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The following topics are dealt with: high efficient power conversion for distributed generation and renewable power systems; integration and control of multiple power converters and system; power electronic converters and controls; distributed generation interfacing technology to the grid and utility grid and power quality; power semiconductor devices; applications of renewable power system, fuel...
Diesel generators are widely used to supply electric power to remote and isolated areas where grid extension is prohibitive due to financial and technical constrains. In order to maintain an acceptable efficiency and moderate operation condition, the conventional constant speed diesel generators are designed to run above a specific minimum load requirement, which is normally over 50% of rated power,...
In order to study the power loss caused by the truncation error, a range of operating points is proposed, during which the misjudgments caused by the truncation error occur. The span of the range of operating points directly decides the amounts of tracking loss. From this point of view, the Perturbation and Observation (P&O) Method and Incremental Conductance (INC) Method are compared. Eventually,...
Renewables are playing an increasing role for the future electrical energy production. As the respective windparks are growing in size, the efficiency in the power collection network gets of increasing interest. To improve the power collection efficiency in high power windparks, it is proposed to move higher voltage levels closer to the single wind turbines. Especially the medium voltage - high voltage...
A high frequency dc link single phase PWM rectifier is proposed in this paper. It has the advantages of high efficiency, high power density, high reliability, and wide range of output voltage etc. A dual loop control scheme for this PWM rectifier is developed, which includes an inner PR (Proportional-Resonant) current controller and an outer PI (Proportional-Integral) controller. Nearly unit power...
This paper explorers modulation strategies for diode-assisted buck-boost voltage source inverter and the relationship of voltage transfer ratio versus modulation index. Two kinds of improved pulse-width modulation strategies with high dc link voltage utilization are presented to obtain maximum voltage gain at given modulation index and minimize the voltage stress at the same time. The operation principle...
Maximum Power Point Trackers (MPPT) systems are essential devices employed to maximize the power flow from a photovoltaic module (or array) to a load. In most applications, the MPPT is composed by a DC-DC converter interposed between the photovoltaic module and the load. Among the main DC-DC converters, the Buck-type and Boost-type are not proper for this purpose, since they cannot ensure that the...
This paper design a simple initial rotor position detection method which is both suitable for surface Permanent Magnet Synchronous Generator(PMSG) and interior PMSG in wind power system which is not need keep still before generator start. Based on the field oriented control, this strategy can be easily applied to PMSG speed sensorless drive system without extra complexity and independent to generator...
This paper describes the principles and characteristics of a novel bidirectional superposed dual active bridge dc-dc converter with an ac-link transformer, which has a mechanism formed from two bridge-type converters that are linked through superposition in additive polarity in series. Conventionally, for an isolated dual active bridge dc-dc converter, the rated voltage of its switching elements is...
With the increased use of distributed generation (DG) such as wind generation with characteristics of intermittence and fluctuation, the ability to maintain a reliable and a secure supply with high power quality in power systems is becoming more challenging. The increased use of power electronic converters within loading systems causes further problems for power quality – harmonics etc. It has been...
A fast algorithm for three-level space vector pulse wide modulation (SVPWM) in neutral point clamped (NPC) inverters based on traditional three-level sinusoidal pulse wide modulation (SPWM) is proposed. The acting time relation of each state in each phase is got by deeply researching the similarities and differences of three-level SPWM and SVPWM. This algorithm can realize all kinds of state sequences...
This work quantitatively evaluates the effect on dc micro-grids availability of both conventional architectures with single-input converters and alternative configurations with multiple-input converters. The analysis indicates that use of diverse power sources is essential in order to achieve high availability levels. Calculations yield that multiple-input converter configurations achieve availabilities...
This paper presented an approach to improve efficiency of EV batteries charger under light load. On the basis of analysis on the original charger built upon capacitor-diode-diode clamp circuit, a modified capacitor-diode-switching clamp circuit was designed to replace the original one in the full-bridge phase-shifted zero-voltage and zero-current-switching PWM DC/DC converter. Operating principle...
This paper presents the implementation of a Maximum Power Point Tracker (MPPT) for photovoltaic (PV) applications by using multilevel boost converter and FPGA Board. The control algorithm for extracting maximum power from the cell is proposed by means of the VHDL code and implemented using Xilinx XC3S400 FPGA Board. In this work, a practical implementation of the real-time Estimate Perturb and Absorb...
The grid connected PV systems represent the future growing market segment today; their influence on the utility is emphasized in this paper. A power balanced model of a grid-connected PV system is developed on PSASP, this model focuses on the injection power of the PV system, the dynamic relationship between the injection power and the solar radiation is mathematically described, the dynamic power...
Permanent magnet synchronous Generator (PMSG) based direct-drive WECS has been attracting wide attentions. For the special application, sensorless control for PMSG is desired. By widely studying the previous contributes, a novel estimator based on back-EMF is proposed. The estimator is composed of back-EMF observer and a phase-lock-loop (PLL) control to get the rotor-flux speed and position. The estimator...
Pulse width modulation (PWM) has been one of the most conventional modulation techniques for switching dc-dc converters. It compares error signal with sawtooth wave to generate the control pulse. Conventional PWM control technique suffers from slow dynamic response due to smooth error signal variation under step line or load variation. A novel PWM control (modulation) method for switching dc-dc converters...
Recently, a high efficiency transcutaneous power regulator for artificial heart with PWM-PLL control has been proposed in the literature. In this paper, a new method of sensing the output voltage inside the human body utilizing the same power transcutaneous transformer as signal transmission media is introduced. The feedback signal is modulated in the secondary at a frequency band above the PWM-PLL...
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