PIER C | PIER Journals

2023-12-01

PIER C

Vol. 139, 31-43, 2024

doi:10.2528/PIERC23102004

download: 32

A Small Size Wideband m -Shaped Polygonal Slot Antenna for X-Band Satellite Applications

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

This paper presents a small size M-shaped polygonal slot antenna for X-band satellite telemetry and Synthetic Aperture Radar (SAR) applications. The proposed antenna has been designed on a Roger RT-Duroid 5880 substrate. The reflection coefficient |S₁₁| of the proposed antenna covers the whole X-band from 6.63 GHz to 12.566 GHz. The proposed antenna is circularly polarized with axial ratio (AR) bandwidth that extends from 7.76 GHz to 8.58 GHz. The proposed antenna provides a simultaneous dual circular polarizations (RHCP and LHCP). The gain of the proposed antenna varies between 6.6 dBi and 9.4 dBi. The proposed antenna realizes an efficiency of 92%. The overall size of the proposed antenna is 17 x 16 x 0.508 mm³ (0.56λ₀ x 0.53λ₀ x 0.016λ₀). Therefore, it is suitable to be employed in satellite telemetry application from 7.9 GHz to 8.4 GHz especially for CubeSats that have limited surface area. Apart from that, this antenna finds its applications in SAR on small satellites from 9 GHz to 10 GHz, military, and RFID tag (tracking-equipment). It has been observed that the measurement results match the simulated ones. The proposed antenna design can be practically employed for the previously mentioned applications.

A Small Size Wideband M-shaped Polygonal Slot Antenna for X-band Satellite Applications

2023-11-24

PIER C

Vol. 139, 21-29, 2024

doi:10.2528/PIERC23092701

download: 40

The Direct Torque Control of Brushless DC Motor Based on Sliding Mode Variable Structure

Gai Liu , Yiran Wu and Qingbo Shao

Aiming at the problem of slow response speed and poor anti-interference ability using the traditional PI control in the direct torque control strategy of brushless DC motor (BLDCM), the direct torque control (DTC) of the BLDCM based on the sliding mode change (SMC) structure is proposed. In the BLDCM DTC system under the new flux linkage set mode, the traditional PI control is replaced by the improved SMC control to realize the new torque given mode and realize the DTC of the BLDCM. Firstly, the integral sliding mode surface is used instead of the traditional linear sliding mode surface to optimize the continuity of the SMC structure and reduce the high-frequency perturbation caused by the differential phase, thus reducing the smooth torque and system steady-state error. Secondly, the system is simulated by MATLAB/SIMULINK; the given torque of the improved SMC is the most stable; and the speed response curve is smoother. Finally, the construction of the BLDCM test platform is completed. The experimental results show that in the BLDCM DTC control system of the new flux linkage set mode, based on the improved SMC, the system has faster response speed and stronger anti-interference, and shows stronger dynamic and static performance.

The Direct Torque Control of Brushless DC Motor Based on Sliding Mode Variable Structure

2023-11-23

PIER C

Vol. 139, 11-20, 2024

doi:10.2528/PIERC23092504

download: 98

Design of Permanent Magnet Synchronous Wind Power Control System

Huajun Ran , Wenjin Wei and Yue Gao

To tackle the slow response and insufficient interference resistance exhibited by permanent magnet synchronous motors (PMSMs) under traditional field-oriented control (FOC). This paper proposes an integral sliding mode controller (SMC) to improve the speed loop, and adaptive law is also developed using a nonlinear smooth function to eliminate the chattering phenomenon of the sliding mode control. Meanwhile, an extended state observer is designed to estimate and compensate for the disturbances caused by wind speed uncertainty and the system's internal disturbances. Then, model predictive control (MPC) is employed for the current loop to eliminate the overshoot and achieve fast tracking. Finally, a step-by-step model reference adaptive scheme (MRAS) is proposed to identify the parameters and eliminate the internal disturbances in addressing parameter perturbation in the motor during operation. The simulation results demonstrate that the enhanced system exhibits almost no overshoot, superior steady-state performance, quick dynamic response, and resistance to both internal and external disturbances, ultimately validating the efficacy of the approach.

Design of Permanent Magnet Synchronous Wind Power Control System

2023-11-19

PIER C

Vol. 139, 1-10, 2024

doi:10.2528/PIERC23081802

download: 80

Design of True Time Delay Line Based Octal Transmit Receive Module for Wideband Phased Arrays

Kilari Sreenivasulu , Kamla Prasan Ray , Alagarswami Vengadarajan and Dharmavarapu Srinivasa Rao

Wideband phased arrays for Electronic Warfare (EW) applications utilize narrowband phase shifters in a switched configuration to cover a multi-octave bandwidth in split bands. Wideband True Time Delay (TTD) line circuits are the best candidates to replace narrowband phase shifters in such systems, covering the complete operating bandwidth in a single step. The Transmit Receive Module (TRM) is a critical component of any phased array system. A novel design of a TTD line-based Octal Transmit Receive Module (OTRM) for a 32-element EW phased array over a frequency range of 1-6 GHz is presented in this paper. The OTRM is designed on a single multi-layer PCB by integrating eight transmit-receive (TR) channels, associated controllers, and power conditioning circuitry in a compact size and weight of 800 grams. The paper addresses challenges associated in design of TR channels to fit within the inter-element spacing of 14 mm and to achieve isolation of ≥40 dB between channels. The designed OTRM tunes time delay up to 508 ps maximum with a step of 2 ps by using a single TTD line circuit for ±45° scan coverage. The OTRM has demonstrated its potential capability for use in wideband Radar, EW, and Communication system applications. Efficient thermal management of the OTRM is achieved by introducing Copper coins below the final power amplifiers and a liquid cold plate to dissipate a heat load of 32 watts per TR channel. The proposed OTRM delivers transmit power of 8 watts (CW), receive gain of 25 dB, and a noise figure of 6 dB per TR channel with an overall efficiency of 19% (min) over a 5 GHz bandwidth. RF path analysis of the TR channel in transmit and receive paths is carried out using the Systemvue software tool. To verify the design of the OTRM over different time delay and attenuator states, measurements are conducted using a Vector Network Analyzer (VNA).