Advanced Materials Research Vols. 960-961

Abstract: According to the requirements on multiport and power flow in the application of renewable energy, a novel multiport converter based on magnetic coupling is proposed in this paper. This multiple converter is capable of charging and discharging the battery while supplying the load. Theoretical method for the analysis of a three-port converter based on magnetic coupling is presented. The principle of the control loop for the converter is given that the maximum power point tracking (MPPT) is applied for the Photovoltaic (PV) part and the independent control is for the power flow part respectively. In addition, this proposed control method is also available for multiple modules. The simulation model is built by Simplorer-Matlab software and the simulated results demonstrate that this proposed converter can realize the power distribution very well. The control strategy proposed is of great isolation and low mutual interference between different ports so that the converter can reliably operate.

Abstract: This paper presents a perturbation based method for small-signal stability analysis in microgrid based on the uncertainty of microgrid parameters. The small-signal state-space model is built including the dynamic characteristics of the controllers, the power measurement and the system circuit and load dynamics model. The system eigenvalues of operating point at a steady-state in microgrid are obtained by the model. Based on perturbation theory, the corresponding low-frequency eigenvaluea and damping ratio of the microgrid system are calculated when the microgrid parameters changing in the range. Then the relationship between small-signal frequency stability and parameters changes can be determined. The validity of the proposed method and the importance of the stablility analysis of the microgrid small-signal are proved by the simulation results.

Abstract: The electron beam welding has high energy density, and has been widely applied in air space, the car and shipping industry. Traditional electron beam welding machine power supply system adopts the technology of the power frequency or medium frequency, with high volume, low efficiency and poor stability of electron beam. I put forward a digital filament power control scheme based on STM32, and introduce the hardware and software implementation method in detail. Experiments show that it can realize soft-start and soft-down process, and also be quickly identified and promptly forbid the output when filament fracture, which realize the intellectualization of filament power supply.

Abstract: Aiming at simplifying the structure of power supply system of new energy, a buck-boost integrated type three-port converter is designed in this paper. The three-port converter can replace three separate converters, which makes the system structure is simplified and manufacturing cost is reduced. The three-port converter realizes the current expansion and ripple suppression by adopting inductor interleaved parallel bridge arm structure. The topology and control strategy of the three-port converter are analyzed in this paper. From the experimental results, the inductor current ripple and realization of soft switch meet the design requirement. The buck-boost integrated type three-port converter is applicable to the new energy power supply system.

Abstract: This paper introduces the power line communications channel estimation method based on sparse Bayesian regression, it is through the use of Bayesian learning framework that provides a sparse model in the presence of noise accurate channel estimation model. Improved channel estimation using the power line for the system to consider the frequency domain equalization (FREQ) transmitter and receiver, the bit error rate and comparing the two methods for generating various channel estimation techniques, and (BER) performance curves simulation the results show that the performance of the method is better than the previous method of least squares technique.

Abstract: Based on the basic principles of anti-islanding detection, this paper puts forward an anti-islanding (AI) detection method which combined/q-axis voltage decoupling and positive feedback with Euler-Lagrange (EL) model .The proposed method is classified as an passive islanding detection method and it is based on the voltage change at the point of common coupling (PCC) that occurs in islanding .In the method, Add the d-axis decoupling voltage of PCC to the d-axis reference current of the EL model. A simulation study shows that the method is simple and feasible.

Abstract: Due to the perturbation between multiple PV Grid-connected power system can’t be synchronized easily, the islanding detection often lose efficacy when multiple PV Grid-connected inverters are running simultaneously. The paper show the in-depth analysis of the principle and the advantages and disadvantages of the detection method of AFDPF and SMS, a composition controller is designed aim at the non-detection zone in multiple PV Grid-connected system in the practical application. Through the software simulation, it shows that the method mentioned in the paper practically improves the effect of the islanding detection.

Abstract: The paper introduces the structure of locomotive energy consumption monitoring system, technical parameters and the method of software design. The system uses electric energy metering chip CS5463, ARM kernel STM32F103R8T6, GPRS wireless communication module and RS485 communication interface to realize the multi-system locomotive AC and DC measurement, remote meter reading and other devices and locomotive communication connection. The liquid crystal display LCD stores the locomotive power information, the current, voltage, power and energy data with their own real-time clock time-sharing data fragmentation such as type test on the system, the system of high precision, strong anti-interference ability, low power consumption, safety etc.

Abstract: By analyzing the control principle of power system stabilizer (PSS),shows that the robustness of PPS is not ideal. Using the methods of state-space pole placement designed the governor-side power system stabilizer GPSS,and built a simplified model of the power system with simulink. The simulation experiment results made ​​in the MATLAB shows that GPSS has good inhibitory effect of low-frequency oscillations.

Abstract: As a member of Electroactive Polymers (EAPs), dielectric elastomer (DE) has shown considerable potential for energy harvesting applications. After the basic principle of DE energy harvesting is studied, a multi-layer DE generator using VHB 4910 (3M, USA) is specially designed and fabricated. Then, an improved energy harvesting circuit is designed to make use of harvested electrical energy. Finally, energy harvesting experiments are implemented under the constant charge (open-circuit) condition and the results prove that the multi-layer DE generator fabricated can produce enough energy to constantly drive a light emitting diode. The harvested electrical energy has good consistent with generated electrical energy and the maximum energy harvesting efficiency ηh can reach 89%.