The Non-Singular Fast Terminal Sliding Mode Control of Interior Permanent Magnet Synchronous Motor Based on Deep Flux Weakening Switching Point Tracking

This paper presents a novel non-singular fast terminal sliding mode control(NFTSMC)based on the deep flux weakening switching point tracking method in order to improve the control performance of permanent interior magnet synchronous motor(IPMSM)drive systems.The mathematical model of flux weakening(FW)control is established,and the deep flux weakening switching point is calculated accurately by analyzing the relationship between the torque curve and voltage decline curve.Next,a second-order NFTSMC is designed for the speed loop controller to ensure that the system converges to the equilibrium state in finite time.Then,an extended sliding mode disturbance observer(ESMDO)is designed to estimate the uncertainty of the system.Finally,compared with both the PI control and sliding mode control(SMC)by simulations and experiments with different working conditions,the method proposed has the merits of accelerating convergence,improving steady-state accuracy,and minimizing the current and torque pulsation.

Model-Free Sliding Mode Control for PMSM Drive System Based on Ultra-Local Model

This paper presents a novel model-free sliding mode control(MFSMC)method to improve the speed response of permanent magnet synchronous machine(PMSM)drive system.The ultra-local model(ULM)is first derived based on the input and the output of the PMSM.Then,the novel MFSMC method is presented,and the controller is designed based on ULM and MFSMC.A sliding mode observer(SMO)is constructed to estimate the unknown part of the ULM.The estimated unknown part is feedbacked to MFSMC controller to performcompensation for parameter perturbations and external disturbances.Compared with the sliding mode control(SMC)method,the results of simulation and experiment demonstrate that the presented MFSMC method improves the dynamic response and robustness of the PMSM drive system.

基于红外相机技术调查佛坪国家级自然保护区兽类和鸟类多样性

2015年1月至2017年12月,在陕西佛坪国家级自然保护区57条巡护样线上布设130台红外相机,对兽类和鸟类多样性进行调查。累计相机工作日101,220天,共捕获独立有效事件36,100次,其中兽类独立照片30,563张,鸟类3,244张。共记录到野生兽类6目15科29种,相对多度较高的前5个物种依次是秦岭羚牛(Budorcasbedfordi,RAI=11.53)、野猪(Sus scrofa, RAI=4.80)、小麂(Muntiacus reevesi, RAI=4.35)、大熊猫(Ailuropoda melanoleuca, RAI=1.81)和中国豪猪(Hystrixhodgsoni,RAI=1.13)。共记录到鸟类8目14科54种,相对多度最高的前5个物种依次是红腹锦鸡(Chrysolophus pictus, RAI=0.97)、红腹角雉(Tragopan temminckii, RAI=0.74)、紫啸鸫(Myophonus caeruleus,RAI=0.51)、红嘴蓝鹊(Urocissa erythrorhyncha, RAI=0.13)、黑领噪鹛(Garrulax pectoralis, RAI=0.12)。保护区鸟类新记录4种,包括白眉地鸫(Geokichla sibirica)、白眉鸫(Turdus obscurus)、长尾地鸫(Zoothera dixoni)和灰脸鵟鹰(Butastur indicus);保护区兽类新记录1种,为亚洲狗獾(Meles leucurus)。本研究利用红外相机技术客观记录了佛坪国家级自然保护区兽类和鸟类的本底情况,不仅初步了解了保护区内的野生动物分布,而且更新了保护区鸟类资源数据库,为保护区未来的保护和管理工作提供了数据基础。

Emission source-based ozone isopleth and isosurface diagrams and their significance in ozone pollution control strategies

In the past decade,ozone(O_(3))pollution has been continuously worsening in most developing countries.The accurate identification of the nonlinear relationship between O_(3) and its precursors is a prerequisite for formulating effective O_(3) control measures.At present,precursor-based O_(3) isopleth diagrams are widely used to infer O_(3) control strategy at a particular location.However,there is frequently a large gap between the O_(3)-precursor nonlinearity delineated by the O_(3) isopleths and the emission source control measures to reduce O_(3) levels.Consequently,we developed an emission source-based O_(3) isopleth diagram that directly illustrates the O_(3) level changes in response to synergistic control on two types of emission sources using a validated numerical modeling system and the latest regional emission inventory.Isopleths can be further upgraded to isosurfaces when co-control on three types of emission sources is investigated.Using Guangzhou and Foshan as examples,we demonstrate that similar precursor-based O_(3) isopleths can be associated with significantly different emission source co-control strategies.In Guangzhou,controlling solvent use emissions was the most effective approach to reduce peak O_(3) levels.In Foshan,co-control of on-road mobile,solvent use,and fixed combustion sources with a ratio of 3:1:2 or 3:1:3 was best to effectively reduce the peak O_(3) levels below 145 ppbv.This study underscores the importance of using emission source-based O_(3) isopleths and isosurface diagrams to guide a precursor emission control strategy that can effectively reduce the peak O_(3) levels in a particular area.

Identification of close relationship between atmospheric oxidation and ozone formation regimes in a photochemically active region

Understanding ozone(O_(3))formation regime is a prerequisite in formulating an effective O_(3)pollution control strategy.Photochemical indicator is a simple and direct method in identifying O_(3)formation regimes.Most used indicators are derived from observations,whereas the role of atmospheric oxidation is not in consideration,which is the core driver of O_(3)formation.Thus,it may impact accuracy in signaling O_(3)formation regimes.In this study,an advanced three-dimensional numerical modeling system was used to investigate the relationship between atmospheric oxidation and O_(3)formation regimes during a long-lasting O_(3)exceedance event in September 2017 over the Pearl River Delta(PRD)of China.We discovered a clear relationship between atmospheric oxidative capacity and O_(3)formation regime.Over eastern PRD,O_(3)formation was mainly in a NO x-limited regime when HO_(2)/OH ratio was higher than 11,while in a VOC-limited regime when the ratio was lower than 9.5.Over central and western PRD,an HO_(2)/OH ratio higher than 5 and lower than 2 was indicative of NO x-limited and VOC-limited regime,respectively.Physical contribution,including horizontal transport and vertical transport,may pose uncertainties on the indication of O_(3)formation regime by HO_(2)/OH ratio.In comparison with other commonly used photochemical indicators,HO_(2)/OH ratio had the best performance in differentiating O_(3)formation regimes.This study highlighted the necessities in using an atmospheric oxidative capacity-based indicator to infer O_(3)formation regime,and underscored the importance of characterizing behaviors of radicals to gain insight in atmospheric processes leading to O_(3)pollution over a photochemically active region.