Lesani, Darabi, Nasiri Gheidari, Tootoonchian,
Volume 2, Issue 1 (January 2006)
Abstract
In this paper, a new field oriented control scheme with maximum torque for permanent magnet hysteresis synchronous (PMHS) motor has been presented. Vector control method provides significant improvement to the dynamic performance of ac motors but in this method d- axis current is controlled such as the ratio of motor torque to motor current is a maximum, then the dynamic performance will be very fast. Furthermore, d and q axis currents are limited such as stator winding currents remain in the allowed range. Feedback method is used for the decoupling the torque-current component from the fluxcurrent component so these two components can be independently controlled. Simulation results for the motor are given and test results validate the theoretical performances.
Mohammad Ali Razavi, Farid Tootoonchian, Zahra Nasiri Gheidari,
Volume 22, Issue 1 (March 2026)
Abstract
Synchros are electromagnetic sensors utilized to determine the angular position of a rotating shaft. This paper examines the impact of leakage flux from the Rotary Transformer (RT) on the induced voltages and the position detection accuracy of the Wound-Rotor (WR) synchro. Various methods are proposed to mitigate the negative effects of leakage flux from the RT. The leakage flux paths, which couple with the signal winding, are identified. Based on this analysis, the optimal distance between the sensor and the RT is calculated to minimize the adverse effects of leakage flux on the synchro's accuracy. Additionally, the RT structure is modified to reduce the leakage flux. Another effective approach involves the use of Electromagnetic Interference (EMI) shielding. In this context, a shield frame is designed for the RT, and the impact of different shield materials on reducing leakage flux is investigated. The results show that a copper-based shield significantly reduces the adverse effects of leakage flux and improves the sensor’s accuracy. To evaluate the effectiveness of the proposed methods, they are assessed through 3-D Time-Stepping Finite Element Analysis (3-D TSFEA) and experimental measurements on a prototype sensor. The experimental results show close agreement with the 3-D TSFEA, confirming the accuracy of the findings.
