears as a promising methodology for partitioning the DTC algorithm between flexible and fast parts. Codesign requires user-specifications to help the partitioning with regard to the awaited control performances. Authors discuss two experimental implementations at extremities of the codesign space, i.e. full-software or full-hardware implementation. For each implementation, the DTC algorithm requires adaptations. Authors detail each development, and full-codes are available on a dedicated web-site. Validation results are presented for both implementations. Performances, advantages, and limitations of both implementations are compared. The necessary specifications for codesign development may then be identified.