The numerical technique for parameters estimation is applicable for the induction machine (IM) with arbitrary number of stator phases and arbitrary number of rotor bars. The self-inductance and ...mutual inductance matrices for the stator side and rotor side are constructed through the magnetic vector potential method. The Clarke transformation is implemented to separate the magnetising inductance and slot leakage inductance of each sequence plane, where the orthogonality theory of trigonometric function is used. The harmonic leakage inductance of each plane is calculated based on the ratios of the harmonic components among air-gap flux density. The 2D eddy current field solver is conducted to obtain the rotor resistance based on the IM equivalent circuit. A classical mathematical model is established using the acquired parameters under Simulink environment to accomplish the comparisons between the simulated and experimental performance. The non-sinusoidal power supply based on the rotor field-orientated control, which is highly dependent on the precision of parameters, is carried out under no-load and heavy load conditions to indirectly verify the accuracy of parameters.
In this article, an universal sensorless starting scheme considering magnetic saturation effects is proposed to control the switched reluctance motor (SRM) drives. In this approach, the full-cycle ...unsaturated inductance can be reconstructed by converting the saturated incremental inductance into the unsaturated inductance with a simple mathematical model in the conduction region. Based on the reconstructed three-phase full-cycle unsaturated inductance, the inductance vector coordinate transformation method and the linear region inductance model based method can be applied for estimating the rotor position even under high load starting case. To verify the validity of the proposed methods, experiments have been implemented in a 1-kW three-phase 12/8 structure SRM prototype. The experimental results verify that the unsaturated inductance reconstruction scheme can transfer the nonlinear magnetic saturation problem into an unsaturation problem, and thus the rotor position estimation at the sensorless starting state can be simplified. The method can realize the initial position estimation and reliable sensorless starting control even under load conditions with only very simple initial inductance data acquisition, position partition logics design, and mathematic modeling. In addition, as the back-electromotive force is eliminated indirectly in the inductance calculation process, the adaptable speed range can also be extended.
Winding inductance is a crucial parameter of machines, which plays an essential role in flux-weakening capability, reluctance torque, power factor, etc. In this article, winding inductance ...characteristics of flux-switching permanent magnet (FSPM) machines are investigated from the perspective of air-gap modulation magnetic field. With the aid of the general air-gap field modulation theory, the air-gap magnetic field contributed by an arbitrary energized winding of FSPM machines is modeled and analyzed. Then, an analytical expression of winding inductance is derived based on winding function and single-phase magnetic field, through which the relationship between winding inductance and single-phase magnetic field harmonics is unveiled. It is found that the direct current (dc) and 2nd harmonic components of winding inductances in FSPM machines are caused by the dc and 2nd time-harmonic components of primitive harmonics, respectively, which are essentially different from that of traditional interior permanent magnet or reluctance machines. Finally, experiments on a prototype three-phase 12/10 FSPM machine are conducted to verify the theoretical analysis.
This work presents analytical expressions for the dc inductance of 3-D air-core inductors with circular cross-sectional pillars (CCSPs) and rectangular cross-sectional pillars (RCSPs). We consider ...the following four types of inductor structures: 1) a toroid with CCSP; 2) a toroid with RCSP; 3) a solenoid with RCSP; and 4) a solenoid with CCSP. For each type, a unique analytical model is developed for obtaining dc inductance. High-frequency (1-100 MHz) effects on inductance are also discussed. The inductance values predicted by the proposed analytical models of the first three types of inductor structures are in an acceptable agreement with numerical finite-element analysis (FEA) solutions, where the maximum difference is 7.3%. Also, our analytical model for the fourth-type inductor reduces the error, when correlated with FEA inductance value, up to <inline-formula> <tex-math notation="LaTeX">6\times </tex-math></inline-formula> compared with previously published models. A comparison of results using the proposed analytical expressions with published measured values as well as our measurement data demonstrates the error ranging from 0.5% to 16.2%, while conventional formulas show errors of up to 143%. The results of the proposed models could serve as a good initial estimate for power supply-on-chip (PwrSoC) and power supply in package (PSiP) applications.
In this article, a new high-frequency PMSM model is derived in order to obtain accurate absolute inductance and inductance saturation profile. Compared to traditional PMSM models, the proposed ...high-frequency model includes the components of high-frequency resistance and inductance derivative relative to current. Through this model, the difference between differential and absolute inductances is discussed in detail and the impact of high-frequency resistance on the inductance estimation is analyzed. In the next step, another method is proposed to decouple and eliminate the effect of high-frequency resistance from the composite inductance. It is shown that this approach yields highly precise absolute inductance measurement and remarkably reduces the effect of inductance derivative relative to current. These findings help to evaluate the saturation more accurately which is essential for robust observer and controller design. Finally, the effectiveness of proposed scheme is experimentally verified using SPMSM and IPMSM.
Frequency-dependent leakage inductance is often observed. The high-frequency eddy current effects cause a reduction in leakage inductance. The proximity effect between adjacent layers is responsible ...for the reduction of leakage inductance. This paper gives a detailed analysis of high-frequency leakage inductance and proposes an accurate prediction methodology. High-frequency leakage inductances in several interleaved winding configurations are also discussed. Interleaved winding configurations actually give a smaller degree of reduction of leakage induction at high frequency. Finite-element analysis simulation and measurement validate the models.
Subsurface electromagnetic sensing is used in the mining, tunnelling, environmental, groundwater, energy and geoscience research sectors of the global economy. For underground applications these ...methods require focused, compact antenna. We introduce the concept of a ferrite core transmitting coil to time domain electromagnetic sensing, with an emphasis of forward scanning detection of subsurface hazards from a borehole. Firstly, we develop an analytical expression for mutual coupling between a ferrite core coil transmitting antenna coupled with an air core receiver coil to demonstrate the focusing potential gained by adding a ferrite core. Next, we complete 3D numerical simulations for a scanning borehole transient electromagnetic device. These simulations include radial scanning and demonstrate the improved resolution achievable with a ferrite core coil transmitting antenna. Finally, a ferrite core coil radial scanning in-hole device was constructed, and field experiments completed in a shallow borehole. A small high conductivity object was hidden in the subsurface then detected with the device within radial plots of subsurface resistivity. Our combined numerical and field experiments present the ferrite core coil antenna as a method for focusing electromagnetic fields with one applicant being hazard prediction ahead of a borehole extended from a tunnelling face. We hope these electromagnetic scanning methods find many earth science and engineering applications.
This article first developed an inductance model that includes the parasitic mutual inductance between parallel current path segments for SiC multichip power modules. Based on the developed model, ...the SiC multichip module's transient response was analyzed, important parasitic inductances were identified. The layout was improved based on the transient analysis. The improved package layout can reduce the parasitic inductance without increasing the fabrication difficulty. Experiments were conducted to validate the reduction of parasitic inductances. The parasitic ringing and the crosstalk effect were significantly reduced with the proposed technique. The thermal performance was also improved with the proposed layout.
This paper first analyzes the current paths on a planar busbar based on insulated-gate bipolar transistor bridge switching states and dc-link capacitor configurations. The busbar's circuit models ...which include both self- and mutual inductances are developed based on the identified current paths. The inductance circuit models are analyzed and reduced for different switching states, transition states, and dc-link capacitor configurations. Inductance and current sharing is analyzed based on circuit theory. Both simulations and measurements are conducted to verify the developed technique.
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