Showing 3 results for Maleki
K. Malekian, J. Milimonfared, B. Majidi,
Volume 5, Issue 1 (March 2009)
Abstract
The main theme of this paper is to present novel controller, which is a genetic
based fuzzy Logic controller, for interior permanent magnet synchronous motor drives with
direct torque control. A radial basis function network has been used for online tuning of the
genetic based fuzzy logic controller. Initially different operating conditions are obtained
based on motor dynamics incorporating uncertainties. At each operating condition, a
genetic algorithm is used to optimize fuzzy logic parameters in closed-loop direct torque
control scheme. In other words, the genetic algorithm finds optimum input and output
scaling factors and optimum number of membership functions. This optimization procedure
is utilized to obtain the minimum speed deviation, minimum settling time, zero steady-state
error. The control scheme has been verified by simulation tests with a prototype interior
permanent magnet synchronous motor.
M. Ghotbi-Maleki, R. Mohammadi Chabanloo,
Volume 17, Issue 4 (December 2021)
Abstract
Expansion of power system causes short-circuit currents (SCC) of networks to exceed the tolerable SCCs of equipment. The utilization of fault current limiter (FCL) in such networks is needed to address this issue. This paper presents a new method for optimal allocation of FCLs to restrain the SCCs under permissible value. In this method, it is suggested to select a line as FCL location where the addition of FCL to this line will have the greatest impact on reducing the SCC of buses which their SCCs exceed the permissible value (known as exceeded buses). Since the optimization algorithms are not capable for optimal allocation of FCL especially in large networks, therefore, the proposed FCL allocation method is presented in the form of a computational process. In this computational process, the candidate lines for FCL location are firstly prioritized by a new index based on the effect of location of FCL on the reduction of SCCs. Then, the FCL size is determined by solving a quadratic equation firstly presented in this paper. The proposed method is implemented on networks with different sizes, and the obtained results show the performance of the proposed method over previous FCL allocation methods.
Davood Maleki, Abolfazl Halvaei Niasar,
Volume 22, Issue 1 (March 2026)
Abstract
In electric propulsion systems for high-power applications, multi-phase Permanent Magnet Synchronous Motors (PMSMs) are highly advantageous due to their fast dynamic response and high reliability. This study investigates a twelve-phase PMSM with double stator windings, where each winding is powered by a single-phase H-bridge inverter. The control of both H-bridge inverters for each phase is managed by a dedicated microcontroller. Given the independence of the control systems (microcontrollers) and the absence of data exchange between them, the modeling is conducted in the 12-phase stationary reference frame. To address non-sinusoidal back-EMF phase voltages and mitigate torque ripple, a harmonic current injection method is independently applied to each phase. A model-free predictive current and speed controller (MFPCSC), based on an ultra-local model, is employed, replacing conventional PI or hysteresis current controllers. Additionally, extended state observers (ESOs) are designed to estimate uncertainties and parameter mismatches. Under fault conditions, a fault-tolerant control strategy is implemented, where the current angle of healthy windings is adjusted to suppress the second harmonic in the remaining healthy windings, thereby reducing torque ripple. The effectiveness of the proposed control methods is validated through simulations, both under normal operating conditions and various fault scenarios.
