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Identification of the stator d -axis and q -axis inductances is essential for the interior permanent magnet synchronous motor (IPMSM) sensorless control system. The signal injection method is an effective way to identify the inductance parameters; however, it requires the rotor position to ensure the accuracy of the injection reference position. To overcome the dependence on the rotor position, a sequence-pulse voltage signal injection method is presented. The matrix least-squares fitting algorithm is utilized to fit the current responses for the inductance identification. Based on the fitting method, the discrete standard orthogonal polynomial with look-up table is introduced to reduce the computation complexity. To reduce the disturbance of the injected signal to the rotor position during the identification process, a double-direction injection position trajectory planning is presented. In addition, the saturation effect on the identification method is also analyzed. The proposed method is verified via a 3.0 kW IPMSM motor drive platform. The identification results are compared with those measured by a standard method and experiment results show that the proposed method can identify the inductance parameters with acceptable accuracy without obtaining the rotor position information.

This paper proposes an indirect input-series output-parallel (I2SOP) dc–dc full-bridge converter system based on asymmetric pulsewidth modulation (APWM) control strategy for high input voltage applications. When a short-circuit fault occurs in a high input voltage dc bus, the proposed I2SOP system can disconnect from the dc bus effectively and avoid the input filter capacitors of constituent modules discharge compared with the traditional ISOP system, facilitating fault handling and protecting the input filter capacitors. Moreover, with the proposed I2SOP structure, it is easy to achieve redundancy design when one or a few constituent modules fail. The APWM control strategy is introduced to the I2SOP system rather than the classical phase-shifted control strategy for the basic full-bridge module to reduce the voltage stress of power switch and the filter requirement. The characteristics of input voltage sharing and output current sharing of the I2SOP system are also analyzed. A three-module I2SOP system prototype was built, and the experimental results verify the correctness and effectiveness of the proposed solution.

© 2002-2011 IEEE. This paper presents a novel axial field flux switching memory (AFFSM) machine, which integrates series permanent magnet (SPM) and an additional dc field winding for improving the flux regulation capability. The configuration and the operation principle of the SPM-AFFSM machine are presented. The design considerations for the SPM and the dc field winding are discussed. The voltage regulation capability and torque-speed characteristics of the SPM-AFFSM machine are investigated by 3-D FEA. Finally, a prototype is developed for experimental verification. The measured results verify structural validity and the finite-element predictions.

By using the vector control for permanent magnet synchronous motor (PMSM), the current static decoupling is realized, however, the dynamic coupling still exists. Some conventional methods achieve dynamic decoupling to some extent but these methods depend on specific motor parameters. To solve this problem, this paper proposes a decoupling control method applied to PMSM drives via vector control and uncertainty and disturbance estimator (UDE). The coupling terms and parameter uncertainties are modeled as disturbance and an UDE is used to observe the disturbances. The observed disturbances are used to compensate for the output of the current-loop PI controller. Additionally, this paper demonstrates the decoupling ability of the proposed method by deriving its equivalent form. The simulation results indicate that the proposed controller has a good decoupling effect and a strong robustness to parameters variation.

In this paper, a double-stator linear-rotary permanent magnet motor (DSLRPMM) for linear and/or rotary movement is presented. Since the two types of permanent magnets are orthogonally arrayed on the inner and outer surfaces of the mover core, respectively, the influences of the orthogonal magnetic field (OMF) on the motor electromagnetic characteristics cannot be ignored. Based on the 3-D finite-element method (FEM), the OMF in the motor and the iron core magnetization characteristics are investigated, and a test device is constructed to verify the results obtained by the theoretical analysis and 3-D finite-element analysis (FEA). On the basis of the measured data, the 2-D FEM is employed to analyze the electromagnetic characteristics of the DSLRPMM, including flux density, flux linkage, back-electromotive force, detent force, and cogging torque. The results are compared with that obtained by the 3-D FEA, and they are in agreement. Moreover, a prototype is built and tested. The experimental results verify the correctness of the predictions.

A double stator linear-rotary permanent magnet motor, which has a long tuber ferromagnetic mover core with permanent magnets (PMs) arranged on its inner and outer surfaces, is proposed for two degree of freedom drive in this study. Due to the topology of the long tuber mover, the end-effects, including the interaction between the outer stator end and the mover, the effects of the inner PM length, and the interaction between the inner stator end and the mover, are presented and analysed. Based on the three-dimensional (3D) finite-element method, the influences of the end-effects on the electromagnetic characteristics, such as the flux distributions, flux density, electromagnetic force and torque, and output power, are investigated. Meanwhile, the topology with the minimised end-effects is given, and a prototype is built. The dynamic performances of the prototype are tested via a specific experimental platform. The results are in agreement with that of the 3D finite-element analysis.

This paper focuses on the multi-objective optimization of an air-cored axial flux permanent magnet synchronous machine (AFPMSM) with segmented PMs. Support vector machine based on radial basis kernel function is combined with orthogonal design to create the surrogate model between output performance and design parameters of a coreless AFPMSM with segmented PMs efficiently, and genetic algorithm is used to obtain the global optimal solutions to decrease the torque ripple and increase the output torque. The effectiveness of the proposed method is verified by finite element analysis.

In the conventional stator resistance measurement method, the introduction of the dead-time results in the distortion of the output voltage, which will affect the accuracy of the identification results. This paper presents an offline stator resistance identification method, which can avoid the influence of the dead-time effect during the resistance identification process. Firstly, a short pulse voltage signal is injected into the d-axis reference position to generate the d-axis current. Then the zero voltage vector is used to turn on the low-side MOSFETs to release energy stored in the inductor by the stator resistor. By measuring the current response, the stator resistance can be identified. Experiments at different exciting currents are carried out and the experimental results show that the proposed method can overcome the dead-time effect and achieve nice identification accuracy and numerical stability at different exciting currents.

The purpose of this paper is to analyze ac copper losses of the ironless brushless dc machine (BLDCM) used in the flywheel energy storage system. The influence factors of the ac copper losses, such as the winding diameter, phase current, and machine speed, are analyzed. The research results show that the winding wire diameter has a huge effect on the ac losses in ironless BLDCM, and the shunt wound structure with multiple wires method can reduce winding ac losses effectively. However, due to induced voltage and impedance unbalance, additional circulating current losses are induced. For circulating current losses calculation, a winding circulating current equivalent calculation model is built. The circulating current losses are calculated by a simplified three-dimensional finite element method and the winding wires arrangement methods to reduce circulating current losses are explored. Three winding wires arrangements are compared and discussed. The results show that the ironless BLDCM using multiwires with suitable arrangements can reduce the copper losses.

This paper investigates a double stator linear rotary permanent magnet motor (DSLRPMM) with orthogonally arrayed PMs. The DSLRPMM, which involves linear and/or rotary movements, is constituted of two stators and a hollow mover. The aim of this paper is to study the electromagnetic features and optimize the design parameters of the motor using a 3-D finite-element method (FEM). The topology and the operating principle are described, and the original design is given. The influences of the main designed parameters on the electromagnetic torque, force, and total losses are also analyzed. The optimal parameters are given and a prototype is built and tested. The experimental results are in agreement with that of the 3-D FEM analysis.

In this paper, a double-stator permanent-magnet motor that involves linear and/or rotary movements is investigated. The double-stator linear-rotary permanent-magnet motor (DSLRPMM) is constituted of two stators and a hollow mover with permanent magnets affixed on its surfaces. This paper focuses on the main electric and magnetic features of the DSLRPMM. First, the structure and operating principles of the motor are described, and the original design of the motor is also given. Then, the electromagnetic characteristics, including fluxes, torques, forces, etc., are studied owing to the three-dimensional finite-element method analyses. Results are given and compared with the measurements.

The hybrid axial field flux-switching permanent-magnet machine (HAFFSPMM) is a novel hybrid excited machine with short axial length and high torque density, which is suitable for electrical vehicle drive. However, the HAFFSPMM exhibits a higher cogging torque than traditional permanent-magnet machines due to the doubly salient structure and the high flux density. To reduce the cogging torque, three cogging torque reduction methods by tangential displacement of stators, asymmetric rotor pole shape, and segment-twisted rotor are investigated in this paper. The influences of the asymmetric angle of the three methods on the cogging torque and the output torque are analytically investigated and numerically verified by a three-dimensional finite-element method. The results show that the cogging torque can be greatly reduced, whereas the output torque decreases slightly even increases. In no terms of output torque, the cogging torque with segment-twisted rotor is less than the other two methods; in terms of output torque, the cogging torque reduction with an asymmetric rotor pole shape is better than the others.

This paper investigates the air-gap magnetic field characteristics of homopolar inductor alternator (HIA), including theoretical analysis, numerical calculation, and experiment. First, the structure and magnetic circuit characteristics of HIA are analyzed. Second, a linear model of distributed magnetic circuit of HIA is established. An analytical formula for calculating the main air-gap magnetic field at different axial positions is deduced and obtained. Third, finite element method (FEM) is used to compute the magnetic field of HIA. The results from FEM are nearly consistent with those from analytical method. Finally, a prototype is constructed to verify the theoretical analysis and numerical computation. The research shows that the distribution of the main air-gap magnetic field of HIA is uneven along the axial direction. The proposed analytical formula contributes to calculate the main air-gap magnetic flux density of HIA.

Memory machines (MMs) equipped with low coercive force (LCF) permanent magnet (PM), e.g. AlNiCo and high coercive force (HCF) PM, e.g. NdFeB, possess the advantages of high power density, high efficiency and high efficient flux-regulation capability. In this paper, a robust control strategy to achieve the maximum torque output in different speed region is proposed and implemented on a hybrid permanent magnet axial field flux-switching memory machine (HPM-AFFSMM). Different from the method strongly depending on the parameter characteristics of machine, the proposed method enables the stator-PM MMs to be seen as various PMSMs with different “rated speed” when the magnetization state (MS) of LCF PM are selected. As a result, the trajectory of maximum torque output control in the different speed region can be easily decided. Furthermore, the flux-regulation pulse is determined by comparing the estimated PM flux with the required one corresponding to the maximum speed of different speed interval. In order to properly magnetize or demagnetize the LCF PM, an adaptive PM flux observer, which is robust to machine parameters, is presented to observe the actual PM flux. Both the simulation and experimentation are carried out to verify the validity of the proposed control strategy.

An outer-rotor permanent magnet (PM) synchronous machine (OR-PMSM) with amorphous stator core (OR-PMSMASC) is proposed in this paper, which exhibits higher efficiency than conventional silicon steel PM machines. On the basis of the electromagnetic characteristics of the amorphous alloy material (AAM), the general design of the proposed machine is studied, including the structure parameters and the stator-slot/rotor-pole combination. The combination principle of permanent magnets and winding turns for OR-PMSMASC is investigated. Based on the 2-D finite element analysis (FEA), the electromagnetic performances of the proposed machine are analyzed and compared with an OR-PMSM with silicon steel stator (OR-PMSMSSS). A prototype of the OR-PMSMASC is manufactured and tested to validate the FEA results.

Axial field flux-switching permanent magnet machine (AFFSPMM) has significant advantages, such as the short axial size and high torque density. It is suitable for the direct drive in-wheel applications for the electric and hybrid electric vehicles. For improving the reliability, a novel fault-tolerant structure is applied in the AFFSPMM. The stator is composed of E-shaped laminated segments. The phase windings are physically isolated to each other by the middle teeth of E-shaped cores. The field windings wounded around the middle teeth are used to regulate air-gap flux in the proposed machine. The electromagnetic performances are investigated and analyzed by three-dimensional finite element method (FEM), including the inductance, the back-EMF, and the torque capability, etc. It is shown that the fault tolerance is improved in the novel AFFSPMM, and a wide speed range of operation can be attained by a small DC field current.

A permanent magnet-inductor hybrid exciting synchronous generator (PM-IHESG) is a special machine operating under both dc-biased magnetics and sinusoidal inductions. The finite element method (FEM) is applied to investigate the iron loss of the PM-IHESG. The influence of the size and types of load on the iron loss of the PM-IHESG is analyzed. The calculation method of the iron loss under dc-biased magnetic induction is discussed. The experiment for testing the material characteristic is performed. The curves of the iron loss of the steel material under dc-biased magnetic induction are obtained. The differences between dc-biased magnetic induction and sinusoidal induction are discovered. The design principle to decrease the total iron loss of the PM-IHESG is presented. The experimental results validate the correctness of the computation and analysis. A few important conclusions are deduced from the FEM calculation and experiments.

A three-phase 12/10-pole axial field flux-switching permanent magnet machine (AFFSPMM) with three different stator structures, including parallel permanent magnet and parallel slot (PPPS), parallel tooth and parallel slot (PTPS), and parallel permanent magnet and parallel tooth (PPPT), is analyzed. Based on a 3-D finite element (FE) method, the static characteristics, such as the flux density, PM flux linkage, back-EMF, cogging torque, and electromagnetic torque for the three stator structures are investigated. The influence of the design parameters on the electromagnetic torque is analyzed. The AFFSPMM with PPPS topology has the larger torque, lower cogging torque, and more sinusoidal back-EMF. The prototype with PPPS structure is built and tested. The experimental results are in agreement with the 3-D FE analysis.

The rotor eddy current losses of a Permanent Magnet-Inductor Hybrid Excited Synchronous Generator (PMIHESG) are calculated by applying numerical computation method. The steady-state temperature fields of the PMIHESG are calculated by three dimensions FEM. The predicted rotor eddy current losses are validated by measuring temperature. The significant conclusions include: the vortex center of the rotor eddy current on the Homopolar Inductor (HI) section of the PMIHESG appears on the side of the rotor salient pole close to the field coil. The eddy current density on the side of the rotor salient pole far away from the field coil is smaller than that close to the field coil. The two dimensions method may be improper to study the eddy current loss of the HI section. Under the same axial length, the rotor eddy current loss of the HI section is much more than that of the Permanent Magnet (PM) section.

This paper investigates a homopolar inductor machine (HIM) for flywheel energy storage in electromagnetic launch applications. An equivalent 2-D finite-element model is presented to predict the machine behavior, and the effectiveness of the equivalence is validated by the comparison of 2-D and 3-D results. Based on the 2-D model, the rotor tooth shape is then optimized to achieve high fundamental value of the air-gap flux density for a given rotor diameter. It is shown that the proposed 3-D to 2-D equivalence can predict the performance of the HIM in an accurate and fast way, which is quite valuable in the design stage of a HIM.

In this paper, a double stator linear rotary permanent magnet motor (DSLRPMM) which has a long tuber ferromagnetic mover core with permanent magnets (PMs) arranged on inner and outer surfaces is presented. Based on 3D finite element method (FEM), the end effects caused by the finite length of the inner and outer stators are investigated. The relationships between the end effects and motor parameters, such as outer stator end length, geometric topology, and linear position, are analyzed, and the optimal parameters are given. Meanwhile, the influences of the end effects on the performance characteristics, including airgap flux density, back EMF, output power, force, and torque, of the motor are also studied. Finally, a prototype with optimal topology and parameters is built and tested. The experimental results are in agreement with that of the 3D FEM analysis.

A novel high-performance magnetic transmission (MT) for converting between rotary and rectilinear motion is proposed. The construction and operation principle of the proposed MT are described. The analytic computational formula for air-gap flux density is obtained. The electrical magnetic distribution of the MT is computed by FEM. The characteristics of the novel MT are analyzed and compared with traditional magnetic transmission without ferromagnetic pole-piece. The optimum shape of ferromagnetic pole-pieces is discovered. The experiments are implemented to evaluate the performance of the prototype MT. The maximum static force and torque of the novel MT are measured. The experimental result verifies the rationality of the structure of the MT. Compared with conventional magnetic gear rack, the static force and torque of the novel MT are improved greatly.

A novel axial field flux-switching permanent magnet (AFFSPM) machine with a doubly-salient structure is developed as a wind power generator. The electromagnetic characteristics of a 0.6 kW, 3-phase 12/10-pole AFFSPM machine, including the air-gap flux density distribution, open-circuit flux linkage, EMF, and winding inductances, etc., are investigated based on 3-D finite element (FE) analysis. A prototype is built to test the characteristics under both open-circuit and load conditions. The theoretical analysis is validated experimentally. It shows that the phase EMF is essentially sinusoidal, and the machine can not only be used as a wind power generator, but also as a permanent magnet brushless AC motor.

DC-biased magnetic induction can occur in homopolar inductor alternator (HIA). In this paper, an experimental method is introduced and the corresponding experimental platform is constructed to measure the magnetic loss characteristics of magnetic material under DC-biased magnetic induction. The curves of the magnetic loss under DC-biased magnetic induction are obtained. The magnetic loss of HIA under DC-biased magnetic induction is calculated. The influence of the structure parameter and excitation current on the stator core loss is investigated. Some significant conclusions include: the magnetic material suffers an increase in magnetic loss under DC-biased magnetic induction relative to sinusoidal induction; the magnetic loss of HIA, which is quite different from the loss of conventional electrical machine under sinusoidal induction, is almost proportional to the operating speed; the stator core loss of HIA achieves to the maximum value when the coefficient of the rotor tooth width is approximate to 0.5.

A dual-rotor axial field flux-switching permanent magnet (DRAFFSPM) machine is proposed. A 3-phase 12/10-pole DRAFFSPM machine is designed. The topology and operation principle of the machine are described in detail. The power equation is deduced and the dimensions of the DRAFFSPM machine are determined. The electromagnetic characteristics including the air-gap field distribution, the PM flux-linkage, the back-EMF, and the cogging torque, are investigated based on the 3-D finite element (FE) analysis. The influences of the rotor pole width and the stator slot chamfer on the back-EMF and cogging torque are investigated. It shows that the sinusoidal back-EMF can be gained and the cogging torque can be greatly reduced.

In this paper, the structure parameters of a novel high-performance magnetic transmission for converting between rotary and rectilinear motion is studied by finite element method (FEM). The structure parameters include the length of air-gap and design parameters of ferromagnetic pole-pieces. In order to explore the influence of individual parameter on force and torque, the variation tendency of force and torque varies with each parameter are described. Response surface method (RSM) is applied into design of experiment (DOE) to find out the relationship between response and parametric variables. A mathematical model is achieved by RSM, which predicts a best set of parameters. The finite element calculation is done to verify the correctness of mathematical model. The study results demonstrate that ferromagnetic pole-pieces have great influence on MT.

Magnetic transmission has the advantages of non-contact transmission, no friction, and noise or vibration weak. In 2001, D. Howe proposed a field modulated magnetic transmission, which has higher torque density and higher gear ratio than the conventional magnetic transmission[1]. Moreover, The existing transmission mainly focuses on single degree of freedom movement. In this paper, a novel high-performance magnetic transmission for converting between rotary and rectilinear motion is proposed by incorporating the merits of field modulation principle and the traditional gear rack. The paper describes the construction, operation principle, design and analysis, performance comparison and experiments. The results show the proposed magnetic transmission possesses significant advantages in maximum static force and torque than traditional gear rack.

As the complexity of modern industrial drive systems, the two degree of freedom (2-DOF) operation is needed in the many industry drive applications [1]. Linear rotary permanent magnet (LRPM) motor with the simple structure, high power/mass ratio and good dynamic performance has been presented for 2-DOF motion in recent years [2]-[4]. A novel double stator linear and rotary permanent magnet (DSPLRPM) motor is proposed in this paper. The equivalent magnetic circuit model (EMCM) of the motor is established, and the magnetic field is analyzed. The results are confirmed by that of 3D finite element analysis (FEA).

A novel Hybrid Axial Field Flux-Switching Permanent Magnet (HAFFSPM) machine is proposed in this paper. Based on 3-D finite element method (FEM) and Design of Experiment (DOE) method, the influence of the rotor design parameters, such as the rotor pole number, rotor pole width, rotor pole shape and rotor thickness, on the back-EMF and cogging torque is investigated with an invariable stator structure. Both the THD of the back-EMF and cogging torque ripple can be greatly reduced by the optimization of rotor structure, and this makes the machine operate at high efficiency and low noise. The THD is 2.82% and the cogging torque ripple is 0.77 N ·m when the rotor pole width and shape angle are optimized to 12°and 10°, in a 6/11 stator/rotor pole machine, respectively.

A noninverting Two-Switch Buck-Boost (TSBB) converter with wide input range is proposed to convert the output voltage of high-speed low-voltage generator to constant. The small-signal model of the TSBB converter is built in different operation modes. The transfer function of the control system is derived. In order to simplify the control circuit, the synchronous switching control method and smooth transitions control strategy are proposed. The whole control system of the converter is easy to design and control. A prototype is built to verify the effectiveness of the proposed converter. The experimental results show that the converter can operate steady in wide AC input range.

A simplified 2-D model is presented in order to investigate the influences of rotor tooth shape on the magnetic field of Homopolar Inductor Alternator. Comparing with the 3-D results proves that the presented simplified 2-D model is convenient and valid for the optimization problem. The analysis based the 2-D model reveals that the fundamental component of the air-gap flux density can reach a peak when the ratio of tooth-width to pole pitch is kept between 0.76 and 0.8. And the ratio of the tooth-height to the air-gap length should be at least 16 in order to yield a lager fundamental component of the air-gap flux density. In addition, the iron core loss under different ratio of the tooth-width to pole-pitch has also been estimated by making use of the computing formula for the loss and the loss change curve is analyzed and explained in detail.

This paper performs an analysis on the magnetic coupling of phases for a novel transverse flux machine (TFM) by comparison of the values of self- and mutual- inductance. It is shown that the proposed TFM inherits the merit of magnetic decoupling of phases as in traditional TFM, and thus can readily achieve fault-tolerant operation and high-precision control.

The inductosyn is a kind of high-precision angle-position sensor. It has important applications in servo table, precision machine tool and other products. The precision of inductosyn is calibrated by its error. It's an important problem about the error measurement in the process of production and application of the inductosyn. At present, it mainly depends on the method of artificial measurement to obtain the error of inductosyn. Therefore, the disadvantages can't be ignored such as the high labour intensity of the operator, the occurrent error which is easy occurred and the poor repeatability, and so on. In order to solve these problems, a new automatic measurement method is put forward in this paper which based on a high precision optical dividing head. Error signal can be obtained by processing the output signal of inductosyn and optical dividing head precisely. When inductosyn rotating continuously, its zero position error can be measured dynamically, and zero error curves can be output automatically. The measuring and calculating errors caused by man-made factor can be overcome by this method, and it makes measuring process more quickly, exactly and reliably. Experiment proves that the accuracy of error measuring system is 1.1 arc-second (peak - peak value).

The mathematical model of reflected reactance supplied by voltage source is established to deeply analyze the coupling characteristic and power transfer characteristic of a contactless transformer used in angle sensor. Firstly, the molding method is studied based on the structure feature of contactless transformers with pot core. Then, the primary and secondary equivalent circuits of a transformer supplied by voltage source are obtained by using the mutual inductance model with contactless electromagnetic coupling structure. On the basis of which, the mathematical model of reflected reactance is derived, and the expressions of some characteristics parameters, such as voltage gain and output power, are obtained. Finally, the prototype of a contactless transformer is made according to the design parameters calculated by means of the finite element model. The experiment shows that the mathematical model can be used to accurately analyze the coupling characteristics and power transfer characteristics of contactless transformers.