谐振状态

This paper proposes a generalized averaging method for modeling resonant inverter applied to electronic ballast.

摘 要：提出了用广义的状态空间平均法建立电子镇流器谐振逆变器数学模型的方法。

A new control method proposed to control the half bridge inverter to supply the lamp with low square wave current.

这种新型的控制方法使灯工作于400Hz的低频方波工作状态，保证不出现声谐振的发生。

The effect of tribology factors on bearing vibration is studied experimentally. AR model and WPT are used to processing the normal arid abnormal signals. The results are as follows:1. The vibration of ball bearings is caused by the tribology action of contact pairs of ball and ring races and has the essential of tribo-dynamics. Any factors affecting the tribology characteristics of contact pairs will affect vibration and noise of bearings consequently.2. Vibration characteristics of bearing keep almostly unchanged with the increasing of axial load expecting the increasing of nature frequencies. When radial load increasing with axial load unchanged, nature frequencies keep unchanged but some new vibration peaks appears in the spectrum.3. Vibration amplitudes are damped and nature frequency are enhanced with sufficient lubrication. Vibration and noise of bearings increase obviously and roar can happen and the contact surfaces scratch slightly under insufficient and unclean lubrication state. Bearing will be disabled in a few minutes without any lubrication.4. Bearing vibration is unstable under low speed. With the speed increasing, the vibration become stable and natural frequencies increase slightly but the amplitudes increase apparently.5. Bearing vibration can be excited only by some harmonics ofwaviness without lubrication and by all harmonics with lubrication based on the theoretical analysis.6. The nature frequencies of ball bearings decrease with the increasing sizes. When international clearance increasing, nature frequencies decrease in radial and increase in axial and angular and the amplitudes increase in radial and decrease in axial and angular. When the number of balls increasing, nature frequencies increase and amplitudes decrease. When the pitch diameter increasing, axial nature frequency increase and others nearly keep no change. When outer race groove curvature radius increasing, nature frequencies increase in radial and decrease in axial and angular and amplitudes keep no change in radial and increase in axial and angular. When inner race groove curvature radius increasing, nature frequencies decrease and amplitudes increase.7. The distortion in amplitude and frequency components of bearing vibration signals picked up by the present probe measurement method is founded and right conclusions cannot be achieved by the signals. When accelerometer is rigidly screwed with steel stud onto a flat outer surface of a ball bearing, vibration signal can be got without distortion and the reliability of research on bearing vibration is assured.8. AR model is suitable for large samples of bearing vibration signals, square root of length of samples can be used as the upper limitation of order determination and the FPE order selection criterion is effective. Many advantages of AR spectrum are founded over the classical based on FFT.9. Time-Frequency analysis is necessary for abnormal noise of ball bearings. WPT overcomes the principle shortcomings of STFT and proved to be a best tool to process the abnormal signals.

理论分析和试验研究表明： 1球轴承振动是钢球—滚道接触副中的各种摩擦学作用引起的，具有摩擦动力学的本质，任何对接触副的摩擦学特性有影响的因素都将对球轴承的振动和噪声特性产生影响； 2中心轴向载荷作用下，载荷增大使球轴承的固有振动频率升高，载荷越大同样的载荷增幅引起的频率升幅减小，足够大的中心轴向载荷作用下载荷的变化对球轴承振动的频率特性不会产生明显的影响； 3轴向和径向联合载荷作用下，径向载荷不大时球轴承振动的固有频率基本不变，但是可能引起变刚度激励的非线性振动，出现新的频峰，过大的径向载荷将使部分钢球脱离接触，使球轴承的振动和噪声呈现不稳定状态； 4润滑对球轴承的振动和噪声特性有重要的影响，良好的润滑对振动有明显的抑制作用，润滑不充分时，振动和噪声的水平会有明显增高，一定条件下还会激发接触副中的谐振，发出啸声，造成接触表面的伤害，无润滑干接触时，短时的运转就会损伤接触副表面，使振动和噪声迅速增大，并随时可能引发严重的磨损和卡滞失效；接触副润滑良好时，油膜的"刚化效应"使球轴承振动的固有频率有所提高，润滑剂中含有弥散性污浊时，振动的幅度总体升高，但弥散性污浊不会改变球轴承振动的频率特性；浙江大学博士学位论文：球轴承振动的研究 5低速时，球轴承振动的基本特征呈现不稳定状态，随着转速的提高，球轴承振动的频率特性趋于稳定，固有频率频峰升高； 6理论分析表明，干接触时钢球和滚道表面波纹度的某些谐波分量能激励球轴承的振动，振动的幅值与谐波幅值成正比，实际球轴承中钢球的分布不可能完全均匀，波纹度的激励作用会随时发生；润滑接触的分析表明，波纹度的任意谐波分量均能激励球轴承的振动； 7球轴承的几何和结构参数分析表明，球轴承尺寸越大，径向、轴向和角振动的固有频率越低；钢球中心圆直径增大，球轴承的径向和轴向振动的固有频率基本不变，角振动的固有频率有所上升，振动的幅频特性基本不变；径向游隙加大使球轴承的径向振动固有频率降低，轴向和角振动的固有频率有所升高，径向振动幅频特性的幅值升高，而轴向和角向降低；钢球的数量增多使球轴承振动的固有频率上升，幅频特性的幅值下降，径向振动的幅值下降最为明显；外圈沟曲率半径系数增大使球轴承径向振动的固有频率升高，轴向和角振动的固有频率降低，径向幅频特性基本不变，轴向和角向幅频特性幅值升高；内圈沟曲率半径系数增大使径向、轴向和角振动固有频率均下降，振动幅频特性的幅值均有升高； 8试验对比表明，传感器采用探针式安装时，由于探针接触副接触特性的影响，钡(量得到的球轴承振动信号有失真，采用专门设计和制作的试验球轴承，以固定式安装加速度计，首次测量得到了球轴承振动的真实信号，通过对振动信号的分析，验证了球轴承振动的理论模型； 9)基于时间序列分析的AR模型适用于大样本球轴承振动信号的分析，以样本长度的均方根值作定阶上界，FPE做判阶准则，给出的AR谱光滑，频率分辨率高，是球轴承振动分析的简便而可靠的手段； 10以时频域分析的小波包变换分析球轴承异音信号能够比较好地定位和聚焦异音发生的时间，时间间隔，频率范围，同样是球轴承振动分析的可靠的手段，可用作球轴承故障诊断技术。

Switching power amplifier of magnetic bearing worked in hard switching. To overcome drawbacks of large loss of switching and current harmonic distortion, a parallel resonant DC link soft-switching power amplifier was adopted in this paper.

为克服磁悬浮轴承开关功率放大器工作在硬开关状态时存在的开关损耗和电流纹波干扰严重的缺点，提出一种磁悬浮轴承并联谐振直流环节的软开关功率放大器电路。

It includes high power high voltage constant-current-charging system, capacitors bank, discharge control system, power supply of preignition for Xe-flashlamps, general control and diagnostic system. The power conditioning system drives flashlamps that pump the SSHCL. Flashlamps are driven by high voltage Silicon Controlled Rectifiers switched, resonant charged, discharge pulse forming network. The system uses microchip and digital circle which is based on CAN-bus for control and diagnostics. Energy diagnosis and thermal management are controlled by computers.

其中大功率高压恒流充电装置采用了L-C串联谐振电路，充电功率大，效率较高；储能装置采用了多节脉冲成形网络，可产生波形良好的强电流放电脉冲；放电控制装置采用高压大功率晶闸管，开关速度快，工作稳定；预燃与触发装置采用了开关电源电路，效率高、功耗小；总控与测量装置采用基于CAN总线的数字电路和单片机技术，控制冷却系统在激光器出光时对脉冲氙灯进行水冷，并对全系统进行控制和状态检测，同时具有过压、过流、过热等保护功能。

Plate and λ/2 plate were placed inside the Nd∶YVO4KTP green laser cavity with angle 90°between their fast axis.The composite plate composed of HWP,QWP and KTP has the function of QWP.The composite plate with Nd∶YVO4 can effectively suppress the coupling of polarized modes,and multi-longitudinal-mode lownoise green laser was obtained.Since the composite plate counteracted the phase shift induced by temperature sensitivity of quartz plate,the green laser operated with lownoise reliability in different output power and different operation temperature.The threelongitudinalmode, the noise of less than 0.5% and output power stability of less then 1% for 12 hour are obtained in the green laser.

介绍了一种LD泵浦腔内倍频全固体Nd∶YVO4KTP多纵模、低噪音、高功率稳定绿激光器在Nd∶YVO4KTP绿激光器组成的谐振腔内放置厚度约相等的石英晶体λ2波片和λ4波片，使两波片快轴夹角互呈90°，HWP、QWP与KTP构成复合波片，其作用相当于QWP，此复合波法与各相异性Nd∶YVO4共同作用有效抑制了腔内偏振模耦合，获得多纵模低噪音绿光输出此复合波片相互作用由于抵消了石英晶体波片温度敏感引起的相位延迟量漂移，所以此激光器在不同功率、不同工作温度下，均能稳定可靠地运转于低噪音状态实验结果为，绿光输出纵模数为3个，噪音小于0.5%，12 h功率稳定性优小于1

Afterwards, a novel control strategy is put forward. A Swept-frequency with separate and self-excitation switching is applied in starting circuit, which can look for resonant point automatically.

然后，提出一种新型的逆变控制策略，启动电路采用扫频方式自动找寻负载谐振工作点；工作状态控制采用锁相环技术和重叠角随动控制相结合的方法。

During the testing process, the circuit use the on-off power supply's pull and push structure as prototype, gaining a additional LC in series resonance circuit, which is also a opposite sharp structure. In the same frequency,and in the work state of work voltage, receiving even more high efficiency and output power.

该电路在实验过程中以开关电源推挽式结构为原型，改进得到一个附加了LC串联谐振回路的反激式结构，在同等工作频率、工作电压的状态下，得到了比推挽式结构更高的效率和输出功率。

The operation condition of a series-resonant converter is equivalently analyzed under open-loop condition. OCC condition and selection basis of resonant parameter and switching frequency are determined. The relationships between LED number, transformer turns ratio and constant current error are also determined, which provide scientific basis for the selection of LED number and transformer turns ratio.

文中通过对串联谐振变换器开环工作状态的等效分析，确定开环恒流条件和谐振参数与开关频率的选择依据，以及LED数目、变压器变比与恒流误差之间的关系，为LED数目及变压器变比的优化选择奠定了理论基础。

Soft switching can improve the converters efficiency and reduce EMI. In comparison of some methods of approaching soft switching, this thesis presents a Diode Auxiliary Resonant Commutating Network which is composed by an auxiliary bridge and a resonant commutating inductor. This topology not only well realizes zero voltage switching, but also overcomes the parasitic oscillation in the secondary side Diodes. Simultaneously, this topology makes both the secondary side diodes and auxiliary diodes operate on the soft switching state too, which reduces more switching losses and provides requirement for the system to run stably under the condition of self-cooled.

软开关能够提高变换器的效率和降低EMI，通过比较目前多种实现软开关技术方案，本文研究了一种由辅助桥臂和谐振电感组成的二极管辅助谐振换流网络，不但很好地实现了ZVS，并且克服了副边二极管上寄生振荡；同时，该拓扑也使副边二极管和辅助二极管都工作于软开关状态，进一步降低了开关损耗，为系统能够在自冷的条件下稳定运行创造了条件。

On the other hand, the more important thing is because the urban housing is a kind of heterogeneity products.

另一方面，更重要的是由于城市住房是一种异质性产品。

Climate histogram is the fall that collects place measure calm value, cent serves as cross axle for a few equal interval, the area that the frequency that the value appears according to place is accumulated and becomes will be determined inside each interval, discharge the graph that rise with post, also be called histogram.

气候直方图是将所收集的降水量测定值，分为几个相等的区间作为横轴，并将各区间内所测定值依所出现的次数累积而成的面积，用柱子排起来的图形，也叫做柱状图。