High Speed Switched Reluctance Motor Research Articles

Single-Phase H-Bridge Rectifier Fed High-Speed SRM System Based on Integrated Power Control

Traditionally, an uncontrollable diode bridge rectifier (DBR) is employed to supply the constant DC voltage for the asymmetric half-bridge (ASHB) converter fed switched reluctance motors (SRMs), which brings about inferior AC side power quality. In this article, a high-speed SRM drive system based on integrated power control scheme is proposed, which not only realizes the regulation of SRM but improves the AC side power quality. For the topology, a single-phase H-bridge rectifier and ASHB converter are connected in a cascade arrangement to form an AC-DC-DC converter to drive the SRM. For the control, the proposed integrated power control scheme governs the rectifier and SRM as one control unit in which stable motor speed and high AC side power factor are realized via regulating the input real and reactive power, respectively. Moreover, the proposed system has bi-directional power flow capability, which means the power can flow out of and into the AC side. Experiments are carried out to investigate the steady-state and dynamic performances of the proposed driving system. The experimental data and performance comparison confirm its effectiveness.

Optimized Power Factor Correction for High Speed Switched Reluctance Motor

The Power Factor Correction (PFC) in Switched Reluctance (SR) motor is discussed in this article. The SR motors are applicable for multiple applications like electric vehicles, wind mills, machineries etc. The doubly salient structure of SR motor causes the occurrence of torque ripples, which affects the power factor of the motor. To improve the power quality, the power factor has to be corrected and the ripples have to be minimized. In order to achieve these objectives, a novel power factor correction (PFC) method is proposed in this work. Here, the conventional Diode Bridge Rectifier (DBR) is replaced by a Bridgeless Hybrid Resonant (HR) converter, which assists in improvising the output in a wider range. The converter is chosen because of having variety of beneficial measures including high gain. The converter’s output is fed to the SR motor by means of an asymmetric Bridge Resonant (BR) converter. The proposed converter operates in continuous mode of conduction with the switching frequency of 10 KHz. A hysteresis current controller and Proportional Integral (PI) controller are utilized for reducing the harmonics in the source current along with the regulation of output voltage. In addition, the speed control of SR motor is accomplished by means of the Whale Optimization Algorithm (WOA) assisted PI controller. The proposed methodology is effective for the control of unity power factor, torque and current ripples. The Total Harmonic Distortion (THD) of the source current is also minimized, which suits the standard of International Electrotechnical Comission IEC 61000-3-2. By this methodology, the power factor of 0.99 is achieved with 97% efficiency and 3.92% THD. The proposed methodology is validated in simulation by MATLAB and in hardware by FPGA Spartan 6E.

Voltage-Sourced Converter Fed High-Speed Switched Reluctance Motor Drive System With Energy Feedback and Near-Unity Power Factor

The diode bridge rectifier fed asymmetric half-bridge converter (AHBC) is conventionally employed to drive switched reluctance motors (SRMs), which leads to poor grid-side power quality. In the proposed system, a topology made up of a voltage-sourced converter and an AHBC is employed to drive the high-speed SRM. Stable SRM operation can be obtained by manipulating the active power flowing to motor side, and on the basis of that, the grid-side power quality is enhanced by directly manipulating input reactive power. Predictive deadbeat control with disturbance observer is employed to follow the power references, thereby achieving controllable speed, energy feedback, near-unity grid-side power factor, and low grid-side current distortion simultaneously. Additionally, an improved asymmetric modulation method is developed for switching frequency reduction. Experiments are carried out to test the proposed drive system in steady and dynamic conditions. Performance comparisons validate the improvement of the proposed high-speed SRM drive system.

Analysis of AC Loss in High-Speed Switched Reluctance Motor for Electric Vehicle Considering Winding Axial Transposition

The 3-D finite element method (FEM) has been widely used for accurate analysis of winding loss with winding axial transposition angle considered. However, its application is limited due to long computation time and complex modeling processes. To address these problems, this article proposed a 2-D equivalent permeability modeling method (EMM). First, according to the proposed method, the 3-D winding model with axial transposition angle could be equivalent to several segmented 2-D models. Through equivalent axial length coefficients, 2-D models with different axial lengths could be solved in one project. Using appropriate segment and equivalent coefficients, to a great extent, the inherent error of the 2-D model could be reduced. Second, with equivalent permeability and conductivity, current density distribution and winding ac loss could be calculated. To verify the correctness and robustness of the proposed method, the study was conducted in the five-parallel-strand model. Single-tooth models with concentrated windings were built to verify the evaluated winding loss. In addition, a 20-kW 12/8 high-speed switched reluctance motor was manufactured, and the temperature rise was tested to verify the effect of winding loss on the temperature rise. Through the comparison of experiments and FEM, the EMM is verified to be with high accuracy and computational efficiency to analyze the ac loss and current distribution.

INVESTIGATING INFLUENCES OF TAPPED SHOE ROTOR POLES ON ELECTROMAGNETIC TORQUES AND RADIAL FORCES OF SWITCHED RELUCTANCE MOTORS

The shape of rotor poles has a significant influence on the performance of electromagnetic torques and radial forces, because the air-gap flux density is depent on the stator and rotor areas and surfaces. Serveral articles have studied influences of the stator/rotor designs on radial forces and electromagnetic torque waveforms as well. Moreover, the electromangetic characteristics of switched reluctance motors are also defined by tapped-shoe-skewing of the stator and rotor poles with the inner holes. However, the total solution designs of the tapped-shoe rotor with diferent tapped angles have not yet implemented by those papers so far. For that, in this paper, the tapped shoe rotor pole design is proposed by different angles for the high speed switched reluctance motor of 30 kW and 18000 rpm.

Design and Optimization of a High-Speed Switched Reluctance Motor

Currently, one of the most used motor types for high-speed applications is the permanent-magnet synchronous motor. However, this type of machine has high costs and rare earth elements are needed for its production. For these reasons, permanent-magnet-free alternatives are being sought. An overview of high-speed electrical machines has shown that the switched reluctance motor is a possible alternative. This paper deals with design and optimization of this motor, which should achieve the same output power as the existing high-speed permanent-magnet synchronous motor while maintaining the same motor volume. The paper presents the initial design of the motor and the procedure for analyses performed using analytical and finite element methods. During the electromagnetic analysis, the influence of motor geometric parameters on parameters such as: maximum current, average torque, torque ripple, output power, and losses was analyzed. The analysis of windage losses was performed by analytical calculation. Based on the results, it was necessary to create a cylindrical rotor shape. The rotor modification method was chosen based on mechanical analysis. Using thermal analysis, the design was modified to meet thermal limits. The result of the work was a design that met all requirements and limits.

A Drive Topology for High-Speed SRM With Bidirectional Energy Flow and Fast Demagnetization Voltage

A drive topology composed of a T-type single-phase three-level voltage source rectifier (VSR) and a four-level switched reluctance motor (SRM) converter is proposed in this article. The commonly used diode bridge rectifier presenting degraded power quality is replaced by the VSR to drive the SRM converter. Compared with the conventional split-dc converter, the four-level SRM converter of the proposed drive topology adopts one more switch and one more diode for each phase, but two more operation modes are formed. With the double-voltage demagnetization mode of the four-level SRM converter, the tailing time of demagnetization current is significantly reduced, which increases the utilization of inductance increasing region. All the operation modes of this converter can be implemented successfully, even in the multiphase excitation region. Moreover, a centralized control strategy is proposed to regulate the VSR and SRM together, within which the speed and grid-side power factor are regulated by the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">d</i> -axis and <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">q</i> -axis component of grid-side current in VSR, respectively. Most importantly, the bidirectional energy flow is realized. An idea-proofed testbench is constructed. The results obtained from the comparative experiments confirm the validity of the proposed drive topology and its control strategy.

A Centralized Control Strategy for Grid-Connected High-Speed Switched Reluctance Motor Drive System With Power Factor Correction

Conventionally, the converter of switched reluctance motor (SRM) is fed by the uncontrollable diode bridge rectifier (DBR), which leads to a low grid-side power factor (PF) and high current total harmonic distortion (THD). In this paper, an alternative solution for the grid-connected high-speed SRM drive system with improved PF is proposed. In the proposed drive system, the three-level active front end (AFE) is connected in cascade with the midpoint converter for SRM operation. A centralized strategy, which controls the AFE and SRM together, is proposed to govern the motor speed and grid-side PF by regulating the real power and reactive power of the system, respectively. Specifically, the real power, reactive power, and the voltage balancing of split capacitors are controlled by the model predictive directed power control (MP-DPC) algorithm, which significantly reduces the control complexity and guarantees the fast dynamic response. Consequently, satisfying speed regulation, high PF, low current THD, and bi-directional power-transfer capability are achieved. An idea-proofed testbench is constructed in laboratory, and the applicability of the proposed drive system is verified by a series of experimental results.

Investigation of Rotor Parameters of High Speed Switched Reluctance Motor for automotive application

This paper presents an analysis of the rotor geometric dimensions influence on the electromagnetic parameters of high speed switched reluctance motor (SRM). This high speed SRM is optimized for automotive application. The paper starts with introduction that describes this type of motor and state of the art of high speed machines. The state of the motor design before this analysis is presented. The next part presents the analysis that was performed in Ansys for case of single pulse operation and hysteresis control. In this analysis, values of maximum phase current, average torque, torque ripple and losses as function of change in rotor geometric dimensions were observed. These dimensions include: rotor outer diameter, length of rotor teeth, rotor pole arc and rotor yoke thickness. Finally, the obtained results are presented and commented.

Comprehensive Investigation of Loss Calculation and Sequential Iterative Fluid-Solid Coupling Schemes for High-Speed Switched Reluctance Motors

This article proposes a comprehensive investigation method for loss calculation and temperature rise prediction in high-speed and high-power switched reluctance machines (SRMs). The losses are analyzed in details and the sequential iterative fluid-solid coupling (SIFSC) scheme is proposed for thermal analysis. In the iterative design stage of the SRM, it is important and urgent to figure out the power losses and temperature distribution in the motor, which affects the endurance of the motor operation, such as the maximum speed and highest operating temperature. A simplified finite element (FE) model of a turn and a proximity loss separation method are developed for the skin and proximity (SP) loss reduction. Then, an additional eddy current loss calculation method is developed with a simplified FE model of the winding. Additionally, the SIFSC scheme is further proposed and implemented by sequentially calculating the fluid and solid fields for airflow velocity and temperature distribution. Compared to conventional thermal calculation schemes, the proposed SIFSC scheme is faster than direct coupling methods and more accurate than thermal network methods. The accuracy and effectiveness of this scheme is verified by the simulation and experimental test for a 160 kW and 18000 r/min 6/2 SRM prototype.

Effect of Cutting and Slot Opening on Amorphous Alloy Core for High-Speed Switched Reluctance Motor

The amorphous alloy material has the characteristics of high resistivity and low loss, but the loss characteristic of the amorphous alloy core is unstable, which can be greatly affected by the processing. Thus, the calculation error of the amorphous alloy core loss turns out to be large, which leads to the difficulty in the design and optimization of the core. In this article, a new loss factor correction model of the amorphous alloy core is proposed to analyze the influence of the processing and core size on the loss. To verify the loss factor correction model, the loss characteristic of amorphous alloy material was tested and analyzed, and the core loss at different core sizes was compared. In addition, a mathematical model of core loss is proposed for the amorphous alloy stator core to optimize and calculate the loss of amorphous stator core. The correctness of the proposed model is verified by the test of core loss.

High speed SRM using vector control for electric vehicle

The high speed motor is effective to realize downsizing motor in an electric vehicle (EV). Switched Reluctance Motor (SRM) is possible to the high speed drive because the rotor structure has simple and robust. However, the vibration and the acoustic noise are large from the drive principle. Moreover, the conventional complicated current excitation results in the difficulty of the torque controller design. To overcome these problems, the vector control has been proposed for SRM drive. However, the vector control has not been applied to the SRM in the high speed drive. In this paper, the drive conditions such as switching frequency, bus voltage for driving the SRM in the high speed region are clarified. It is shown that the proposed SRM can be driven by the vector control in the high speed region and can realize low vibration.

Quasi-Optimal Design of the Switched Reluctance Motor

The article deals with issues that arise in the process of designing a high-speed switched reluctance motor electric generator for working together with a steam microtubule. A method of two-stage optimization of the geometric relations of the stator and rotor of a switched reluctance motor is described. The first of them is used to search for geometric relationships without taking into account the losses in the magnetic system and the shape of the current pulse in the windings. At the second stage, rational parameters of the voltage pulse applied to the winding are determined for the selected options, losses in the magnetic system and in the windings of the electric machine under consideration are calculated, and one of the options is selected, which is considered quasi-optimal, providing minimum losses at the maximum developed moment.

Two-level current reference method for speed control of switched reluctance motors

ABSTRACTSwitched reluctance motors operate at very high-speed ranges. At high speed, the switched reluctance motor drives are losing the capability of high torque production. In this paper, a novel method is proposed for controlling high speed switched reluctance motor using both continuous and discontinuous conduction modes. The proposed method controls the machine torque in continuous-conduction mode using four control parameters. Simulation test-beds are constructed using three-dimensional finite element, and co-simulation to demonstrate the effectiveness of the proposed method.

Complex Performance Analysis and Comparative Study of Very High-Speed Switched Reluctance Motors

This paper presents the comparative analysis of the characteristic features of two 4/2 switched reluctance motors (SRMs) designed for a very high-speed drive. The use of two-phase construction of SRM with irregular air-step gap makes it possible to achieve the required parameters of the drive. The analysis presents the comparison of two distinct structures designed for the same very high-speed drive. In this paper, a novel mathematical model that takes into account the nonlinearity of the magnetic circuit is presented. The results of numerical calculations and laboratory tests of the influence of the possible use of an anisotropic magnetic material in the rotor magnetic circuit are presented. The influence of control parameters on the motor properties is specified. Both the structures were compared with the respect to employed electric parameters. It is important for high-speed structures that a maximal speed of the motor should not affect permissible parameters of the rotor in a negative way. The high-speed structures should be properly designed to ensure a safety margin. The selected laboratory test results that show electric parameters are presented following the specification of the first critical speed based on the Campbell diagram, the maximum speed limited by allowable stresses. It was shown that both the structures analyzed fulfill the condition of a safety margin. A number of thermal problems of the structures analyzed are discussed. The design assumptions related to the possibility of using a higher current density in the motor windings were verified under laboratory conditions.

One‐cycle decoupling control method of multi‐leg switching power amplifier for magnetic bearing system

The traditional current control algorithm of the multi-leg switching power amplifier (SPA) is complicated since the control of different phase currents is intercoupling. To address this problem, a novel control strategy based on one-cycle control is proposed in this study, which can enforce the average current of each phase is equal to the reference in each control cycle. Since it sets the duty cycle of the neutral leg as a constant, this method presents significant advantages such as quick dynamic response, easy control and decoupling of the phase currents. Taking a five-phase six-leg SPA, e.g. the mathematic model of the system was built, the duty cycle of the neutral leg was analysed, the principle of the novel control strategy was introduced, and the detailed implemented process was presented. Thereby, a high-speed switched reluctance motor system using the magnetic bearing is constructed to test this method. Both the simulation and experimental results have demonstrated the simplicity and effectiveness of the proposed method.

Design and Control of a High Speed 2-Phase 4/2 Switched Reluctance Motor for Blender Application

This paper presents the design and control of a high-speed 2-phase 4/2 switched reluctance motors (SRM) for blender application. The proposed SRM is designed to replace a universal motor that equipped with the blender. In this study, the single- and 2-phase SRMs were considered as good candidates for high-speed and low-cost applications. The blender requires a high-speed motor drive with self-start ability. To overcome torque dead-zone that exists in single- and 2-phase SRM, stepper rotor with wider rotor pole arc was considered. The rated speed is up to 18,000 rpm and 40,000 rpm at no-load. A low-resolution encoder was used for high-speed SRM drive to reduce the cost. To verify the design, a prototype of the proposed SRM was manufactured for laboratory test.

Dynamic model of High Speed Switched Reluctance Motor for automotive applications

Abstract In this paper, dynamic model of the already designed a 3 phase, high speed, Switched Reluctance Motor (SRM) is presented. This high speed SRM was designed for automotive applications. The paper begins with state of the art from the point of view of electrical machines high-speed utilization and a description of the switched reluctance motor. Simulation model of SRM is described and used for dynamic simulation. The switching angles in the simulation models are set to achieve the maximum average torque. This analysis is performed for different rotational speed. The results of the dynamic simulation are following waveforms: average torque, torque ripple, losses and efficiency as a function of rotational speed.

An improved simulation model of switched reluctance motor including transient core losses for steady-state operation

PurposeAn improved simulation model of switched reluctance motor (SRM) for steady-state operation that considers the core losses in the stator and rotor is established to obtain the steady performance of the high-speed SRM during the design, analysis and control of SRM driving system more accurately.Design/methodology/approachThe transient core loss model for the material and SRM is presented. Then a new method for calculating the flux density of the motor in real time is introduced, and a steady-state simulation model of the SRM including real-time transient core losses calculation model is established according to the transient flux density. Because the transient core losses calculated by above method are the total core losses of the motor, a core losses distribution method is proposed and the steady-state simulation model of the SRM including the distributed core losses’ effect on the phase winding is established.FindingsThe comparison results show that the proposed model has higher accuracy than the traditional model, excluding core losses, especially at the moments when phase voltage is turn-on and turn-off. The proportion of the core losses to the motor losses increases with the increase in speed. So, the core losses’ effect on the steady-state performance of the high-speed SRM cannot be ignored.Originality/valueThe method to obtain flux density in the real time is presented and the improved steady-state simulation model of SRM that considering transient core losses is proposed.

Design and Experimental Validation of a High-Speed Electric Turbocharger Motor Considering Variation of the &lt;inline-formula&gt; &lt;tex-math notation="LaTeX"&gt;${\boldsymbol{L}}/{\boldsymbol{D}}$ &lt;/tex-math&gt; &lt;/inline-formula&gt; Ratio

The commercialized electric turbocharger (ETC) made by Valeo includes a high-speed switched reluctance motor (SRM), ball bearings, impeller, and controller. SRMs are generally very noisy and have low efficiency (70%) at high speed. No ETC has yet been commercialized that includes a permanent magnet (PM) motor. The Korea Electrotechnology Research Institute, Changwon, South Korea, is developing a high-speed surface PM type of synchronous motor and a pulse width modulation-driven inverter. This system operates at a power density of 3 kW/kg at 100000 r/min and is intended to fit 1600 cc diesel vehicles to reduce turbolag to within 0.5 s. The design and analysis of the PM synchronous motor (PMSM) for the ETC have been successful by considering the electric and mechanical performance using multiphysics analysis. Validation by experiment was performed and matched within 1% error in terms of the efficiency. Design, analysis, and experiments with the PMSM for ETC applications were conducted successfully by utilizing an action–reaction torque sensor and the resistance load test method.