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Homopolar inductor machine (HIM) has caught much attention in the field of flywheel energy storage system (FESS) due to its merits of robust rotor, brushless exciting, high reliability, etc. Compared with permanent magnet HIM (HIM-PM), the HIM with field winding (HIM-FW) can effectively eliminate the idling loss caused by the no-load magnetic field by cutting off the excitation current, while the charge/discharge efficiency of HIM would be decreased due to the copper loss of field winding. To address this contradiction, a novel PM HIM with mechanical flux modulator (HIM-MFM) is proposed to achieve low idling loss and high charge/discharge efficiency. Firstly, the special structure and operation principle of the HIM-MFM are investigated. Afterwards, the characteristic of equivalent magnetic circuit of the HIM-MFM is analyzed and several key structure parameters of it are optimized. Moreover, the electromagnetic performance indexes of the HIM-MFM, including back-EMF, flux weakening ability, losses, etc. are fully analyzed. Finally, a prototype of the HIM-MFM is designed, manufactured, and tested. Experiment results confirm those obtained by simulations. Results show that the proposed HIM-MFM inherits the merits of high charge/discharge efficiency of HIM-PM and almost no idling electromagnetic loss of HIM-FW.

The urban rail transit system has the characteristics of wide voltage fluctuation, intermittent and strong impact load, limited heat dissipation capacity. The high-speed flywheel energy storage system (FESS) is used to provide network voltage stability and regenerative braking energy recovery due to its high power density, unlimited number of charge-discharge cycles, fast response and environmental friendliness. When considering the design of high-speed FESS converter with 3.6 kHz fundamental frequency and 330 kW rated power used in 1500 VDC urban rail transit system, the two-stage topological converter reduces the efficiency and increase the cost and size, meanwhile, the series-connected converters and the multilevel converter increase the difficulties of control and insulation, so the two-level and I-type three-level converters of high-speed FESS are designed and evaluated. Several comparisons are made by detailed experimental data from the perspective of the traction load characteristics of the 1500 VDC urban rail transit system and the technical and economical requirements of the high-speed FESS. It is found that the three-level converter has significant advantages in matching the traction load characteristics for its higher duty cycle capability, as well as improving the technical and economical performances such as efficiency, du/dt value, THD, voltage stability, and reducing the cost by 40% when compared to the two-level converter. While in the future MW class high-speed FESS development, the maximum output power capacity of the three-level FESS is relatively lower than that of the two-level FESS. The theoretical analyses were verified by experiments.

Homopolar inductor machine (HIM) has been applied in the field of flywheel energy storage system (FESS) due to its merits of simple structure, high reliability, and low idling losses. However, the HIM features unipolar air-gap flux density, which makes its power density lower than that of the electrical machine with bipolar air-gap flux density. Addressing this issue, a novel outer rotor homopolar inductor machine (OR-HIM) is proposed in this article. First, the special structure and operation principle of the OR-HIM are illustrated. Then, the unit motors of the OR-HIM are obtained and investigated based on the magnetic equivalent circuit method to facilitate the design. Moreover, the performance indexes, including power density, output characteristics, losses, and rotor stress of the OR-HIM, are fully analyzed. Finally, a 13-kW prototype is designed, manufactured, and tested. The back electromotive force, load voltage, output torque, and efficiency are measured and compared with those obtained by the finite element analysis. The results indicate that the proposed OR-HIM is a promising candidate for the application of FESS.

Brushless structure is beneficial for air-core compensated pulsed alternator (ACPA) because its field current and rotation speed are too large for the slip rings and carbon brushes. To achieve the brushless structure, a cascaded brushless self-excited ACPA (CBSACPA), which consists of an exciter and a generator in cascade, is proposed, in this article. The exciter and generator have a common rotor. A novel squirrel-cage rotor winding (SCRW), which can eliminate the end winding compared with conventional wound rotor winding (WRW), is proposed to simplify the rotor structure and improve the performance. First, the structure of the CBSACPA with the SCRW is introduced. Second, the operation principles of the machine are elaborated. Third, the dynamic mathematical model is presented. Fourth, the operation principles are demonstrated by the finite-element method. In addition, the performance of the SCRW is compared with the WRW as well. Finally, a prototype of CBSACPA is developed and tested to validate the analyses and simulations. In conclusion, this study gives detailed introduction, analyses, and validation about the CBSACPA, which provides a new solution to achieve a brushless structure for the ACPA.

Homopolar inductor machine (HIM) has been applied in the field of flywheel energy storage system (FESS) due to its merits of simple structure, brushless exciting, and low idling losses. The rotor of HIM not only plays the role of energy conversion but also serves as a flywheel to store kinetic energy, which is different from other electrical machines used in FESS. Meanwhile, the HIM usually operates at high speed to improve the power density and storage energy. To obtain good performance and high reliability, the design and optimization of HIM should consider multiphysics, including storage energy, electromagnetic performance, rotor stress and dynamics, and so on. However, the existing researches mainly focus on the analysis of electromagnetic performance and lack multidisciplinary design. To solve this problem, a multidisciplinary design method of HIM is proposed and investigated. First, the operation principle of HIM is illustrated, and the multidisciplinary design method is proposed. Then, the storage energy, electromagnetic performance (including no-load air-gap flux density, saliency ratio, torque, and electromagnetic power), rotor stress, and modal of HIM are deeply analyzed according to the proposed design flow. Finally, a prototype of HIM is manufactured and tested. The results calculated by finite-element analysis are validated by experiments. The design method proposed in this article provides a straightforward procedure for the multidisciplinary design of HIM.

Ribosome biogenesis is a fundamental process required for cell proliferation. Although evolutionally conserved, the mammalian ribosome assembly system is more complex than in yeasts. BCCIP was originally identified as a BRCA2 and p21 interacting protein. A partial loss of BCCIP function was sufficient to trigger genomic instability and tumorigenesis. However, a complete deletion of BCCIP arrested cell growth and was lethal in mice. Here, we report that a fraction of mammalian BCCIP localizes in the nucleolus and regulates 60S ribosome biogenesis. Both abrogation of BCCIP nucleolar localization and impaired BCCIP–eIF6 interaction can compromise eIF6 recruitment to the nucleolus and 60S ribosome biogenesis. BCCIP is vital for a pre-rRNA processing step that produces 12S pre-rRNA, a precursor to the 5.8S rRNA. However, a heterozygous Bccip loss was insufficient to impair 60S biogenesis in mouse embryo fibroblasts, but a profound reduction of BCCIP was required to abrogate its function in 60S biogenesis. These results suggest that BCCIP is a critical factor for mammalian pre-rRNA processing and 60S generation and offer an explanation as to why a subtle dysfunction of BCCIP can be tumorigenic but a complete depletion of BCCIP is lethal.

The surface-mounted permanent magnet linear synchronous motor (PMLSM) is a good candidate for the Electromagnetic Launch System due to its merits of high-power density, power factor and efficiency. However, this kind of machine needs a lot of permanent magnets (PMs) on the long stator, which is costly. To solve this problem, a novel PMLSM is proposed in this paper. The stator of novel PMLSM has the consequent poles structure and the mover of novel PMLSM has two iron cores, which sandwiches a mover PM. Firstly, the structure and operation principle of the proposed PMLSM have been investigated. Then, the analytical calculation of thrust and detent force is analyzed and the structural parameters of the motor are optimized for larger thrust and less detent force. Finally, for a fair comparison, the proposed motor is designed and built based on an existing PMLSM with similar electromagnetic and geometrical parameters. The thrust performance indexes of the novel PMLSM are estimated and compared with the conventional surface-mounted PMLSM, which indicates that the proposed PMLSM can keep similar performances with the exciting PMLSM. Moreover, it has a simple structure, less thrust ripple and can save many PMs, which can help reduce costs.

The BRCA2 tumor suppressor protects genome integrity by promoting homologous recombination-based repair of DNA breaks, stability of stalled DNA replication forks and DNA damage-induced cell cycle checkpoints. BRCA2 deficient cells display the radio-resistant DNA synthesis (RDS) phenotype, however the mechanism has remained elusive. Here we show that cells without BRCA2 are unable to sufficiently restrain DNA replication fork progression after DNA damage, and the underrestrained fork progression is due primarily to Primase-Polymerase (PRIMPOL)-mediated repriming of DNA synthesis downstream of lesions, leaving behind single-stranded DNA gaps. Moreover, we find that BRCA2 associates with the essential DNA replication factor MCM10 and this association suppresses PRIMPOL-mediated repriming and ssDNA gap formation, while having no impact on the stability of stalled replication forks. Our findings establish an important function for BRCA2, provide insights into replication fork control during the DNA damage response, and may have implications in tumor suppression and therapy response., Tumor suppressor BRCA2 is known to stabilize and restart stalled DNA replication forks. Here the authors show that BRCA2 is recruited to the replication fork through its interaction with MCM10 and inhibits Primase-Polymerase-mediated repriming, lesion bypass and single strand DNA gap formation after DNA damage.

Homopolar inductor machine (HIM) has a wide range of applications in the field of flywheel energy storage system and ship propulsion due to its merits of simple structure, brushless exciting, and low idling losses. However, the three-dimensional finite element method (3-D FEM) is mainly used to investigate the electromagnetic performance indexes of HIM due to its intrinsic 3-D flux density distribution, which is time-consuming. To facilitate the analysis of HIM, an analytical method (AM) is necessary, especially in the initial design stage. Hence, this article presents an AM for analyzing the electromagnetic performance of HIM. First, the structure and operation principle of HIM are illustrated. Second, the magnetic equivalent circuit of HIM is built considering the saturation of stator and rotor core. Third, the air-gap permeance function is obtained considering the affection of stator and rotor slots. Finally, the magnetomotive force, air-gap flux density, back electromotive force, inductances and electromagnetic torque of HIM are calculated, then validated by 3-D FEM and corresponding experiments. The results indicate that the proposed AM can provide reasonable results to estimate the electromagnetic performance of HIM, which would be helpful for the analysis of HIM.

© 1972-2012 IEEE. A novel hybrid excited asymmetric stator pole doubly salient machine (HEASPDSM) is proposed in this paper. The new topologies and operational principle are first investigated by using a simplified equivalent magnetic circuit model. The harmonic components of air-gap flux density are then analyzed. The influence of key structural parameters of the proposed machine on the flux regulation ability and torque is studied. A full comparison on main electromagnetic performance indexes of the proposed 12/7 (stator/rotor poles) HEASPDSPM and several traditional doubly salient machines is presented. A prototype is fabricated and tested to validate the theoretical analysis. The results well demonstrate that the HEASPDSPM possesses various merits, such as strong flux regulation capability, high torque density, low cogging torque, and low torque ripple.

Air-core compensated pulsed alternator (ACPA) has been applied to the field of pulsed power technology, especially electromagnetic launch. The high-field current and the rotating speed of the ACPA bring the benefits of high power and energy density, but also make it suffer from low reliability and poor performance due to the serious heat and wear in the slip rings and brushes. To solve this problem, a novel brushless self-excited ACPA (BSACPA) is presented in this paper. It consists of two submachines in cascade, namely, an exciter and a generator, for which the air-gap flux rotation directions are opposite. The rotor windings are specially arranged and adopt the principle of negative sequence alternate current excitation, thus eliminating brushes and slip rings, and no rotary rectifier diode is needed. First, the structure and the operation principle of the BSACPA are described. Second, the magnetic field distribution and the coupling between the two submachines are analyzed. Third, the mathematical model of BSACPA is established. Finally, the validity of its operation principle is verified by finite-element and circuit analyses. In conclusion, BSACPA achieves the brushless structure and provides a new solution to improve the performance and the reliability of a conventional ACPA.

Pulsed power technology is widely used in medical treatment, military, and scientific research, such as laser burst and electromagnetic launch. Compensated pulsed alternator (CPA) is a kind of device generating that pulsed power. One of the shortages for the air-core pulsed alternator is the huge excitation loss. In order to solve the problems, a multidisk axial flux CPA (MAFCPA) is proposed, which replaces the excitation windings with permanent magnets, saving the self-excitation process. In addition, multidisks are designed, especially to reduce subtransient reactance when the CPA discharges, which contributes to increasing the discharging current. This paper mainly focuses on researching the feasibility of MAFCPA in aspects of thermal issues, rotor statics, and dynamics problems. First, the topology and principle of MAFCPA are introduced, and the properties of the materials are listed as well. Second, the loss of discharging is calculated and the temperatures of both stator and rotor are solved. Then, the maximum stresses of different materials are obtained. Afterward, the critical speeds are researched in order to avoid resonance. Finally, the conclusion is made that MAFCPA can work safely under a speed of 10000 r/min and supply a pulse of over 50 ms.

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.

In recent years, several novel homopolar inductor machine (HIM) topologies, such as rotors with the rectangular, arc-shaped, sinusoidal and triangle rotor slots, are developed. However, the influence of different rotor slots on the performance of HIM is not clear, and there is no basis for selecting rotor slots. Addressing this issue, a comprehensively comparative studies of these topologies with different rotor slot shapes are implemented. Firstly, the topology and operation principle of the HIM are illustrated. Then, the influences of rotor slot shape on the performance including the no-load air gap flux density, back electromotive force, inductance, torque, torque ripple and losses are systematically studied. Moreover, the stress distribution, modal and rotary inertia of rotor with four different rotor slots are analyzed. Based on the above analyses, the HIM with arc-shaped rotor slots is selected and its prototype is developed. Some electromagnetic performance indexes are tested to verify the rationality of analyses. This work clearly points out the advantages and disadvantages of HIMs with different rotor structures, which could be good reference for the selection of rotor slot shape.

Permanent magnetic bearings (PMB) are used nowadays in many applications ranging from turbomachinery to energy storage flywheels due to their simple construction, no contact, and no wear. The calculation of the magnetic force is of great significance in the optimal design progress. However, the current magnetic force expression obtained by the equivalent magnetic charge model is a multidimensional integral with a complex integrand. In order to simplify the calculation under the premise of ensuring accuracy, the equal distribution sequence Quasi-Monte Carlo method (QMC) is used to calculate the magnetic force between two ring magnets in this paper. Based on Monte Carlo method (MC), it is proposed to solve the multidimensional integral by using a sequence of low-discrepancy irrational numbers that are more uniform than the randomly generated point distribution to avoid aliasing of projections and have a faster rate of convergence. The integral is programmed in MATLAB using MC and QMC and verified using the finite element method (FEM), then the results are compared with the data in published literature. The results show that QMC has higher accuracy and better repeatability than MC, and the calculation efficiency is higher. The results of the proposed method are in good agreement with FEM and published literature, and the required time is shorter than FEM, which is a more suitable method for magnetic force calculation in some cases.

Permanent magnet synchronous machines (PMSM) are widely used due to their small size and good running performance. However, PMSM have the disadvantages of multivariable and strong coupling, which make it difficult to design the regulator parameters. To solve this problem, this paper studies the use of three-vector model predictive current control (TV-MPCC) in PMSM. The traditional TV-MPCC uses speed sensors, which increases the cost and installation difficulty. The extended Kalman filter (EKF) algorithm which is applied for detecting rotor position and speed is proposed in this article. By comparing the traditional TV-MPCC algorithm with sensorless algorithm, the results indicate that there is no significant difference between sensorless algorithm and the traditional MPCC algorithm, sensorless algorithm has an analogous dynamic and steady-state performance.

BCCIP was originally identified as a BRCA2 and CDKN1A/p21 interaction protein. Although a partial loss of BCCIP function is sufficient to trigger genomic instability and tumorigenesis, complete deletion of BCCIP is lethal to cells. Using Rosa26-CreERT2 mouse models, we found that induced Bccip deletion in adult mice caused an acute intestinal epithelial denudation that cannot be relieved by co-deletion of Trp53. The critical role of Bccip in intestine epithelial renewal was verified with a Villin-CreERT2 mouse model. The epithelium degeneration was associated with a rapid loss of the proliferative capability of the crypt progenitor cells in vivo, lack of crypt base columnar stem cell markers, and a failure of in vitro crypt organoid growth. RNA-Seq analysis of freshly isolated intestinal crypt cells showed that Bccip deletion caused an overwhelming down-regulation of genes involved in mitotic cell division but an up-regulation of genes involved in apoptosis and stress response to microbiomes. Our data not only indicate that intestinal epithelium is the most sensitive tissue to whole-body deletion of Bccip but also point to Bccip as a novel and critical factor for the proliferation of the intestinal progenitors. These findings have significant implications for understanding why a hypomorphic loss of BCCIP functions is more relevant to tumorigenesis.

© 1972-2012 IEEE. This article presents the design and analysis of a 12/7 (numbers of stator/rotor poles) hybridly excited asymmetric stator pole doubly salient machine (HEASPDSM) with a main focus on the special topology and operational principle by using the analytical and 2-D finite element analysis. A full comparison is conducted on the average torque, torque ripples, no-load back electromotive force and flux regulation capacity under the condition of different structural parameters, which can provide good references to the machine design. A 12/7 HEASPDSM is designed and the main performance indexes are analyzed in detail. Based on the parameters, the performance of 12/7 HEASPDSM is compared with traditional 6/7 doubly salient permanent magnet machine (DSPMM) with the same volume and thermal load. Finally, a prototype of the 12/7 HEASPDSM is manufactured and tested to validate the theoretical analysis. The results fully demonstrate that the HEASPDSM possesses the merits of strong flux regulation capability, higher torque density, and wider constant power speed range benefitted from the dc field winding than the traditional DSPMM.

An axial-flux permanent-magnet (PM)-assisted claw-pole generator (APCG) is designed based on an equivalent magnetic circuit model (EMCM). It is designed for generating power in vehicle with the merits of high power density, no brush, and wide airgap flux density modulation range. This paper mainly focuses on establishing the EMCM of the APCG and designing a set of optimal structure parameters. First, the topology and operation principle of the APCG are introduced in detail, including material, fabrication, and magnetic flux distribution. Second, the magnetic circuits in claw poles are simplified and the relationships among the key parameters are discussed. Finally, based on the simplified model and the relationships among the key parameters, the EMCMs of current and PM excitation are established, respectively. According to the EMCM, a scheme of a 4 kW APCG is carried out. Comprehensive investigations demonstrate that the EMCM is time-saving and relatively accurate when compared with a finite element method.

Doubly salient permanent magnet machine (DSPMM) has received extensive attentions recently due to its simple structure, high reliability, high torque density, etc. An improved 4/4 stator/rotor single-phase asymmetric-stator-pole doubly salient permanent magnet machine (SP-ASPDSPMM) is proposed in this paper. Firstly, it investigates the topologies and operation principle based on graphical description and torque expression. Then, the effect of main structure parameters on the torque is studied based on two-dimensional finite element algorithm (2-D FEA). And then, comprehensive comparison on main electromagnetic performances for the two machines is made. Finally, one prototype for the improved structure is made and tested. It indicates that lower cogging torque, lower torque ripple and stronger starting performance can be obtained by the improved structure. The theoretical results are well validated by the experiments.

The homopolar inductor machine (HIM) is of particular interest in the field of flywheel energy storage system, where it has the potential to significantly reduce self-discharge associated with magnetic losses. However, the conventional HIM suffers from low power and torque density due to its unipolar air-gap flux density. Besides, the air-gap flux density of HIM is limited by the cross section of rotor, and the rotor diameter is limited by the maximum tip speed of the rotor. Thus, the maximum effective length and diameter of rotor should be within a certain range, which constrains the output power and stored energy of the HIM. To solve these problems, a novel multi-unit out-rotor HIM (MO-HIM) with bipolar air-gap flux density is proposed in this paper. First, the structure and operating principle of MO-HIM is illustrated. Then, the characteristics of the proposed machine are analyzed, indicating that MO-HIM can be regarded as a superposition of multiple unit machines. Finally, to verify the superior performances of the proposed MO-HIM, it is compared with a unipolar out-rotor HIM with multi-segment stator cores in terms of air-gap flux density, back electromotive force, and output torque. Results show that the proposed MO-HIM has larger fundamental air-gap flux density, higher power, and torque density.

A vehicular generator has stringent requirements on its weight and volume. As a combination of permanent magnet and electric excitation motor, hybrid excitation machine could meet the requirements of vehicular generator, with small size, light weight, adjustable output voltage. In this paper, an axial flux stator partition hybrid excitation brushless synchronous generator (ASHG) is proposed. First, the structure and operation principle of ASHM is illustrated. Afterwards, the shape of the magnetic pole is optimized to obtain the air-gap flux density with low harmonic content. Moreover, the regulation performance of the magnetic field and output voltage are investigated by three dimensional finite element analysis (3D FEA). The result indicates that ASHG has a high performance of adjusting terminal voltage. It can improve the generator efficiency, power density and stability comparing with the conventional vehicular generator.

Traditional moving-magnet transversal-flux linear oscillatory machines (MTLOM) suffer from high fabrication difficulty and cost, low robustness and reliability, and low material utilization ratio, etc. In this paper, a novel stator-magnet moving-iron transversal-flux linear machine (SMTLOM) is proposed, with magnets inserted into the stator yoke (rather than mounted on stator poles) and mover composed of iron core only. First, the topology of proposed SMTLOM is described, as well as its operation principle. Then, the comparison rules are built to make fair comparison between the conventional MTLOM and the novel SMTLOM, from the perspective of practical application, including the same maximum size limitation, output thrust, and thermal source. By using a three-dimensional finite-element analysis (3-D FEA), comparisons of some key performance indexes, such as back electromotive force, thrust per coil length, thrust per magnets volume, thrust per machine volume, temperature distribution, material cost and structure reliability, etc., are made between these two types of machines. The results from 3-D FEA demonstrate that the novel SMTLOM has enjoyed merits of lower fabrication cost and weight, much higher reliability, thrust density, material utilization ratio, etc., which indicate that the novel SMTLOM is more suitable for driving compressor and easier for mass production.

The homopolar inductor alternator (HIA) has some merits over classical machines for applications such as a high-temperature superconducting machine and as flywheel energy storage system. For the design of HIA, the back electromotive force (back-EMF) and air-gap flux density are two key parameters. Due to the intrinsic three-dimensional (3-D) magnetic circuit structure, 3-D finite-element analysis (FEA) is required for accurate modeling of HIA, which is, however, very consuming. To solve this problem, a 2-D analytical model is proposed in this paper. First, the method of air-gap flux density spatial overlay analysis is illustrated. Based on it, the structure and equivalent principle of 3-D converting to 2-D model of HIA are investigated. Finally, the analytical model is applied to HIAs with different rotor structures to prove the accuracy of the proposed model. An experimental platform is built to verify the effectiveness of this model. The results indicate that the proposed model can accurately calculate the back-EMF and air-gap flux density. Meanwhile, it takes much shorter time than 3-D FEA method does.

The torque ripple is a main source of the noise and vibration which has a considerable effect on the performance of the machine. A design technique, tooth notching, which was extensively used in permanent magnet machines, has been innovatively applied to a wound-rotor brushless doubly-fed machine (BDFM) to reduce the torque ripple. First of all, the winding structure, the winding space harmonics and magnetic fields of the stator and the rotor were studied. Then, general analytical expressions of the electromagnetic torque (EMT) for the BDFM were deduced. Finally, prediction of the results was verified by several models which were calculated by the finite-element analysis method, meanwhile, the influences of different tooth-notching structures and the notch depth on the EMT were investigated. It is shown that the torque ripple can be reduced by the suggested design with small increment of the magnetic field saturation and the currents of the control winding and the rotor winding.

© 2017 IEEE. In this paper, one novel heteropolar radial hybrid magnetic bearing (HRHMB) with low-power loss is proposed for flywheel energy storage system. First, its structure and equivalent magnetic circuit (EMC) are introduced in detail. Then, some main design parameters are analyzed based on EMC, including air-gap bias flux density, magnetic pole area, permanent magnet (PM) dimensions, and control current. Furthermore, to improve the performances of the novel HRHMB, the optimizations are implemented both on its structure and some key size parameters, such as the second air-gap length, PM height, and width. Finally, the optimal scheme is verified by the 3-D finite-element analysis, which indicates the maximum control current can be reduced to only 40% that of initial design by the optimizations.