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To solve the problems of rotor flux field orientation loss and operation performance degradation caused by neglecting iron loss in the conventional vector control system, a new vector control strategy based on iron loss model of induction motor (IM) is proposed in this paper. In this strategy, a slip-type indirect field oriented vector control (IFOC) is designed by setting the magnetizing currents...
Common mode current suppression is important to grid-connected photovoltaic (PV) systems and depends strongly on the value of the parasitic capacitance between the PV panel and the ground. Some papers address that the parasitic capacitance of PV panel becomes larger in the humid environment. However, they do not give detailed explanation, and some give confusing address. This paper presents clarified...
The resonant stability problems of LCL filter have become big challenges for grid-connected inverter in weak grid. This paper takes the effect of non-minimum phase time delay on the ratio between resonance frequency and sampling frequency into account and use it to design the LCL filter. Both LCL resonance frequency and inverter-side inductor and filter capacitor related L1C resonance frequency are...
The performance of interior permanent magnet synchronous motor (IPMSM) drive system is affected by parameters variation and digital control delay, which increases the difficulty and complexity of analyzing and designing, a visualization technique is proposed in discrete time domain. First of all, D-partition method is used to obtain stable region of IPMSM current loop, while the sampling & computation...
Open-end winding induction motor can be powered by double inverters at both ends. Comparing with conventional single-ended inverter induction motor drive, this new configuration produces some advantages, such as high error tolerance capability, high flexibility, and low DC voltage rating, and so on. Under single DC power supply however, the zero-sequence currents may be produced by the common mode...
With the development of renewable energy, the influence of photovoltaic power plant on power grid is increasing. In order to study the influence of large-scale photovoltaic power plant on power system, it is necessary to establish a centralized equivalent model of large-scale photovoltaic power plant composed of many power generation units to avoid the problem that simulation time is too long. In...
For interior permanent magnet synchronous motor (IPMSM) drives, high-frequency (HF) rotating voltage signal injection method is widely employed to estimate the initial rotor position. However, conventional demodulation method based on current phase is complex and susceptible to filters and digital control delays, an amplitude demodulation algorithm is proposed in this paper. With the proposed method,...
Understanding user behavior is essential for source optimization in mobile networks, including urban planning, road traffic engineering, and content distribution. In this paper, we take the first step to investigate the basic characterization of user behavior over 340,000 users of a 4G mobile network in a large metropolitan area. Our study is carried on from two aspects: mobility and application usage...
An amplified feedback DFB laser with extended modulation bandwidth is experimentally demonstrated in this paper. All the three sections of laser cavity, including DFB section, phase section and amplified feedback section, have the same active layer, which can avoid the butt-joint re-growth process. The gratings in both DFB section and amplified feedback section are fabricated by the Reconstruction...
To study the impact on stability and security of the power grid that large-scale Photovoltaic (PV) generation systems integrated, the need for new models and simulation methods is increasing. Firstly, in this paper, a novel simplified phasor model is proposed based on the description of common detail model and averaged model for the PV generation system. The structure of the simplified phasor model...
High frequency (HF) signal injection scheme is widely used to estimate the initial rotor position of Interior Permanent Magnet Synchronous Motors (IPMSM). The accuracy of the estimated rotor position, however, may be degraded by the phase delay caused by pulse width modulation (PWM), digital filters in signal demodulation process, non- ideality of inverter, and so on. To solve this problem, the main...
Electromagnetic torque can be used to form a model reference adaptive system (MRAS) to achieve online identification of rotor time constant in an induction motor drive. The steady-state torque error caused by rotor time constant error is established in this paper. Based on the steady-state analysis, the converging relationship in the MRAS is found out to be lost for some operating points. Then the...
An adaptive sliding-mode observer is proposed in this paper to update the rotor resistance in indirect field oriented controlled induction motor drives. Although the observer is implemented in stationary reference frame, the design and theory analysis are made in the rotor-field oriented reference frame. Through coordinate transformation, the essence of the sliding- mode manifold and the theory foundation...
The current static analysis approaches for detecting stack overflow vulnerabilities in binaries are only usable to the functions in system libraries and not suitable for user defined functions. In this paper, we model the characteristic of stack overflow vulnerabilities and propose a static taint analysis method, which can recognize user defined functions that may have that type of vulnerabilities...
The proliferation of affordable virtual reality (VR) head mounted displays (HMD) provides users with realistic immersive visual experiences. However, HMDs occlude upper half of a user's face and prevent the facial action recognition from the entire face. Therefore, entire face cannot be used as a source of feedback for more interactive virtual reality applications. To tackle this problem, we propose...
Base station (BS) sleeping operation in transient process has been widely analyzed in current studies to save cellular network energy consumption. In this paper, we propose a hysteretic BS sleeping strategy in 5G cellular network. The BS adjusts its transmitting power to adapt to the traffic load in active state, and frequently goes to sleep state and keeps sleeping until N requests assembled. When...
Rotor time constant is a key parameter in an induction motor drive with indirect field oriented control. In this paper, a modified Model Reference Adaptive Controller (MRAC) utilizing d-axis stator voltage is proposed for online updating of rotor time constant. Compared with the traditional d-axis voltage model, the information of torque current and stator frequency is incorporated into the adaptive...
A multiterminal Energy Interconnection System Based on MMC was developed, which connected active sub-modules, DC grids and AC grids. However, the power imbalance of the active sub-modules exists in this system, for example, inconsistent maximum power points of the PV panels will lead to system power loss. In order to solve the problem, this paper first presents a power control scheme between the three-terminals,...
In this work, HfO2 based resistive random access memory (RRAM) is fabricated and 3-bit storage capacity per cell is demonstrated under both DC and AC mode. In the AC mode, a new operation scheme of balancing set process and reset process is proposed to improve the resistance distribution uniformity (relative standard deviation about 21.1%). The relatives between set and reset parameters are also discussed...
A highly compact and low power consumption neuromorphic circuit with digital control signals which achieves the functional properties of biological neuron and synapse is proposed in this paper. The excitatory or inhibitory synapse could convert pre-synaptic spikes to current to charge or discharge the neuron. During the presence of the post-synaptic current (PSC), the ring oscillator (RO) based neuron...
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