Through comprehensive study for the power converters that have emerged previously for switched reluctance machine (SRM) drive system, this paper proposes an evaluation approach to determine the suitability of these converters for using in SRM-based electric vehicle (EV) drive system. This evaluation reflects the relative differences of these converters in terms of their cost as well as their capability to offer best technical performance for the drive system of EVs. From technical viewpoint, four factors are considered as follow: the converter efficiency, the converter reliability, the capability of the converter to reduce torque ripple, and to increase power productivity. A benchmark consists of number of converter characteristics is identified. The operation of the converters is analyzed to determine, in quantitative way, their fulfillments to these characteristics. Expressions for the evaluation factors are proposed in terms of the converters’ characteristics. Accordingly, the converters are relatively scored to reflect their differences in cost as well as in technical impact on the SRM drive system. The results provide useful indication for trade-off between gaining some of advantages and losing others for EV applications. In addition, they identify of potentials for optimization based on the cost and the technical performance of different SRM converters.

In photovoltaic systems, parasitic capacitance is often formed between PV panels and the ground. Because of the switching nature of PV converters, a high-frequency voltage is usually generated over these parasitic capacitances; this, in turn, can result in a common-mode current known as leakage current. This current can badly reach a high value if a resonance circuit is excited through the PV’s parasitic capacitance and the converter’s inductive components. Transformers are usually used for leakage current mitigation. However, this decreases the efficiency and increases the cost, size, and weight of the PV systems. Number of strategies have been introduced to mitigate the leakage current in transformer-less converters. Among these strategies, using common-ground converters is considered the most effective solution as it offers a solid connection between the negative terminal of PV modules and the neutral of the grid side; thus, complete mitigation of the leakage current is achieved. Number of common-ground inverters have been recently presented. These inverters are different in their size, cost, boosting capability, the possibility of producing DC currents, and their capability to offer multilevel shaping of output voltage. This work introduces a comprehensive review and classification for various common-ground PV inverters. Therefore, a clear picture of the advantages and disadvantages of these inverters is clarified. This provides a useful indication for a trade-off between gaining some of the advantages and losing others in PV systems. In addition, the potentials for optimization based on different performance indicators are identified.

To enhance the stability and reliability of the system, the converters’ parallel operation can be cascaded to address the constraints posed by the substantial integration of renewable resources. Buck-boost DC-DC converters are often controlled via a cascaded control approach to allow parallel operation. The converter’s output current and its voltage will be controlled by nested loop control. This study proposes adaptive droop control parameters that are updated and verified online using the principal current sharing loops to minimize the fluctuation in load current sharing. When the converters in the microgrid are paralleled, load sharing will be accomplished using the droop control approach in addition to nested proportional-integral-based voltage and current control loops. To restore the correct voltage across the DC microgrid, an outer addition voltage secondary loop will be used, rectifying any voltage disparities caused by the droop management strategy. Several common load resistances and input voltage variations are used to test the suggested method. Using a linearized model, this work assesses the stability and performance of the proposed method. It then confirms the findings with an adequate model created in MATLAB/SIMULINK, Real-Time Simulation Fundamentals, and hardware-based experiments.

This paper proposes a novel single-phase micro-inverter fit to process the power of two photovoltaic (PV) modules; in a modular way. The proposed topology combines a full bridge inverter integrated with two DC-DC boost converters, in addition to a DC link consists of switched capacitor (SC) networks. The operating modes of the proposed topology are illustrated. The voltage stress of all components is identified. A modulation technique along with a control system are developed for proper operation of the proposed topology. A comparative study with other topologies is introduced and shows the following merits for the proposed one: 1) the power of two PV modules can be harvested individually or simultaneously without any circulating current issues, 2) very high gain can be acquired; thus no series connection of PV modules is required for grid-tie applications, 3) Transformer-less operation, 4) multi-level shaping of the output voltage; thus reduced filter size is required, and 5) self-balancing for the DC-link capacitors; thus simple control systems can be used. The performance of the 7-level version of the proposed topology is validated using real-time simulation and experimental prototype under grid-tie and stand-alone conditions, respectively

Conventional LED drive has a limited lifetime due to present of bulky electrolytic output capacitor (E-Cap) which is essential to make the power difference balancing between the constant output power and the pulsating input power. In fact, LED chip has a longer lifetime than E-Cap. Therefore, it is insufficient to use this type of capacitors in LED driver. Increasing the LED lamp lifetime can be achieved through changing the E-Cap with Film or Ceramic one. But the LED current peak will be double as a result of using low energy density capacitors. However, the LED can be driven by a pulsating current with a defined peak value. Peak to average ratio (PTAR) of LED current has to be limited (less than 1.4) to save LED from overdriven, failure and flux saturation. Recently, the methodology of injecting a predefined value of harmonics to limit the PTAR is costly and complex to be used in interior and exterior LED applications. This paper will present an optimization methodology for the LED driver control circuitry to be simpler and more cost-effective. Three major parameters will constrain the design of the control circuitry are cost reduction, lifetime expansion and simplicity in implementation. The feasibility of the proposed control circuit has been verified by simulation and real prototyping as well.

This paper presents a new axial flux modular stator hybrid excitation switched reluctance motor (AFMHSRM) by applying modular stator and hybrid excitation structures. First, the initial dimensions of three AFMHSRMs with permanent magnet (PM) located at different positions in the stator are presented. The torque and flux linkage characteristics of the AFMHSRM are qualitatively analyzed and compared based on the magnetic equivalent circuit (MEC)method. The influence of the PM itself and PMs’ position in the stator on the static characteristics of the AFMHSRM is compared by the finite element analysis (FEA) method. Simultaneously, it is analyzed the influence of the PM thickness and the number of rotor poles on the torque of the proposed motor. The AFMHSRM structure with optimal performance is identified as the final topology and optimized for performance. Subsequently, the steady and transient state performances of the three AFMHSRMs and the conventional axial flux modular-stator switched reluctance motor (AFMSRM) are compared in the MATLAB/Simulink environment. Finally, an AFMHSRM prototype is fabricated based on the optimized dimensions. The simulation and experimental results verify the effectiveness of the proposed structure and the performance enhancement of the hybrid excitation structure for the axial flux switched reluctance motor.