A Review on Parameters Identification Methods for Asynchronous Motor

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1 (IJACSA Intenational Jounal of Advanced Compute Science and Applications, A Review on Paametes Identification Methods fo Asynchonous Moto Xing Zhan,Guohui Zeng,Jin Liu,Qingzhen Wang,Sheng Ou College of Electonic and Electical Engineeing Shanghai univesity of engineeing science Shanghai, China Abstact The decoupling of excitation cuent and toque cuent is ealized by Vecto contol so that the speed egulating pefomance of asynchonous moto is compaable with that of dc moto. The contol pecision is diectly affected by accuacy of paamete identification in asynchonous moto. In this pape, based on the existing liteatues, the existed paametes identification s both online and offline ae analyzed and compaed, and the advantages and disadvantages of the vaious algoithms ae listed it tables. Theefoe, a compehensive identification of adjustable model which makes the least squae as adaptive of model efeence is pesented. Finally, the outlook of developing diection fo paametes identification of asynchonous moto ae put fowad to. Keywods Vecto contol; Paametes identification; MRAS; the least squae I. INTRODUCTION Since the vecto contol was pesented by Felix Blaschks, the ac speed egulating pefomance of asynchonous moto is compaable with that of dc moto. Vecto contol which is though the mathematical fomula and the matix tansfomation to make decoupling between the excitation cuent and toque cuent of asynchonous moto [1], and the contol pefomance of asynchonous moto is enhanced geatly by a simila dc moto contol. Now, the paametes identification s of asynchonous moto ae mainly off-line identification and online identification. Because of the basic paamete of vecto contol can be povided and the opeation is simple, the off-line identification is used most. But in the pocess of the moto opeation, the stato esistance ( R s and oto esistance ( R, and the time constant of Moto oto ( T L / R ae influenced by the change of envionment, such as the change of tempeatue, ai humidity, high pessue, dust, and so on. The change of the time constant of oto is affected by the change of esistance [2], which leads to magnetic field oientation is not accuate, and a bette decoupling will not be poduced between the excitation cuent and toque cuent of asynchonous moto. Finally, inaccuacy and deflection ae emeged, and industial poduction is also affected. Off-line identification techniques [3]: (a on one hand, the moto speed can be made to close to the synchonous speed by the taditional no-load expeiment; On the othe hand, the moto speed can be made to be zeo by locked-oto expeiment. (b The moto paametes can be identified though the data of moto stuctue. (c Diffeent voltage ae injected to moto based on a convete, the moto paametes can be identified by the moto to inspie diffeent voltage. (da mathematical pogam is povided by least-squaes, and a fitting cuve is gain, which is about the fitting of minimum vaiance sense and an expeimental data of completely measuing. Then the esult of identification is obtained. The excitation component and toque component of stato cuent ae decoupled by fomula (1 and fomula(2. The ac speed egulating pefomance of asynchonous moto is compaed with dc moto speed contol. asynchonous moto s opeation, moto paametes ae easily influenced by envionment. But the off-line identification cannot solve this poblem absolutely. In ode to contol the pecision of moto, the online identification of asynchonous moto is equied. At pesent, thee exist 4 types of online identification techniques: (a ecusive least squaes [4-5]. The estimated value of objective function is coected continuously, and the paamete is estimated step by step until the satisfied paamete value is gained. (b The extended Calman filte [6] is ecusive estimation [7]. The estimated value of cuent state is calculated though the estimated value at the state of a moment befoe and the obseved value of cuent, and this is used in linea stochastic systems [8-9].(cMRAS is used to identified the moto paamete, and a suitable adaptive law is found [10-11]. The output s eo between the efeence models without identified paametes and the adjustable models with Diffeent voltage ae injected to moto based on a convete is a moe eliable than othe off-line identification. This has many advantages, such highe ecognition efficiency, highe pecision, moe convenient, and so on. The electonic esistance ( R s, leakage inductance of stato and oto (, oto esistance ( R,and the mutual inductance ( L m could be identified though this. The time constant of oto ( T L / R can be deduced by the above identified paametes. Then, the stato cuent of moto is decomposed into toque component ( i st and excitation component ( i sm via the mathematical model of vecto contol and coodinate tansfomation. This wok is suppoted by the Natual Science Foundation of Shanghai unde Gant No.14ZR and the Innovation Foundation of Shanghai Education Commission unde Gant No.13YZ111 and the Innovation Foundation of SUES unde Gant No.E P a g e

2 (IJACSA Intenational Jounal of Advanced Compute Science and Applications, T e pnlm L L i st i (1 m sm TP 1 (2 identified paametes tends to zeo finally [12]. Then the moto s paametes ae identified [13]. (d The algoithms of atificial and intelligent identification is used to simulate natual biological systems, and totally dependent on its instinct to optimize the existence to adapt to the envionment [14]. II. THE FACTORS OF PARAMETERS The paametes ae in change fo moment in the mathematical model of asynchonous moto and effected easily by factos.with changes of envionmental factos and asynchonous moto, the paametes is changing. The paametes mainly contain stato esistance ( R s, oto esistance ( R, stato inductance L, oto inductance L, and the mutual ( s inductance between stato and oto ( L m. The main factos of the change of the asynchonous moto unning paametes ae shown in table 1: ( TABLE I. THE MAIN FACTORS OF THE CHANGE OF THE ASYNCHRONOUS MOTOR RUNNING PARAMETERS Factos Influence mechanism Paametes ae influenced Change law Tempeatue changes The enegy change into heat enegy in the pocess of electical enegy tansfom into mechanical enegy, the change of extenal envionment, moto s aging degee and the degee of wea and tea. Stato esistance of moto ( R s, oto esistance ( R Ra t R t a b b ( R a is the esistance in the tempeatue (t a, R is the esistance in the tempeatue (t b ( b K R 6.5 K X h 1cm K R K X Fequency changes The skin effect is caused by fequency changes of cuent, which is elated to the oto s slot type of asynchonous moto. Roto esistance ( R, oto inductance ( L f / Hz Fig. 1. The cuve is about the elationship between oto esistance and inductance and fequency B The factos of the satuated magnetic Asynchonous moto is in the linea pat of the B - H cuve, while the ion coe eluctance is smalle. When the magnetic is satuated, oto esistance inceases, and the inductance deceases [10]. Roto esistance ( R, oto inductance ( L, the coefficient of leakage inductance ( 0 0 H Fig. 2. B-H cuve The stay loss Eddy cuent loss is poduced by magnetic-flux leakage, Eddy cuent and hysteesis ae poduced when Winding in the metal stuctue, highe-ode Hamonic losses [9]. ( L stato inductance s, oto ( L inductance, mutual inductance L ( m P a g e

3 (IJACSA Intenational Jounal of Advanced Compute Science and Applications, III. THE IDENTIFICATION METHOD OF PARAMETER A. The off-line identification Cuently, the off-line identification is studied in the wold and advantages and disadvantages of each ae shown in table 2. TABLE II. ADVANTAGES AND DISADVANTAGES OF THE OFF-LINE IDENTIFICATION METHOD Identific ation Identification Pinciple Identificati on paametes Advantages Disadvantages Lockedoto of moto Roto winding of asynchonous moto is cut out and oto is stuck to otate unusually. Then paametes ae calculated though the cicuit pinciple. The equivalent cicuit is shown in figue 3. Resistance, inductance, mutual inductance. The paametes of esistance, inductance, and mutual inductance can be calculated. In many conditions, not only this kind of expeimental conditions cannot be gotten, but also the load of system is vey uneasy to be installed and emoved. And the skin effect of oto is vey seious [11]. Noload expeim ent Moto does not dag any load, and the oto speed of moto is almost equivalent to the synchonous speed. Equivalent cicuit is shown in figue 4. Excitation eactance and the excitation esistance Convenient is ealized. In the case of moto s contol pecision is not high, the equied paametes ae measued. The oto cicuit is ignoed, and the identification pecision is not high. In many occasions, the load is caied by moto. It is not convenient to no-load emoved load. Autotuning of moto paametes Diffeent test signal is injected into moto to make the moto in diffeent state. The featues of fequency convete ae used to pefom some pocedues. Finally, the pupose of identifying moto s paametes is achieved. Stato esistance ( R s, leakage inductance ( oto esistance ( R. Pecision is highe and good eliability. This is suitable fo being used in a contol system with fequency convete, and it is not convenient to be used in the contol system with no fequency convete. The least squae The expeimental data in the whole stage is sampled though a complete measuement. Then the least squaes cuve is offline calculated and fitted, and the identified esults ae obtained. Roto esistance and inductance. High pecision. A lage amount of data and the expeimental data in the whole stage ae need to be measued, and measuement and t calculation ae tedious. R s Ls L R s Ls L U R m U R m L m R L m Fig. 3. The equivalent figue of moto cutting-out Fig. 4. The equivalent figue of moto no-load B. Online identification The above off-line identification s ae the identification that in the case of moto no-load o in a moment the moto is changing with tempeatue and envionment in the opeation pocess. In a high-pecision contol system, the offline identification cannot meet the equiements. Thus, the paametes ae equied to be identified online and identified at evey moment. Online identification is shown in table P a g e

4 (IJACSA Intenational Jounal of Advanced Compute Science and Applications, TABLE III. THE ONLINE IDENTIFICATION METHOD dentification The extended Calman filte 7 Identification pinciple The state equations of moto is used diectly. The paametes which need to be identified and states ae set as quantities of augmented state. The optimal estimation of the state is given solving iccati equations in online 8. Identification paametes Roto esistance, mutual inductance, flux linkage Advantages With high identified pecision and moe paametes. And othe unpedictable state can be estimated. Itself has filteing effect and can educe some intefeence 9. Disadvantages The algoithm is complex and good pefomance of pocesso is equied MRAS The actual unning of moto is used as the efeence model, and the state obsevation equation of moto is used as the adjustable model. Moto s paametes of the adjustable model ae coected in eal time by some measuable deviation Roto esistance, stato esistance, mutual inductance. A small amount of calculation and high pecision. Refeence model is difficult to be detemined The impoved least squae Intelligent algoithm[15] The expeimental data in the whole stage is sampled though a complete measuement. Then, the least squaes cuve is calculated offline and fitted, and the identification esults ae obtained. Neual netwok and genetic algoithm ae included in this [16]. The fome makes the function value of eo to be minimized by leaning system s Input and output. The latte is a kind of andom seach algoithm, which can simulates the natual evolution [17]. Resistance, inductance, time constant of oto. Resistance and inductance High pecision and good eliability. Both online and offline identification. The pecision is vey high. It is Sensitive to noise of measuement and fluctuation of speed. The estimated value exists multi solutions and deviation poblems owing to the singulaity of stuctue matix. The calculation is so huge and the equiement fo pocesso is elatively high. IV. COMPREHENSIVE IDENTIFICATIONSYSTEM Accoding to the analysis and study of existing liteatue, the single identification has defects moe o less. A kind of that both off-line identification and online identification ae put fowad by autho based on existing liteatues. The is combined with model efeence adaptive and impoved least squae. The adjustable model is constucted by the impoved least squae, and the least eo is made to be minimized between the efeence model and the adjustable model. A. The pinciple of model efeence adaptive THE PRINCIPLE OF MODEL REFERENCE ADAPTIVE IS SHOWN IN FIGURE 5. X Refeence Model Adjustable Model Fig. 5. Pinciple of model efeence adaptive Adaptation Model y m y s + - e This system has the same extenal input(x, while the (X is input to the efeence model and the adjustable model. ( y m and ( y s ae the output of the efeence model and the adjustable model. Finally, the esult of e y m y is s calculated to be minimized o zeo though the adaptive adjustment. The design of adaptive contol mainly includes: 1 The optimization theoy of patial paametes. The stuctued distance between the efeence model and the adjustable model is defined, o two times pefomance index of state distance. The of paamete optimization is used to detemine the adjustment of paametes of the contolle. Rules make the adjustable model close to efeence model to achieve the pupose of identifying paametes. 2 Popov supe stability theoy. Fistly, the model efeence adaptive system should be tansfomed into equivalent nonlinea time-vaying feedback system. Namely, the system is fomed by a linea fowad link and a nonlinea feedback link. A suitable law of adaptive contol is gotten P a g e

5 (IJACSA Intenational Jounal of Advanced Compute Science and Applications, unde the guaantee of meeting the two conditions. This makes the whole nonlinea system is stable, which can ensue the system eo tends to zeo and achieve the pupose of adaptive contol. B. B. The least squae A linea elationship exists between the vaiables ( and one dimensional vaiable 1 2 n, namely: y c1 x1 c2x2 c3x3 c n x n c y x The value ( is estimated based on the obseved values ( and ( in diffeent time. This equies epeated computation unde the need of update data, this poblem is solved by ecusive least squaes. A new set of data don t need to be added and calculated again, and the amount of calculation is educed geatly. The basic idea of ecusive least squae is: the new estimate value = the old estimate value + coection tem. So that and e y m - x i is its minimum. V. CONCLUSION y (x,x, x x x 3 y x i Though analyzing and concluding the existing liteatues, Conclusions can be gotten as follows: 1 As shown by the table 1, the oto esistance of asynchonous moto is changed mostly by the envionmental factos. As shown by the fomula (1 and fomula (2, the oto flux linkage is changed diectly by the change of oto esistance. Then, the decoupling of oto flux linkage is not sufficient. If a cetain contol accuacy is equied by a contol system, a contol which main identifies oto esistance can be chosen. 2 Offline identification has many kinds of classes. Being compaed with the locked-oto of moto no-load expeiment and the least squae,auto-tuning of moto paametes is used most widely, the technology is most matue, and the identification accuacy is moe accuate and eliable. 3 The system which equies high pecision of identification, low cost and eliable pefomance and easy to implement, the least squaes is a bette, because this can not only ealize the off-line identification but also ealize the online identification. 4 As to the contol system which vey high accuacy of identification, intelligent algoithm can be used as the focus of futue eseach s. This has the vey good contol pecision. With the apid development of the economic in China, the moto s contol technology with high pecision is widely used in all kinds of industial fields. The highe equiements fo the identification accuacy of asynchonous moto is put fowad. At pesent, China is still elatively backwad in tems of manufactuing and contol of asynchonous moto. Especially the gap fom Westen counties in pocesso manufactuing is lage. How to make the moto contol moe accuate, which equies highe paamete identification. Although the geneal industial poduction equiements can be satisfied by the identification of existing paametes, it is not enough in some high pecision contol system. In genetic algoithm, genetic algoithm and neual netwok algoithm ae continuous optimization and find out the optimal solution, which needs highe equiements fo the pocesso to be put fowad. Theefoe, the intelligent algoithm has a boad pospect in the futue and it can be developed fom two aspects. On one hand, the intelligent algoithm could be impoved [18-19]. The algoithm is simple and high pecision of paamete identification could be achieved. On the othe hand, the pefomance of pocesso could be impoved so that the pocesso speed is faste and cheape. REFERENCES [1] Boshi Chen, Minxun Chen. Ac speed egulating system [M]. 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