Removal of Phosphorus from Domestic Sewage by a Constructed Wetland Coupled Microbial Fuel Cell System

A constructed wetland (CW) coupled microbial fuel cell (MFC) system that treats wastewater and generates electricity was constructed. The total phosphorus in the simulated domestic sewage was used as the treatment target, and the optimal phosphorus removal effect and electricity generation were determined by comparing the changes in substrates, hydraulic retention times, and microorganisms. The mechanism underlying phosphorus removal was also analyzed. The experimental results showed that the best removal efficiencies of the two CW-MFC systems that used magnesia and garnet as substrates were 80.3% and 92.4%, respectively. Phosphorus removal by the garnet matrix mainly depends on a complex adsorption process whereas the magnesia system relies on ion exchange reactions. The CW-MFC system can also generate electricity. The highest output voltage and stable voltage of the garnet system were both higher than those of the magnesia system. The maximum stable voltage of the garnet device was 500 mV, while that of the magnesia device was 290 mV. The microorganisms in the soil and in the electrode within the wetland sediments also substantially changed, indicating that microorganisms positively respond to the removal of organic matter and power generation. Combining the advantages of constructed wetlands and microbial fuel cells also improves phosphorus removal in the coupled system. Therefore, when studying a CW-MFC system, the selection of electrode materials, matrix, and system structure should be taken into account in order to find a method that will improve the power generation capacity of the system and remove phosphorus.

Intelligent voltage regulator for distributed generation-based network

Power grids are being transformed into a smart distribution network that incorporates multiple distributed energy resources (DERs), ensuring stable operation and improved power quality at the same time. Many research papers have been published in recent years that discuss the voltage violation issues that emerge from the high penetration of distributed generation (DG). In this paper, we propose a new optimal voltage control technique based on feedforward neural networks (FFNN) to maintain a stable voltage profile. MATLAB®/Simulink® has been used to carry out the simulation. The simulation results show the efficiency of this method in voltage control. The proposed approach ensured a stable voltage profile for the considered schemes.

Electromagnetic Design and Flux Regulation Analysis of New Hybrid Excitation Generator for Electric Vehicle Range Extender

Aiming at the problem of uncontrollable magnetic field of permanent magnet generators, a new hybrid excitation generator (HEG) with parallel magnetic circuit is proposed. The HEG consists of combined permanent magnet rotor (PMR) and brushless electric excitation rotor (EER). The PMR has surface-mounted and embedded magnets. The PMR provides the main air gap field, and the brushless EER is used to adjust the air gap field. The operating principle and electromagnetic design scheme of the proposed generator are given in detail. Besides, the matching with two different types of rotors and the flux regulation characteristics is analyzed by using the finite element method. Finally, the output performance of the proposed generator including no-load and load characteristics and output voltage are tested. The results show that the two different types of rotors can be matched efficiently and operated reliably. The internal magnetic flux is easy to adjust in both directions, and the proposed HEG can output stable voltage in the range of wide speed and load.

Optimal Adaptive Gain LQR-Based Energy Management Strategy for Battery–Supercapacitor Hybrid Power System

This paper aims at presenting an energy management strategy (EMS) based upon optimal control theory for a battery–supercapacitor hybrid power system. The hybrid power system consists of a lithium-ion battery and a supercapacitor with associated bidirectional DC/DC converters. The proposed EMS aims at computing adaptive gains using the salp swarm algorithm and load following control technique to assign the power reference for both the supercapacitor and the battery while achieving optimal performance and stable voltage. The DC/DC converter model is derived utilizing the first-principles method and computes the required gains to achieve the desired power. The fact that the developed algorithm takes disturbances into account increases the power elements’ life expectancies and supplies the power system with the required power.

The Performance of a Three-Phase Induction Motor under and over Unbalance Voltage

Voltage unbalance is an adverse global phenomenon impacting three-phase induction motor output. Three-phase source voltage may become imbalanced in a variety of respects, while a balanced system preserves stable voltage magnitude and angles in three phases, but a completely balanced state is difficult to get. Imbalanced cases may differ in multiple ranges which may practically affect the motor. So, this work is an effort to analyze the operations with appropriate propositions. The output of a three-phase induction motor working with an imbalanced supply grid, MATLAB/SIMULINK is further used for simulation purposes and programming based on the asymmetrical component approach is adopted. A new design for system rerating is being proposed. As a case study, a 10 HP three-phase induction motor was used. The findings of the study show that to determine the output of the induction motor, positive voltage series must be respected under the voltage unbalance factor (VUF) or proportion voltage unbalance index with six various voltage magnitude imbalance conditions, the copper losses of three-phase induction motors were calculated under full load conditions by simulation. So, the qualified percentage change in total copper losses for the motor operating under imbalanced and balanced voltages was determined.

Optimal Adaptive Gain LQR-based Energy Management Strategy for Battery-Supercapacitor Hybrid Power System

This paper aims at presenting an energy management strategy (EMS) based upon optimal control theory for a battery-supercapacitor hybrid power system. The hybrid power system consists of a Lithium-ion battery and a supercapacitor with associated bidirectional DC/DC converters. The proposed EMS aims at computing adaptive gains using salp swarm algorithm and load following control technique to assign the power reference for both the supercapacitor and the battery while achieving optimal performance and stable voltage. The DC-DC converter model is derived utilizing the first-principles method and compute the required gains to achieve the desired power. The fact that the developed algorithm takes disturbances into account increases the power ele-ments’ life expectancies and supplies the power system with the required power

Exploration of DG Placement Strategy of Microgrids via FMFO Algorithm: Considering Increasing Power Demand and Diverse DG Combinations

Distributed energy resource (DER) has been widely deployed, and distributed generation (DG) can complement the distribution system. Favorable DG deployment provides the grid-connected microgrid (MG) with stable voltage and reduces emission and power generation costs. DGs are considered distributed feeders, and MG is required to be operated under the optimal state. Reconfiguration is a practical approach to optimizing resource allocation. The optimal global solution is obtained via optimization algorithms. In this paper, three objectives are defined, namely, minimization of economic cost (ECC), emission cost (EMC), and voltage deviation (VD). Consequently, a fuzzy moth-flame optimization (FMFO) algorithm is proposed to coordinate the interests of multiple objectives. Moreover, the simulation is conducted based on the standard IEEE 33-bus radial distribution system (RDS), under which the impact of deployment of various DG type and quantity on the MG is explored. In particular, diverse DG combinations are tried under the increasing power demand, and a high-stable voltage strategy is proposed to meet the specific demands. The simulation results reveal that: (1) the DG type has a significant impact on ECC and EMC; (2) penetration level of DG shows a positive-like relationship with the MG stability; and (3) the proposed FMFO algorithm exhibits an efficient performance in convergence.