Investigation of the Emission Higher Harmonics into the Generator Grid

The article considers a section of the grid with generator voltage busbars (GRU-10 kV) of one of the hydroelectric power plants HPP-I of a large cascade HPP, which supplies electricity to an aluminium plant via two busbars. It is described that the plant load includes converter units, including: transformers, bridge rectifier blocks and saturation chokes, which are powerful sources of harmonic disturbances. An overview of the developed model and the principles of its construction for studying the influence a powerful non-linear load on the generator is given. Analysis of the results calculations on the model showed that the load of an industrial enterprise creates current and voltage distortions in the electrical s not only of the plant itself, but also in urban grids, and on the busbars of the generator voltage HPP-I. The article analyzes the influence of the current effects of a large industrial enterprise load in asymmetric modes on hydrogenerators by evaluating torsional vibrations and tangential vibrations in generators. It is shown that tangential forces of double frequency (100 Hz) practically do not create significant vibration displacements when the natural frequency of the frontal parts basket is adjusted.

Cost-Effective Scheme for a Brushless Wound Rotor Synchronous Machine

This paper proposes a new scheme for a brushless wound rotor synchronous machine (WRSM) by generating an additional, two-pole component of magneto-motive force (MMF) with a series-connected additional three-phase winding with the armature three-phase winding. Unlike existing brushless excitation schemes, which use the inverter to inject harmonic currents in the stator windings, the proposed scheme uses series-connected additional winding on the stator with the armature winding in a two-pole configuration. Consequently, as the current flows in the armature winding, it creates a fundamental rotating air gap flux to interact with the field flux. At the same time, additional rotating flux is created from the additional three-phase winding, which cannot synchronize with the field winding. This additional flux can cause the induction of a voltage in a winding with exactly the same number of poles. For this purpose, a harmonic winding is installed in the rotor along with the field winding connected through a diode bridge rectifier, in order to feed the direct current (DC) to the field winding for rotor excitation without an input current from the brush-slip-ring assembly. The 2D finite-element analysis (FEA) was performed to validate the brushless operation of the proposed machine system.

Voltage Flip Efficiency Enhancement for Piezo Energy Harvesting

In this paper, we analyze the effect of an enhanced voltage flip technique on the power performance of a piezoelectric energy harvester. The enhanced voltage flip principle is based on a synchronized-switch-based architecture, and is referred to as FAR (Full Active Rectifier). It uses a tiny amount of the stored charge to boost the voltage flip. This work aims to demonstrate that, beside the enhanced flip efficiency, the FAR also contributes to improve the power efficiency of the harvester, especially under changing load constraint. Therefore, the paper proposes a thorough comparison between the FAR and its conventional counterpart, the Switch-only technique. The FAR is easy to implement and does not require any external inductor or capacitor. It only needs a reduced set of switches, an active diode and a simple control sequence, and can thus be implemented on a fully integrated circuit. The FAR can be used as a standalone voltage flip solution or in addition to further boost the flip efficiency in a state-of-the-art architecture such as SSHC for example. Tests were performed on a 0.35-µm process CMOS prototype IC. Experimental results revealed that the FAR extracts 19.1μW from an off-the-shelf piezoelectric transducer when the output voltage is regulated at 1V with 1 V open-circuit voltage and delivers up to 20% more power than the conventional Switch-only technique under load constraint. It also shows over 11× power efficiency improvement compared to a conventional diode-based full bridge rectifier.

SINGLE-PHASE HYBRID FILTER FOR DECENTRALIZED POWER SYSTEMS

The analysis of the single-phase hybrid filter of network current harmonics, which can be applied in the decentralized power system, was carried out. Mathematical modeling of such a system that feeds a bridge rectifier with a capacitive filter and the 10 kW active load was performed. A comparison of current spectrograms and current diagrams of different configurations of a hybrid filter implemented in the active part on the basis of an active corrector of the parallel type, and in the passive part - a broadband LMC filter with an additional winding Ld was carried out. The maximum current deviations from the shape of the first harmonic of the current consumption for different structures of the passive filter were determined, which is decisive for the calculation of the power part of the active filter. The installed power of the active filter was calculated, the harmonic coefficients of the current consumption of the power supply network were obtained. Ref. 11, fig. 5, table.

Implementation of a Fault-Tolerant AC/DC Converter for Permanent Magnet Synchronous Motor Drive Systems

Fault tolerant drive systems have played an increasing role for electric vehicles in order to improve reliability, availability, and to reduce maintenance. For safety reason, a fault-tolerant drive system, which includes some redundant devices and a traditional motor drive system, has been developed. This fault-tolerant system executes real-time fault detection, diagnosis, isolation, and control to make the fault-tolerant drive system operate normally even though some faults have happened. In this paper, an AC/DC converter faults, which includes a single-phase full-bridge rectifier diode fault, a three-phase full-bridge rectifier diode fault, and a DC-link capacitor fault are investigated. The fault-tolerant processes include fault detection, diagnosis, isolation, and control to improve the reliability of the drive system and reduce the disturbances during faulty interval. A digital signal processor, manufactured by Texas Instruments, type TMS320F2808, is used as a control center to achieve the fault tolerant processes. Experimental results validate theoretical analysis to demonstrate the correctness and feasibility of the proposed methods. The proposed method can be easily implemented in industrial products due to its simplicity.

Study the Simulation of Hybrid Solar Wind Charging Station

Electric vehicles play a vital role in energy saving and emission reduction of harmful greenhouse gases. electrical vehicles dispersion into the vehicles market has not been up to the mark because of less value effective and these vehicles have to be compelled to be compelled to recharge once in sixty five to seventy klick drive. The novel hybrid vehicle charging station carries with it fully totally different sources like PV systems, wind systems, the AC provide, batteries area unit used as a main energy storage system, kind DC little grid permanently energy delivery. Thus, grid offers decent quality of power to 3 totally different hundreds notably 110-volt AC single-phase output ,100 v DC output. The grid is at 230 V rms with fifty cps connected isolator in relation to the DC bus. The three-part output of the grid is regenerated to the rippled DC by utilization of DBR (Diode Bridge Rectifier). The regenerated DC voltage is fed to graphic symbol device that might be a DC-DC devices, making the rippled DC to constant DC with the use of a buck device, this paper justifies comparative performance hybrid charging station mistreatment buck and letter convertor to stabilize the DC voltage. planned system analysis in MATLAB Simulink.