With ever-increasing concerns on energy issues, the development of renewable energy sources is becoming more and more attractive. This paper first reviews both the wind power and photovoltaic (PV) power generation techniques and their maximum-power-point tracking (MPPT) methods. Then, a new stand-alone wind-PV hybrid generation system is proposed for application to remote and isolated areas. For the wind power generation branch, a new doubly excited permanent-magnet brushless machine is used to capture the maximum wind power by using online flux control. For the PV power generation branch, a single-ended primary inductance converter is adopted to harness the maximum solar power by tuning the duty cycle. The experimental results confirm that the proposed hybrid generation system can provide high efficiency with the use of MPPT.

This paper proposes a novel model predictive control for a three-phase permanent magnet synchronous motor (PMSM) with enhanced robustness against parameter variation and higher current control precision. First, the extended set of voltage vectors are adopted to increase the current control precision. Then the parameter sensitivity problem is avoided in the first stage using an indirect reference vector strategy for the sake of computation time reduction. Subsequently, the inductance disturbance observer is adopted in the current prediction process to enhance the robustness against machine parameter mismatch. The intrinsic connection between the discrete control sets precision and disturbance is analyzed. The proposed method improves the robustness against parameter mismatch and current control precision simultaneously. Experimentations are conducted to verify the effectiveness of the proposed method.

This paper presents a new field-modulation double-stator electrical excitation synchronous machine (FM-DSEESM) and analyzes its harmonic components of double-layer air-gap magnetic field. The key is that both the types and sources of various harmonic-components of air-gap magnetic field are derived by taking into account the permeance components of both inner and outer stator teeth and modulation-ring rotor. The selection criteria of main working harmonic components of excitation field is clarified to achieve the armature-winding configuration. Then, the working harmonic components of air-gap magnetic field, which have the same pole pairs, rotating direction and rotating speed respectively, can be figured out by comparing the mathematical derivation and finite-element analysis results from the excitation field and armature reaction magnetic field. By analyzing the contributions of the air-gap flux density components to the electromagnetic torque, it is found that the electromagnetic torque of the proposed FM-DSEESM mainly consists of two parts, namely the reluctance torque components generated by the stationary working harmonic components and the armature reaction torque components provided by the rotating working harmonic components. A low-speed direct-drive FM-DSEESM prototype is fabricated to verify the validity of the proposed analysis approach.

Benefiting from flexible flux control and short-circuit withstand ability, hybrid excitation machine is an emerging starter generator solution for hybrid electric vehicle propulsion. However, to realize a brushless hybrid design in conventional PM machines, a three-dimensional magnetic circuit is usually adopted, leading to complicated mechanical structure and torque density sacrifice. To address this issue, a new relieving-DC-saturation hybrid excitation Vernier machine is proposed in this paper, which integrates good torque density and bidirectional flux control within a simple and brushless structure. The key is to artificially construct reluctance effect in a consequent-pole Vernier PM machine (CP-VPMM) by introducing extra DC field excitation equipped with relieving-DC-saturation ability. In this way, the advantages of bidirectional flux control in stator-DC-excited reluctance machine and good torque density in CP-VPMM are well combined in this topology, making it especially suitable for multi-mode starter generator application. In this paper, the machine structure and its design mechanism are introduced, with its electromagnetic performance evaluated by the finite element simulation. A prototype is manufactured and tested. Experiment results verify the feasibility of this new topology.

This paper aims to propose a new hybrid reluctance machine equipped with relieving-DC-saturation ability for electric vehicle in-wheel drive. The proposed machine uses integrated AC and DC current excitation to eliminate extra DC field coils for the efficient torque generation. Besides, considering the inherent DC saturation in stator core caused by DC current excitation, slot PMs are artificially introduced to provide reliving-DC-saturation effect and thus boost torque density. Moreover, with a modular magnetic field configuration, the proposed topology exhibits excellent fault-tolerant potential at both open-circuit and short-circuit condition, making it suitable for safety-critical in-wheel vehicle propulsion. In this paper, the machine configuration and operation principle are introduced, with emphasis on its reliving-DC-saturation effect and corresponding design consideration. Further, performance of this new topology is evaluated by both finite element analysis and prototype experiments. It is revealed that, with this relieving-DC-saturation ability, torque density of the proposed machine can be enhanced by about 25% under relatively high current density.