Control System for a Single-Phase DC-Excited Flux-Switching Machine With a Torque Ripple Reduction Scheme

Single-phase dc-excited flux-switching machines (DCFSMs) are suitable for operations in harsh environments and cost-sensitive applications due to their rugged structure. However, the practical application of DCFSMs is limited because significant torque ripple is generated in them as the armature current commutates. However, with a marginal modification to the rotor structure, the single-phase DCFSM exhibits a unique property that its reluctance torque is complementary to its electromagnetic torque. A significant reluctance torque can be generated by the field current near the commutation positions. To explore the characteristics of the complementary torque, this paper presents a speed control system with a torque ripple reduction scheme for single-phase DCFSMs. In this scheme, the armature and field currents are controlled with precalculated profiles such that the reluctance torque compensates for the loss of the electromagnetic torque near the commutation positions. The experimental results indicated that with the proposed control scheme, the maximum torque ripple reduced to 56% near the commutation positions when the machine provided the rated torque. Moreover, because the studied DCFSM generated highly linear torque, satisfactory speed control performance was achieved.