摘要
Abstract
Usually mechanical shafts are thought to be rigid,actually all shafts are elastic one,in order to transfer torques,they have to be turned through an angle.If their elastic deformation can not to be ignored,it makes the shaft systems become oscillating units and it is possible to cause torsional vibration,many motor shafts had been seriously damaged.A conventional suppressing method for dual-loop adjustable speed drive system is inserting a notch-filter into speed-loop of the system.It is effective but is not convenient to tune.A proposed method was introduced by drawing electrical damping into shaft system through controlling motor torque.Its principle was investigated and it was shown that the dual-loop system can obtain electrical damping via its speed feedback to suppress torsional vihration. Two further enhancing damping methods,installing speed-differential-block and load-observer,were discussed. Stick-slip vibration of gas and oil drillers is happened frequently during drilling.It is the vibration of elastic drill-strings caused by suddenly changing load torque when the friction of drill bit changes from static one to dynamic one and is harmful to driller.The stick-slip vibration belongs to shaft torsional vibration and can be suppressed by electrical damping,but its implementation method is different from usual owing to its very low vibration frequency(<1 Hz)and small speed variation amplitude.关键词
双环系统/轴扭振/电气阻尼/转速微分/负荷观测/钻机黏滑振荡Key words
dual-loop system/shaft torsional vibration/electrical damping/speed-differential-block/load-observer/stick-slip vibration of driller分类
信息技术与安全科学
