Advanced Materials Research Vols. 765-767

Abstract: The commercial power system simulation software data formats are different.The type of data format conversion is a widespread yet to be solved problem.It is likely to achieve the PSD BPA interface transient model description and develop PSD BPA interface/ODM adapter program due to the improvement and expansion of open data model (ODM),using the adapter to achieve BPA Interface ODM/Inter PSS data conversion,finally verify the development of adapter is correct through IEEE9 node and a practical system conversion thus illustrating the feasibility and convenience of data conversion based on ODM..The development of procedures is open in ODM item and is meaningful to the development of other data formats.

Abstract: When Neutral Point Clamped (NPC) three-level photovoltaic grid-connected inverter is overloaded or in short state, the control by software could not judge immediately, but the power switch components of the inverter would be broken. The technology of Pulse by Pulse is an important method to protect the power switch components. This paper studies the principle of traditional technology of Pulse by Pulse, then analyzes a new technology of Pulse by Pulse based on Complex Programmable Logic Device (CPLD), finally a 3KW NPC three-level grid-connected inverter is set up with the new technology of Pulse by Pulse and the feasibility is demonstrated through the experiments.

Abstract: The paper propose a new control of a three-phase three-level neutral-point-clamped (NPC) pulse width modulated (PWM) inverter in photovoltaic generation systems. The control scheme is mainly based on voltage-oriented control (VOC) with an improved maximum power point (MPP) tracking (MPPT). A cascaded control structure with an outer dc link voltage control loop and an inner current control loop is used. The currents are controlled in a synchronous dq reference frame using a decoupled feedback control. Furthermore, in order to achieve a unity power factor, the q-axis current reference is set to zero. The experimental results have proven an excellent performance and verified the validity of proposed system.

Abstract: The paper proposes a new control of a transformerless singe-stage single-phase grid-connected inverter in photovoltaic generation systems. The control scheme is mainly based on voltage-oriented control (VOC) with help of second order Generalized Integrator (SOGI). A cascaded control structure with an outer dc link voltage control loop and an inner current control loop is used. The currents are controlled in a synchronous dq reference frame using a decoupled feedback control. The simulated results have proven an excellent performance and verified the validity of proposed system.

Abstract: Taking account of the mutual impacts of distributed generation and reactive power, to determine the optimal position and capacity of the compensation device to be installed, the paper proposed an improved Tabu search algorithm for reactive power optimization. The voltage quality is considered of the model using minimum network active power loss as objective Function. It is achieved by maintaining the whole system power loss as minimum thereby reducing cost allocation. On the basis of general Tabu search algorithm, the algorithm used memory guidance search strategy to focus on searching for a local optimum value, avoid a global search blindness. To deal with the neighborhood solution set properly and save algorithm storage space , some corresponding improvements are made, thus, it is easily to stop the iteration of partial optimization and it is more probable to achieve the global optimization by use of the improved algorithm. Simulations are carried out on standard IEEE 33 test system and results are presented.

Abstract: Considering the multi-value mapping resulting status of equipment response event to voltage sag, a lattice ordered evaluation method is proposed. In this method, interval number between the upper and lower possibility of equipment status is used to present its lattice ordered characteristics. Possibility degree matrix is used to compare resulting statuses. Simulation results have shown that this method is accurate, less-sample-dependent and applicative.

Abstract: Making use of Cortex M3 processor, a multi-channel wireless alarm is proposed in this paper (patent number: 201220357699.3). The proposed multi-channel wireless alarm can be used in the place where have a large number and dense monitoring points. In order to realize the target of one receiving unit and many transmitting units, the modules of PT2262/PT2272 and STM32F103RBT6 microcontroller which had Cortex M3 core were used in this system. Compared with the traditional 80C51 microcontroller systems, this design overcome the disadvantage of the IO ports of 80C51 microcontroller which only have the high level and low level stages. This disadvantage make 80C51 microcontroller could not full use the addressing ability of PT2272 address pins which could be high resistance, high level and low level stages, So the design of this paper effectively expanding the number of alarm system monitoring.

Abstract: Aiming at the problem that the generation power of the vibration generator is small, which is based on current electromechanical energy transducer materials, the conventional circuit could not meet the power supply requirement of the load. First of all, the principle of vibration energy harvesting is analyzed. Furthermore, a new vibration energy harvester based on magnetically controlled shape memory alloy (MSMA) is designed, which were introducing to the intelligent power circuit. The vibration energy harvester based on MSMA solved the problem of low electromagnetic signal change and less deformation that based on other intelligent materials. Last but not least, simulation results show that the new intelligent power circuit can harvest the output power and drive the load to work. Comparing with traditional harvesting circuit, it is superior with lower power consumption and higher efficiency of energy conversion and energy harvesting.

Abstract: This paper introduces a dynamic voltage restorer with independent three-phase structure, which is controlled on repetitive control strategy. Computer simulation of the whole repetitive control system is performed by Matlab/Simulink, and the results show that the effect of dynamic compensation can meet the request when voltage sags happened in electric power system.

Abstract: The mechanism of voltage sags due to three main voltage sag sources, such as line faults, startup of large induction motor and transformer energization, was analyzed theoretically. Based on the typical structure of the distribution network of a large industrial enterprise, the paper presented a simplified analytical model for voltage sag sources and conducts a test with the above three kinds of voltage sag sources in Matlab/Simulink. The results show the proposed model is correct and suitable for the analysis of distribution network.