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With the increasing penetration of photovoltaic (PV) power system into the utility network, the issue caused by the fluctuation and intermittence of PV power output draws more attention. In order to predict the hourly power output for a PV system without any complex meteorological instrumentation, a NARX network-based forecasting model is proposed in this paper. Hottel's radiation model is applied...
Power harmonic estimation is essential for evolving suitable protection and control strategies of power networks. Parametric approaches exhibit super-resolution and have been gradually applied in practice. However, they are susceptible to the presence of noise in the signals. The analysis accuracy will be abruptly reduced and even ineffective under non-Gaussian or impulsive noise environment. In this...
Power harmonics estimation is essential for evolving suitable protection and control strategies of power networks. Parametric approaches exhibit super-resolution and have been gradually applied in practice. However, they are susceptible to the noise in the signals. The analysis precision will be abruptly reduced and even ineffective under non-Gaussian or impulsive noise environment. In this paper,...
Supervisory control and data acquisition (SCADA) systems are used in photovoltaic (PV) power plants for monitoring, control, remote communication purposes. The ingredient of SCADA system in PV power plants is introduced in this paper. In order to improve security and reliability of the SCADA system in PV plants, this paper provides two effective solutions, security access control strategy and redundancy...
In this paper, a novel microgrid energy trading model (METM) is proposed to determine an optimal schedule of all available units over a planning horizon so as to meet all system, plant and unit constraints, as well as meet the load and ancillary service demands. As the optimization greatly depends on the power generation and the power output from renewable sources strongly depends on the weather,...
Current and voltage harmonics distortion is an important issue in power quality (PQ) of power systems. In order to monitoring the PQ of distributed generators in real-time, an efficient method for tracking power harmonic parameters is presented in this paper. Firstly, a state-space model used for non-stationary harmonic analysis is constructed based on the definition of instantaneous frequency, in...
A new scheme adopting bi-directional converter is proposed to function both a DC-DC boost converter and a battery charger simultaneously in on-line UPS. The detail analysis of the proposed bi-directional soft-switched DC-DC full-bridged converter is given, this paper also gives the scheme of realizing soft-switching, the experimental setup is built and the results verify the feasibility of the proposed...
Basing on the analysis of inverter model and its corresponding control system, this paper gives the expression of inverter equivalent output impedance, which is not only related with the main-circuit parameters, but also related with the controller parameters. Then the simulation results of two paralleled inverters under different controller parameters are given to prove the validity of the inverter...
This paper introduces the principle of maximum power point tracking (MPPT) strategy and then proposed a new combined MPPT method, increment conductance method (IncCond) with variable step-size and CVT startup. In order to realize this method, a push-pull circuit is adopted and the DSP is used. The principle of the main circuit is presented and the complete flow chart of the proposed algorithm is given...
As the development of energy market and the interest for new energy recourses such as wind energy and solar energy, energy management system of distributed generation (DG) becomes significant for the stability and economic operation of the DG system. This paper introduced a basic structure of DG system and illustrated the principle of power forecasting using neutral network. Finally a novel energy...
Based on a three-phase PV grid-connected inverter with LCL filter, a two-current-loop control strategy which utilizes the grid-current as the outer-loop variable and filter-capacitor current as the inner-loop is adopted. Since the decoupling of the LCL filter is too complicate under dq coordinates, a PR controller is adopted in the outer loop under alphaszlig coordinates to avoid the complicated decoupling...
According to the basic characteristics of air plasma cutting inverter, the cutting inverter with sliding mode control (SMC) is researched and designed. Unlike the traditional PI control with the contradictory between the small voltage overshoot and the fast response time, SMC has not only effectively solved the voltage overshoot during the cutting process, but also realized a faster voltage response...
Based on the p-q-r theory, this paper presents a direct control strategy of unified power quality conditioner (UPQC) used in the nonlinear and unbalance three-phase four-wire system. A algorithm of calculating the series compensation current and shunt compensation voltage in the proposed system is introduced. An analysis of the proposed control strategy and its schematic diagram is described in particular...
Based on the p-q-r theory, this paper presents a direct control strategy of unified power quality conditioner (UPQC) used in the nonlinear and unbalance three-phase four-wire system. A algorithm of calculating the series compensation current and shunt compensation voltage in the proposed system is introduced. An analysis of the proposed control strategy and its schematic diagram is described in particular...
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