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In this article, a novel model predictive torque control (MPTC) method for switched reluctance machines (SRMs) is proposed based on the equivalent linear SRM model and the improved switching table. First, an improved switching table with only six switching states is developed based on the inductance characteristics. The adoption of this improved switching table not only reduces the computational burden by 25% but also improves the torque control performance and system efficiency at high-speed region. However, the look-up-table (LUT) based MPTC methods suffer from occupying numerous storage space. To ease this issue, the simple linear SRM model is utilized. The flux-linkage and torque equivalent transformations are introduced to address the difference between the linear and nonlinear SRM models. With these transformations, the MPTC realized on the linear SRM model is proposed. Compared to 1530 storage units consumption to store three two-dimensional (2-D) LUTs in the LUT-based MPTC methods, the proposed method only occupies 228 storage units. Experimental results on an 8/6 SRM setup verify that the proposed method effectively eliminates the commutation torque ripple with lower execution time, less storage space, and improves the torque control performance at a high-speed range compared with the conventional LUT-based method. [ABSTRACT FROM AUTHOR]

This article presents a simple and practical method to estimate the lumped radial force characteristics for the switched reluctance machines (SRMs). First, the relationship between the square root of the lumped radial force and the flux linkage is discussed and analyzed. With the geometry data of the studied SRM, the abovementioned relationship under nominal air-gap length and nominal material magnetic property conditions can be obtained through the finite-element analysis (FEA) software. As the radial flux density dominates the magnitude of the radial force and it concentrates on the overlapping area, the abovementioned relationship is analyzed to be roughly held when the air-gap length and/or material magnetic property vary. Based on this relationship obtained from the FEA and the actual measured flux-linkage characteristics, the lumped radial force can be easily reconstructed for the actual SRMs regardless of the possible air-gap length variation and material magnetic property deviation during the manufacturing process. Simulation results on the 8/6 SRM and 12/8 SRM verify that the proposed method provides good radial force estimation results when the air-gap length is reduced or increased up to 50%. Superior estimation results are also observed on the condition that the magnetic ${B}$ – ${H}$ curve is linearly varied by ±25%. The accurate and simple radial force estimation method proposed in this article provides a solid basis for the radial-force-shaping-based advanced control methods to suppress the acoustic noise. [ABSTRACT FROM AUTHOR]

Relatively high torque ripple limits the further development of the switched reluctance machine, and the application of the ripple suppression method will reduce the efficiency of the system. To simultaneously improve the efficiency and torque ripple of the switched reluctance machine, a new commutation and online optimization strategy is proposed. According to the torque per ampere characteristics of the machine, two rotor position angles are defined, which are the boundaries for the high and low torque per ampere operation modes of the two adjacent phases, respectively, and for different operating modes, specific torque hysteresis control schemes are performed. Furthermore, an objective function is constructed with the efficiency and torque ripple coefficient, and during the operation of the machine, the defined boundary angles are online optimized by the genetic algorithm to maximize the value of the objective function. The effectiveness of the method is verified by detailed simulation and experiment under different operating conditions. [ABSTRACT FROM AUTHOR]

According to the modular power converter, a novel phase current reconstruction method using single dc-link current sensor is proposed for three-phase switched reluctance machine (SRM), and the control method is implemented with the reconstructed phase current as well. A highly integrated modular power converter is constructed by a three-phase full bridge and a dual switch module. The phase windings are in star-connection, and the bipolar phase currents are applied. Based on the special operating modes and single pulse width modulation signal injection, the dc-link current is decoupled and the phase current in both magnetization and demagnetization regions is reconstructed, which is very critical for the implementation of some advanced methods that require complete period phase current. The conventional control methods of the SRM, such as single-pulse voltage and hysteresis current control methods, are carried out under different operating conditions with both simulation and experiment to verify the effectiveness of the proposed method, and the reconstruction errors and performance influences are detailed analyzed as well. [ABSTRACT FROM AUTHOR]

This paper proposes a novel dynamic torque estimation method, which can quickly and accurately obtain the instantaneous torque with an online calculation based on the local linearization of the energy conversion loop on the flux linkage-current plane of the switched reluctance machine. According to the real-time information of the points on the loop, six situations are illustrated and analyzed. For each situation, the output mechanical energy is obtained first by calculating the area of the corresponding segmented regions, and then, the instantaneous torque is obtained by the difference algorithm concerning the output mechanical energy and rotor position. For the entire process, the unsaturated phase inductance of the machine, which can be conveniently measured, is the only information required in advance. To verify the effectiveness of the proposed method, detailed simulations and experiments are performed under different operating conditions. [ABSTRACT FROM PUBLISHER]