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For linear-rotary switched reluctance motors (LRSRMs) with two radial windings, the coupling between torque and axial force increases the complexity of control. Due to the calculation of current in existing control method for LRSRMs, the complicated derivation of current expression was necessary, and some constraints were also introduced which meant the difficulties on designing the current control algorithm were greatly increased. In order to solve these problems, a direct torque and direct axial force control method is proposed in this article. By the way of selecting appropriate space voltage vectors, the proposed method can directly regulate torque and axial force at the same time to achieve rotation and linear motion and significantly reduce the ripple of the torque. Moreover, the mechanism of two-DOF motion and the principle of the proposed method are demonstrated in detail based on a 6/4 LRSRM with two radial windings. Based on MATLAB/Simulink and the experimental prototype, the feasibility of the proposed control method has been verified according to the simulation and experimental results.

For 6/4 linear-rotary switched reluctance motors (LRSRMs), the magnetic-flux paths of the two windings are coupled in the radial direction, thus it is difficult to design the two-winding current algorithm for the linear and rotary control simultaneously. To solve this problem and achieve linear motion and rotation at the same time, speed and axial position control method is proposed by employing the equal magnetomotive force of two windings to calculate the given currents. This control method has the advantages of simple principle, easy implementation and can realize the coordinated control of rotation and linear motion. In addition, the mathematical model of LRSRM is established to facilitate the design of current algorithm. Simulation and various experiments are completed to verify the demonstrated performance of the proposed control method.

In order to eliminate the input current harmonics and dc-link voltage ripples of Vienna rectifier under unbalanced input, a novel control strategy applicable to wide variable frequency (360–800 Hz) aircraft electrical system is proposed in this article. To serve this purpose, current references on natural frame are first derived, which contain quadrature signals of grid voltages. Then, a natural-frame-based control strategy is designed, in which the second-order generalized integrator (SOGI) frequency-locked loop (FLL) is employed for variable frequency grids. Compared with traditional dual-frame control strategy, the proposed strategy reduces the algorithm complexity and has better frequency adaptability. The proposed strategy is suitable for all the unbalanced conditions, which is defined by test procedures DO-160G. Simulation and experimental results verify the effectiveness of the proposed control strategy.