Generator Shaft Research Articles

Constrained Model Predictive Control for Generation Power Distribution on Aircraft Engines

Aiming at the increasing demand for electric energy in aircraft in the future, a multi-objective optimization aircraft engine constrained model predictive control method based on generation power distribution is proposed. Firstly, based on the aircraft engine component level model and the equilibrium manifold theory, the aircraft engine equilibrium manifold expansion model is established. Secondly, the influence of the power generation is modeled, and the influence of the low- and high-pressure shaft generators on the normal operation of the aircraft engine is studied and compared. The control variables such as fuel flow and total generation power are taken as the constraint conditions to design the constraint model predictive controller. Furthermore, the multi-objective grey wolf optimization algorithm is introduced to intelligently optimize the parameters of the designed controller. At last, the simulation based on the component level model shows that the high-pressure shaft generator has less influence on the state quantity, including engine thrust, than the low-pressure shaft generator. The proposed control method using the multi-objective gray wolf optimization (MOGWO) algorithm has rapid response and no steady-state error.

Investigation of the influence of the number of poles on the external characteristic of a brushless DC machine in the generator mode

The article presents the results of a study on the generator mode of operation of a brushless DC machine (BLDC) when operating under active load. For analysis, two models were created with the number of permanent magnets on the rotor differing by a factor of two. The relevance of the research is due to the wide range of applications of BLDC in various fields. One of the key advantages of BLDC is the absence of a brush-commutator unit, which is replaced by a controller with semiconductor elements. This increases the reliability of BLDC and expands the range of operating modes. The main objective of this study is to determine the impact of the number of permanent magnets on the external characteristic of BLDC in generator mode. To achieve this goal, computer modeling was performed using ANSYS Maxwell software. This software is designed to study and calculate the magnetic field pattern using the finite element method in electromechanical devices, providing accurate results for analysis. For each BLDC model, the degree of saturation of the magnetic system elements was determined, and graphs of voltage, current, and braking torque at the generator shaft over time were obtained. Analysis of the calculation results for BLDC models with 46 and 92 permanent magnets demonstrated an impact on the voltage and current waveforms, leading to some slight distortion of their shape. The obtained calculation results allowed determining the efficiency and constructing the external characteristic for both BLDC models. Higher efficiency was obtained for the BLDC model with 92 permanent magnets on the rotor. The external characteristic for the generator mode of BLDC operation demonstrated a change in voltage when transitioning from idle to nominal current operation within the range of 15% and 21%, indicating the stiffness of the characteristic. The conclusions of the study indicate the potential for improving the efficiency of BLDC through optimization of the magnetic system design and cooling conditions, and can be useful for engineers and developers of electromechanical systems aiming to improve the performance of their products.

Design of voltage and frequency stabilization system for fishing vessel shaft generator based on UPS backup power supply

Abstract A fishing boat shaft generator is a kind of power supply device driven by the main diesel engine, which has the advantage of saving energy compared with a diesel generator and eliminating the need to be equipped with an additional diesel engine, witnessing wide applications in the use of power supply equipment for fishing boats. However, because the shaft generator is mounted on the main diesel engine, the fishing boat encounters bad sea conditions at sea, and the speed of the diesel engine fluctuates, resulting in the instability of the power frequency and voltage sent by the shaft generator, which will endanger the electrical equipment of the fishing vessel in serious cases. In this paper, a design of a voltage and frequency stabilization system for a fishing vessel shaft generator based on a UPS backup power supply was proposed. The system consists of a three-phase shaft generator, inverter, battery, and electrical equipment. The inverter control strategy is introduced, and the battery charge/discharge and DC boost are designed.

РЕМОНТ КОРЕННЫХ И ШАТУННЫХ ШЕЕК КОЛЕНЧАТЫХ ВАЛОВ ДИЗЕЛЬНЫХ ДВИГАТЕЛЕЙ ПРИ ПОМОЩИ ДИСКРЕТНОГО УПРОЧНЕНИЯ

Studies to assess the effect of discrete hardening of the crankshaft journals on its fatigue strength have been carried out. For this purpose, fatigue tests were carried out on two control parts of the D80 type crankshaft. It was established that the destruction of control part No. 1 occurred after 322,000 cycles, control part No. 2 after 201,000 cycles. The destruction zone of both control parts passes along the R8 mm transition fillet of the connecting rod journals. This allows us to conclude that the discrete hardening factor is not associated with fatigue failure of the control parts. In order to determine the service life of the crankshaft of the KamAZ 740 engine, strengthened in a discrete way (shaft of the fourth repair size), it was installed on a KamAZ 5320 vehicle. As a result of the tests, it was found that during the entire testing cycle the vehicle's mileage was 109,000 km. Moreover, at the time of completion of the tests, all parameters of the car’s engine met the technical requirements. The KamAZ 5320 vehicle is in operation to this day. Its mileage was 269,000 km without stopping for major repairs. To conduct operational tests of a cast iron crankshaft with discrete hardening of a D80 type engine, a 1D80B diesel generator engine was taken, which after assembly was subjected to full-scale testing. These tests included a 100-hour engine run-in, determination of the vibration level and amplitudes of torsional vibrations of the diesel generator shaft line in the operating speed range. The analysis of the vibration state of the engine showed that in all test modes the vibration level at the points under study does not exceed the norms (0.350 mm on the turbocharger housing and 0.150 mm on the generator foot). The maximum stresses from torsional vibrations were: 8, about 17.5 MPa; 4, 5 order 10.5 MPa; 1.5 order 10.0 MPa. The resulting stress levels are significantly lower than permissible. Tests of the 1D80B diesel generator showed its full compliance with the technical requirements for the operation of this engine.

Torque fluctuation and critical clearing time in wind power generation by induction machines.

Squirrel cage induction machines represent a common solution widely adopted in wind generation. The induction machine is simple, reliable, cheap and requires very little maintenance. Some problems are, however, connected with the use of induction machines in wind power generation systems. In particular two effects have to be taken into account: the torque fluctuations at the generator shaft and the critical clearing time (CCT). Both problems represent a serious limitation for weak networks in which the first effect can cause flicker effect while the CCT is very short. In the paper a full modelling of a wind energy plant constituted by n machines is presented. Using the set-up model the behaviour of the plant for a different number of connected machines is analysed. In particular, the system stability connected with voltage sags and network faults is studied

Research on Improving Energy Efficiency Through Optimal Load Control Between a Ship’s Shaft Generator and Diesel Generator

Research on Improving Energy Efficiency Through Optimal Load Control Between a Ship’s Shaft Generator and Diesel Generator

Investigation of transients in asynchronous generators used in microhydroelectric power plants

In this article, a study of transients in autonomous asynchronous generators used in microgenerators is carried out. This article analyzes the transients occurring in an asynchronous generator by starting an asynchronous motor by exciting an asynchronous generator using capacitor elements of reactive power consumption. To start the asynchronous generator, mechanical energy is supplied to the shaft of the asynchronous motor at a speed 5-10% higher than the nominal number of revolutions, after which the asynchronous motor starts working in generator mode and generates electricity. To launch the CASSY Lab program, the electrical parameters of an asynchronous generator were considered, as well as transients occurring in operating modes by digitally transmitting the parameters of the electrical energy generated by the generator. Starting an asynchronous generator with the help of this program, a real experimental test was also carried out to determine the sinusoidal forms of voltage and current in three phases in the yuksiz, load and overload operating modes. In the course of a real experiment, it was concluded that the improvement of transients occurring in the modes of operation of an asynchronous generator, i.e. transients during the transition from a non-loading mode of operation to a mode of operation with a load, depends on the mechanical energy transmitted to the shaft of an asynchronous generator for grinding.

РАСЧЕТ ЭНЕРГЕТИЧЕСКОГО БАЛАНСА МНОГОАГРЕГАТНОЙ ВЕТРОЭНЕРГЕТИЧЕСКОЙ УСТАНОВКИ В УСЛОВИЯХ НИЗКИХ СРЕДНЕПЕРИОДИЧЕСКИХ СКОРОСТЕЙ ВЕТРА

Energy supply of small facilities of the agro-industrial complex of Russia in remote rural areas using wind energy is an urgent task. Classical wind power plants operate efficiently at a wind speed of more than 7 meters per second, but in most of Russia such a wind speed is rare. Therefore, the utilization rate of the installed capacity of a wind farm is only 0.2. (Research Purpose) The research purpose is developing a method of increasing the utilization rate of the installed capacity of a wind farm and calculating its energy balance at average periodic wind speeds from 4 to 6 meters per second. (Materials and methods) To implement the proposed method, a multi-unit wind power plant consisting of wind receiving devices of various types driven by hydraulic pumps was used. As a result, the working fluid is feed into the hydraulic accumulating unit, from where the working fluid is fed to the hydraulic motor, which provides rotation of the generator shaft. (Results and discussion) At a wind speed of 4-11 meters per second, the total supply of the working fluid of all hydraulic pumps is greater than the required flow rate of the hydraulic pump. It was found out that in a typical period with an average periodic wind speed of 4-6 meters per second, the total volume of fluid supply by hydraulic pumps is 605.2; 758.0; 844.6 liters per hour, respectively. At the end of the period, 5.2 and 158.0 to 254.6 liters of liquid remain in the storage unit, which can compensate for calm periods up to 15-20 minutes. (Conclusions) The proposed method for increasing the utilization rate of the installed capacity of a wind power plant provides the required supply of hydraulic fluid at an average periodic wind speed of 4-6 meters per second, the annual utilization rate of the installed capacity of a wind power plant is 40-50 percent.

Thermoplastic polymer track with gearing mechanism to harvest green energy for sustainable development

Consumption of energy and its demand is increasing constantly. There are various ways to generate energy. Non-renewable energy sources are in high demand, which causes harmful effects on the atmosphere. So environmentally friendly energy sources are very much required. Recently various researchers have been working towards green and environment friendly renewable energy causes. Energy generation from renewable sources, India is within top five position throughout the world. Support towards enhancement of energy generation by renewable sources has been declared by our Honourable Prime minister. The present work deals with a designed model to generate electricity by utilizing energy from footstep movement and vehicle motion. The designed model consists of a gearing mechanism, lever, and thermoplastic polymer track attachment. Thermoplastic tracks are easy to use because of their easier attachment and smooth surface. It is required to attach our designed system in places where maximum mobility of people and vehicle motions is possible. Generally, the places are national highways, temple roads, mall areas, etc. Due to movements on the track, the pressure energy of the foot and vehicle wheels transfers to rotational energy through the gearing attachments of our designed system. This rotational energy is utilized to rotate the armature of the generator to generate electricity and that electricity is stored in the battery for utilization on demand. The lever arm and thermoplastic track are placed with a 10 mm gap so that when load is applied on the track, the thermoplastic will deflect and the load will be transferred to the lever. Due to the provision of a gearing mechanism in our designed system, less input on the track will produce the required rotation of the generator shaft. Natural walking on the track to harvest energy without disturbing the body is very suitable for the stability of this designed system due to the provision of thermoplastic tracks.

Black Widow Optimization Algorithm-Based Sub Synchronous Resonance Investigation with Series Compensation

The integration of wind farms into the transmission network has raised various concerns and objections. To address these challenges, the deployment of series compensators has gained significance as an effective method for enhancing the power transmission capacity of existing lines, particularly for the integration of large-scale wind farms. However, the use of series reactive compensation lines can lead to a phenomenon known as sub-synchronous resonance (SSR) in turbo generators. This SSR can cause electrical instability at sub-synchronous frequencies and potential damage to the turbine’s generator shaft, particularly during periods of peak production. As a result, the assessment of SSR through comprehensive surveys is crucial for wind power engineers to make informed decisions and ensure the safety of turbines. This study explores the potential of SSR through the utilization of the black widow optimization technique. The analysis takes into account variables such as variations in the speed of the wind, compensation spectrum, and wind velocity and examines the eigenvalue and involvement components under various operating situations. To validate our findings, electromagnetic transient simulations are conducted using the PSCAD/EMTDC software, employing the initial IEEE reference systems. This research contributes to a deeper understanding of SSR and its implications for wind energy systems.

A dual-kinetic energy harvester operating on the track and wheel of rail deceleration system for self-powered sensors

Alternative energy sources play a crucial role in Outback rail systems, where electrical infrastructure is unavailable for automated power devices used for traffic lights, surveillance cameras, sensors, and other safety equipment at railway stations and intersections. The current study proposes an innovative dual-kinetic energy harvester design to reduce train speed at intersections and before it comes to a halt at the station. Additionally, it harvests energy from both the train track and wheel simultaneously. The proposed device consists of three main units. The first unit utilizes vibrational movement based on a rack pinion. An efficient dual-kinetic energy harvesting system has been developed, utilizing a novel concept that captures the vibration energy generated by the movement of the rail under the influence of the train’s weight. Additionally, as the train passes at high speed, the train wheel’s energy will be transmitted to the top of the device, moving the rack to a depth of 30 mm. A spiral spring is employed to restore the rack to its initial position after the wheel has passed. The tension force of the spring causes the rack to adhere to the track, enabling the transmission of vibrations generated by the track’s movement and releasing energy, causing the motion to be induced during the return stroke. The second component is the transmission unit. The bidirectional rotational motion from the rack pinion is converted into unidirectional rotational motion using three bevel gears, two roller clutches, and a planetary gearbox to enhance the rotations of the generator shaft. The third component is a 1500 W/180 V DC motor for electricity generation. Lastly, the charging circuit was developed to recharge supercharged capacitors. The proposed system was installed before the railway station, and practical tests were conducted, which showed an efficiency of up to 55%.

Challenges of Large Converter-Fed Synchronous Machines for Variable-Speed Pumped Hydro Storage

The green energy transition of electrical energy production is leading to an increasing share of total energy production for volatile renewable energy sources, mainly wind and solar power. To handle this volatile production, flexible and efficient energy storage is required. The development of high-power converters has enabled the generation of variable-speed pumped hydro storage power plants, combining the so-far-unequalled energy storage capacity of classical pumped-storage hydro power plants and the recently increased operation requirements. The introduction of large-scale converters has led to new challenges in the overall design of power plant systems. This paper intended to take a closer look at a large-scale converter-fed synchronous generator, especially the distribution of the current and voltage harmonics caused by the converter in the implemented generation system. Thereby, holistic design considerations for an ideal loss distribution as well as possible measures to limit the effects of harmonic coupling at the generator shaft and bearings are discussed. Furthermore, basic considerations of harmonic emission to the connected network are described. These topics are addressed by analyzing on-site measurements at an 85 MVA converter-fed synchronous generator with a voltage source inverter, underpinned with the theoretical background.

An electromagnetic vibration energy harvesting system based on series coupling input mechanism for freight railroads

Vibration energy harvesting technology is characterized by wide distribution, is pollution-free and independent of weather and climate, and is suitable for powering low-power sensors to ensure efficient and safe operation in freight railroads. This paper proposed an electromagnetic vibration energy harvester based on a series coupling input mechanism for the self-powered sensors in freight railroads. The design utilizes only one rack for vibration energy input to minimize the moment acting on the vibration source during the working process. Two pinions meshed with the rack convert the up and down vibrations into a two-way rotation. The one-way bearings and another pair of gears convert the opposite rotations of two parallel shafts into one-way rotation of the generator shaft, generating electricity. Supercapacitors and rectifier voltage regulator modules are utilized to store electrical energy efficiently. A peak power of 10.219 W and maximum mechanical efficiency of 64.31% is obtained in the experiment equipped with a flywheel under the 8 mm-4 Hz sinusoidal vibration excitation. The experimental results showed that the flywheel can enable the proposed harvester to achieve better power generation performance when the amplitude and frequency are relatively high.

Condition Evaluation of Steam Turbine Generator Using Minute-Interval Integrated Vibration Signals

Vibration levels are a primary indicator for condition monitoring of Electrical Machine (EM) systems. This work employs Singular Spectrum Analysis (SSA) to analyze vibration time series of shaft and bearings of a real 250MW industrial power plant steam turbine Synchronous Generator (SG) in Greece. The SG operates under reduced power due to increased vibration conditions according to threshold guidelines. This work attempts to retrieve fault indications from the minute-interval integrated signal sample via its trend and periodicity components to predict vibrations under full load operation and establish correlations to discern whether the reduced output is justified. The successful application of this novel procedure is important due to ease of storing and handling low frequency signals, especially in remote environments. Rules are established using fuzzy logic due to the nature of the dataset and industrial application. The predictor employed is based on Sugeno-based Adaptive Neuro Fuzzy Inference System (ANFIS).

Effects of non-symmetric non-uniformly distributed welding residual stress on fatigue failure initiation and propagation in a hydropower generator shaft

PurposeThis article aims to investigate and model the effects of welding-generated thermal cycle on the resulting residual stress distribution and its role in the initiation and propagation of fatigue failure in thick shaft sections.Design/methodology/approachExperimental and numerical techniques were applied in the present study to explore the relationship(s) between welding residual-stress distribution and fatigue failure characteristics in a hydropower generator shaft. Experimental techniques included stereomicroscopy, optical and scanning electron microscopy (SEM), chemical analysis and mechanical testing. Finite element modelling (FEM) was used to model the shaft welding cycle in terms of thermal (temperature) history and the associated development of residual stresses within the weld joint.FindingsExperimental analyses have confirmed the suitability of the used material for the intended application and confirmed the failure mode to be low cycle fatigue. The observed failure characteristics, however, did not match with the applied loading in terms of design stress levels, directionality and expected crack imitation site(s). FEM results have revealed the presence of a sharp stress peak in excess of 630 MPa (about 74% of material's yield strength) around weld start point and a non-uniform residual stress distribution in both the circumferential and through-thickness directions. The present results have shown very close matching between FEM results and observed failure characteristics.Practical implicationsThe present article considers an actual industrial case of a hydropower generator shaft failure. Present results are valuable in providing insight information regarding such failures as well as some preventive design and fabrication measures for the hydropower and other power generation and transmission sector.Originality/valueThe presence of the aforementioned stress peak around welding start/end location and the non-uniform distribution of residual-stress field are in contrast to almost all published results based on some uniformity assumptions. The present FEM results were, however, the only stress distribution scenario capable of explaining the failure considered in the present research.

High-efficiency regenerative shock absorbers considering twin ball screws transmission for increasing the vehicles’ driving range using a hybrid approach

This article proposes a hybrid system for increasing the electric vehicles’ (EVs) driving range considering regenerative shock absorbers. The proposed hybrid approach is a combination of atomic orbital search (AOS) and wild horse optimizer (WHO); later, it was called AOSWHO method. The major objectives of the proposed work are to extend vehicle range, reduce the charging time of the vehicle, reduce the battery size, and increase the efficiency of vehicle. In this proposed work, linear Permanent magnet (PM) generators are used as the sole instrument and on-board source is utilized to absorb vibration energy of the moving vehicle. Here, the proposed method has four key modules: (a) suspension vibration input, (b) transmission mechanism, (c) generator module, and (d) power storage. A suspension vibration is mostly pretentious by road roughness and speed vibration, which is optimally handled by the proposed hybrid technique. The conversion of the alternating linear vibration into unidirectional rotation of generator shaft is processed by proposed hybrid technique. Based on the volume and efficiency of the dampers, a small volume, brushless DC motor with low rotor inertia is selected to produce electricity. By then, the proposed AOSWHO run on MATLAB site and its performance is related to several existing systems. From the simulation result, it is concluded that proposed system delivers an State of Charge (SOC) of 40.33, which is high compared to existing approaches.

Energy regenerative shock absorber based on a slotted link conversion mechanism for application in the electrical bus to power the low wattages devices

In recent years, using electric buses based on sustainable energy technologies has become very popular due to their advantages of protecting the environment from hazardous pollutants. However, the power supply of electric buses is the most challenging issue and hinders it from making efficient electric buses. In this study, an energy regenerative shock absorber (ERSA) was designed to be employed in the electric bus to harvest kinetic energy from rough road profiles and enhance the efficiency of electric buses. The proposed ERSA is based on a slotted link conversion mechanism to convert linear vibrations to unidirectional rotations of the generator shaft for energy harvesting and comprises four modules: the energy input model, the motion converter model, the model of a generator, and the electrical energy storage model. Firstly, the energy input model induced vibration into the proposed shock absorber; the motion converter model converts linear vibrations to unidirectional rotations using a slotted link conversion mechanism to drive the generator. Subsequently, the generator model generated electric energy stored in the power storage model. The theoretical model was developed, and simulations were performed using MATLAB software; after that, the real-scale prototype was evaluated through an experimental study using a mechanical bench test (MTS machine) under similar parameters. An average output power of 6.591 W with an efficiency of 39.37% was achieved. Moreover, the ERSA system showed a maximum efficiency of 67.7% during sinusoidal excitations of 7.5 mm and 2.5 Hz. Furthermore, the feasibility analysis was conducted to verify the suitability of the proposed system for powering the auxiliary devices in the electric bus. The suggested ERSA can reasonably power light detection, range sensors, stereo vision cameras, an inertial measurement unit, an accelerometer, and a global navigation satellite system.

Mathematical modeling of a hybrid magnetic gear for an autonomous low-power wind turbine

In traditional wind turbines, a mechanical gearbox is used to transmit the torque. This device converts the low rotation speed of the wind turbine blades into the high rotation speed of the generator shaft. Mechanical gearboxes are characterized by low reliability. They consist of rotating gears, all the torque between which is transmitted through the contact of the teeth at one point, which is accompanied by friction. Magnetic multipliers are more efficient than gear reducers. They contain no wearing parts and have a relatively high torque density. The modulator transforms the magnetic field between the inner and outer rotor, due to which the speed of rotation changes. This device has a number of advantages over a mechanical gearbox - the interaction between rotating elements (torque transmission) occurs over their entire area, while the gears of mechanical gearboxes perceive all the transmitted force at one point of contact between them. Research of autonomous wind turbines built on the basis of magnetic gearboxes is a relevant direction. This will reduce operating costs, increase the efficiency of converting wind energy into electricity, and increase the reliability of the wind turbine as a whole. The purpose of the work is the development of a two-dimensional field mathematical model of a hybrid magnetic gearbox for the evaluation of its parameters and characteristics and the optimization of its geometric dimensions. A generator with a built-in magnetic multiplier is the object of this study. The magnetic multiplier during operation creates a rotating magnetic field that can be used to induce emf in the generator winding. Such a generator is more compact than a gear drive, so this option was chosen as a prototype in this study. Geometrical models of a hybrid generator with a magnetic gearbox were developed and numerical field mathematical models were developed for the analysis of its parameters and characteristics. An analysis of the electromagnetic field and characteristics of the basic generator was carried out in the COMSOL Multiphysics software complex, on the basis of which optimization of its geometric dimensions was carried out to optimize mass and dimensional indicators

Input Power Measurement System For Driving Motor In Testing Low-Speed Generator

Rapid technological advances are affecting the greater use of electrical energy. One of the devices that can generate electrical energy is a generator. Testing the characteristics of the generator required a drive motor to rotate the generator shaft. This research aims to create a three-phase input power measurement system for driving a motor. The method of measuring input power is by measuring the current and voltage of each phase. The power is obtained from the multiplication between current and voltage. The system consists of current sensors, voltage sensors, a signal conditioning circuit, and an Arduino Mega microcontroller for data processing. The system is equipped with a graphical user interface, data storage, and application. The generator input power measurement system has been created and tested. The measurement system has successfully measured the input power of the generator's driving motor, which in real-time is displayed on the trend graph via the graphical user interface on the laptop. The input power measurement data on the three-phase generator and the time data have been successfully stored inside the micro-SD. The average error of the voltage reading is 2% compared to the measurement of the reference voltmeter. The current reading error was 2% compared to the reference meter ampere measurement.

Alternative Surface-Mounted Permanent Magnet Topology for Reducing Voltage and Torque Harmonics in Shaft Generators

Traditional diesel generators on a merchant ship, composed of a wound rotor synchronous generator and a four-stroke diesel engine, supply electrical power for various loads. Recently, shaft generators for merchant ships have been increasingly replacing diesel generators to reduce CO2 emissions through fuel efficiency improvement. In particular, permanent magnet synchronous generators have replaced induction generators due to their high-efficiency characteristics at light loads. The surface-mounted permanent magnet rotor can be a suitable topology owing to the relatively short constant power range. This generator can also operate as a motor according to the propulsion mode, so minimizing the harmonics of the induced voltage with the torque pulsation being essential. This paper proposes an alternative surface permanent magnet topology. Three magnets comprise one pole, with one bread-loaf magnet and two rectangular magnets. It helps to simplify the magnetization and assembly of the rotor because of the flat bottom shape of the magnet. Due to the low remanence of two rectangular magnets at the pole edge, this rotor structure effectively makes the air-gap magnetic flux density sinusoidal with production costs reduced. The step-skew suppresses higher-order harmonics. The total harmonic distortion comparison of the two-dimensional finite element analysis and the no-load test result shows under 6% difference from the interior permanent magnet prototype machine. A comparison of harmonic characteristics with other rotors shows that the proposed modular pole has sufficient competitiveness compared to the tapered bread-loaf type. It can be applied as a substitute for the tapered bread-loaf magnet in direct-drive ship propulsion systems and is expected to shorten the manufacturing process and time.