An E-Band SiGe High Efficiency, High Harmonic Suppression Amplifier Multiplier Chain With Wide Temperature Operating Range

2021 ◽  
pp. 1-10
Author(s):  
Peigen Zhou ◽  
Jixin Chen ◽  
Pinpin Yan ◽  
Jiayang Yu ◽  
Debin Hou ◽  
...  
Keyword(s):  
High Efficiency ◽  
High Harmonic ◽  
Harmonic Suppression ◽  
Operating Range ◽  
Temperature Operating

A Compact High-Efficiency Rectifier With a Simple Harmonic Suppression Structure

2020 ◽  
Vol 30 (12) ◽  
pp. 1177-1180
Author(s):  
Zhongqi He ◽  
Hang Lin ◽  
Huacheng Zhu ◽  
Changjun Liu
Keyword(s):  
High Efficiency ◽  
Harmonic Suppression

scholarly journals Optimum State-of-Charge Operating Range for Frequency Regulation of Energy Storage Systems Using a Master–Slave Parallel Genetic Algorithm

Electronics ◽  
2020 ◽  
Vol 9 (8) ◽  
pp. 1298 ◽  
Author(s):  
Sung-Min Cho ◽  
Jae-Chul Kim ◽  
Sang-Yun Yun
Keyword(s):  
Genetic Algorithm ◽  
Lithium Batteries ◽  
High Efficiency ◽  
State Of Charge ◽  
Frequency Regulation ◽  
Parallel Genetic Algorithm ◽  
Calculation Time ◽  
Operating Range ◽  
Computational Performance ◽  
Non Linear

Lithium batteries are used for frequency regulation in power systems because of their fast response and high efficiency. Lithium batteries have different life characteristics depending on their type, and it is necessary to set the optimal state-of-charge (SOC) operating range considering these characteristics to obtain the maximum gain. In general, narrowing the operating range increases the service life but may lower the performance of charging and discharging operations in response to frequency fluctuations, and vice versa. We present performance assessment indicators that consider charging and discharging due to frequency variations and lifespan of the batteries. However, to evaluate the performance, while reflecting the non-linear life characteristics of lithium batteries, simulating the entire operation is necessary, which requires a long calculation time. Therefore, we propose a master–slave parallel genetic algorithm to derive the optimal SOC operating range with reduced calculation time. A simulation program was implemented to evaluate the computational performance that determines the optimal SOC range. The proposed method reduces the calculation time while considering the non-linear life characteristics of lithium batteries. It was confirmed that a more accurate SOC operating range could be calculated by simulating the entire life span.

Design and Performance Analysis of a Supercritical CO2 Centrifugal Compressor With Variable Geometry

2021 ◽  
Author(s):  
Gang Fan ◽  
Kang Chen ◽  
Shaoxiong Zheng ◽  
Yang Du ◽  
Yiping Dai ◽  
...  
Keyword(s):  
Centrifugal Compressor ◽  
Optimization Design ◽  
High Efficiency ◽  
Superior Performance ◽  
Variable Geometry ◽  
Power Cycles ◽  
Operating Range ◽  
Stable Operating ◽  
And Performance ◽  
Geometry Method

Abstract The supercritical carbon dioxide (SCO2) Brayton cycle is one of the most promising power cycles due to its high efficiency, compactness and environmentally friendliness. The centrifugal compressor is a key component of small and medium SCO2 Brayton cycles, and its efficiency has a significant impact on the cycle efficiency. Since the required electric load of power cycles always fluctuates over the year, the SCO2 compressor will operate away from its design point and the narrow stable operating range of a compressor is always a restriction. In this paper, the variable-geometry method, which refers to the combination of a variable inlet-guide-vanes and variable diffuser vanes is proposed for the operating range extension of SCO2 compressors. A set of one-dimensional (1D) loss correlations has been found to accurately predict various losses of the SCO2 compressor components. Based on the 1D thermodynamic model, two programs with internal MATLAB codes coupled with the NIST REFPROP database have been developed for preliminary optimization design and off-design performance predictions of the variable geometry SCO2 compressor. The contributions from the variable-inlet prewhirl and variable diffuser vanes to the shifts of the surge line and choke line are discussed in this paper. The results show the variable-geometry SCO2 compressor has a superior performance at off-design conditions and a wider operating range.

A Low Phase Noise and Low Spurious Frequency Source based on Programmable Frequency Dividers

2014 ◽  
Vol 971-973 ◽  
pp. 310-313
Author(s):  
Chen Liang
Keyword(s):  
Phase Noise ◽  
High Performance ◽  
Low Cost ◽  
High Harmonic ◽  
Phase Detector ◽  
Frequency Resolution ◽  
Harmonic Suppression ◽  
Frequency Dividers ◽  
Frequency Source ◽  
Low Phase Noise

In this paper, based on the programmable frequency dividers HMC394 and AD company's integer PLL chip ADF4107, in the premise of not reducing the phase detector frequency, improved the frequency resolution and effectively inhibits the phase stray. Designed a frequency source with high performance index: high resolution is 10kHz, low phase noise is-91.27dBc/Hz @10kHz, low spurious is less than-60dBc, high harmonic suppression is less than-60dBc,the design method is simple, low cost, flexible control, high performance and widely used.

Development of a Novel Axial Compressor Generation for Industrial Applications: Part 2 — Blade Mechanics

2014 ◽  
Author(s):  
Dirk Anding ◽  
Henning Ressing ◽  
Klaus Hörmeyer ◽  
Roland Pisch ◽  
Kai Ziegler
Keyword(s):  
High Efficiency ◽  
Axial Compressor ◽  
Forced Response ◽  
Operating Conditions ◽  
Strain Gauges ◽  
Blade Design ◽  
Operating Range ◽  
Resonance Frequencies ◽  
Wide Range ◽  
Blade Vibrations

Blade vibrations resulting in alternating stresses are often the critical factor in determining blade life. Indeed, many of the failures experienced by turbomachinery blades occur due to high-cycle fatigue caused by blade vibrations. These vibrations can arise either through self-excited oscillations known as flutter or through aerodynamic forcing of the blades from factors such as periodic wakes from up and/or downstream vanes or unsteady flow phenomena such as compressor surge. The current paper deals with the design and the analytical and experimental verification of the axial blading for a new generation of industrial compressors, a hybrid axial compressor that combines the advantages of conventional industrial compressors — broad operating range and high efficiency — with the advantages of gas turbine compressors — high power-density and high stage pressure ratios. Additionally, the surge robustness of this novel compressor blading has been greatly improved. During the development phase extensive efforts were made to ensure safe operation for future service life. This was achieved by designing blades that will not flutter, do not have high resonance amplitudes throughout their entire operating range and are extremely robust against surge. This strongly increased robustness of the new compressor blading was achieved by the implementation of a “wide-chord” blade design in all rotor blade rows in combination with a proper tuning of resonance frequencies throughout the entire operating range. For the verification of the new blading well-established methods accepted by industry were used such as CFD and FEA. Furthermore, coupling of the two into a method referred to as Fluid Structure Interaction (FSI) was used to more closely investigate the interaction of flow and structural dynamics phenomena. These analytical techniques have been used in conjunction with extensive testing of a scaled test compressor, which was operated at conditions of dynamic similitude (matching of scaled blade vibration frequencies, flow conditions, and Mach number) with full-scale operational conditions. Strain gauges placed on the blades and a state of the art technique known as “tip timing” were used to verify blade vibrations over a wide range of combinations of guide vane positions and rotational speeds. No propensity was found of any of the blades to develop high vibration amplitudes at any of the operating conditions investigated in the rig tests. The comparison of non-linear forced response analyses and the rig test results from strain gauges and tip timing showed close agreement, verifying the analysis techniques used. In conclusion it can be stated that the blade design exhibits a very high level of safety against vibrations within the entire operating range and during surge.

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