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Induction heating can convert electrical energy to thermal energy with high conversion efficiency and quick heating. Currently, a current source rectifier/inverter-fed parallel resonant circuit is widely used as an induction heating power supply for forging applications. However, the conventional induction heating power supplies composed of phase-controlled rectifier and SCR inverter have low efficiency...
This paper proposes a self-tuning model predictive direct power control (MPDPC) strategy for power flow control and power quality improvement in grid-connected power converters. At each sampling instant, a fuzzy logic controller is used to determine online the best weighting factor values for a given operating point. These values are then used to solve the multi-objective optimal control problem associated...
This paper presents an improved single phase seven-level active rectifier architecture controlled by finite control set model predictive control (FCS-MPC). The FCS-MPC is designed to enable power conversion with a unity power factor and generate seven level voltage waveform at the input. The proposed active rectifier architecture reduces harmonic contents of the rectifier input current by producing...
This paper proposes a novel control strategy for the brushless DC motor drive system fed by electrolytic capacitor-less inverter. In order to obtain high power factor, this paper proposes a new control method that regulates the inverter input current. The calculated compensation current of small film capacitor is subtracted from the ideal ac input current, which is regarded as the ideal inverter input...
The performance of reactive power sharing in an islanded microgrid is significantly affected by feeder impedance, mismatch parameters and unbalanced local load. To reduce the negative impact of mismatched link impedance on reactive power sharing, the adaptive virtual impedance strategy for voltage compensation is proposed with paralleled inverters in an islanded mode. The on-line adaptive control...
This paper describes the soft start and grid connection control strategies for high power synchronous compensator fed by low-voltage load-commutated inverters (LCI). In the start-up stage, field weakening method is used to make the motor start stably, and the back electromotive force (EMF) basically remain stable within the LCI withstand voltage at the same time. When the motor speed up to above the...
On-site small-scale electricity generation through a cluster of micro-sources with their local loads known as, microgrid has attracted significant attention as an alternative to traditional centralized power generation plants. The advantage of microgrid lies in its capability to work in stand-alone (island) and grid-connected mode. During the transition from grid-connected mode to island mode, there...
In this paper, an advanced droop control using a multinomial model for operating the parallel-connected uninterruptible power supply (UPS) inverters is proposed. To control the parallel inverters without any physical communications, the control method using a P/Q droops is conventionally used. The conventional method droops voltage and frequency using the monomial model. In conventional droop control,...
In order to ensure three-phase grid-connected inverter output voltage symmetry under unbalanced grid voltage, an improved control strategy is proposed in this paper. The proposed control strategy includes power, voltage and current three loops. The complex coefficient-filter (CCF) is used to obtain the positive and negative sequence of unbalance output voltage and current during the grid faults. By...
The output active power and reactive power of new energy inverter can be controlled independently using vector control, but there are degrees of coupling between them under the influence of transmission line parameters. In this setting, an overall evaluation of the coupling degree of power is vital to achieve decoupling control. This paper indicates the root cause of inverter power coupling and necessity...
Under the condition of low short circuit capacity and high grid impedance of weak grid, the grid voltage is easily fluctuated due to the load change, affecting the power quality of the grid. In view of this problem, firstly, this paper analyzes the principle of the grid-connected voltage change caused by the load change. Secondly, an improved voltage-power control method (PQ-U) for three-phase grid-connected...
Solar voltaic panels are getting common as a micro grid energy source day by day. Ample requirement of power quality improving devices are there in the grid. The scenario gives rise to a question that how we can avail more power quality improving devices, like static reactive power compensators by effective utilization of available devices. All the grid connected solar plants requires a three phase...
Average absolute frequency deviation value (AFDVavg) based active islanding detection technique is recently introduced for islanding detection of active distribution system with a single active DG. This paper implements, evaluates and analyze the performance of AFDVavg technique for active distribution system with parallel inverter. The main focus is on islanding detection of an ADN with parallel...
This paper based on the commutation mechanism of series capacitor commutated converter (CCC), the CCC is applied to UHVDC transmission system, and the mathematical model of reactive power demand of CCC inverter is established. According to the actual parameters of Jiuquan-Hunan ±800 kV UHVDC transmission project, the simulation model of CCC- UHVDC system is built by PSCAD/EMTDC simulation software...
Brushless DC (BLDC) motors have been applied extensively in household and industrial scale because of the advantages such as high efficiency and low mechanical losses because it does not use a brush such as DC motors. Application of the BLDC motors use rectified AC source to minimize battery usage. However, the use of BLDC motors and rectifying circuit causing poor power factor and facing harmonic...
Because of the inherent defects of the traditional High-Voltage Direct Current (HVDC ) transmission systems, this paper proposes a control method of flexible HVDC transmission system based on shuffled frog leaping algorithm(SFLA), which will improve the anti-interference ability of the power system by optimizing active disturbance rejection controller(ADRC).
This study covers grid-tied photovoltaic (PV) renewable energy (RE) resources and uses SynerGEE Electric 5.0 as a simulation tool for a distribution impact study (DIS). The DIS refers to a set of technical studies used to assess the possible effects of a proposed expansion, reinforcement, or modification of the distribution system or a user development, and to evaluate incidents. Despite its usefulness,...
This paper presents an analysis of the optimal reactive power of distributed generators (DGs) in distribution networks for improving the energy efficiency. In recent years, the increasing awareness of the pollution problem, social issues, and economic factors have rapidly increased the penetration of DGs in the distribution networks. Because of the smart inverter technology, the reactive power of...
The proliferation of Distributed Energy Resources (DERs) in the Distribution Network (DN) has affected the optimal operation of the grid due to multiple technical issues such as voltage rise, reverse power flow, voltage unbalance, islanding etc. Therefore, optimal management of DERs is becoming a key research area to improve the system power quality. In this context, several active network management...
Performance of multilevel inverters (MLI) are distinguished because of their low harmonic waveform generation, low filtering requirements on AC side and high voltage application. Among different (MLI) topologies, cascaded multi-level inverters (CMLI) are easier to implement and are much more cost effective. The main drawback of multilevel inverters is requirement of more than one isolated DC source...
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