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In order to reduce the permanent magnet synchronous motor cogging torque and improve the motor output performance, a method of motor stator slot offset was proposed with the example of 3-phase 8-pole 36-slot built-in combined permanent magnet synchronous motor. Firstly, a mathematical model of motor stator slot offset was established by theoretically deriving the stator tooth air gap permeability function. Secondly, the effects of peak cogging torque, output torque and torque pulsation at different offset angles under different numbers of stator slot offsets were analyzed, and adaptive genetic algorithms were used to determine the target values under the offset angles for the number of stator slot offsets. Finally, a trial prototype was produced and the experiment was conducted. The results show that the peak cogging torque of the optimized motor is reduced by 49.56%, the torque pulsation is reduced by 39.2%, the average output torque is appropriately improved, and the air-gap magnetic density harmonics are appropriately reduced; the average output torque increases and the motor output performance is improved. The proposed stator slot offset structure and multi-objective joint simulation method are rational and effective, which can provide some reference for cogging torque optimization and output performance improvement of the same type of motors.

The combination of permanent magnets and electrically excited windings creates an air gap magnetic field. The development of a hybrid magnetic circuit motor with an adjustable magnetic field is of great significance. This article introduces a hybrid magnetic circuit motor design that combines salient pole electromagnetic and permanent magnets. A tubular magnetic barrier has been designed to reduce inter-pole leakage and enhance the usage rate of permanent magnets in the hybrid magnetic circuit motor. The optimum eccentricity of the rotor has been accurately designed, resulting in an improved sinusoidal distribution of the air gap magnetic density waveform. An analysis of the static composite magnetic field under various excitation currents has been conducted, showcasing the capability of the hybrid magnetic circuit motor to stably adjust the air gap flux density level and output torque. A prototype has undergone comprehensive trial production and testing, conclusively confirming the machine’s superior output performance.

The armature reaction of the hybrid excitation starter generator (HESG) under load conditions will affect the distribution of the main magnetic field and the output performance. However, using the conventional field-circuit combination method to study the armature reaction has the problem of low accuracy and inaccurate influencing factors. Therefore, this paper proposed a graphical method to analyze the armature reaction and a new type of HESG with a combined-pole permanent magnet (PM) rotor and claw-pole electromagnetic rotor. The analytical formula of the voltage regulation rate under the armature reaction was derived using the graphical method. The main influencing parameters of the armature reaction magnetic field (ARMF) were analyzed, and the overall output performance was analyzed using finite element software. On this basis, comparison analyses before and after optimization and the prototype test were carried out. The results show that the direct-axis armature reaction reactance, quadrature-axis armature reaction reactance, and voltage regulation rate of the optimized HESG were significantly reduced, the output voltage range of the whole machine was wide, and the voltage regulation performance was good.

The urgent need in lightweight of vehicle body promoted the application of multi materials with high specific strength, and this involves the reliable welding of dissimilar materials. In this study, AA5052 aluminum alloy and HC420LA steel were welded by magnetic pulse welding. The mechanical degradation of the dissimilar Al–Fe joint after different salt spray corrosion duration was investigated. The atomic force microscopy-scanning Kelvin probe force microscopy (AFM-SKPFM) and immersion tests were also performed. The fracture of the Al–Fe joint was observed by optical microscopy, scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). The ultimate shear strength of the Al–Fe joint only declines for 10% after three weeks' corrosion. Crevice corrosion is found in the overlapping region, and galvanic corrosion and stress corrosion occur in the weld region. The corrosion in the flat welding interface is mainly galvanic corrosion due to the high corrosion driving force, while the corrosion in the wave welding interface is mainly stress corrosion.

To solve the problems of the non-adjustable magnetic field of the permanent magnet (PM) generator, large excitation loss and high failure rate of electric excitation generator, this paper proposes a parallel electromagnetic and PM hybrid excitation generator (HEG). The designed generator adopts a high power density PM rotor composed of built-in tangential PM steel and V-shaped PM steel and a salient-pole electromagnetic rotor (EMR) with short axial length, less electromagnetic loss, simple and reliable structure. By adjusting the axial length of two rotors and the size of magnetomotive force sources, the generator can adjust the rotor power distribution to meet various power requirements. Meanwhile, the HEG can adjust the electromagnetic magnetic field (EMMF) by adjusting the size and direction of the excitation current, and then can adjust the size of the synthetic magnetic field to achieve the purpose of stabilizing output voltage. In this paper, the magnetic circuit model of the HEG is established by using the equivalent magnetic circuit (EMC) method, and the rationality of the designed magnetic circuit is verified and analyzed by the finite element method. The prototype is trial-manufactured and tested, and the results show that the designed HEG has a wide magnetic regulation range, stable output voltage, and good output performance.

As an increasingly important application of mobile social media usage, online healthcare platforms provide a new avenue for patients to obtain and exchange information, referring not only to online doctor’s advice but also to the patients’ comments on a doctor. Extant literature has studied the patients’ comments facilitated with the direct numeric information gathered in the web pages including the frequencies of “thanks letter,” “flowers,” and “recommendation scores.” Adopting the text analysis method, we analyzed patients’ comments on the healthcare platform, focusing on the comments from two aspects, namely, comment contents and content sentiment. Based on the analysis of the data collected from one of the most popular healthcare apps named “Haodaifu” in China, the results show that the vast majority of the comments are positive, which basically follows the L-shaped distribution. Meanwhile, comment sentiment covering sentiment tendency and proportion of positive comments demonstrates significant effects on recent 2-week consultation by a doctor. One of the comment contents “patience explanation” has significant effects both on the total consultation and recent 2-week consultation by a doctor. The research findings indicate that the online preferences for and evaluations on doctors provide strong support and guidance for improving doctor-patient relationships and offer implications for medical practices and healthcare platforms improvement.

To solve the problems of the low power density of pure electric excitation generator and nonadjustable magnetic field of pure permanent magnet (PM) generator, a salient-pole hybrid excitation generator (HEG) was proposed in this paper. The designed generator realized coexcitation of two magnetic fields by changing the shape of the pole shoes and embedding the combined-pole PM steels. Compared with other HEGs, it had the advantages of high power density, less excitation loss, and small volume. The paper deduced the analytical expressions of the main magnetic field and armature reaction magnetic field of the HEG and analyzed the armature reaction magnetic circuit, the main influencing parameters, and the influence law of each parameter on the generator output performance to complete the parameter matching of the whole machine. The prototype was trial manufactured and tested with the optimized parameters. The results show that the designed HEG has a low voltage regulation rate, good no-load characteristics, and regulation characteristics. It can ensure the regulated output voltage under rated load conditions and meet the application requirement.

Aiming at the problem of uncontrollable magnetic field of permanent magnet generators, a new hybrid excitation generator (HEG) with parallel magnetic circuit is proposed. The HEG consists of combined permanent magnet rotor (PMR) and brushless electric excitation rotor (EER). The PMR has surface-mounted and embedded magnets. The PMR provides the main air gap field, and the brushless EER is used to adjust the air gap field. The operating principle and electromagnetic design scheme of the proposed generator are given in detail. Besides, the matching with two different types of rotors and the flux regulation characteristics is analyzed by using the finite element method. Finally, the output performance of the proposed generator including no-load and load characteristics and output voltage are tested. The results show that the two different types of rotors can be matched efficiently and operated reliably. The internal magnetic flux is easy to adjust in both directions, and the proposed HEG can output stable voltage in the range of wide speed and load.

Permanent magnet generator (PMG) for vehicles has attracted more and more attention because of its high efficiency, high power density, and high reliability. However, the weak main air-gap magnetic field can affect the output performance and the normal use of electrical equipment. Aiming at the problem, this paper took the rotor magnetomotive force (MMF), the direct influencing parameter of the main air-gap magnetic field, as the research object, deduced the analytical expression of rotor MMF of the built-in radial PMG in detail, and analyzed its main influencing factors in analytical expression, including the permanent magnet steel (PMS) material, the thickness of PMS in magnetizing direction, the vertical length of the inner side of PMS, and the effective calculation length of PMS. Based on this, the rotor parameters were optimized to obtain the best values. After that, the finite element simulation and prototype test of the optimized generator were carried out. The comparative analysis results showed that the optimized rotor parameters could effectively improve the rotor MMF and optimize the output performance of the generator.

The motor is an important component that affects the output performance of new energy vehicles (using new energy sources such as electric energy and hydrogen fuel energy to drive the motor and provide kinetic energy). Motors with high power and low noise can effectively improve the dynamic performance, passability and smoothness of new energy vehicles and bring a comfortable experience to driver and passengers. The magnetic field analytical model of the inner-mounted permanent magnet synchronous motor (IPMSM) is studied to improve its output quality. The motor is divided into four subdomains: the stator slot subdomain, the stator slot notch subdomain, the air-gap subdomain, and the permanent magnet (PM) subdomain. The general solution of the vector magnetic potential of each subdomain is solved, and the expression of magnetic flux density of each subdomain is derived. Meanwhile, the analytical model of the non-uniform air gap is established according to the uniform air-gap model. The model’s accuracy is verified by finite element analysis and prototype tests. The results show that the calculation results of the analytical model are effective. The model can be applied to predict the no-load back electromotive force (EMF) and cogging torque of the motor under different main air gaps. It also provides an effective and fast analysis method for the design and optimization of IPMSM for new energy vehicles.

The structure and magnetic circuit of the modern permanent magnet (PM) generator are often very complicated, which makes the traditional finite element analysis of magnetic field highly difficult. This paper establishes an equivalent magnetic circuit model of a new double-radial PM generator using the traditional equivalent circuit method and data analysis, introduces the calculation formulas of permeance and leakage permeance (LP) in magnetic circuits in detail, analyzes the influence factors of the LP, and provides the solutions. These studies will have a certain guiding significance for the design and optimization of generator circuits. To obtain the best matching parameters, the main parameters of the generator are tested and analyzed, such as the thickness of PM steel in the magnetization direction, length of PM steel, number of pole pairs, and the thickness of spacer bush. Finally, a prototype is tested, and the results show that the output characteristics of the designed double-radial PM voltage-stabilizing generation device are very good.

Aiming at the problems of large excitation loss and low power generation efficiency of silicon rectifier generators and the unstable output voltage of permanent magnet (PM) generators, a hybrid excitation generator (HEG) with suspended brushless claw pole electrical excitation rotor (EER) and combined magnetic pole PM rotor is proposed in the present work. With only one fractional slot winding stator, the generator adopts PM field as the main magnetic field and electrical excitation field as the auxiliary magnetic field, which not only retains the advantages of high efficiency of PM generators but also effectively reduces excitation consumption. The main structure parameters and the design method were analyzed, and a simulation analysis of no-load magnetic field distribution and flux regulation ability was carried out using finite element software to verify the rationality of the hybrid excitation parallel magnetic circuit design. Moreover, the no-load, load, regulation, and voltage regulation characteristics of the designed generator were tested, and the results show that the designed generator has a wide range of voltage regulation, which can ensure stable output voltage under variable speed and load conditions.

Due to the increasing energy crisis and environmental pollution, the development of drive motors for new energy vehicles (NEVs) has become the focus of popular attention. To improve the sine of the air-gap flux density and flux regulation capacity of drive motors, a new hybrid excitation synchronous motor (HESM) has been proposed. The HESM adopts a salient pole rotor with built-in dual-V permanent magnets (PMs), non-arc pole shoes and excitation windings. The fundamental topology, operating principle and analytical model for a magnetic field are presented. In the analytical model, the rotor magnetomotive force (MMF) is derived based on the minimum reluctance principle, and the permeance function considering a non-uniform air-gap is calculated using the magnetic equivalent circuit (MEC) method. Besides, the electromagnetic performance including the air-gap magnetic field and flux regulation capacity is analyzed by the finite element method (FEM). The simulation results of the air-gap magnetic field are consistent with the analytical results. The experiment and simulation results of the performance show that the flux waveform is sinusoidal-shaped and the air-gap flux can be adjusted effectively by changing the excitation current. This study provides design methods and theoretical analysis references for this type of HESM.

In this study, the tangential magnetic field Nd-Fe-B permanent magnet generator is designed and analyzed. In the generator, the adjacent permanent steel is sequentially arranged on the radial groove by the way of same polarity-oriented manner. The optimal design parameters of the generator are obtained by analyzing the influence rule of the generator leakage magnetic flux and leakage coefficient which is affected by the change in rotor pole pairs, permanent steel thickness, magnetic isolation air width, and air-gap length. The mathematical model of the magnetic field is developed and analyzed using the finite element method. Using the finite element method model, the diagrams of magnetic force line distribution, magnetic flux density modulus value, and magnetic flux density vector are obtained, which can be used to verify the validity of the main design parameters. A three-phase half-wave impulse-type controlled rectifier voltage regulator is developed with the function of regulator and rectifier, which proposes a solution to the output voltage instability of the Nd-Fe-B permanent magnet generator in a wide speed and load range.

The flywheel-type dual-stator permanent magnet starter generator combines engine flywheel and starter generator rotor into a single unit, which has the advantages of high efficiency, high power density, and compact structure. This paper proposes a new type of dual-stator permanent magnet starter generator topology in which the two stators are concentric and share the same permanent magnet rotor. Equivalent magnetic circuit modeling of the inner stator's magnetic field, outer stator's magnetic field, and synthetic magnetic field using the equivalent magnetic circuit method list the system of flux equations and solve the main magnetic flux, leakage flux, and leakage coefficient, and the results show that the equivalent magnetic circuit method has smaller error and higher accuracy than the finite element method. The harmonic electric potential of the starter generator is modeled and analyzed. The permanent magnet rotor and inner and outer stator structures are optimized to obtain the optimal parameters, and the prototype is manufactured and tested. The optimized starter generator no-load induced electromotive force fundamental amplitude is improved. The induced electromotive force harmonic distortion rate is reduced, and the output performance of the whole generator is significantly improved. [ABSTRACT FROM AUTHOR]