Loss minimization in wound-field cylindrical rotor synchronous motor drives

The loss minimization problem in wound-field cylindrical rotor synchronous motor drives (SMDs) is investigated. From the theoretical analysis, a system of two loss model controllers (LMCs), for determining the optimal air-gap flux and optimal excitation current that minimizes the losses, results. The suggested LMCs are simple, and their implementation does not affect significantly the cost and complexity of the drive. Although the conception of the suggested LMCs is based on the loss model of the synchronous motor, it is shown that their implementation does not require knowledge of the loss model. All the theoretical results are verified experimentally.