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An ac voltage regulating system of doubly Salient Electro-magnetic Generator has been performed in this paper. In order to maintain the high voltage 360VDC stable, the dual boost converter with fixed frequency PWM controlled is adopted. Three-phase dual buck inverter was adopted to output 115VAC/400Hz. the generating system configuration, control strategy of dual boost converter and three-phase dual...
In this paper is presented the structure and working principle of the cascaded H-bridge multilevel converter with PWM rectifier and phase-shift transformer. Using the leak inductance as the filter reactor of the PWM rectifier can reducing the volume and cost of the converter; the phase-shift secondary side of the transformer can eliminate the current harmonics caused by the single power unit, restraining...
This article, firstly, introduced the operating principle of variable speed constant frequency (VSCF) wind power generation based on a structure of dual PWM converter. Then the mathematical model of network-side and rotor-side converter was set up. Decoupling control and vector control technique were presented based on grid voltage orientation and stator flux orientation to simplify the control strategy...
Stability issues are a major concern in railway grids. Although these problems are most experienced in 16.7-Hz applications, low-frequency oscillations also occur in 50-Hz railway grids. In this paper, an advanced multivariable control concept is presented. Beside achieving very good dynamic behavior, the approach improves the introduced stability problem. The proper operation of the control is verified...
Economical and ecological motives are pushing shoreside power supply by power electronics systems for merchant ships as well as for cruise ships. Also, final tests of on-ship power systems and generation are simplified considerably. Fault scenarios on-ship and within the harbour grid and the variability of the parameters of on-ship distribution - each ship is special, and large consumers or generators...
Stability aspects are a major concern in railway-traction applications. It is well-known that low-frequency oscillations occur in 16.7-Hz railway-grids. They can be initiated either by impedance variation or by multiple traction vehicles active in one feeding section. This paper focuses on the emulation of many traction vehicles starting up in the same feeding section and hereby causing instability...
It is proposed in this paper a methodology to obtain optimal controllers gains for the rotor-side converter of doubly fed induction generators (DFIGs) using a genetic algorithm approach. The main objective is to enhance the operational security and robustness of the power system, by a more effective contribution of the DFIG controllers to the system controllability. To reach this goal, the crow-bar...
This paper explores the performance of alternative voltage control strategy applied to direct drive synchronous wind generators, more specifically with permanent magnetic (PMSG). The reactive power control of the grid-side converter is investigated for voltage control purposes. In Brazil, the Grid National Operator (ONS) requires that wind turbines stay connected to the grid during voltage dips, but...
This paper presents a simple method based on commercially available operation amplifiers (Opamps) for realizing the square-rooting voltage-to-frequency converter (VFC). The realization of square-root function is provided through the use of the opamp supply-current sensing, which utilizes an inherent quadratic characteristic of the opamp class-AB output state. Experimental results verifying the performances...
This paper discusses a novel approach for damping interarea oscillations in a bulk power network using multiple unified power flow controllers (UPFCs) utilizing ultracapacitors, also known more generally as electrochemical capacitors (ECs). In this paper, a new control is introduced to mitigate interarea oscillations by directly controlling the UPFCs' sending and receiving bus voltages that better...
This paper aims at the application of a half bridge DC-DC converter as a power factor correction (PFC) converter for a permanent magnet brushless DC motor (PMBLDCM) driven air conditioner. This PFC converter is fed from single-phase AC mains through diode bridge rectifier (DBR) and connected to a voltage source inverter (VSI) feeding the PMBLDCM. The proposed PFC half-bridge converter based PMBLDCM...
Switched mode power supplies (SMPS) have become an indispensable part of modem electronic systems. In this paper, a generalized MATLAB/SIMULINK modeling techniques is presented. The proposed techniques have been successfully integrated into SMPS design course at Lunghua University, Taiwan. The main objective of the course is to teach final year undergraduate students and first year Master's students...
As wind turbine (WT) generation has been explosively introduced worldwide, the problems in the wind farm has been brought up. In this paper any kind of wind farm configurations and connections, include AC transmission system and VSC based HVDC transmission system are considered and the general tendency in lightning overvoltage at wind farm and lightning overvoltages of valve in VSC based HVDC based...
This paper describes a fully digital controlled switching mode DC-DC converter based on digital V2 control algorithm. V2 control in analog or digital realization can provide faster transient response compare to the conventional voltage or current-mode control. However, the reported digital V2 control scheme suffers from steady state oscillation problem. In this paper, we proposed a new digital V2...
This paper presents a marine generator control system which BDFM control winding side is controlled by commercial converter. Two problems of the commercial converter in control system is solved. One is the common commercial converterpsilas output voltage and frequency at constant V/F curve, the other is it canpsilat feedback energy to AC power. Based on generator voltage and frequency loop , we discuss...
This paper introduces the SMES into the DC bus of UPFC through a DC-DC chopper interface. This integrated power regulator can work as power flow regulator, bus voltage maintainer, power oscillation damper and uninterruptible power supplier. The detail working principle and work models are stated. The coordinated controller is studied for the property operation of the DC-DC chopper and the series/shunt...
This paper presents a mathematical model for a novel quantum series resonant inverter. This inverter can operate in six resonant modes. The differential equations derived from its equivalent circuit in all operation modes are generalized. At the same time, using the new control technique, the quantized output level which is inherent in the quantum converter can be completely overcome. Thus the output...
In this paper, two control strategies for three-phase series-parallel uninterruptible power supplies are compared. A series-parallel UPS consists of a parallel and a series converter. In this topology, most power required by load is supplied directly from AC line during standby mode. Therefore the overall efficiency is higher than that of a conventional UPS. Traditionally, the control strategy of...
Design an electrical locomotive 110 V D.C. source with PFC based on the structure of two-stage switching converter. Discuss the design scheme of main circuit and control circuit. Expound the calculation method of the key parameters. The experiments indicate that the device gets good performance on output and reliability. The electric source is appropriate for electrical locomotive and the other similar...
The control for a diode-clamped three-level half bridge converter is researched in this paper. The reasons for the input current distortion around the zero-crossing point of the input voltage based on the voltage zero-crossing detection control are analyzed in detail, and a hybrid control which combines the reference voltage feed-forward control with the feedback control is proposed to prevent the...
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