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Nonlinear control strategies of variable speed constant frequency(VSCF) wind power generator systems, especially passivity-based control(PBC) methods, have been a focus in the literature. The main purpose of this paper is to develop a control algorithm that forces the wind driven doubly fed induction generator(DFIG) to track reference flux and speed trajectories with time-varying load torque. To achieve...
Supercapacitors are well known for their good power performances and for their very high life time expectancy when compared with batteries. However, individual supercapacitor is only capable of operating a relatively low voltage, normally between 1V and 3V. For higher voltage or current applications, many of these capacitors must be linked in series or in parallel. For supercapacitor module, there...
In this paper, repetitive control is employed to design the current controller of active power filter for reducing the steady-state error due to periodic command. Zero steady-state error for current control is realized. Discussions on the design of the current and voltage control loops are given. Simulation results verified the feasibility of the proposed method.
Power system is migrating from the conventional grid to the smart grid creates many active research areas to realize the objectives and the expected requirements from it. Different challenges facing the transformation of the conventional grid into a smart grid exist and need to be addressed by future research. This paper identifies the challenges facing the development of the smart grid, future research...
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...
This paper investigates the operation of a current controlled Voltage Source Converter (VSC) under weak grid conditions caused by large grid impedance. Three different current controller structures are investigated; the conventional decoupled PI-controller in the synchronously rotating reference frame, Proportional Resonant (PR) controllers in the stationary reference frame, and the phase current...
A circuit topologies family of single-stage parallel uninterruptible AC/DC converter with high power factor are presented. The topology includes four sections, i.e. full bridge rectifier, parallel converter with power factor correction(PFC), uninterruptible power supply and fast output voltage regulation. The converter has lots of advantages such as: single stage power conversion, uninterruptible...
A high voltage power vertical double-diffused MOSFET with reduced JFET area by using an overall implantation was discussed. The reduced JFET area realizes a low gate charge and a high switching speed, due to the reduction of the gate-drain overlapped area. The measured gate-drain charge and gate charge can be improved by 61.1% and 71.8 %, respectively. The F.O.M of the proposed device and the conventional...
A decentralized control strategy is proposed to coordinate multiple shunt active power filters (APFs) to improve power quality at the point of common coupling (PCC) in terms of power factor correction and harmonic elimination. Under the proposed control strategy, each APF uses locally measured current signals to decide the amount of power quality improvement task, which is limited to its power rating...
Communication system in microgrid is very important to microgrid operation. Except for meeting the demand of reliability, it should fulfill the characteristics of plug and play, dispersion in distributed devices, and the need of data information in controlling. A constraint set and a common communication platform are designed considering architecture and control of microgrid. In the process of designing...
Aimed at the application of directly driven PMSG (Permanent Magnet Synchronous Generator) in MW wind power system, a strategy of compound vector control with the orientation at the direction of stator current is proposed in this paper. This strategy adopts the MTCRC (Maximum Torque / Current Ratio Control) mode to perform normal power generation within the range between the cut-in speed and a turning...
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...
Because the building integrated photovoltaic (BIPV) is commonly installed on the terminal of the distribution network, BIPV central inverter control strategy combined with reactive power compensation, harmonic suppression and grid-connected power generation is developed in the paper aiming at the present status of containing nonlinear loads and the poor performance of the power quality indices. The...
This paper presents a novel indirect current control technique applied to a Single-Phase PWM rectifier to increase power factor and reduce harmonic current. It is applied to railway traction converters with low switching frequency, high voltage and high power. To get better stability and easier realization, indirect current control scheme is used in the inner loop control. Much computing such as extraction...
For acquiring of better quality and reducing the harmonic of the high frequency link matrix inverter-HFLMI output, a new envelope curve modulation method is discussed. The method can make the cycle duty of the front stage circuit of the HFLMI's driving signals variable and the HFLMI can gain better output voltage and current by working with de-re -coupling SPWM modulation. The carrier wave for front...
The fault characteristic of inverter interfaced DG is very different from that of synchronous rotating generators. Traditional protection methods based on large fault current are no longer applicable to inverter-only supplied microgrid. This paper analyzes the fault behaviour of inverter based microgrid, and proposes an adaptive fault current protection algorithm for this type of microgrid. According...
At present, distributed generation (DG) has been a research focus all over the world. As a kind of DG system, cogeneration system utilizing waste heat from sintering-cooling process plays an important role in modern iron and steel enterprises. In this paper, we studied the composition and characteristics of waste heat resources. Based on the first and second thermodynamic laws, the cogeneration system...
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...
In this paper, high voltage and high frequency Capacitor Charging Power Supply based on serial resonant topology is analyzed. Considering the nonlinear and parasitic parameters, the charging current is a decay one. A 700W experiment prototype is completed based on DSP digital control. Experiment waveforms verify the charger operating with a output current of 1A and charging the 47μF capacitor to a...
For rectification of the three-phase AC voltages of permanent magnetic synchronous generator (PMSG) applied to variable speed constant frequency wind generation, a synchronous PI current control technique is proposed based on a novel topology called three-phase PFC rectifier. It consists of three single-phase power factor correction (PFC) circuits, each of which is for one phase of PMSG. The stator...
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