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The air-core pulsed alternator capable of miniaturization and lightweight has become one of the most potential power supplies for electromagnetic railguns equipped in all-electric vehicles or ships that have strict restrictions on volume and weight. Although the air-core machine has undergone decades of continuous research, a systematic theoretical basis is still in absence, especially for electromagnetic analysis and transient operating analysis. Besides, researchers are less willing to share their latest achievements for the sake of national interests, and the detailed experimental results of this alternator are seldom made public in recent years. In this article, the electromagnetic theoretical analysis, including the analytical expressions of magnetic flux density and inductance parameters, is carried out. Then, a comprehensive transient operating theoretical analysis of four stages is put forward with some typical operating parameters derived. Based on these two kinds of theoretical analysis, the scheme of a six-pole and seven-phase alternator is determined. Simulations are executed to verify the theoretical analysis and prove that the designed alternator can meet the proposed operating targets. Finally, some preliminary experiments for the fabricated prototype are conducted under low experimental parameters. The experimental results indicate that the power electronic devices can work properly, and the self-excitation rectifier takes effect in lifting up the field current. Although the discharge experiment is not carried out under rated experimental parameters, it still makes sense since it reveals the superiority of the prototype in releasing a discharge current very close to an ideal trapezoidal wave to ensure that the projectile can move steadily in its acceleration process.

As a kind of high power pulse power supply, the air-core compensated pulse alternator (CPA) is widely used in electromagnetic emission, laser weapon, pulse capacitor charging, and other fields. A brush structure or a brushless structure can be used in the air-core CPA. Because the brushless structure is more suitable for high-speed operation and has higher reliability, more and more scholars have studied the brushless structure air-core CPA. In this article, an electric excitation brushless air-core CPA which the equivalent pole-pairs number is one is proposed. The CPA adopts a brushless rotor winding designed based on the principle of magnetic field differential modulation, which can simultaneously produce two and three pole-pair magnetic fields rotating in the same direction. The rotor winding can couple the field winding and the armature winding at the same time, thus realize electromechanical energy conversion. Under the same conditions, the pulsewidth of pulse discharge current can be significantly increased by reducing the number of pole pairs of the CPA and the output energy of a single pulse can be improved. In this article, a detailed design method of the differential modulation rotor winding of the CPA is presented, and the harmonic content of the CPA is calculated by analytical and numerical methods. Finally, the finite element model is used to analyze the related performance of the CPA, and the analysis results verify the effectiveness of the design scheme.

The pulsed power supply based on air-core pulsed alternators, with advantages in terms of miniaturization and lightweight, has been a preferred power source for electromagnetic launch (EML) systems in all-electric vehicles or ships. However, when an air-core pulsed alternator is used to drive the electromagnetic railgun, the bulk of the inertial energy storage converts into energy losses. These losses not only reduce the efficiency of the system but also cause temperature rising of the alternator, leading to a limit on its repetitive output performance, affecting the performance of the electromagnetic railgun, and ultimately, the alternator’s volume and weight will also increase. Therefore, it is necessary to develop research relating to those losses. In this article, the operation principle of the EML system is explained first, and four typical operating stages are described. Then, the influence of the rotor eddy current on the performance of the alternator is analyzed. After that, the various losses generated in the pulsed power supply system are analyzed in detail. The eddy current losses are obtained from simulation. The copper losses and switch losses are calculated by formulas derived in different stages and different members. The formulas of windage and mechanical losses are obtained too. Based on these analyses, losses can be calculated by the parameters of the EML system or derived from a cosimulation model. Also, the influence of alternator parameters and structures on losses is studied. Finally, a seven-phase six-pole air-core prototype is introduced, and the windage and mechanical losses are tested on the prototype. Moreover, the cosimulation model of the EML system is built, its losses are evaluated, and the efficiency of the EML system is derived.

Although the pulsed power supply (PPS) based on capacitor has been successfully applied to engineering prototype of electromagnetic (EM) railgun, its large volume makes it poor adaptability and flexibility due to relatively low energy storage density. In this article, a novel hybrid energy storage system based on battery and pulsed alternator is proposed. The topology principle of the system, the design scheme of the pulsed alternator, and the cosimulation results of multimodules are described in detail. The research results show that the proposed system can be used as the driving power of EM railgun with 40 MJ muzzle kinetic energy, and the effective energy storage density (energy released in a single pulse) of the pulsed alternator can reach 6.3 MJ/m3. Taking into account the charging motors, converter thyristors, and other auxiliary components, the effective energy storage density of PPS system will be 3 MJ/m3 and the overall volume can be reduced to one-third of the current capacitive PPS.

Rotational speed detection is important for alternator-voltage-regulator (AVR) to starts-up and generates regulated electric power for vehicles. However, the rotational speed detection in standby mode for self-start is challenging with low loss rectifier, such as the Schottky diode. In this paper, a novel rotational speed detection method by sensing phase voltage or field voltage at specific modes is proposed to solve the issue without extra wiring or external components. The analysis of phase voltage in standby mode considering rectifier leakage current explains the challenges of conventional detection. The derivation of field voltage in standby mode with ANSYS Maxwell simulation verifies the proposed method. The experimental platform with a three-phase six-pole pairs alternator verified that the proposed method can detect rotational speed even in self-start and low speed of 200 rpm.

During the evening rush hour of 24 July 1903, New York City's Manhattan Elevated Railway experienced a shutdown that began in its 74th Street power station and quickly involved the entire system. This station, one of the most advanced of its time, had been in operation for only seven months. It contained eight 5,000-kW, threephase, 25-Hz, 11,000-V alternators driven by reciprocating steam engines. Figure 1 shows one of these vertical steam engines with the large-diameter multipolar alternator attached. A frantic effort returned operation by late evening. However, just before midnight, another major system fault occurred. The trains were running again within 24 h, but the cause of the shutdown was unknown and resulted in much speculation in the engineering press.

This paper proposes a novel simulation method to analyze the characteristics of the electromagnetic noise of claw pole alternators under stator winding interturn short circuit faults. For the two types of faults: short circuit between two wires of the same phase and short circuit between turns of the same wire, a general circuit model built in Matlab/Simulink was introduced to obtained the phase current and output current signals. The phase current was then used as current source and the claw pole alternator was simulated as an electric motor rather than a generator to analyze the magnetic force and electromagnetic noise by using 3-D finite element method and boundary-element method, respectively. A noise bench test was conducted to verify the simulation results. It is shown that under the stator winding interturn short circuit faults, the output current harmonics and electromagnetic noise of the three-phase 12-pole/36-slot claw pole alternator would increase greatly. The 12th order noise replaces the 36th order noise as the most dominant order noise at low speed. The method proposed in this paper can also be used to diagnose the stator winding interturn short circuit faults of claw pole alternators.

To solve the problems associated with damping the electromechanical oscillation in electric power systems as well as to support the static stability there are many methods: one of them is the optimimum excitation for automatic control of alternator's (EACA). Improvement of EACA requires up-dating methods to operate the electric power stations at high efficiency. This paper p resents a technique to achieve this improvement aim. In this technique; the electromechanical formulation of EACA is determined and it consequently depends on the following points: (i) electromechanical oscillation parameters; (i) sensitivity coefficients for changing the real parts of the system equations roots corresponding to the variation of stability coefficients; (iii) construction of an independent area for static stabilities which determines the EACA parameters. The suggested technique is applied to a system containing six power units feeding a ring power system. The ring system is composed of 220 kV transmission lines with different tapping loads. The obtained results show that, (i) EACA gives high equal damping oscillation of electromechanical system at various conditions; (ii) minimum computation time even in case of multi power units. The suggested technique gives the equality between the control area of stabilities and the stability degree of EACA.

In real time automotive electrical systems, an alternator is usually used for charging the vehicle. The alternator generates AC voltage which is converted into DC voltage through rectifier of an alternator and this DC voltage helps to charging the vehicle’s battery. The alternator further coupled with the vacuum pump, provides vacuum to the suction line of the vehicle’s braking system. The rotor of the vacuum pump is made of mild steel which weighs high. Hence, it may act as a load to the alternator and reduces its efficiency. In the proposed model, efficiency and performance characteristics of the alternator are improved by reducing the mass of the rotor. Here, the mild steel is replaced by aluminum metal which weighs less. By using this, the mass of the vacuum pump is reduced, due to which the output power of the alternator gets increased. This increase in output power improves the efficiency of an alternator and subsequently the performance of the vehicle’s charging system is improved.

Compulsator provides an excellent approach to achieve compact energy storage and pulsed power generation for several multi-MJ, multi-GW applications, including electromagnetic launchers, directed energy systems, and fusion reactors. There is a continuous research effort toward increasing the power capability and compactness of this machine since its invention. In general, specific machine designs aim to maximize the output current and power by minimizing the transient inductance of the armature winding. The field and the inductance of the armature winding are some of the most important parameters in the compulsator design. This article presents the development of a generic method to analyze the magnetic fields and inductances of the armature windings in compulsators based on fundamental principles. It derives analytical models for inductance calculation in various types of alternators as unified terms of simplified formulas. These are used for the design, analysis, and optimization of all air-core, iron-core, compensated, and uncompensated pulsed alternators (PAs). By comparing the distribution of armature reaction fields and the self-inductances in compulsators having different configurations, this article investigates the basic relationships between the topology of the alternator and the fields and inductances. This is not limited only to the study of PAs but it can also be used in both slotless and air-core conventional machines.

This paper investigates the internal shape correctness of alternator stators occurring in high and low temperature storage tests. This kind of failure can affect the adequate operation of alternators since vibrations can occur during rotation of the other part of the alternator, the rotor. This error can reduce the efficiency of the alternator. The aim of this study is to examine the influence of different testing parameters, such as the temperature and the running time of the test, and whether or not the stator is equipped with a damping element. For the experiments we used the full factorial experimental design method. The measurement of the cylindricity of the specimens was done with a circular and position error measuring machine. From the measured data, special improvement ratios can be calculated in order to define the appropriate range of testing parameters that resulting greater deformity. A further aim is to compare the different cylindricity parameters and the features of theirs measured values.

Pulsed alternators (PAs) are ac generators which are specifically designed to generate pulsed currents of very high magnitudes for a given duration. An induction coilgun is being designed and developed in the author’s laboratory to propel projectiles of different sizes. The scope of this work is to design and develop a PA for the same. A single-phase, iron core, slotted stator, cylindrical rotor, and no-compensation topology of the PA has been selected for this application. For the parametric analysis, a coupled circuit model of the PA has been used by considering the correction factors which include the skin effect and the magnetic saturation of the iron parts of the alternator. Eddy currents induced in the rotor core have been modeled as one circuit on each axis. A number of designs have been modeled and simulated and their performances have been analyzed for different design variables of the PA. Peak current, projectile velocity, and the temperature rise of the coil per current pulse are the output parameters which have been analyzed for every design. From the parametric analysis, PA with a particular configuration has been selected which results in the desirable performance of the PA–coilgun system. The design has been validated by modeling the same in finite element method (FEM)-based software. The performance of the PA driving the coilgun has been compared with that driven by the capacitor bank, and the feasibility of the multistage operation using the PA has been studied.

Due to the merit of very-short end turns, Gramme-ring windings are widely used in high-speed permanent-magnet motors (HSPMMs). This study investigated the thermal issues of a 300 kW, 12,000 rpm Gramme-ring-winding HPSMM with housing water jacket and forced air cooling, based on the computational fluid dynamics (CFD) and numerical heat-transfer calculations. The reasons that cause the overheat of the prototype in the experimental test are thoroughly analysed. The high wind resistance of air gap as the ventilation duct and the large interface gap between the stator lamination and housing water jacket is thought to be the main reasons. Then improvement of the ventilation structures is studied to decrease the wind resistance. Besides, the modification of water channels is also investigated to avoid the influence of a large interface gap on the water cooling performance. Finally, a new cooling structure, combining the slot ventilation ducts and inside water channels, is proposed for the HSPMM with Gramme-ring windings. With the new cooling structure, the temperature rise of the motor is decreased, and the power density can be increased.

In this article, we investigate rotor design of claw-pole alternators for automobile applications to increase output and decrease core loss. First, the electromagnetic field distribution is calculated by the three-dimensional (3-D) nonlinear time-stepping finite-element method, which considers eddy currents generated at a solid rotor core and a laminated stator core. From the results, a novel rotor design is proposed. Experimental verification is carried out to confirm the advantage of the proposed design. The mechanism of output increase and loss reduction by the proposed alternator is revealed by analyzing detailed 3-D flux paths in the rotors.

This paper investigates the internal shape correctness of alternator stators which is caused by high and low temperature storage test. This kind of failure can affect the adequate operation of alternators since vibrations can occur during rotation of the other part of the alternator, the rotor. It can be stated that the effects of this error reduce the efficiency of the alternator. The aim of this study is to examine the influence of different testing parameters, such as the temperature and the running time of the test and that the stator is equipped with damping element or not. To planning and executing the experiments we use full factorial experimental design method. The measurement of the cylindricity of the specimens was done with a circular and position error measuring machine type Taylor Hobson Talyrond 365. From the measured data, special improvement ratios can be calculated in order to define the appropriate range of testing parameters which results greater deformity.

As internal combustion engine in automobile operates much quieter than before, the noise emitted by claw-pole alternator becomes more non-negligible. To address this problem, the magnetic force, which caused acoustic noise, was analyzed. Force harmonic relevant to the noise peak was identified and set as an optimization object to weaken. The influence of each rotor structural parameters on the force harmonic and output current was analyzed, and the four most influential parameters were chosen as the optimization variables. With the genetic algorithm, an optimum rotor shape generating minimum force harmonic, without severely deteriorate the output performance of the alternator, was obtained. Calculated by the noise predicting model which was verified by experiment, acoustic noise produced by the optimized claw-pole alternator was 14.3 dB (A) less than the initial one, with the output current decreased within 5 percent.

This study presents the implementation of a DC-DC power converter for battery charging from 200 V lithium-ion or nickel metal hydride (NiMH) battery to lead-acid battery (typically 12 V) utilised in hybrid vehicles such as Toyota Prius. For hybrid car, a low-voltage (LV) battery is utilised to power air conditioner, main lights, and different actuators in engine controlling unit etc. The LV battery is usually recharged by car alternator. For the sake of improving fuel efficiency, it is important to regulate charging by using the charging control scheme, where the battery charging is implemented in deceleration interval avoiding the acceleration interval of the car. The hybrid car is equipped with a high-voltage (HV) NiMH battery. The lead-acid LV battery is charged from the HV storage battery. The advantage of this charging method is recognised not only to replace the alternator from the car, but also to make efficient braking touching for the car driver, because the regenerative breaking recovered energy can be totally absorbed in the main HV battery. Moreover, the overall efficiency could be easily improved because the total efficiency of charging DC-DC circuit is greater than that of the car alternator.

A premature failure of alternator assembly of an aircraft was reported. After stripping of the assembly, one of the pole piece was found fractured. Material of the pole piece was low carbon steel (AISI C1006). Hardness of the pole piece was slightly higher than the standard values. Detailed investigations revealed that the pole piece was fabricated by cold forging, which induced fine surface cracks. Subsequently, during service the fatigue cracks initiated and propagated under high cyclic fatigue loadings from pre-existing fine surface cracks. A modified design of the pole piece was suggested after determining the endurance limit using “four point correlation method” and stress levels during service using “finite element modeling”. The modified design helped to reduce the stresses well below the endurance limit from 27 MPa to

A tanulmány a generátor állórészek belső alakhibájának vizsgálatával foglalkozik, melyet magas és alacsony hőmérsékleten való tesztelési eljárás idéz elő. Ez a fajta meghibásodás befolyásolhatja a generátorok megfelelő működését, mivel a generátor egy másik alkatrészének, a rotornak a forgása során rezgések léphetnek fel. Kijelenthető, hogy ennek a hibának a hatása csökkenti a generátor teljesítményét. A publikáció célja annak vizsgálata, hogy a különböző tesztelési paraméterek úgy, mint hőmérséklet, tesztelési idő, az állórész el van-e látva rezgéscsillapító gyűrűvel vagy sem, milyen hatással bírnak. A kísérlet megtervezéséhez és végrehajtásához a teljes faktoriális kísérlettervezés módszerét alkalmaztuk. Az egyes elemek hengerességének mérése Taylor Hobson Talyrond 365 gyártmányú köralak- és helyzethiba-mérőberendezésen valósult meg. A mért adatokból speciális viszonyszámokat alkottam, annak érdekében, hogy meghatározzam azt a paramétertartományt, mely a legnagyobb mértékű deformációt okozza.

The demand for increased power and improved fuel economy are driving changes in alternator technology for automotive applications. To meet these demands requires a drive system with capabilities of torque assist, regenerative braking and power generation to supply vehicle loads while keeping the battery charged. Furthermore, to minimize add-on cost, the system must be air-cooled with minimal changes to the vehicle hardware and operate at 12 V with the same or smaller packaging footprint of the current alternator. In this paper, a low cost 12 V, 4 kW air-cooled permanent magnet-assisted synchronous reluctance machine drive system for a micro-hybrid vehicle is presented. The design and analysis in terms of machine, inverter, controller, and control algorithm are discussed in detail. Thermal performance of the system under different operating conditions, which is another key aspect for the harsh environment application, is also studied. Fuel economy analysis of the proposed low-cost micro-hybrid system for a Segment B vehicle shows significant reduction in fuel consumption resulting in a direct benefit to the customer. Finally, a prototype drive system was built and tested and found to meet the cost, performance, and packaging requirements.

The air-core pulsed alternator has the integrated advantages of high energy density and high power density. It has important applications in new concept kinetic energy weapons such as electromagnetic launching and has become the research focus of many countries at present. However, the air-core machine with a current up to mega-ampere level still lacks testing, it is impractical and unscientific for the machine to drive the railgun directly without any experimental basis, and its huge risk and cost for testing must be taken into consideration. This paper presents an equivalent load instead of the electromagnetic railgun, which is used to accomplish the relevant testing research and theoretical verification. In this text, the design scheme for the equivalent load is proposed according to performance requirements, and it is composed of an inner cylinder and an outer cylinder with a coaxial configuration. Then, the design is carried out by taking parameters of resistance, inductance, maximum temperature rising, stress, and length into consideration. Finally, it is necessary to develop simulations to verify electrical and mechanical performances of the load. The results provide a technical guidance and support for the actual railgun testing. It is helpful to promote the development of the air-core pulsed alternator, directly driving the electromagnetic railgun.

There is an active technological development effort into the fuel efficiency enhancement of the existing internal combustion engine vehicles. As part of this technological development effort, researches are being conducted on the use of lithium batteries as the starter battery for internal combustion engine vehicles, in place of lead–acid batteries. While the use of lithium starter battery is expected to result in various advantages and disadvantages, there is a lack of specific research on this area. Therefore, in this paper, we present a quantitative analysis of the characteristics and performance of internal combustion engine vehicles with different types of starter batteries. For this purpose, we simulate the power-net system of a vehicle, including charging control, through a test bench based on actual vehicle data, and develop an automotive power-net hardware-in-the-loop simulation (HILS) by combining the test bench with a powertrain model. HILS-based test and evaluation were performed for vehicles equipped with absorbent glass mat (AGM) battery and those with lithium battery, using an actual road evaluation pattern to compare their characteristics and performance with impedance measurements for each type of battery.

The free-piston generator has more merits than the traditional reciprocating engines, and has been under extensive investigation. This study focuses on the development two novel perspective ideas unlike already advanced the linear free piston generator. These are: (1) to make both piston and cylinder free that provides ideally balancing of the system; (2) to turn from the linear scheme of a generator to rotary design because of simplicity and compactness. The mathematical simulation of operation of the linear two-stroke cycle alternator with both free piston and cylinder was conducted with using the model of zero-dimensional dynamics. Combustion of methane-air mixture with excess air ratio of 1.2 was considered. Both heat and friction losses were taken into account. Operation particularities of such system were analyzed. It was found that oscillation amplitude of moving parts did not exceed of 70 mm at frequency of ∼50 Hz for alternator with following basic parameters: cylinder bore of 80 mm, length of 400 mm, piston length of 120 mm. Mass of both piston and cylinder was chosen identical and equal of 3 kg. It was shown that the efficiency of the chemical energy conversion reached of 46%, and specific power was high as 40 kW/l at compression ratio of 40. The lab scale pneumatic alternator in rotor variant with both free rotor and cylindrical body was assembled for experimental demonstration of rotary design capability. The alternator was fed with compressed air of low pressure below of 6 atm. The electrical power in the load reached of 10 W at input power with intake compressed air about 100 W. The results indicate that alternators with both free piston and cylinder in linear and rotary designs have the potential to achieve high efficiency and provide the vibration – free operation. Keywords: ICE, Alternator, Free piston, Hybrid engines

This paper presents a novel control strategy for a conventional six-phase Lundell alternator fed at the output with a MOSFET-based active rectifier. The signal references for the controller are calculated from a cost-function aiming to minimize the alternator stator copper losses in an effort to maximize the alternator–rectifier system overall efficiency. The system is initially simulated and tuned in MATLAB/Simulink and then experimentally verified. The steady-state efficiency results from experimental measurements of the alternator/rectifier system are compared against a standard passive rectifier. The results indicate a better overall efficiency compared to the passive rectifier, for an alternator speed of up to approximately 5000 rpm, corresponding to city driving.

This article presents a synchronous rectification scheme using a six-phase Lundell alternator and a bespoke MOSFET-based active rectifier. The control of the alternator-rectifier system is divided into the hysteresis DC-link voltage control and the switching pattern algorithm. The first allows to keep the DC-link voltage at the required 14V level, while the latter reproduces the same switching pattern as that of a passive rectifier. The system is tested at three different speeds and the results are compared against the body diodes of the MOSFETs in the active rectifier. The harmonic analysis of the generated waveforms indicates the capability of the control algorithm to generate the same switching pattern of a passive rectifier. Finally, the efficiency measurements illustrate a significant efficiency improvement using a synchronous rectification scheme and MOSFETs with low on-resistance.

The compensated pulsed alternators (CPAs) have good applications in high-energy lasers, electromagnetic rail guns, and other electromagnetic launch devices. Among various electrical machine topologies, homopolar inductor alternators (HIAs) have attracted interest as CPAs due to their merits of simple and reliable structure, brushless excitation, and high-speed operation. However, the length of the conventional HIA is difficult to expand because it is limited by the rotor diameter, and the rotor diameter is restricted by the maximum speed of rotor tip, which results in low-energy storage capacity of a single machine. Besides, HIA suffers from the relatively low-power density due to its unipolar air-gap flux density (UAFD). To solve these problems, two novel HIAs with multistage stator cores (HIA-MSCs) are proposed in this paper. One is HIA with UAFD (HIA-UAFD) and the other is HIA with unipolar and bipolar air-gap flux density (HIA-UBAFD). First, the structure and operation principle of HIA-MSCs are illustrated. Then, the key parameters of HIA-MSCs are derived, and the corresponding models are built. Finally, the electromagnetic performances of HIA-MSCs are investigated by 3-D finite-element analysis method. Compared with HIA-UAFD, HIA-UBAFD has relatively higher discharge current and output power, which indicates that HIA-UBAFD is a better candidate for the pulsed alternator.

Continuous addition of electrically powered peripherals in vehicles has created a need for a more efficient and reliable power source that can replace conventional starter lead-acid (Pb-Acid) batteries. Due to their high energy-to-weight ratio, Lithium-Ion (Li-Ion) batteries can act as a potential alternative to the Pb-Acid batteries used in cars for engine ignition. However, it is not possible to use Li-Ion batteries as a drop-in replacement of Pb-Acid batteries due to differences in internal resistance and voltage thresholds for charging and discharging. In addition, Li-Ion batteries require balancing of cell strings connected in series whereas Pb-Acid batteries manage cell balancing during charging near full charge. To use Li-Ion cells as a battery pack, it is necessary to install a battery management system (BMS) that keeps the voltages of each cell balanced. This paper proposes a new design methodology for a scalable BMS that employs active balancing using analog discrete components. The analog control system of a BMS integrated with a DC-DC bi-directional Cuk converter allows increased reliability and efficiency. For a comparative analysis, balancing of the Li-Ion battery pack is also performed by implementing a digitally controlled BMS, and the results are compared with the designed analog BMS. Finally, an architecture comprising a DC-DC boost converter is also introduced to manage control over battery charging through alternator of the internal combustion engine (ICE) vehicle.

This paper proposes an analytical method to calculate the magnetic flux in the air gap of a claw-pole alternator, created by a NdFeB permanent magnet in the rotor. The proposed method can also be used to calculate the dimensions and the volume of a permanent magnet that will create a desired voltage in the machine. The possibility to obtain a certain value of the machine voltage with lower volume of rare earth material will lead to a decrease in the cost of the final product. The need for such a method is grounded on the complex geometry of this type of electrical machines, which would require a time consuming 3D modelling with FEM analysis software. Knowing the air-gap magnetic flux of the machine permits the right choice of permanent magnet type and volume, which facilitates the designing phase of the alternator. The influence of the permanent magnet’s cross section and length on the magnetic flux in the air-gap of the alternator is analyzed. A comparison between the electromotive forces created by a permanent magnets with different grades is made and presented.

Homopolar inductor alternator (HIA) has obvious advantages to achieve fast charging and repetition frequency output, and it has been used in the capacitor charging power supply (CCPS) system. However, for the capacitor charging power supply with homopolar inductor alternator (HIA-CCPS), the influence on parameters of alternators and systems on charging has not been studied quantitatively. Also, there is still no proper method on how to combine these parameters with the alternator design for the existing HIA design methods. The application of voltage-behind-reactance (VBR) model in HIA-CCPS system greatly simplifies the analysis of parameters on the capacitor charging system. In this paper, based on the VBR-model, the influence of various parameters in the charging process on the performance of the charging system will be quantitatively studied, and according to the research results, the alternator design process based on the above analysis will be presented, at the same time, a prototype of HIA-CCPS system is designed to verify the above analysis.

The air-core pulsed alternator with miniaturization and light-weight is the preferred pulsed power supply for mobile combat platforms which have strict restrictions on volume and weight. After the air-core machine discharges to the load, massive magnetic energy remains in the alternator and the railgun due to the high residual currents. Usually, this magnetic energy is consumed by resistors in the circuit, but it leads to a low system efficiency. In this paper, two methods are put forward to get the magnetic energy reclaimed and thereby reused in the next projectile launching. One is to control the triggering signal of the rectifier circuit so that it can work as an inverter and the magnetic energy in field windings can be recovered into the kinetic energy in rotor. The optimum triggering angle is selected based on its value range calculated. The other is to design a resistance-capacitance absorption circuit installed on the muzzle to absorb the residual discharge current and realize the conversion of the magnetic energy in rails into the electric energy in absorption capacitor, which can be reused as an ignition capacitor.

The electrical energy in a car, when the combustion engine is running, is made, for the most period of time (peak loads can, also, be taken by the battery), by the claw-poles alternator. The article presents an alternator with permanent magnet surfaces in the rotor, the stator being identical, from a constructive point of view, with the stators from the classic alternators (Lundell). The permanent magnets are rectangular in shape and replace the claw-type poles from the the classic alternators with the coiled rotor. To obtain a variable speed, the alternator with permanent magnets is driven by a belt through a three-phase induction motor powered by a variable frequency driver. Experiments were performed with this alternator at variable speed, without and with buck converter (two types) for voltage stabilization, without and with power resistors (of different values) and with lead-acid battery. The use of alternators with permanent magnets in vehicles is another solution for producing electricity and can be a more reliable solution than the classic one.

The present work describes the development of robust control strategy for a SI engine. During the idle condition the speed of the spark ignition engines fluctuates. The principle aggravation for speed vacillation varieties in engine load torque (electric load on the alternator, Ac blower and so forth). Other causes for speed fluctuations include variation in inlet air temperature, air fuel ratio, engine coolant temperature, etc. also at idle conditions the emissions from engine is more compared to normal cruising conditions. Thus to reduce emissions modern engines have low idle speed. Due to low idle speed sudden load changes reduces the engine speed and causes to stall of engine. In conventional engine indolent speed regulator systems two parallel control loops are used to control speed and mixture fraction. In conventional idle speed control systems, the working of one loop affects the other. To address this problem a H∞ based robust controller is designed. The engine info factors constrained by controllers are fuel infusion, throttle position, and sparkle advance. In this work only the variation in the engine torque is considered as disturbance and factors are considered as noises. A linear mean value engine modeling is used to model the engine. Though the time scale of the mean Value Engine model (MVEM) is not suitable to represent engine in each cycle the time scale of MVEM can be obtained easily for an engine it is suitable for control studies. The linear models fundamental the control combinations are derived from a nonlinear engine model. The resultant controller along with the linear engine model is simulated using MAT lab software. The outcome affirms that the Genetic calculation based vigorous H vastness regulator offers a superior low recurrence unsettling influence dismissals high recurrence commotion dismissal and better execution.

To prevent Carbon footprint, safe renewable energy is the only option. But renewable energy production still has a long way to go to achieve higher efficiency and reliability. In a harsh climate, solar panels or wind power often becomes less efficient or completely ineffective. To solve this issue, the Ion harvesting technique can be used as Ion is always available in nature. If can be harnessed this ion source and use for energy generation purposes, the overall efficiency and reliability of renewable energy production can be increased. By using ion repulsion theory, a corona motor spins an alternator to generate AC power. In a corona motor, where one prong is up high in the sky (minimum 150 ft) and another prong is grounded, the ions collected from the environment run the motor and thus start spinning the alternator which is coupled with it. The primary prototype has been able to power a small radio device or a 5V router device continuously in any harsh climate. This system can be used in remote locations or areas of high ground (hilly areas) where establishing a sustainable mobile network is hard without harming the environment or its natural habitat. In such places where a large number of solar panels is not possible to mount or wind power is not significant, this system can be useful if used as a bunch.

The measurement and control system is the auxiliary device of the pulsed alternator power supply system. Its main task is to complete the monitoring and protection of the system reliably.

Negative impacts from the dominant use of petroleum-based transportation have propelled the globe toward electrified transportation. Toward overcoming it, here proposed to design an efficient dynamic induction charging vehicle for the future road transportation in view of pollution-free environment. To charge the vehicle while driving without any mechanical contact used electric motors, boost converter, battery packs, smart switching system, alternators and microcontroller. Self-charging electric vehicle is designed and developed and it is in the working condition capable of carrying or taking a load up to 500 kg by the motor.

ABSTRAC Electricity is a source of energy that is widely used for the needs of household electrical appliances that are needed within 24 hours of continuously supplying electricity. Most of the mains voltage is supplied from the state 220 volt. When the electricity goes out, the electrical equipment cannot function properly, therefore there must be an alternative source of electricity to replace it. The purpose of this research is to design an alternative power plant from the initial drive system of a dc motor with mechanical motion transfer using pully and van belt as the drive for the dc alternator. The research method used in this research has the following stages: 1). Designing a dc motor and a dc alternator as a producer of electrical energy, 2). Installing AS bearings, vanbelt and pully, 3). testing and measuring dc motors and dc alternators, 4). Calculate and analyze the design results. From this research, the direct current generated by the accumulator with a voltage of 12 Vdc with a current charge of 10 AH, so that it can be used to turn on the inverter as a means of converting the voltage of a direct power source into an alternating current with a voltage of 220 V to turn on household electrical appliances when supplied. from PLN experiencing a blackout. So that our daily work can run smoothly without any constraints on the flow of electricity.Keywords: MotorDC, PullyVanBelt, Alternator

The world of electronics, technology and the upcoming Industry 4.0 is set to transform the face of the world’s manufacturing and supply chain industry, but we are running short of the force that runs it-energy. Many have tried to find innovative, regenerative, reproductive and renewable sources of energy. Most succeeded but many failed as well. Generating electricity from rotating shafts of vehicles was one of the most innovative method of energy harvesting, but it didn't work every time. The Indian Railways had installed an alternator on the ICF coaches for self-generation, but it didn't work the same with the new LHB coaches. To find a solution to the bigger problem of energy harvesting and the particular problem of implementation on LHB coaches, this paper talks about a model which can provide them both by the design of a permanent magnet alternator.

The reliability of the vehicle electrical equipment is determined by the performance of the vehicle alternator, as the main source of electricity on board. Defects in automobile alternator s lead to a decrease in the generated energy, which is characterized by a change in the output voltage and current strength. It is proposed to diagnose the technical condition of an automobile alternator by assessing changes in its parameters during the load cycle. The load cycle of the alternator has been developed for testing it directly on the vehicle. The load cycle includes typical modes of vehicle movement, characterized by a change in the speed of movement and the current strength of consumers, which make it possible to assess the performance of an automobile alternator. The numerical values of the load cycle parameters are obtained when testing a serviceable alternator in a passenger vehicle. Further studies are aimed at determining the numerical values of the cycle corresponding to alternator with the most characteristic faults.

R&D production is complex and takes relatively a long time. This paper studies production schedule control for R&D production. The case study can provide a reference for similar companies to take schedule control of trail production for R&D.

The pulsed power supply based on air-core pulsed alternator can output a current up to the megampere level in an extremely short time, with outstanding advantages of high energy density, high power density, and high integration degree. It has been a preferred power source for electromagnetic launch (EML) system. To achieve the required amplitude of the output current pulses, the field current of the alternator is often required to be up to tens of thousands ampere level. Therefore, the self-excitation method is often used to achieve the required field current in very short time. How to maintain high field current after the self-excitation process, is the key technology of the air-core pulsed alternator to achieve multiple railgun projectile launches in short time. However, the operation principles already proposed are only suitable to achieve single railgun projectile launch after the field current is built by self-excitation. If multiple railgun projectile launches are required, multiple self-excitations are required, which will not only require long time, but also causes a large amount of losses generated in the field winding. In this paper, a novel operation principle of the EML system, based on the air-core pulsed alternator, to achieve multiple electromagnetic railgun projectile launches after a self-excitation process is introduced. Based on the operation principle above, the changing trend of the field current is modeled and analyzed. Finally, the entire operation process of the EML system is simulated to verify the feasibility of the proposed operation principle.

The increase in the number and capacity of the installed electric consumers onboard the vehicles leads to the growth of heat load of the alternator as the main source of electric power. A thermal model has been developed to analyze the thermal state of an automobile alternator, which allows determining the contribution to the general temperature background of individual elements, as well as its change in case of malfunction. The thermal model includes the main sources of heat emission and thermal resistances of the automobile alternator elements, as well as analytical expressions to determine its parameters. As a result of experiments, the influence of the type of current, rotor speed and stator winding current on the parameters of the thermal model of an operative alternator was established. Further researches will be directed on definition of parameters of thermal model at modeling of characteristic faults and development of practical recommendations on diagnostics of the automobile alternators on parameters of thermal condition.

The failures of the diodes of the rectifier assembly are one of the main reasons of the automobile alternators breakdown. Assessment of the technical condition of the automobile alternator rectifier according to the value of output voltage does not enable to identify certain failure and is insufficiently informative at the initial stage of the failure's development. It was proposed to diagnose the failures of the automobile alternator rectifier based on the output voltage spectrum analysis. The results of the physical simulation of the sporadic and group failures of the rectifier are presented. The analysis of the amplitude-frequency characteristic enabled to identify the indicator harmonic components corresponding to the specific failures of the rectifier. The use of the spectrum analysis during diagnostics of the failures of the automobile alternator rectifier significantly increases the efficiency and reliability of the results obtained.

The paper is devoted to a 3D-FEA based comparison between different topologies of claw-pole alternators, namely: conventional claw-pole alternator (CPA), inter-pole PM claw-pole alternator (IPM-HECPA) and hybrid-excited brushless claw-pole alternator (HEBCPA). The study is initiated by a description of the studied topologies and an analysis of their rotor-stator main linkage flux. Then, a special attention is paid to their on-load features which is predicted by 3D-finite element analysis (FEA), with emphasis on the armature voltage and current waveforms, their harmonic contents as well as their output current waveform. In order to highlight the effects of the inter-pole PMs and the removing of the brush-ring system, the investigation of the onload features is started by the conventional CPA with a single DC-excitation in the rotor, then it is extended to the hybrid excited topologies.

In a fundamental alternator, the mechanical energy is converted to electrical energy while this is likewise true for a rim alternator, besides it additionally converts gravitational potential energy to electrical energy and consequently expands the effectiveness of the device. To be explicit, rim alternator is an external modular device, to be fit into the metal edge of a vehicle. By the method for rim alternator, following Faraday's Law of Electromagnetic Induction, an initiated electromotive force, will create a flow in the loop, which will be utilized to revive the engine of the electric vehicle and support its drive. Subsequently, this thus lessens the recurrence of charging required by vehicles and diminishes the load on the lithium ion cells, consequently requiring a couple of cells in particular; conquering both the issues.

This paper proposes an approach to emulate the behaviour of different IEEE excitation system models or industry provided excitation system models using a micro-alternator in the laboratory. An IGBT based buck converter is used as an exciter for the alternator. A time constant regulator is used, to emulate the field time constants of large machines using microalternator. In this paper DC1A, AC4A and ST1C excitation systems are used as reference excitation systems whose terminal characteristics need to be emulated. The trajectory of the field voltage of the reference model is tracked by the buck converter based exciter using a PID controller. The proposed emulation approach is tested under various small and large disturbances in MATLAB/SIMULINK environment.

The article discusses ways to reduce the ripple of rectified voltage in alternators based on synchronous electrical machines. To that end, the paper compares alternators that differ in the number of phases as well as in the circuitry of the semiconductor rectifier. The authors consider odd- and even-phased alternators with armature windings made of three-phase groups. Half-wave and full-wave rectifying circuits are considered. The ripple coefficient was used as the comparison criterion. Analysis reveals the performance with a relatively small number of phases can be maximized using an aggregated generator, the armature winding of which is divided into two parts offset by 30 electrical degrees against each other and connected to separate bridge rectifiers connected in series or parallel to the load.

Claw-pole alternators are particularly important for vehicle power generation due to their low cost, simple design, and mechanical robustness. High and low temperatures around vehicle claw-pole alternators (VCPAs) change their internal temperature distributions, thus thermal analysis is required for designing VCPAs. Aiming at improving the accuracy of evaluating the temperature of VCPAs, a novel lumped parameter thermal network (LPTN) is proposed to analyze the steady-state temperature of a double excitation VCPA under various ambient temperatures. The forced convection coefficients are calibrated in order that the LPTN can simulate the real heat transfer of the VCPA. The nonlinear least square method is applied to obtain the calibrated coefficients within a range of the tested ambient temperatures. Moreover, the effectiveness of the proposed method is verified via simulation studies, whereby the results show that the proposed LPTN with calibrated convection coefficients can accurately evaluate the temperature of VCPAs. Finally, these results soundly supply the technical knowledge for the thermal analysis and facilitate selecting the optimal scheme for machine designers.

The paper focuses on the modeling of iron losses for synchronous electric machines. Specifically, the paper describes the inclusion of iron-loss resistance parallel to the main inductance of a dual-voltage alternator model. Integration of the iron loss resistance is implemented in two different models: a quadrature direct (QD) axis model and a voltage behind reactance (VBR) model. Simulations with both models are performed and compared against measurements with a machine prototype. The measurements show that the usually made assumption of constant iron loss resistance does not accurately represent the iron losses of a claw-pole alternator. Therefore, the parallel resistance is implemented also as lookup table (LUT) and derived from measurements. The presented models can be parametrized as conventional 2 $\times$ 3-phase synchronous machine with one-voltage level.

More and more gas reciprocating generator units are integrated into offshore platforms, due to their compact structure and high efficiency. This paper concentrates on the transient stability analysis of one special type of AC microgrids containing a gas reciprocating generator unit. Firstly, the operation principle for the gas reciprocating generator unit is presented, which mainly consists of a reciprocating internal combustion engine and a linear synchronous alternator (LSA). Afterwards, the mathematical model for the core part of the gas reciprocating generator unit LSA is proposed, based on the principle of armature reaction in traditional synchronous and asynchronous machines. Finally, the simplified model of the independent offshore power system with a gas reciprocating generator unit is derived, and numerical simulations on the transient stability of this typical AC microgrid are performed, from which the effectiveness and correctness of the LSA model are validated. The transient stability analysis method of the independent offshore power system and the mathematical model of LSA can provide beneficial guidance for the stable operation of other types of stand-alone AC microgrids.