Browsing by Author "Shestaka, Anatoliy"

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    Advanced Space Vector Modulation with “Fractional” Power Cells
    (Elsevier B.V., 2025) Busher, Victor; Shestaka, Anatoliy; Melnikova, Lubov; Kuznetsov, Vitaliy V.; Mykhailenko, Oleksii; Kovalenko, Viktor; Kutyk, Viktor; Osadchyi, Dmytro; Osypenko, Iryna O.; Abdel Gawad, Samer
    ENG: The paper develops a model and studies various operating modes of a 5-phase multi-level cascade inverter as part of high-voltage powerful variable-frequency drives (VFD) with the most typical fan load for this type of electric drives. The aim of the work is to test the efficiency of the balanced spatial-vector pulse-width modulation method in a multi-phase high-voltage multi-level inverter in emergency modes by simulating the electric drive in the MATLAB/SIMULINK/Simscape Electrical environment. The paper studies the features of using the balanced spatial-vector pulse-width modulation method in a five-phase frequency converter in normal and emergency modes and, especially, the differences from a three-phase inverter with a similar control principle. The model with a 5-phase synchronous motor from the MATLAB ac8_example.slx database is taken as a basis, which allows us to consider the simulation results reliable. The rules for calculating phase voltages in normal and emergency modes are formulated and the corresponding blocks of the inverter control system model are prepared - a block for calculating basic vectors and a block of spatial vector pulse-width modulation (PWM). The output signals of this block are used for further processing in the modules for controlling power cells with 2- or 3-level PWM. Such a model for a 5-phase electric drive has been built for the first time, which is a scientific novelty of the work. Calculations of transient processes showed the absence of any oscillations, shocks when the system switches from normal to emergency mode and vice versa. That is, the proposed method of balanced spatial vector modulation preserves the symmetry of electromagnetic fields in the engine when individual H-bridges are damaged. It is shown that in normal mode, a 5-phase inverter using the spatial vector modulation method allows increasing the utilization factor of voltage sources by 23.1%. When individual power cells in phases fail, the utilization factor may decrease, but in any case it remains greater than 1. The method ensures compensation for emergency damage even in the event of a short circuit of one or two inverter phases. This significantly increases the service life of the electric drive, which is especially important in critical mechanisms and technological processes, where such complex inverters are actually used. The study found that when using the proposed method in a 5-phase VFD, unlike a 3-phase one, the current balance in the load is disrupted, which leads to increased heating of individual phases of both the motor and the power section of the inverter. The second point of scientific novelty of the work is that in order to reduce this negative effect, it is proposed to improve the algorithm for calculating the output coordinates of the regulator by using the so-called “fractional” power cells with a voltage that is not a multiple of their rated voltage. This leads to a smooth change in phase shifts and asymmetry when individual H-bridges and even one or two phases are damaged. This, in turn, reduces the current imbalance and the corresponding overheating from 2...3 to 12...15%, which gives confidence in the efficiency of using this improvement. It is also important to note that such a change in the control algorithm does not require any changes in the circuit and does not increase the requirements for the computing power of the processors used.
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    Optimization of the Control of Electromagnetic Brakes in the Stand for Tuning Internal Combustion Engines Using ID Regulators of Fractional Order
    (MPDI, 2022) Busher, Victor; Zakharchenko, Vadim; Shestaka, Anatoliy; Kuznetsov, Valeriy; Kuznetsov, Vitalii V.; Nader, Stanislaw
    ENG: This work is aimed at developing a stand for tuning the fuel system of an internal combustion engine based on two electromagnetic retarders connected to the driving wheels of a car to simulate a load, and a microprocessor-based torque control system for each brake. In accordance with the terms of reference from the specialists of the automotive service center, such a stand should provide two main modes of operation: (1) stabilization of the speed of the drive wheels in the entire range of loads (fuel supply); (2) engine acceleration and deceleration according to linear tachograms in the range from minimum to maximum speed to determine the dependence of engine power and torque on speed. The purpose of this research is the synthesis of controllers, testing, the choice of the structural scheme, and the parameters of the control and data processing system in the stand for the precision tuning of internal combustion engines. Based on a preliminary analysis of the system, taking into account the mechanical connection of the wheels through the main gear and the car differential, the nonlinear dependence of the electromagnetic torque on the current and retarder speed, and subsequent experimental results, we obtained two types of controller—a third-order aperiodic transfer function and a fractional aperiodic transfer function of order 1.6. This made it possible to synthesize a family of controllers that ensure the operation of the stand in the required modes: synchronization of wheel speeds during engine acceleration; stabilization of the reference speed when the engine torque is changed from minimum to maximum due to fuel supply; measurement of the maximum power and torque of the internal combustion engine during the formation of a triangular tachogram with a given acceleration to compensate for the dynamic component of the torque due to mechanical inertia. The system with the PID controller configured in MATLAB in the “Tune” package has the best performance, but the smallest overshoot and the best dynamic accuracy are ensured by the PIDII_ fractional–integral controller, where the system is characterized by a fractional order of astaticism 1.6. Such a controller for each electromagnetic retarder serves as the basis of the microprocessor-based control, data acquisition, processing, graphical display system, and will also be used to develop a similar bench for tuning four-wheel-drive vehicles.