Permanent Magnet (PM) machines with rare-earth magnets have been widely used in electric vehicle applications in contemporary times. However, there are many challenges associated with the utilization of PM in these machines. The Variable Flux Machines (VFMs) have the potential to overcome or mitigate some of these challenges. This paper investigates a hybrid-PM VFM with various rotor configurations. The hybrid-PM VFM will be examined twice using two different Low-Coercive Forced (LCF) PMs in each time. A comparison between the different configurations will be conducted before and after the optimization process. The main goal is to explore the behavior of the LCF PMs in each topology and their impact on the VFM.

This paper proposes two novel hybrid permanent magnet variable flux machines (hybrid-PM VFMs). Neodymium Iron Boron (NdFeB) PM is utilized as a HighCoercive-Force (HCF) PM in both machines, while AlNiCo and the new PM Iron Nitride (FeN) are utilized as a Low-Coercive-Force (LCF) PM in the first and second machines, respectively. The Demagnetization Ratio (DR) of LCF PMs with different sizes is explored in this paper. Moreover, 2D FEA designs are developed to investigate the potential for enhancing the electromagnetic performance in the machines. The flux density (B) is calculated based on the equivalent magnetic circuits (EMC) of both machines and the outcomes are assessed with the FEA results under different operation conditions. An optimization process is used for both designs and the outcomes are compared to the Nissan Leaf conventional baseline IPM design machine. Furthermore, efficiency maps will be provided at various levels of demagnetization.

The integration of multiple energy sources has emerged as a major technique for addressing the complicated challenges of enhancing reliability and range in electrified transportation. In this paper, a modified brute-force approachbased multi-objective optimization of hybrid energy sources (HESs) in electrified transportation is described. The modified brute force optimization method involves providing a thorough search and evaluation of all feasible solutions within a given solution space, considering the priority of desired characteristics. The top source combination options for two key applications, including land and air transportation systems, are obtained, and discussed. This research also resulted in the development of a webbased platform for hybrid energy system application research and optimization (HESARO). The initial version is capable of performing thorough optimal HES selection of a two-source combination for air and land electrified transportation.

Integration of the electrical machine and drive system is an ongoing research topic among scholars in both academia and industry with the goal of increasing power density and efficiency to fulfill the requirements of aviation applications. The drive system structure and the modulation scheme impact the stator current ripple which affects torque ripple and efficiency. The case study of this paper is an integrated motor drive system of a 250 kW and 5,000 rpm direct drive surface permanent magnet machine. The imposed current ripple for different three- phase topologies (two-level VSI, and modular single-phase) using different modulation schemes (SVPWM for two-level VSI and Unipolar PWM for single-phase) are analytically studied. It is shown that in a modular single-phase full-bridge topology, the maximum peak to peak value of the current ripple is significantly lower than modular single-phase half-bridge and three-phase SVPWM modulated two-level VSI over the entire operating range. Furthermore, the torque ripple, stator core loss, and winding loss are evaluated for different current profiles through finite element analysis (FEA) simulations.

Permanent Magnet Assisted Synchronous Reluctance Machine (PMASynRM) possesses the advantage of both reluctance and electromagnetic torque, which makes it a cheaper alternative compared to surface PM machines. Further improvement in cost and performance is achieved by adjusting the contribution of each torque component either by optimizing the rotor structure or utilizing a combination of different magnet grades. This paper employs both alternatives through the design optimization of a U-shaped PMASynRM topology featuring 2-layers of rotor magnets incorporating a blend of various magnet types. Four arrangements of Iron Nitride magnets combined with different types of rare-earth (RE) and rare-earth-free (RE-free) magnets are suggested for 8-pole and 6-pole PMASynRM topologies. The optimal designs for each magnet combination in both the 8-pole and 6-pole configurations are utilized to investigate how altering the number of poles influences various performance characteristics of the machine. The comparative analysis of various results is utilized to derive insights into the most suitable topology for the given application.

Multilevel Converter (MLC) design and control have been interesting topics in the last few decades. Due to the increased number of semiconductors in such topologies, the control problem becomes complex. Model Predictive Control (MPC) has been introduced in the 1980s and owing to significant advancements in processing power nowadays it is considered a viable option to control power converters. Fast dynamic response, simplicity, and the ability to include system nonlinearities and constraints in the cost function make MPC an interesting alternative for conventional linear controllers. In this paper, conventional Finite Control Set Model Predictive Control (FCS-MPC) has been improved by limiting the viable switching options based on the reference value. The performance of the proposed Model Predictive Nearest Level Control (MP-NLC) method is compared to the conventional FCS-MPC. The proposed method is applied to a 9-level inverter. To investigate the performance of the proposed MP-NLC method, simulations were carried out under linear and nonlinear loads. The presented results verify the fast dynamic response, and robustness of the proposed method. In addition, parameter mismatch analyses have been carried out on the proposed method as well. Based on the presented results, by using the proposed method total efficiency and specific power of the system are increased.

Photovoltaic (PV) systems are among the most convenient renewable energy sources (RESs) and are popular due to their easy implementation and low maintenance. Multi-input multilevel converters (MLCs) are suitable choices to harvest energy from PV systems and integrate solar farms into the existing power grid. In this paper, a new reconfigurable and multi-input converter is proposed for solar PV applications. It is also a practical solution for various medium to high voltage and power applications such as traction and HVDC. The symmetric and asymmetric configurations of the proposed MLC help achieve a higher number of output voltage levels and hence better-quality waveforms. The redundant output voltage vectors have improved the fault tolerance behavior of the proposed converter which enhances the reliability of the overall solar power system. Moreover, the proposed converter benefits from an improved model predictive control (MPC) technique which is customized for multilevel converters by adopting the nearest level control (NLC) algorithm. The proposed model predictive NLC (MP-NLC) method leads to high quality output voltage waveform (1.23% THD) under various load conditions while realizing an average switching frequency of lower than 6.8 kHz. A nominal load efficiency of 98.3% is recorded for the proposed MLC. The simulation results using Plexim PLECS software validate the functionality of the proposed converter and control method.

Increasing integration of various energy sources to the power grid, demand for higher power density, and higher cyber security resulted in a growing attention to multi-port power converters. Although several multi-port converter (MPC) topologies exist in the literature, there is an absence of a systematic method to design, develop, and control MPCs. This paper proposes a systematic method that can be used to design MPCs for different applications. This method includes the approach to develop topologies for MPCs and a general approach to design proper control systems for them. The proposed method is applied to four sample cases from the existing MPCs in the literature to demonstrate its effectiveness. Moreover, the control method is applied to one of the sample cases and the simulation and experimental results are presented.

Increasing tendency in online businesses and work from home, attracted many businesses and individuals to consider single-phase uninterruptible power supplies (UPSs). However, low power UPSs are normally incapable of operating for extended time periods. In order to extend UPS ranges, researchers integrated auxiliary energy sources to UPSs. However, integrating auxiliary power sources require additional power electronics active and passive components. This will result in low power density and bulky UPSs. To overcome this issue, multi-port converters have been proposed as an alternative to employing multiple converters. Nevertheless, using multi-port converters require more advanced control methods. This paper proposes a novel multi-port UPS with a finite control set model predictive controller. Simulations are conducted to demonstrate the effectiveness of the proposed converter. The results show the load current THD of 0.77%, resilient transient response, and efficiencies up to 97.5% using SiC MOSFETs.

The upward trend of employing renewable energy sources in today’s power grid, the tendency to utilize energy storage systems in addition to these sources, and the benefits of using hybrid energy storage systems (including the transportation electrification sector) have put the multi-port converters (MPCs) under the spotlight. Fewer number of active and passive components, higher power density, and lower risk for cyber- attacks are among the reasons for MPCs’ popularity. This paper proposes a novel three-port power converter for the hybrid energy storage and hybrid renewable and energy storage applications. This converter is designed to operate for loads up to 20kW and for voltages 400-24V which is suitable for HESSs in residential and electric vehicle auxiliary power units. The voltage levels of this TPC are suitable for the electric vehicles auxiliary power units and DC zonal microgrids. This paper discusses the development and control of this three-port converter and demonstrates the effectiveness of this converter by simulating it under various operating modes for a 2.5kW hybrid energy storage system This TPC achieved efficiencies between 90.7% to 94.5% in different modes with a switching frequency of 50kHz.

In recent years, there has been an increasing interest in DC-DC multi-port power converters for transportation applications. Multi-port converters benefit from fewer components compared to multiple-converter architectures. As a result, higher power density and lower prices are among the main incentives for utilizing multi-port DC-DC converters in transportation sector. Moreover, fuel cell is among the permissible green energy resources that has been broadly considered for transportation applications. This paper proposes a novel multi-port converter for fuel cell-based hybrid streetcar application. Furthermore, an energy management scheme has been proposed for the presented multi-port converter to achieve the suitable modes of operation. Simulation results are provided to demonstrate the effectiveness of the proposed multi-port converter and the presented energy management scheme. Power loss analysis for this converter are provided and efficiencies of 92.7% and 95.1% for two- and single-stage modes are recorded, respectively.

AC microgrids are considered the most compatible method for integration of renewable energy sources and energy storage systems into the existing power grid. Photovoltaic (PV) systems are among the most popular renewable energy sources. However, due to the DC nature of their produced power, power electronics converters are required to process their harvested energy. This paper proposes a power electronics-based solution named solar converter unit (SCU) that operates as an interface between the PVs modules and the AC microgrid. The modularity of the proposed topology improves the reliability of power conversion process. Moreover, this topology benefits from a modified hysteresis band control algorithm that provides regulated and high-quality waveform at the consumer side with maximum of 6% error margin. Furthermore, a THD value of 0.72% is recorded for the consumer side. Various integration scenarios using SCU are discussed comprehensively in this paper and a scenario selection algorithm is proposed. Simulations are conducted for key functions of SCU to demonstrate its capabilities and functionality. The simulation results show that the proposed SCU converts and manages the power in the AC microgrid properly.

Multi-port power converters have gained attention in renewable energy applications due to their higher power density caused by fewer number of components. Three-port converters (TPCs) provide desirable solution to many applications combining renewable energy sources (RESs) and energy storage systems (ESSs). This paper proposes a new TPC with an adaptive variable-frequency PWM (VF-PWM) control scheme to assure its operation in boundary current mode (BCM). The proposed TPC provides a feasible solution to combine a PV with a battery system for residential PV systems. This paper discusses the proposed TPC and its operation modes. Moreover, the suggested VF-PWM method is introduced to achieve BCM of the proposed TPC. The provided simulation results verify the effectiveness and feasibility of the proposed TPC and its VF-PWM method for BCM operation. Quantitative discussions on benefits of BCM from various aspects are also presented.

In this study, an investigation of winding structures is performed for 3-phase unbalanced and asymmetric winding permanent magnet (PM) machines including different slot-pole combinations. There are two different cases for unbalanced winding (UBW) structure: 1) Stator slot number of the machine is divisible by three, 2) Stator slot number of the machine is not divisible by three. Only the first case is examined in this paper. The unbalanced winding layouts are created for minimum unbalance and maximum winding factor. Total magneto motive force (MMF) distributions for nine different slot-pole combinations and their harmonic contents are presented. Variation of the amount of unbalance for different slot-pole combinations is also provided in the paper. A prototype motor with 39-slots and 12-poles has been manufactured for experimental verification. A comparison between the finite element analysis (FEA) results and experimental results is presented for the prototype motor for both no-load and on-load conditions.

In this paper, two different winding configurations and phase angle displacements of an unconventional nine-phase permanent magnet (PM) motor have been investigated in terms of flux weakening capabilities. The focus has been on a 117-slot 36-pole unbalanced and asymmetric winding motor since these motors have certain benefits. In addition, it is not possible to create a balanced winding structure for this motor due to the selected slot-pole combination. Performance of the designed motors have been verified experimentally and flux weakening capabilities have been investigated using 2 Dimensional finite element analysis (2D FEA) and test results. It is shown that the flux weakening capabilities of the proposed 9-phase PM motors with two winding options yield similar results compared to a conventional balanced multi-phase PM motors.