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A performance comparison between a rareearth and a rare-earth-free five-phase PMa-SynRMs operating at maximum torque per ampere (MTPA) control is present in this paper under different open phase faults. The five-phase machines show inherent higher fault tolerance advantageous over the conventional three-phase machine under different number of open-phase conditions. Ferrite (Fe) magnets are cost effective replacement of the rare-earth material e.g. neodymium (Nd) magnets. Both magnets in PMa-SynRMs show degraded electromagnetic torque characteristics under different open phase faults. Traditional MTPA control method is not able to improve performance under faulty conditions. Advanced fault-tolerant MTPA control method is required to achieve satisfactory performance both under healthy and faulty conditions. In this paper, the fault tolerant control method is modified with MTPA technique to achieve higher performance. The proposed technique is applied on both machines under open phase faults to compare their performances. Detail theoretical analysis is carried out through MATLAB and finite element analysis (FEA). Experimental test results are provided for the Nd-based PMa-SynRM.

This paper proposes the design of a five-phase bearingless permanent magnet assisted synchronous machine (PMaSynRM) for high speed applications. The bearingless machines are suitable for various industrial and medical applications as they offer wear-free operation, longer lifetime, and higher efficiency by eliminating mechanical bearings. However, the levitation of the rotor is critical aspect in these machines which needs very smooth and sustainable force to hold the rotor and shaft at proper position. In that regard, multiphase PMaSynRM, which offers very low torque ripple and high fault-tolerance, is a suitable candidate for bearingless machine applications. Therefore, this study proposes a five-phase bearingless PMaSynRM that generates desired torque using main five-phase winding and generates the rotor-levitating force using an additional winding. The design procedure of the main motor and the suspension winding has been described in details. A thorough FEA analysis has been provided to show the performance characteristics under various operating conditions. The simulation results show that the motor generate required levitation force at cost of very low suspension winding current. The motor performance with and without the suspension has been compared to ensure desired output of the motor.

This paper presents a detailed performance review of permanent magnet assisted synchronous reluctance motors (PMa-SynRMs) designed for traction applications. As the machine design innovations favor towards reduced and elimination of permanent magnets, PMa-SynRMs are the most trending traction motors in the industry recently. However, extensive designs have been proposed for reduced permanent magnet motor designs such as PMa-SynRMs. In addition, to solve their design challenges such as requirement to generate higher torque density with lower torque pulsations, several multi-objective optimization techniques have been implemented. This study presents a generalized design procedure for the optimal choice of PMa-SynRM specifications apposite to the traction motor designs. A series of two internal and two external rotor multi-phase PMa-SynRMs are optimally designed to use reduced permanent magnets and generate higher average torque with minimum torque ripple. In addition, advantages of adapting five-phases over conventional three-phase PMa-SynRM designs are highlighted. Experiments have been carried out on the prototypes to present comparisons between the 4 traction motor designs considered.

This paper presents a comparative study of the transient stability between a five-phase and three-phase permanent magnet assisted synchronous reluctance motor (PMa-SynRM). In automotive industries, the reliability of the motor drive system has become a critical concern to ensure optimal safety. Five-phase PMa-SynRMs are suggested in the critical applications for their fault-tolerant capability. However, their transient performance over the conventional three-phase system has not been discussed in detail. Additionally, PMa-SynRMs show higher cross-coupling effects which cause strong dynamic outcomes. This paper presents the stability comparison between an optimally designed three-phase and five-phase PMa-SynRM. Detail theoretical analysis is carried out through the MATLAB and finite element analysis (FEA).

This paper presents the performance comparisons between rare-earth and rare-earth free external rotor permanent magnet assisted synchronous reluctance motors (PMa-SynRMs) under static eccentricity (SE), dynamic eccentricity (DE), and mixed eccentricity (ME) conditions. Recently, external rotor motors are proposed as high power density motors for traction applications in electric vehicles and more electric aircraft. However, these in-wheel external rotor motors are usually under continuous stress of rotational forces due to the tire-road friction which can result in eccentricity faults due to stator and rotor misalignment. Therefore, it is critical to assess the external rotor motors performance under eccentricity faults in traction motors. In this study, various failure modes due to eccentricity faults such as SE, DE, and ME conditions are analyzed on optimal 3.8kW rare-earth based and 3.7kW rare-earth free external rotor PMa-SynRMs. Effects of these eccentricity conditions are translated to performance loss in terms of increased torque ripple and unbalanced magnetic pull (UMP) in the electric motor designs. Also, 3rd harmonics of back-electromotive force (back-EMF) have been analyzed for both motors in all eccentricity conditions to compare their performance in fault detection. Experimental setup is developed to test the motors under load conditions and finite element simulation results are presented to validate the proposed theory.

This paper presents a detailed comparison between fault-tolerant five-phase external and internal rotor permanent magnet assisted synchronous reluctance motors (PMa-SynRMs). Critical applications such as electric vehicles and more electric aircraft demand high power density and fault-tolerant capability in their traction motor designs. Five-phase external rotor motors are proposed to generate higher torque density compared to conventional internal rotor motors of same size. However, under fault conditions such as single-phase, two-phase adjacent, and two-phase non-adjacent faults, the fault-tolerant capability of such high torque density motors needs to be investigated. Furthermore, severe torque pulsations under such faults have to be restrained in traction motors. In this study, five-phase external rotor PMa-SynRMs are optimally designed to generate higher torque density with lower torque ripple and better fault tolerant capability when compared to a same size five-phase internal rotor PMa-SynRM. Finite element simulations are carried out to compare the performance of external rotor PMa-SynRMs under single-phase, two-phase adjacent and two-phase non-adjacent faults. Experiments under no-load conditions and load are carried out to validate the simulations.

This paper presents the process of determining demagnetization-free operating region of multi-phase permanent magnet assisted synchronous reluctance motor (PMa-SynRM) under fault tolerant operating condition using finite element analysis (FEA) tool. The five-phase PMa-SynRM has been considered as a suitable candidate for many critical service applications such as aircraft, electric vehicles, and electric ships due to low cost and high fault-tolerance capability. These machines can generate required torque under single or two-phase fault using only the unaffected phases. However, under the fault condition, the air-gap magnetomotive force (MMF) will be distorted and cause additional harmonics loss and torque ripple. Although the adoption of fault tolerant control (FTC) scheme can improve the performance, there will be large rise and fall in the air-gap MMF which can be threatening to the permanent magnet (PM) for irreversible demagnetization. Therefore, multiphase PMa-SynRM should be carefully operated under FTC to avoid the irreversible demagnetization of its PMs. This study determines the demagnetization-free operating region of a 3 kW five-phase rare-earth (NdFeB35) PM based PMa-SynRM under single and two-phase open fault conditions. Finite element analysis (FEA) has been performed for different thermal levels of the PMs to evaluate the operating range of the motor without demagnetization.

This paper presents a five-phase external rotor permanent magnet assisted synchronous reluctance motor (PMa-SynRM) with low torque ripple and cogging torque for in-wheel applications. Multi-phase internal rotor electric motors have been proposed for vehicular applications as they possess low torque ripple and low back-EMF harmonics. However, increase in the power density while maintaining the same size and amount of PMs has been a challenging issue. In comparison to the internal rotor motors, external rotor motors can be optimally designed to produce higher torque density with low torque ripple. In this study, the design technique to develop an optimal five-phase external rotor PMa-SynRM model is discussed in detail. Detailed finite element simulations are conducted on the optimally designed 3.8kW five-phase external rotor PMa-SynRM and the results are compared with five-phase internal rotor PMa-SynRM. With the same size, volume, and lower PM composition, the 3.8kW five-phase external rotor PMa-SynRM is capable of generating higher torque density with lower torque pulsation and almost negligible cogging torque in comparison to the 3kW five-phase internal rotor PMa-SynRM. Experimental results are compared between five-phase internal and external rotor PMa-SynRMs to validate the simulation results.

This paper provides a performance comparison between three-phase and five-phase ferrite-based permanent magnet assisted synchronous reluctance motor (PMa-SynRM). Recently, research on PMa-SynRM has got significant attention, especially in vehicular applications. They can meet the performance requirements of electric vehicles with reduced or no use of rare-earth-based permanent magnets (PMs). However, these motors face the challenges of lower torque density, irreversible demagnetization tendency, and intolerance to the augmented stress due to the relatively higher amount of PM. These challenges can be mitigated by employing five-phase winding which can develop higher power density with lower torque pulsation compared to the conventional three-phase motor. This paper compares the electromagnetic performance of a three-phase and five-phase Ferrite magnet based PMa-SynRM. A thorough finite element analysis (FEA) has been presented to validate the superior demagnetization preventing capability, and stress tolerance capability of the five-phase PMa-SynRM over the three-phase PMa-SynRM. Experimental results of the induced voltage for fabricated three-phase and five-phase PMa-SynRMs will be provided to validate the FEA results.

This paper presents the design optimization of rare-earth-free permanent magnet assisted synchronous reluctance motor (PMSynRM) with an objective to improve the demagnetization prevention capability. Ferrite magnet is a common rare-earth-free permanent magnet (PM) which is attracting the manufacturers with its lower price and abundant supply compared to rare-earth materials such as Neodymium, Samarium, and Cerium based PMs. However, due to lower coercive force, Ferrite magnets have a higher risk of getting demagnetized than rare-earth magnets. Therefore, Ferrite based motor should be carefully designed so that the magnets do not get demagnetized at any desired operating condition. This study proposes a Ferrite magnet based PMSynRM (F-PMSynRM) with non-conventional flux-barrier structures to improve its demagnetization prevention capability while maintaining the same output power as a conventional F-PMSynRM. The equivalent magnetic circuit (EMC) has been used to obtain and justify the proposed motor of improved demagnetization prevention capability. Besides, finite element analysis (FEA) results have been presented to compare the proposed motor and conventional motor in terms of their electromagnetic torque, back-emf, stress and demagnetization preventive capability. Experimental results of the no-load induced voltage have been provided to validate the analytical and simulation results.

This paper compares the performance of five-phase external rotor permanent magnet assisted synchronous reluctance motor (PMaSynRMs) for two different winding configurations. In vehicle applications, five-phase winding improves power density, fault tolerant capability and reduces torque pulsation compared to a conventional three-phase winding whereas the adoption of external rotor architecture increases the power density. However, the degree of freedom reduces in selecting winding configuration for multiphase motors which is very critical for performance of PMaSynRM. Therefore, for the design external rotor PMaSynRM, the winding topology like slot/pole combination and coil-distribution should be carefully selected to obtain higher power density with higher efficiency and lower cost. This paper compares the electromagnetic performance of two motors having two different winding topologies, one has fractional-slot concentrated winding (FSCW) with 15slot/12pole and the other one has fractional-slot distributed winding with 25slot/12pole. The analytical modeling and optimization procedure to obtain these motors have been discussed briefly followed by thorough finite element analysis to compare the performance of the motors. Finally, the experimental results have been presented to verify the induced voltage of one motor at no load condition.

This paper presents the design considerations of a five-phase outer rotor interior permanent magnet motor (IPM) for an electric bicycle (e-bicycle). Conventional e-bicycles employ three phase outer rotor surface permanent magnet motors which are less reliable compared to the five-phase IPM motors. Moreover, the traditional electric motors use rare-earth permanent magnet materials such as neodymium which are expensive. Ferrite based magnets can be a better substitute to rare earth materials to make the motor more affordable. In this study, the design of a highly reliable and economical five-phase ferrite based IPM motor to be accommodated in a hub motor drive (HMD) for an e-bicycle is presented. The proposed motor design is optimized using a lumped parameter model (LPM) based optimizer. Detailed analysis on the design parameters and constraints considered for optimization is discussed. Thorough finite element simulations in terms of torque developed, cogging torque, back-EMF, and mechanical stress have been conducted to verify the effectiveness of the proposed motor design.

This paper presents the design of optimal five-phase permanent magnet assisted synchronous reluctance motor (PMa-SynRM) for integrated starter generator (ISG) application. PMa-SynRM is the hybrid structure of interior permanent magnet (IPM) motor and synchronous reluctance motor (SynRM). In this study, an optimized 15kW five-phase PMa-SynRM has been proposed as a better substitute for three-phase IPM motor for ISG operation in Honda Civic Hybrid car. A new reverse engineering technique (RET) has been applied to model the Honda IPM ISG. In order to develop a better PMa-SynRM ISG, the model developed using RET has been used as reference. Thorough analytical and finite element analysis have been performed to obtain the optimal PMa-SynRM design which has better performance characteristics compared to the Honda IPM ISG. Lumped parameter modeling (LPM) has been utilized with differential evolution (DE) optimizer to extract the best optimal design for the five-phase PMa-SynRM ISG. For the same power and volume, five-phase PMa-SynRM design has shown better performance characteristics in terms of cogging torque and torque developed.

This paper presents fault detection and its analysis for permanent magnet assisted synchronous reluctance motor (PMa-SynRM). The PMa-SynRM has been increasingly studied for critical service application where high efficiency and reliability is required in industry. However, the research on the fault in a PMa-SynRM has been limitedly studied, and no study on the eccentricity fault diagnosis for multiphase PMa-SynRM has been documented so far. The three-phase and five-phase PMa-SynRM has been comparatively analyzed under eccentricity condition to identify a fault diagnosis index which is independent from phase numbers. The simulation model for PMa-SynRM has been developed using finite element method (FEM). Through FEM, static eccentricity (SE), dynamic eccentricity (DE) and mixed eccentricity (ME) are designed to evaluate the performance of the multiphase PMa-SynRM motors under faulty conditions. The fault features have been extracted through average torque, torque ripple, and back-EMF harmonics. Theoretical analysis with designed motors has been done to evaluate extracted features under eccentricity condition.

This paper focuses on multi-objective optimization of multi-phase Permanent Magnet Assisted Synchronous Reluctance Motor (PMa-SynRM) using Lumped Parameter Model based Optimizer (LPO). Optimized PMa-SynRM are cost efficient compared to Interior Permanent Magnet Motor (IPM). Five-phase PMa-SynRMs offer lower torque ripple and higher fault tolerant capability. Depending on various industry application and their application environment, PMa-SynRMs should be customized with appropriate design specification including different current rating, torque ripple, converter cost, magnet cost and overall machine cost. The developed LPO can efficiently extract optimized multi-phase PMa-SynRM models from different design families through defined Objective Functions (OFs). To prove the accuracy of developed LPO for different OFs, four PMa-SynRM models have been obtained while minimizing torque ripple, phase current, machine cost, and magnet costs respectively. Finally, Finite Element Analysis (FEA) of these models has been performed to validate accuracy of the LPO by comparing predicted performances through LPO and FEA.

This paper proposes an efficient and reliable five-phase ferrite magnet assisted synchronous reluctance motor (Fa-SynRM) which exhibits comparable performance to a five-phase rare-earth permanent magnet based PMa-SynRM. Five-phase PMa-SynRM offers higher reliability and lower torque ripple compared to conventional three phase PMa-SynRMs, and low-cost ferrite magnet potentially decrease the manufacturing cost. However, lower strength of ferrite magnets require more magnet composition and increase stress towards the edges of flux barriers. Demagnetization of ferrite magnets is another factor to be considered in designing the Fa-SynRM. Initially, to develop an optimal and sustainable design, a lumped parameter model (LPM) based optimizer and a finite element model (FEA) has been used to extract an optimal model. The designs are further optimized to reduce the cost and develop more robust models to stress and demagnetization. Finally, the performance and cost of the developed models have been compared to those of benchmark model and initial LPM model.

According to “Bangladesh Economic Rivew-2013”, the number of registered poultry farms in Bangladesh till February, 2013 is about 65902. This is believed to be more than two hundred thousand by non-government statistics. The number is increasing rapidly with the growing demand of protein and dependency on poultry-birds for this. Each and every farm draws certain amount of electric power. Most of these farms draw power from the national grid; some of them use natural gas or diesel generators and very few farms use their own poultry droppings for producing biogas and generating electricity. Unfortunately, these few biogas plants not even run to the peak of their capacity. The over reliance on national grid and fossil fuels aids to the emission of greenhouse gases and it is going to spiral up every year. If these poultry farms could produce sufficient energy from the poultry droppings then their annual costs, greenhouse gas emission as well as fossil fuel dependency will become nominal. The aim of this study is to reveal the prospect of self-sufficient poultry farms using their poultry droppings only. A comparison is made among the annual costs, energy efficiency and greenhouse gases emissions from different sources of energy or different mix of them. It is seen that coproduction of electricity and fertilizer optimize the mentioned constraints.

In Bangladesh, biogas has a huge potential with it's over 200000 poultry and about 200 million of poultry birds. Contrary to the immense potential of producing 1.33TWhr electricity per year from poultry industry, only few number of biogas plants have been deployed in some farms till date. Besides, most of these plants are unable to produce the expected amount of biogas for their technical shortcomings. Most of these plants run by locally made equipment and don't have any scheme for controlling the significant factors of biogas production. However, there are few bigger sized plants consisting imported digesters, monitoring and controlling systems which yield larger amount of biogas production. In this study the impacts of some major factors on biogas production was analysed comparing biogas production between locally made digesters and imported digesters. The result reveals that up to 75% more biogas is generated in imported digesters than the locally made digesters.

A good chunk of population of Bangladesh are not blessed with electricity, are living in medieval conditions, use charcoal and wood as the sources of energy, and of course, fire hydrocarbons for lighting their houses. For sustainable development, this huge population should be brought under the coverage of electricity, which is very difficult for country like Bangladesh as natural resources are scarce and budget is inadequate. But with proper planning, widespread rollout of renewable sources could change the scenario and provide a facelift to the insipid pastoral Bangladesh. As solar panels are costly, wind power could be the mantra for the future. Despite of the huge potential, very limited works have been done on assessment and development of biogas technology. This paper has attempted to assess the performances of hypothetical wind farms at different heights at different locations of Bangladesh in terms of plant capacity factor (PCF). Keywords— Wind Speed, Wind Power Density, Wind Energy, Plant Capacity Factor