PIER B | PIER Journals

2024-05-28

PIER B

Vol. 106, 73-84, 2024

download: 38

Decoupling Control of Six-Pole Axial-Radial Active Magnetic Bearing Based on Improved Linear Active Disturbance Rejection Optimized by Least Square Support Vector Machine

Zhen Wang , Gai Liu , Jintao Ju and Huangqiu Zhu

To improve the coupling problem between radial degrees of freedom in six-pole axial-radial active magnetic (AR-AMB), a decoupling control method based on an improved linear active disturbance rejection decoupling control strategy optimized by the least square support vector machine (LSSVM-ILADRC) is proposed. Firstly, the structure and working principle of the six-pole AR-AMB are introduced, and the mathematical model of suspension force is derived. Secondly, cascaded linear extended state observers (LESOs) are used to estimate the disturbance in degrees of freedom step by step, with LESO1 providing an initial estimate of the total disturbance, and LESO2 estimating and compensating for the difference between the initial estimate and the actual disturbance. The regression prediction function of LSSVM is employed to enhance the response speed and estimation accuracy of the LESO to the disturbance. Finally, the simulation and experimental research show that the proposed LSSVM-ILADRC decoupling control method has better decoupling performance and anti-interference performance than the ILADRC decoupling control method.

Decoupling Control of Six-pole Axial-radial Active Magnetic Bearing Based on Improved Linear Active Disturbance Rejection Optimized by Least Square Support Vector Machine

2024-05-26

PIER B

Vol. 106, 57-72, 2024

doi:10.2528/PIERB24030302

download: 54

Wideband Circularly Polarized Exponential Slot Antenna with Rectangular Island for X-Band Satellite Applications

Mostafa Mahmoud Rabie , Mohamed S. El-Gendy , Angie Reda El Damak , Fawzy Ibrahim and Hadia El-Hennawy

This paper introduces a compact, circularly polarized exponential slot antenna with a rectangular island. The concept of the proposed antenna is similar to that of fractal antennas as it is based on designing an asymmetric slot shape with an increased electrical length within a small area, thanks to the exponential path. The obtained results are as follows. The reflection-coefficient |S₁₁| of the proposed antenna covers the band from 5.5 GHz to 9 GHz. The proposed antenna is circularly polarized with an axial-ratio (AR) bandwidth that extends from 6.87 GHz to 8.9 GHz. It offers simultaneous dual circular polarizations (RHCP and LHCP). The gain of the proposed antenna varies between 4.2 dBic and 5.4 dBic. The efficiency reaches 94%. The size of the antenna is compact making it suitable for CubeSats with limited surface area. The proposed antenna intended application is X-band Earth-Space satellite communication. The proposed antenna can be employed for both the X-band satellite downlink (from 7.25 GHz to 7.75 GHz) and uplink (from 7.9 GHz to 8.4 GHz) frequency bands. Additionally, the antenna can be utilized in military applications, and RFID tag tracking-equipment. A prototype of the proposed antenna has been fabricated and then measured using Vector-Network-Analyzer (VNA) and inside an anechoic chamber. The measurement results of the proposed antenna are in excellent match with the simulated ones.

Wideband Circularly Polarized Exponential Slot Antenna with Rectangular Island for X-band Satellite Applications

2024-05-22

PIER B

Vol. 106, 39-55, 2024

doi:10.2528/PIERB24022804

download: 47

Study on Electromagnetic Performance of Permanent Magnet Rotor and Dual Stator Starter Generator for Electric Vehicle Range Extender

Mingling Gao , Zhenhai Yu , Wenjie Jiao , Wenjing Hu , Huihui Geng , Yixin Liu , Shiqiang Liu and Yishuo Liu

The flywheel-type dual-stator permanent magnet starter generator combines engine flywheel and starter generator rotor into a single unit, which has the advantages of high efficiency, high power density, and compact structure. This paper proposes a new type of dual-stator permanent magnet starter generator topology in which the two stators are concentric and share the same permanent magnet rotor. Equivalent magnetic circuit modeling of the inner stator's magnetic field, outer stator's magnetic field, and synthetic magnetic field using the equivalent magnetic circuit method list the system of flux equations and solve the main magnetic flux, leakage flux, and leakage coefficient, and the results show that the equivalent magnetic circuit method has smaller error and higher accuracy than the finite element method. The harmonic electric potential of the starter generator is modeled and analyzed. The permanent magnet rotor and inner and outer stator structures are optimized to obtain the optimal parameters, and the prototype is manufactured and tested. The optimized starter generator no-load induced electromotive force fundamental amplitude is improved. The induced electromotive force harmonic distortion rate is reduced, and the output performance of the whole generator is significantly improved.

Study on Electromagnetic Performance of Permanent Magnet Rotor and Dual Stator Starter Generator for Electric Vehicle Range Extender

2024-05-22

PIER B

Vol. 106, 17-38, 2024

doi:10.2528/PIERB24020602

download: 15

Negative Group Delay Prototype Filter Based on the Reciprocal Transfer Function of a Low-Pass Butterworth Filter Capped at Finite Out-of-Band Gain

Miodrag Kandic and Greg E. Bridges

A Negative Group Delay (NGD) prototype filter design based on the reciprocal transfer function of a low-pass Butterworth filter of a given order, is presented. The out-of-band gain of the prototype transfer function is capped at a finite constant value via multiplication by a transfer function of a low-pass Butterworth filter with 3 dB bandwidth that is wider than the reciprocal function bandwidth. Such synthesized transfer function exhibits maximal magnitude characteristic flatness within the 3 dB bandwidth (Butterworth-like property), while it also exhibits NGD and satisfies Kramers-Kronig relations (causal transfer function). The prototype design achieves an NGD-bandwidth product that in the upper asymptotic limit as the design order increases, is a linear function of out-of-band gain in decibels. This is an improvement compared with previously reported cascaded first-order and second-order designs, which have NGD-bandwidth functional dependency of out-of-band gain in decibels to the power of 1/2 and 3/4, respectively. It is shown that the transfer function of the corresponding design transformed to a non-zero center frequency can be exactly implemented with a Sallen-Key topology employing parallel resonators, or approximately implemented with an all-passive ladder topology. An in-band magnitude/phase distortion metric is applied to the prototype designs, evaluated for Gaussian and sinc pulse input waveforms, and compared with values obtained for a well-known commonly used medium. It is also shown that when the specified bandwidth corresponds to the entire bandwidth over which the group delay characteristic is negative, the magnitude characteristic variation approximately equals half the out-of-band gain value in decibels. Therefore, for any NGD design with large out-of-band gain (typically higher than 6 dB), using the entire bandwidth where group delay is negative can result in strong levels of distortion and should be checked for applied waveforms.

Negative Group Delay Prototype Filter Based on the Reciprocal Transfer Function of a Low-pass Butterworth Filter Capped at Finite Out-of-band Gain

2024-05-06

PIER B

Vol. 106, 1-16, 2024

doi:10.2528/PIERB24031403

download: 54

Research on the Grounding Grid Electrical Impedance Imaging Algorithm Based on Improved Tikhonov and Lp Regularization

Lele He , Lei Yang , Xiaoheng Yan , Weihua Chen and Shangfei Huang

In this paper, an improved hybrid regularized grounded network imaging algorithm (ITR-Lp) combining Tikhonov regularization and Lp regularization is proposed; through the improvement of the filtering function, the correction of small magnitude for large singular values and increasing magnitude of correction with decreasing singular values for small singular values is implemented for the improvement of the convergence of the solution. The proposed algorithm constructs a regularization matrix to achieve selective correction of singular values and improve the convergence of the solution, while Lp regularization is used to enhance the sparsity of the solution and improve the boundary contrast. the effect of node distribution on convergence is investigated, and finally the ITR-Lp algorithm is validated by simulation and experiment. The results show that the ITR-Lp algorithm proposed in this paper achieves the lowest resistivity relative errors of 0.1695 and 0.1089 for resistive networks with 1 corrosion and 2 corrosions, respectively. The method has good convergence and boundary contrast, which effectively improves the pathology of the inverse problem of imaging the electrical impedance tomography of grounding grid.