斜盘柱塞式液压变压器的流量特性

为分析斜盘柱塞式液压变压器配流噪声高的原因,基于斜盘柱塞式液压元件的工作原理,建立了液压变压器瞬时流量及其流量跳动率的数学模型,并运用MATLAB软件进行了仿真研究。结果表明:模型揭示了斜盘柱塞式液压变压器的流动情况,解释了配流噪声高的原因,为配流盘的设计提供了理论指导。     

基于分数阶PID的液压变压器配流盘控制性能

针对液压变压器流量控制问题, 提出采用分数阶PID控制器对配流盘的位置进行精确控制.针对分数阶PID参数整定复杂性问题, 提出了一种混合时频域性能要求的多目标参数整定策略, 结合一种自适应差分进化算法实现了参数的最优整定, 最后通过数值仿真以考察所提方法.时域分析结果表明:该控制策略明显优于传统的PID、模糊及模糊PID控制策略;频域分析结果表明:该伺服系统具有较强的鲁棒性及稳态保持性.验证了基于分数阶PID控制器实现配流盘位置控制的可行性和优越性.     

油浸式变压器进口油速对绕组热点温度的影响

油浸式变压器主要由铁芯、绕组、绝缘系统和散热器构成,通过改变散热器的位置可以改变油箱进口处的油速,进而影响绕组的热点温度.通过有限元法,建立变压器在不同进口油速时绕组区域温度场与流场的流固耦合模型,分析绕组在不同进口油速时的热点温度变化,并通过光纤温度传感器直接测温实验验证模型的有效性.通过对比不同进口油速时绕组热点温度可知,油速在0.002～0.03 m/s之间,随着油速的增加绕组热点温度降低了3.2 K;在0.03～0.05 m/s之间,随油速增加热点温度降低缓慢,温度降低了0.5 K.     

基于ANSYS软件的油浸式变压器温度场有限元仿真计算

应用传热学和流体力学原理分析了变压器内部生热以及散热机制,建立了流固耦合的变压器温度场有限元分析模型,并在此基础上选取了适当的边界条件及求解参数,在综合考虑非线性热源以及随温度变化的油动力粘度的前提下,采用有限元分析软件ANSYS计算了变压器内部的温度场分布,确定了热点的温度及位置.     

Research on the hydraulic transformer with new distribution pairs

A new distribution pairs of the hydraulic transformer (HT) has been proposed to extend its output pressure range. A common pressure rail (CPR) test-rig was built to test the performance of the HT. The simulation and the test were carried out to explore the output pressure, the displacement and the speed stability of the HT. The research results have shown as follows. Firstly, the designed HT can realize regulating the pressure, and its output pressure is determined by the control angle of the port plate and affected by the load. The ratio of the load pressure (p _B) to the supply pressure (p _A) of the HT varies from 0 to 1.2. Secondly, the HT is a hydraulic component of variable displacement, and the displacement of the every port of the HT depends on the control angle and is not affected by loads. Finally, the speed stability of the HT becomes better with the control angle rising, and the movement zone exists while the control angle is lower than 15°. The high pulsation of the driving torque of the HT results in the poor speed stability. The research will contribute to the improvement of the HT performance in the future. Supported by the National Excellent Young Scientists Fund (Grant No. 50425518) and the National Natural Science Foundation of China (Grant No. 50305032).