基于合理调压下自动电压控制系统控制质量分析与治理方案研究

随着用户对电网电能质量要求日益严格和自动电压控制系统(Automatic Voltage Control,AVC)控制质量问题的不断暴露,迫切需要对AVC控制质量进行有效的分析。结合江西电网,提出了AVC控制质量评估方法并给出了综合的治理方案。首先基于MATLAB建立了江西某变电站等效电网模型,验证了模型准确性和控制策略与AVC的一致性。针对AVC控制质量不高的情况,分析了降低AVC频繁控制次数、提高AVC控制成功率等治理措施。在实际应用中验证了治理措施的有效性和准确度,为AVC控制质量综合治理提供理论及措施参考。

Controlled Remote Preparation of a Two-Qubit State via an Asymmetric Quantum Channel

I present a new scheme for probabilistic remote preparation of a general two-qubit state from a sender to either of two receivers.The quantum channel is composed of a partial entangled tripartite Greenberger-Horne-Zeilinger (GHZ) state and a W-type state.I try to realize the remote two-qubit preparation by using the usual projective measurement and the method of positive operator-valued measure,respectively.The corresponding success probabilities of the scheme with different methods as well as the total classical communication cost required in this scheme are also calculated.

Controlled Teleportation of Two-Partic le Entanglement via a Cluster State

In order to teleport an unknown two-par-ticle entangled state via a cluster state, a controlled teleportation schelre is proposed. It is shown that an unknown two-particle entangled state can be successfully transmitted from the sender Alice to the receiver Bob with the help of the supervisor Charlie via the only one four-particle cluster state. The receiver can reconstruct the teleported state according to the lmasurement results of the sender and supervisor. Quantum Controlled-NOT （CNOT） gate and POVM are used, which have been accom-plished in a quantum experiment, so it is believed that this scheme will be realized by experirnent. By analysis, the success probability of the proposed scheme reaches 1.0.

Generating W State with Qubits of Superconducting Quantum Interference Devices via Adiabatic Passage

A scheme is proposed to generate W state with qubits of superconducting quantum interference devices （SQUIDs）, based on adiabatic passage along dark state. Taking advantages of adiabatic passage, the scheme is very robust against decoherence, and it does not need to control the classical field and the interaction time accurately. Because of the achievable strong coupling between SQUID qubits and cavity, W state can be generated with high successful probability.

Design of remote ultrasonic signal generating system based on Kinetis60 and AD9951

A kind of remote ultrasonic generating system is designed in this paper.Microcontroller unit(MCU)Kinetis60and direct digital synthesizer(DDS)AD9951constitute the core section of this ultrasonic generating terminal in this system.A friendly and easy-operating host computer software is contrived to control the terminal to generate sinusoidal,rectangular and triangular waveform with variable frequency,amplitude and phase through ZigBee wireless transmission protocol.In order to enhance the practical driving ability,this system also includes power amplifier circuit and transformer matching design,which enable the ultrasonic generating terminal to output enough power for applying to different types of ultrasonic energy convertors.Through experimental verification,the host computer can precisely and swiftly control the ultrasonic generating terminal to generate the above three waveforms with variable wave elements.Oscilloscope is used to verify the terminal output performance of this remote system.

Research on Program-controlled Power Source Based on DDS

Direct Digital Synthesis （DDS） chip was used in the design of program controlled power source in this paper. With the accurate control of Dual DDS chips by Micro Controller Unit （MCU）, illter and power amplifier, this power source can generate voltage and corrent output with variable frequency, amplitude and phase. There are several advantages of this power source such as high power, high accuiracy, output stable, light and conveaient.

Probabilistically Controlled Teleportation of an Arbitrary Two-Qubit State via Positive Operator-Valued Measure

We propose a tripartite scheme for probabilistically teleporting an arbitrary two-qubit state with a fourqubit cluster-class state and a Bell-class state as the quantum channels. In the scheme, the sender and the controller make Bell-state measurements (BSMs) on their respective qubit pairs. With their measurement results, the receiver can reconstruct the original state probabilistically by introducing two auxiliary particles and making appropriate unitary operations and positive operator-valued measure (POVM) instead of usual projective measurement. Moreover, the total success probability and classical communication cost of the present protocol are also worked out.

First experimental demonstration of an exact quantum search algorithm in nuclear magnetic resonance system

The success probability of searching an objective item from an unsorted database using standard Grover's algorithm is usually not exactly 1. It is exactly 1 only when it is used to find the target state from a database with four items. Exact search is always important in theoretical and practical applications. The failure rate of Grover's algorithm becomes big when the database is small, and this hinders the use of the commonly used divide-and-verify strategy. Even for large database, the failure rate becomes considerably large when there are many marked items. This has put a serious limitation on the usability of the Grover's algorithm. An important improved version of the Grover's algorithm, also known as the improved Grover algorithm, solves this problem. The improved Grover algorithm searches arbitrary number of target states from an unsorted database with full success rate. Here, we give the first experimental realization of the improved Grover algorithm, which finds a marked state with certainty, in a nuclear magnetic resonance system. The optimal control theory is used to obtain an optimized control sequence. The experimental results agree well with the theoretical predictions.

A game-theoretic method for prediction of microgrid growing trends in China

This paper presents a game-theoretic method to predict microgrid(MG) development tendency in China. As many distribution generators(DGs) are integrated in distribution systems, analysis of MG formation necessity is conducted from the aspect of DGs. In order to maximize the profit brought by DGs and to earn money from arbitrage, it may be necessary for customers to combine their DGs and loads and to construct an MG to obtain maximal control ability. A game model is built to emulate trading between MGs and the distribution system based on MG power control, in which both trading profit and outage cost are considered for each MG. Nash equilibrium(NE) is calculated, and sensitivities of NE to some boundary conditions are studied. The results show that variable MG trading prices with appropriate net generation cost(i.e., DG generation cost minus government subsidy price) may encourage the growth of MGs. Government subsidies, generation costs, and trading prices may also affect DG use, and therefore they may impact customer motivation to build MGs.