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In this study, parallel connection of separate voltage sources has been realized using cuk converters. For this aim, output voltages of converters are measured continuously and then fixed to a reference value. The PWM signals which are required to control the converters and to sense the current and voltage signals are generated by an FPGA. Since the FPGA has parallel processing feature, voltage and...
This paper deals with the power efficiency improvement of the composite resonant DC-DC converter, which is developed to be applied to the power conditioner of the photovoltaic generation system. To improve the power efficiency, following three approaches are taken: 1) optimum design of the transformer 2) use of the voltage doubler rectifier. 3) reduction of the winding loss of the transformer. The...
This paper proposes photovoltaic (PV) cell booster which amplifies voltage and current in small-size PV cell. The booster simulates large-size PV cell with a flyback converter and a control circuit including variable current source. Principle of proposed PV cell booster is described at first. Prototype of the booster is built and tested to confirm the effectiveness of the PV cell booster.
In General, the dispersed power supply system is possible to be robust and small compare with centralized power system. In the satellite system, we aim to downsize the power supply system by using the dispersed power system and cooperative control, which is constructed by solar panel and some bi-directional DCDC converters. In this paper, we describe the evaluation results for the behavior of the...
This paper presents an experimental study with a hybrid microgrid system, which is proposed and implemented in the Tagajo campus of Tohoku Gakuin University, Japan. The developed microgrid consists of renewable power generations of PV and wind power generator, two types of energy storage devices of secondary battery and EDLC (Electrical Double-layer Capacitor), together with programmable DC load and...
The purpose of this paper is to show performance characteristics of the reference modification control dc-dc converter which uses neural network and model controls. In the presented method, the neural network controller is used to modify the reference in the proportional control term of the conventional PID control. The neural network controller is repeatedly trained using former predicted data to...
This paper proposed a single-phase three-level inverter that has constant voltage constant frequency (CVCF) operation system. Harmonic analyses with linear and nonlinear loads have been realized to measure the robustness of the proposed technique. It has been shown that the proposed technique has 15% less harmonic distortion and better performance than the conventional inverter for the same load and...
The purpose of this paper is to proposed digital controlled integral gain switchover method dc-dc converter. The integral coefficient changes for the continuous current mode(CCM) and discontinuous current mode(DCM). The integral coefficient is changed by the reactor current detection. The integral coefficient changes in the CCM using the average value of reactor current. It is confirmed that the regulation...
Renewable energy and high energy efficiency are big challenges today and for the future in research and development. While more than 55 % of the whole generated electric energy is used in electrical drives, lighting systems are not negligible and need up to 20 % (according to the Department of Energy in the USA even 22 %) of power going into the grid. This amount can be reduced by more than 25 % by...
In this paper fuzzy compensator controller is proposed in order to improve dynamic stability of grid connected converter through LC filter. The fuzzy logic technique is used to regulate the parameters of PI controller by injected gain compensator according to deviation of grid voltage. Linear block model of the grid connected converter system is also developed to obtain dynamic response fast and easily...
This paper presents a simple control strategy for a variable speed wind energy conversion system with a permanent magnet synchronous generator (PMSG). PMSG is connected to the grid through a switch mode rectifier and a voltage source inverter. The grid should be supplied by certain levels of powers for certain times from wind energy system according to a certain schedule. Batteries bank is connected...
This paper describes a simple grid current control method for the grid-connected operation, and inverter voltage control method based on the phase locked loop (PLL) for the intentional islanding operation at the three-phase grid-connected inverter. The PLL controller based on the pq theory with a simple P-controller is used to synchronize the phase of inverter output voltage with a grid voltage at...
In this paper, a novel single-stage parallel topology power circuit is presented. It can be used in LED street lights for widely power range, from 80 W to 300 W. This topology contains two control methods. One is the constant-voltage feedback, and the other is the constant-current feedback. With this design, this power circuit can provide LED a stable constant current. Besides good stability in linear...
This paper presents a new fast response digitally controlled full bridge converter which combines the fast proportional-differential control with the FIR filter. In the proposed method, the sample timing for proportional-differential control is contrived. Thus, the delay time for proportional-differential control is minimized. The FIR filter is used in order to minimize the steady-state-errors. It...
In East Japan Railway Company, photovoltaics equipment has so far been introduced. However, these had the small scale and needed to consider the effective use at the time of introducing on a large scale. Then, even when large-scale introduction of the photovoltaics was carried out, efficient control of the power distribution system was considered that power generation electric power should be utilized...
Telecommunication and data centers are moving to greener technology to minimize operating costs and lessen environmental impact. Ultimately, the networking and computing loads in these applications are DC rather than AC, and many renewable energy sources develop DC power as well. Energy storage systems are also DC, such as those required for Uninterruptable Power Supplies (UPS), as well as those needed...
This paper presents a mathematical analysis of a medium scale Photovoltaic (PV) power generation system connected to the distribution network and of its control system, in which the conversion stage is unique thanks to the absence of a boost chopper. Boost choppers are usually used as actuator for maximum power point tracking (MPPT). The conducted analysis leads to the conclusion that the used inverter...
This paper presents a new control technique for a digitally controlled buck converter. In the proposed method predictive PID control is employed in order to improve transient response and margin of stability. The application of the proposed method is demonstrated for the prototype buck converter. The frequency response is discussed and the transient response is examined to confirm the performance...
This paper presents a real time operation of tap changing transformers and converters interfaced with distributed generators (DGs) in unbalanced three-phase distribution systems. The unbalanced three-phase power flow equations are solved using Newton Raphson method, and the three phase elements models are considered. Since the renewable energies are attracting worldwide attention, the DGs considered...
One of the most promising technologies for the non-carbon based electricity production is solar photovoltaics. Novel power electronics devices and converters together with new control concepts in the frame of “green electronics” are necessary. For a novel buck-boost converter two controls that make it possible to control the mean value of the output voltage, this is e.g. the voltage across a DC machine...
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