Performance analysis of multi-level high voltage direct current converter

<p class="Abstract">The conventional three-phase alternating current (AC) to direct current (DC) converter can be modified using two isolated-gate bipolar transistor (IGBT) as by-pass switches connected to tapping points on the secondary side of the transformer. This scheme yields a reduction in both harmonic contents and reactive volt-ampere absorption. This modified converter possibly eliminates the need for an on-load tap-changer on the converter transformer. The modified AC/DC converter is fully analyzed and implemented under balanced conditions using MATLAB-Simulink. The expressions of the output DC voltage are derived for different cases. The supply current harmonic contents, the reactive power absorption and the power factor have been compared for three schemes; the conventional bridge, the modified bridge using one by-pass IGBT valve and the modified bridge with two by-pass IGBT valves. </p>

A STUDY ON DYNAMIC CH AMIC CHARACTERISTICS OF A NEW REMO TERISTICS OF A NEW REMOTE TRANSFORMER CURRENT CONVERTER WITHOUT COMPENSA COMPENSATING CAP TING CAPACITOR

In this research paper, analytical equations of the transient characteristics of a new remote transformer current converter without a compensating capacitor have been obtained when a stepwise, linearly increasing, sinusoidal and sinusoidal with a damped amplitude of effects was applied to their input. It has been shown that the developed current converter can be represented in the structural schemes of monitoring and control systems in the form of a series-connected real ifferentiating link without statism and inertial (aperiodic) link of the first order, and in the case of neglecting active losses in the magnetic circuit and when the converter is operating in idle mode, i.e in the form of ideal differentiating link.It has been established that the transient response of the developed current transducer has an aperiodic character when a surge primary current is fed to its input, and with a relatively very large value of the time constant of the secondary circuit compared to the time constant of the magnetic circuit, transient response approaches transient response of a real differentiating link.

Robust sampled-data control for direct current to direct current converters via switched affine description and error tracking strategy

In this article, a novel sampled-data control method is proposed for direct current to direct current converter. According to its switching property, the direct current to direct current converter is described as a switched affine system. A novel error tracking switching law is designed based on the multi-Lyapunov functions method and sampled-data control strategy with variant sampling intervals. The sufficient condition concerning the state of the constructed switched affine system converging to a finite region is developed, which guarantees the outcome voltage can approach the desired value and achieve the voltage adjustment. Based on it, the condition under uncertain parameters is developed as well, which would be more desirable in applications. The effectiveness of the proposed method is verified by numerical simulations. The proposed method is also applicable to other types of power converters.

Numerical Study of The Airfoil Pitch Angle on The Darrieus-Savonius Combination Turbine

The Darrieus turbine is used as an ocean current converter to generate renewable electrical energy. One way to improve turbine performance is to determine the optimal pitch angle. Therefore, the purpose of this study was to determine the optimal pitch angle of the NACA 0018 airfoil with angle variations of -6°, -2°, 0° and 2°. Numerical method with the help of Ansy Fluent software was carried out for the construction of the turbine. The result of this research is that the angle of 2° produces the largest coefficient of power and torque compared to other angles. This happens because the direction of the lifting force on the forward airfoil is in accordance with the rotation of the turbine.Keywords: Ocean Current, Turbine, Pitch Angle

DEVELOPMENT OF A BLOCK DIAGRAM AND SIMULATION MODEL OF A CHARGING AND DISCHARGING DEVICE FOR HIGH-CAPACITY LITHIUM-ION BATTERIES

Зарядно-разрядное устройство (ЗРУ) используется в качестве оборудования для проведения ресурсных испытаний аккумуляторных батарей. В данной статье разработаны структурная схема и имитационная модель ЗРУ, содержащего импульсный преобразователь тока и импульсный преобразователь напряжения. The charging and discharging device (CDD) is used as the equipment for carrying out service life tests of accumulator batteries. In this article, a block diagram and a simulation model of a CDD containing a pulse current converter and a pulse voltage converter are developed.