In this paper, a new electric drive system based on a six-phase ten-pole dual-winding fault-tolerant permanent magnet (DFPM) motor for aerospace applications is proposed and investigated. The proposed DFPM motor consists of optimal surface-mounted permanent magnet rotor and 12 slots stator with two sets of independent three-phase concentrated armature windings on alternate teeth, which incorporates the merits of high power density and high efficiency of permanent magnet (PM) motor and high fault-tolerance of dual-winding motor. To achieve the fault-tolerant performance of the electric drive system, the redundant fault-tolerant control strategy based on the failure diagnosis and redundancy communication is proposed and applied to the electric drive system. Then, the operational performance of the drive system under open-circuit and short-circuit fault have been verified by simulation and experiment. The research results show that the open-circuit and short-circuit fault can be detected immediately and the output performance of the DFPM motor under fault conditions is almost the same as normal condition, which verified the proposed electric drive system, DFPM motor and fault-tolerant control strategy. Index Terms-Dual-winding motor, fault-tolerant drive, redundancy, open circuit or short circuit fault, permanent-magnet machine.  Manuscript

At present, three-phase 115V/360-800Hz variable frequency AC power system is mostly used in the main power system of More-Electric Aircraft. With the increase of EMA (Electro-Mechanical Actuator), EHA (Electro-Hydrostatic Actuator), DC/DC power supply and power electronic devices in More-Electric Aircraft, harmonic and reactive power problems are brought, which seriously affect the power supply quality of variable frequency power supply for aircraft. According to the characteristics of high frequency and wide range of aviation variable frequency power supply, this paper studies a three-level active filter which can effectively improve the power quality of aviation variable frequency power supply system. This paper analyzes the working principle of the diode clamped three-level topology active filter, and deduces its mathematical model; proposes the frequency detection of the aviation variable frequency power supply based on the improved Rife method; the ip-iq method based on the instantaneous reactive power theory, accurately detects the harmonic current of the aviation variable frequency power supply system; uses the quasi PR controller to track the current, and improves the harmonic suppression effect. Finally, the experimental hardware platform is built to verify the feasibility of the proposed control strategy.

The direct torque control (DTC) and direct force control (DFC) method were introduced to reduce the torque and levitation force ripple in single-winding bearingless switched reluctance motors (SWBSRMs). However, it still has some disadvantages. Firstly, the flux-linkage control is not suitable for the DTC method in SWBSRMs. On the one hand, it can increase the torque ripple. On the other hand, the RMS current can be increased and then the torque-ampere ratio is decreased. Secondly, the vectors selection is also unreasonable, which can increase the torque ripple further. In order to solve these problems, an improved control method based on DTC and DFC method for SWBSRMs is proposed in this paper, which can obtain high torque-ampere ratio and low torque ripple simultaneously. In the proposed method, the flux-linkage loop control is not needed and the space voltage vector table is improved. The experimental results show that the torque ripple is reduced by 66.7%, the torque-ampere ratio is increased by 200% and the switching times in one electrical period are reduced by 47.3%. Index Terms-single-winding bearingless switched reluctance motor, direct torque control, direct force control, torque ripple, torque-ampere ratio. NOMENCLATURE θ Rotor angular position. θsr Angle between stator and rotor flux linkage. ia1-ia4 Winding currents of phase A in BSRMs. Ta Instantaneous torque of phase A. Fα , Fβ Radial forces on the direction of α-axis and β-axis, respectively. p0 Number of rotor poles. Lm Mutual inductance. Ls , Lr Stator and rotor inductances amplitude, respectively. Ψs ,Ψr Stator and rotor flux-linkage amplitude, respectively. σ Leakage inductance coefficient. is Current of stator winding in SRMs. c Constant 1.01. h Lamination length of the iron core. l0 Air-gap length between the stator and rotor poles. Ns Number of winding turns. r Radius of rotor. μ0 Permeability of vacuum.

Low-frequency wide-band hybrid energy harvester based on piezoelectric and triboelectric mechanism

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Although the conventional control strategy of Bearingless Switched Reluctance Motors (BSRMs) can realize stable suspension of the motor shaft, it still has disadvantages such as relying on the model calculation, strong coupling between torque and displacement, and poor anti-interference ability. In order to solve these problems, this paper studies a direct displacement control (DDC) strategy for singlewinding BSRMs (SWBSRMs). This strategy draws on the control idea of magnetic bearings, and realizes the stable suspension of BSRMs on the premise of separating from the mathematical model online calculation. At the same time, the strategy realizes the decoupling of torque and suspension displacement, and has good anti-disturbance. Finally, experimental results show that compared with the conventional control strategy and DTC and DFC method, the DDC strategy reduces the execution time of the algorithm by 36.6% and 41.2% during steady-state; reduces the speed-up time by 60% and 23% during dynamic conditions; and reduces the speed-down time by 20% and 86.6%.

In conventional 12/8 bearingless switched reluctance motors (BSRMs), the generation and control of torque and levitation forces are always coupled and interacted, which increases the complexity of the current control algorithm. In this paper, a novel BSRM with 12 stator poles and 4 rotor poles is proposed to simplify the control of torque and levitation, which has wide flat inductance region. Through allocating the generation of torque and levitation forces to different inductance regions of each phase, the levitation control can be similar as that of magnetic bearings, and the torque control can adopt the methods of conventional switched reluctance motors, e.g. current chopping control and angle position control. Accordingly, the current control algorithm of proposed BSRM becomes very easy and flexible. Extensive experiments were completed to verify the demonstrated performance of proposed motor. T Required torque current ia1-ia4, i b1 -i b4 Winding currents of phases A and B, respectively l0 Air-gap length between the stator and rotor poles Ns Number of winding turns Pa1-Pa4 Air-gap permeances of phase A, respectively P b1 -P b4 Air-gap permeances of phase B, respectively r Radius of rotor Manuscript received .