为解决风机受谐波干扰引起电压畸变和频率波动从而影响风机并网稳定运行的问题,提出频率自适应锁相方法,以谐波提取电路为基础,设计具有滤除风机谐波功能的NSOGI (new second-order generalized integrator)锁相环。首先,在谐波提取电...为解决风机受谐波干扰引起电压畸变和频率波动从而影响风机并网稳定运行的问题,提出频率自适应锁相方法,以谐波提取电路为基础,设计具有滤除风机谐波功能的NSOGI (new second-order generalized integrator)锁相环。首先,在谐波提取电路中加入基波谐振电路,验证谐波提取前后锁相环的锁频精度;其次,在传统锁相环基础上加入直流抑制器,对输入信号的频率进行跟踪;最后,进行理论和仿真分析,对比DSOGI-FLL谐波提取前后电路中的频率偏差,验证2种锁相环的锁频精度。结果表明:在谐波提取电路中加入基波谐振电路,减少了谐波对基波源的影响,提升了谐波提取的效果;在抑制风机电压畸变和直流谐波方面,NSOGI锁相环效果较好,锁频精度较高,验证了方法的可行性和正确性。采用NSOGI对电压和频率进行控制,能够提升供电可靠性,改善并网电能质量,为风机并网稳定运行提供了理论参考。展开更多
Incipient faults of gears and rolling bearings in rotating machineries are very difficult to identify using traditional envelope analysis methods.To address this challenge,this paper proposes an effective local spectr...Incipient faults of gears and rolling bearings in rotating machineries are very difficult to identify using traditional envelope analysis methods.To address this challenge,this paper proposes an effective local spectrum enhancement‐based diagnostic method that can identify weak fault frequencies in the original complicated raw signals.For this purpose,a traversal frequency band segmentation technique is first proposed for dividing the raw signal into a series of subfrequency bands.Then,the proposed synthetic quantitative index is constructed for selecting the most informative local frequency band(ILFB)containing fault features from the divided subfrequency bands.Furthermore,an improved grasshopper optimization algorithmbased stochastic resonance(SR)system is developed for enhancing weak fault features contained in the selected most ILFB with less computation cost.Finally,the enhanced weak fault frequencies are extracted from the output of the SR system using a common spectrum analysis.Two experiments on a laboratory planetary gearbox and an open bearing data set are used to verify the effectuality of the proposed method.The diagnostic results demonstrate that the proposed method can identify incipient faults of gears and bearings in an effective and accurate manner.Furthermore,the advantages of the proposed method are highlighted by comparison with other methods.展开更多
文摘为解决风机受谐波干扰引起电压畸变和频率波动从而影响风机并网稳定运行的问题,提出频率自适应锁相方法,以谐波提取电路为基础,设计具有滤除风机谐波功能的NSOGI (new second-order generalized integrator)锁相环。首先,在谐波提取电路中加入基波谐振电路,验证谐波提取前后锁相环的锁频精度;其次,在传统锁相环基础上加入直流抑制器,对输入信号的频率进行跟踪;最后,进行理论和仿真分析,对比DSOGI-FLL谐波提取前后电路中的频率偏差,验证2种锁相环的锁频精度。结果表明:在谐波提取电路中加入基波谐振电路,减少了谐波对基波源的影响,提升了谐波提取的效果;在抑制风机电压畸变和直流谐波方面,NSOGI锁相环效果较好,锁频精度较高,验证了方法的可行性和正确性。采用NSOGI对电压和频率进行控制,能够提升供电可靠性,改善并网电能质量,为风机并网稳定运行提供了理论参考。
基金sponsored by the National Natural Science Foundation of China(No.51875105).
文摘Incipient faults of gears and rolling bearings in rotating machineries are very difficult to identify using traditional envelope analysis methods.To address this challenge,this paper proposes an effective local spectrum enhancement‐based diagnostic method that can identify weak fault frequencies in the original complicated raw signals.For this purpose,a traversal frequency band segmentation technique is first proposed for dividing the raw signal into a series of subfrequency bands.Then,the proposed synthetic quantitative index is constructed for selecting the most informative local frequency band(ILFB)containing fault features from the divided subfrequency bands.Furthermore,an improved grasshopper optimization algorithmbased stochastic resonance(SR)system is developed for enhancing weak fault features contained in the selected most ILFB with less computation cost.Finally,the enhanced weak fault frequencies are extracted from the output of the SR system using a common spectrum analysis.Two experiments on a laboratory planetary gearbox and an open bearing data set are used to verify the effectuality of the proposed method.The diagnostic results demonstrate that the proposed method can identify incipient faults of gears and bearings in an effective and accurate manner.Furthermore,the advantages of the proposed method are highlighted by comparison with other methods.
