A wavelet fuzzy neural network using asymmetric membership function (WFNN-AMF) with improved differential evolution (IDE) algorithm is proposed in this study to control a sixphase permanent magnet synchronous motor (PMSM) for an electric power steering (EPS) system. First, the dynamics of a steer-bywire EPS system and a six-phase PMSM drive system are described in detail. Moreover, the WFNN-AMF controller, which combines the advantages of wavelet decomposition, fuzzy logic system, and asymmetric membership function (AMF), is developed to achieve the required control performance of the EPS system for the improvement of stability of the vehicle and the comfort of the driver. Furthermore, the online learning algorithm of WFNN-AMF is derived using back-propagation method. However, degenerated or diverged responses will be resulted due to the inappropriate selection of small or large learning rates of the WFNN-AMF. Therefore, an IDE algorithm is proposed to online adapt the learning rates of WFNN-AMF. In addition, a 32-bit floating-point digital signal processor, TMS320F28335, is adopted for the implementation of the proposed intelligent controlled EPS system. Finally, the feasibility of the proposed WFNN-AMF controller with IDE for the EPS system is verified through experimental results. Index Terms-Asymmetricmembership function (AMF), differential evolution (DE), electric power steering (EPS), six-phase permanent magnet synchronous motor (PMSM), wavelet fuzzy neural network (WFNN).NOMENCLATURE J m Inertia of EPS motor. B m Damping coefficient of EPS motor. T e Electric torque of EPS motor. θ r Rotor angle of EPS motor. K m Torsion stiffness of EPS motor shaft. X r Displacement of rack. G Gear ratio of worm gearbox. Manuscript

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An intelligent control for a stand-alone doubly-fed induction generator (DFIG) system using a proportional-integral-derivative neural network (PIDNN) is proposed in this study. This system can be applied as a standalone power supply system or as the emergency power system when the electricity grid fails for all sub-synchronous, synchronous, and super-synchronous conditions. The rotor side converter is controlled using field-oriented control to produce 3-phase stator voltages with constant magnitude and frequency at different rotor speeds. Moreover, the grid side converter, which is also controlled using field-oriented control, is primarily implemented to maintain the magnitude of the DC-link voltage. Furthermore, the intelligent PIDNN controller is proposed for both the rotor and grid side converters to improve the transient and steady-state responses of the DFIG system for different operating conditions. Both the network structure and online learning algorithm are introduced in detail. Finally, the feasibility of the proposed control scheme is verified through experimentation.

Analysis and implementation or a single-phase half-bridgc active power filter with the function of uninterruptible power supplies is presented. The system provides the combined functions or battery bank energy storagc, power-factor compcnsation, harmonics elimination and unintcrruption of the power supply. When the utility is in normal operation, thc proposed system will not only supply DC power for battery charging, but also function as an active power filter for improving the power factor and reducing the current harmonics on the utility side. If the utility power fails. the proposed system will fLmction a s an inverter immediately, to supply the battery power to the AC load. Analysis for the proposed system is given first, and a personal coinp~itcr is then used to implement digitised control of the proposed system to facilitate experimental evaluations for a 1 kVA prototype. The feasibility and niulti-fLiiictional results obtained indicate that the proposed system can be realiscd by using a digital Yignal processor as the core controller for cost reduction and reliability enhancement.List of symbols K,, -K,'4 = proportional controllers gain d,, L12 = switching functions of the insulated-gate bipolar transistors (IGBTs) duty ratio of d , current of the AC-side inductor, L,, command current of i,, current of the battery-side inductor, L,)/ command current of Ql