Power Matching and Energy Efficiency Improvement of Hydraulic Excavator Driven with Speed and Displacement Variable Power Source

Mobile machinery energy efficiency and emission pollution are the national and worldwide issues. This paper contributes in solving these problems by applying a speed variable power source. Unfortunately, almost all of the speed variable systems have the dynamic response problem when the motor starts with full load or heavy load. To address this problem, a hydraulic accumulator is used to balance the load of the power source for assisting starting of the motor and a matching method combined with speed and displacement control of the pump is proposed to improve the energy efficiency and dynamic performance simultaneously under different working conditions. Also, the power source/valve combined control strategy of an independent metering system is designed to realize flow matching of the whole system. Firstly, a test system is established to study the dynamic performance and energy efficiency of the speed variable power source with an auxiliary accumulator. Working performance and energy consumption of the power source under different rotating speeds and different loads are studied. And then, the hydraulic excavator test rig with the proposed system is constructed. Furthermore, the working performance of the excavator with the speed-fixed and speed-variable strategy are studied comparatively. Results show that, compared with fixed-speed strategy, the electric power consumption during the idle period and partial load condition can be reduced about 2.05 kW and 1.37 kW. The energy efficiency of speed variable power source is about 40%-71%, which is higher than that of the fixed-speed power source by 3%–10%.

Analysis of Power Matching on Energy Savings of a Pneumatic Rotary Actuator Servo-Control System

When saving energy in a pneumatic system,the problem of energy losses is usually solved by reducing the air supply pressure.The power-matching method is applied to optimize the air-supply pressure of the pneumatic system,and the energy-saving effect is verified by experiments.First,the experimental platform of a pneumatic rotary actuator servo-control system is built,and the mechanism of the valve-controlled cylinder system is analyzed.Then,the output power characteristics and load characteristics of the system are derived,and their characteristic curves are drawn.The employed air compressor is considered as a constant-pressure source of a quantitative pump,and the power characteristic of the system is matched.The power source characteristic curve should envelope the output characteristic curve and load characteristic curve.The minimum gas supply pressure obtained by power matching represents the optimal gas supply pressure.The comparative experiments under two different gas supply pressure conditions show that the system under the optimal gas supply pressure can greatly reduce energy losses.

Matched Filter Based Spectrum Sensing When Primary User Has Multiple Power Levels

In this paper,we investigate the matched filter based spectrum sensing in a more reasonable cognitive radio(CR) scenario when the primary user(PU) has more than one transmit power levels,as regulated in most standards,i.e.,IEEE 802.11 Series,GSM,LTE,LTE-A,etc.This new multiple primary transmit power(MPTP) scenario is specialized by two different targets:detecting the presence of PU and identifying the power level.Compared to the traditional binary sensing where only the presence of PU is checked,SU may attain more information about the primary network(making CR more "intelligent") and design the subsequent optimization strategy.The key technology is the multiple hypothesis testing as opposed to the traditional binary hypothesis testing.We discuss two situations under whether the channel phase is known or not,and we derive the closed form solutions for decision regions and several performance metrics,from which some interesting phenomenons are observed and the related discussions are presented.Numerical examples are provided to corroborate the proposed studies.

Study on Matching a 300 MVA Motor Generator with an Ohmic Heating Power Supply in HL-2M

A new 300 MVA/1350 MJ motor generator （MG） will be built to feed all of the poloidal field power supplies （PFPS） and auxiliary heating power supplies of the HL-2M tokamak. The MG has a vertical-shaft salient pole 6-phase synchronous generator and a coaxial 8500 kW induction motor. The Ohmic heating power supply （OHPS） consisting of 4-quadrant DC pulsed convertor is the one with the highest parameters among the PFPS. Therefore, the match between the generator and the OHPS is very important. The matching study with Matlab/Simulink is described in this paper. The simulation results show that the subtransient reactance of the generator is closely related to the inversion operation of the OHPS. By setting various subtransient reactance in the simulation generator model and considering the cost reduction, the optimized parameters are obtained as xd＂ = 0.405 p.u. at 100 Hz for the generator. The models built in the simulation can be used as an important tool for studying the dynamic characteristics and the control strategy of other HL-2M PFPSes.

Matching and Simulation of Power Parameters of Electric Transporter based on Cruise Software

In view of the characteristics of warehouse or freight yard carrying out transfer and loading conditions,the performance parameter matching of the power system of an electric transfer vehicle was studied,and the driving motor and power battery of the key components of the vehicle were reasonably selected.Cruise software was used to simulate the loading process of the vehicle.The results show that the performance design of the power system of the electric transport vehicle and its key components is reasonable,meeting the requirements of maximum speed,climbing performance and starting driving performance,and providing a reference and credible basis for the design of the power system of the vehicle.

Xiangfan Coal-fired Power Plant - a matched large power plant for Three Gorges Project starts to construct

Xiangfan Coal-fired Power Plant, a key energy construction project matched with Three Gorges Project, approved by the State Council. formally started to build in the suburb of Xiangfan City, Hubei Province on November 29, 1996.

燃料电池增程式动力系统能量管理策略研究

以某款纯电动客车为研究对象,以增加车辆续驶里程为目的,提出燃料电池增程式混合动力系统结构,根据性能指标对动力系统各部件进行匹配计算和选型.提出了开关/功率跟随式能量管理策略,基于Cruise和Simulink分别搭建了整车动力系统模型和燃料电池及能量管理策略模型并进行联合仿真.结果表明,采用文中提出的能量管理策略车辆经济性相对于开关式和能量跟随式两种控制策略分别提高62%和31%,续驶里程相对于该两种控制策略分别提高41%和18%.

X-band inverse class-F GaN internally-matched power amplifier

An X-band inverse class-F power amplifier is realized by a 1-mm Al Ga N/Ga N high electron mobility transistor（HEMT）.The intrinsic and parasitic components inside the transistor,especially output capacitor Cds,influence the harmonic impedance heavily at the X-band,so compensation design is used for meeting the harmonic condition of inverse class-F on the current source plane.Experiment results show that,in the continuous-wave mode,the power amplifier achieves 61.7% power added efficiency（PAE）,which is 16.3% higher than the class-AB power amplifier realized by the same kind of HEMT.To the best of our knowledge,this is the first inverse class-F Ga N internally-matched power amplifier,and the PAE is quite high at the X-band.

OPTIMIZATION DESIGN METHOD FOR INPUT IMPEDANCE MATCHING NETWORK OF LOW NOISE AMPLIFIER

According to the theories of optimal noise match and optimal power match, a method for calculating the optimal source impedance of low noise amplifier （LNA） is proposed based on the input reflection coefficient S11. Moreover.with the help of Smith chart, the calculation process is detailed, and the trade-off between the lowest noise figure and the maximum power gain is obtained during the design of LNA input impedance matching network. Based on the Chart 0. 35-μm CMOS process, a traditional cascode LNA circuit is designed and manufactured. Simulation and experimental results have a good agreement with the theoretical analysis, thus proving the correctness of theoretical analysis and the feasibility of the method.

基于深度强化学习的Π型阻抗匹配网络多参数最优求解方法

针对电力线信道阻抗变化复杂、负载阻抗不匹配造成通信质量差等问题,提出一种基于深度强化学习的Π型阻抗匹配网络多参数最优求解方法,并验证分析了深度强化学习对于寻找最优匹配参数的可行性。首先,建立Π型网络结构,推导窄带匹配和宽带匹配场景下的最优匹配目标函数。其次,采用深度强化学习,利用智能体的移动模拟实际匹配网络的元件参数变化,设置含有理论值与最优匹配值参数的公式作为奖励,构建寻优匹配模型。然后,分别仿真验证了窄带匹配和宽带匹配两种应用场景并优化模型的网络参数。最后,仿真结果证明,经过训练后的最优模型运行时间较短且准确度较高,能够较好地自动匹配电力线载波通信负载阻抗变化,改善和提高电力线载波通信质量。

直线加速赛车动力系统匹配设计

以直线加速赛车为研究对象,以赛车的动力性能指标最优为目标,结合直线加速大赛要求,对动力系统主要零件——电动机、电池进行参数计算以及选型,同时计算传动系统参数,完成动力系统参数匹配设计。利用ADVISOR软件对整车的动力性及电池性能进行仿真分析,结果表明各项参数匹配均处于合理的范围内,设计满足要求。

碳纤维烘干容器的中频感应加热设计

在粘胶基碳纤维的脱胶回收过程中需要将碳纤维进行烘干加热并碾磨成粉,整个工作环境中会存在碳纤维粉尘,遇到明火容易产生爆炸,因此提出使用中频感应加热技术取代传统的明火加热对碳纤维进行烘干加热。首先计算310S不锈钢材质筒体容器加热时所需功率及电流等各项参数;根据计算所得数据选择使用COMSOL Multiphysics有限元软件对筒体容器进行加热仿真,验证将中频感应加热技术应用到粘胶基碳纤维脱胶加热工艺中的可行性与计算结果准确性;然后对电源内部谐振电容与变压器等元器件进行匹配;电源装配完成后结合实际应用进行验证。实验结果证明,中频感应加热技术可以满足对粘胶基碳纤维的烘干加热,且相较于传统加热方式,中频感应加热技术在碳纤维加热工艺中更加安全高效。

基于磁耦合谐振的多自由度电机无线电能传输

针对多自由度电机无线电能传输中传输效率较低的问题,提出基于磁耦合谐振的多自由度电机无线电能传输方法。该方法根据共振原理构建磁耦合谐振式无线电能传输模型,通过反射系数描述阻抗匹配状态,获取最佳负载阻抗;采用混沌优化算法优化电机线圈损耗率,实现多自由度电机无线电能传输优化。实验结果表明,应用该方法后,多自由度电机的电能输出功率达到了893 W,传输效率提升了0.10以上,提高了电能输出功率和传输效率,方法有效,具备可行性。

基于PSA的中压电力线载波通信自适应阻抗匹配

在中压电力线通信中,针对复杂电器元件的种类、数量不断变化等因素导致线路阻抗不匹配而影响通信质量的问题,提出了一种中压电力线载波通信自适应阻抗匹配方法。首先,建立了中压阻抗匹配系统模型,在该模型的基础上提出了一种π型自适应阻抗匹配电路。然后,根据该电路设计了符合阻抗共轭匹配原理的目标函数,通过PID搜索算法(PID-based search algorithm, PSA)寻找最优元件参数,实现目标函数最优。最后,在此模型基础上仿真分析了PSA算法、粒子群算法(particle swarm optimization, PSO)和遗传算法(genetic algorithm, GA)的优劣性。结果表明,PSA算法在收敛速度和寻优精度方面优于PSO和GA算法,能够有效实现阻抗匹配进而改善载波通信质量,为中压电力线通信进一步研究提供了可行性方案。

基于谐波控制的Doherty功率放大器设计

功率放大器是无线通信里面重要的射频前端电路。为满足现代无线通信对功率放大器高效率的要求,首先基于谐波控制理论分析,设计了一种新型谐波控制电路,此新型谐波控制电路可对功率管产生的封装寄生参数进行补偿,也可对二次谐波、三次谐波进行谐波控制,提高了Doherty功率放大器效率。随后,针对传统Doherty功率放大器限制带宽的问题,提出了采用后匹配结构的方式设计Doherty功率放大器,提高了Doherty功率放大器的带宽。最后,采用Cree公司的CGH40010F GaN HEMT设计一款Doherty功率放大器并进行测试。在1.85~2.15 GHz工作频带内,Doherty功率放大器输出功率可达到44.3~44.8 dBm,增益为12~15 dB,输出漏极效率(DE)大于75%,6 dB回退效率大于60%。结果表明,提出的Doherty功率放大器在效率方面具有显著优势。

面向装备平台的敏捷交换芯片设计与实现

在构建车载、舰船、航空航天等装备平台网络系统时,需要综合考虑功能、性能、体积、功耗、易用性等制约因素,传统高性能的商用网络交换芯片功耗高、配置和使用复杂,难以满足相关需求。对此提出了一种面向装备平台的可编程、低功耗的敏捷交换芯片架构。该架构引入协议无关的超长内容匹配-动作流水线,提供可编程的转发配置、流限速、报文修改等功能,支持现存各类网络协议及用户自定义协议。架构提供灵活的管理配置模式,可满足远程配置、无管理CPU的轻量化配置等多种应用需求。另外,通过敏捷交换协议的扩展功能,可将查表结果、动作处理记录、用户配置信息等随原报文一同送出芯片,实现单个报文粒度的精细化处理和灵活的功能扩展。基于敏捷交换架构,流片制造了YHHX-DS160敏捷交换芯片,该芯片可提供160 Gbps全接口线速交换能力,最大功耗仅6.6 W,能效比达到24 Gbps/W。

燃料电池汽车动力系统匹配及能量管理

为了分析燃料电池汽车动力系统参数匹配设计以及能量管理方案对整车性能的影响,以某款燃料电池汽车为研究对象,对其主要动力系统部件进行了参数匹配.以提升整车经济性能为目标,提出了功率跟随式能量管理策略和基于模糊控制的能量管理策略,并采用滑动平均滤波算法对模糊控制策略输出量进行优化.基于AVL-Cruise和Simulink建立了联合仿真平台,搭建整车及能量管理系统模型,验证了整车动力性能,对比分析了3种控制策略下的整车经济性能.结果表明:经过优化后的能量管理策略燃料电池输出功率曲线更加平滑,且一直处于高效率输出区间内,基于燃料电池优先保护原则,经过优化后的能量管理策略性能最佳.

一种用于反无人机设备的三频段功率放大器

在现有双频匹配理论的基础上,设计了一种可同时工作在1.5/2.4/5.8 GHz三个频段的射频功率放大器。为满足对抗无人机的实际应用需求,首先匹配2.4 GHz和5.8 GHz两个频率,然后匹配1.5 GHz,并设计相应的三频段输入输出匹配网络,完成了三频段功率放大器整体电路的设计。ADS仿真结果表明,当输入功率为28 dBm时,在三个频段设计的射频功率放大器的输出功率分别为39.88 dBm、40.94 dBm和39.25 dBm,效率分别达到了46.52%、60.54%和39.40%。该功率放大器可应用在基于信号抑制或信号欺骗的反制无人机设备中,提升放大器效率与设备集成度。

一种基于磁阻式线圈的模拟冰雹发射装置设计与仿真

基于光伏板模拟冰雹撞击试验的实际需求,开展了磁阻型线圈发射装置与脉冲功率源之间的匹配性研究。通过理论对续流前置型和续流后置型两种基本脉冲放电电路进行了适用性分析,结果表明,续流前置型脉冲放电电路与发射装置具有更优的匹配性。针对发射过程中剩余脉冲电流的反向制动问题,设计了一种可以快速消除剩余脉冲电流的泄能电路,用于改进续流前置型脉冲放电电路的拓扑结构,进一步提高其适用性,并借助仿真进行验证。结果表明,泄能电路能快速消除剩余脉冲电流的反向拉力影响,使抛体的发射性能显著提高,抛体出口速度相比传统放电电路提升50.8%,系统发射效率提高127.5%。该项研究可为磁阻式线圈发射技术应用在模拟撞击试验领域的研究提供参考。

基于SAR阻抗匹配的WPT最大效率跟踪控制方法

无线电能传输(WPT)技术因其安全、便捷、非接触等优点而备受关注。最大效率传输是WPT系统中一个重要课题。传统的最大效率跟踪方法通常设定系统在固定耦合条件进行负载阻抗匹配,然而,耦合系数会在初级和次级线圈相对位置变化时不可避免地发生变化。提出基于耦合系数辨识与半有源整流(SAR)阻抗匹配的最大效率跟踪控制方法,该方法利用SAR结合耦合系数识别进行阻抗匹配,开关控制电容(SCC)补偿其阻抗虚部,避免了整流电路中非线性因素的影响。同时系统响应较快且控制方法便于实现。仿真和实验结果表明,耦合系数和等效负载变化时,都可以准确估计耦合系数并跟踪至最大效率点和输出恒压。