朱李超
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基于線性化EKF的永磁同步電機(jī)無(wú)位置傳感器控制
朱李超
(上海大學(xué)機(jī)電工程與自動(dòng)化學(xué)院,上海200072)
本文分析了傳統(tǒng)擴(kuò)展卡爾曼濾波器在永磁同步電機(jī)無(wú)位置傳感器控制中的應(yīng)用原理,針對(duì)其非線性、計(jì)算量大的特點(diǎn),構(gòu)建了旋轉(zhuǎn)坐標(biāo)系下的擴(kuò)展卡爾曼濾波器模型,并考慮了轉(zhuǎn)動(dòng)慣量的影響,最終提出了一種基于換元法的線性化算法。通過(guò)理論推導(dǎo)和仿真實(shí)驗(yàn),比較分析了該算法和傳統(tǒng)擴(kuò)展卡爾曼濾波器算法。結(jié)果表明該算法計(jì)算量小,能準(zhǔn)確地估計(jì)轉(zhuǎn)子位置和轉(zhuǎn)速,具有良好的穩(wěn)態(tài)精度和動(dòng)態(tài)特性。
擴(kuò)展卡爾曼濾波器;永磁同步電機(jī);無(wú)位置傳感器
永磁同步電機(jī)(PMSM)因其具有結(jié)構(gòu)簡(jiǎn)單、體積小、重量輕、損耗小、效率高的特點(diǎn)而被廣泛應(yīng)用于工業(yè)生產(chǎn)場(chǎng)合,如電動(dòng)汽車、精密機(jī)床、軌道交通、船舶推進(jìn)、航空航天等等。一般的永磁同步電機(jī)閉環(huán)控制系統(tǒng)中,為了得到轉(zhuǎn)子位置和速度信號(hào),需要在轉(zhuǎn)軸上安裝傳感器。這類傳感器會(huì)造成控制系統(tǒng)環(huán)境適應(yīng)性差、體積增加、成本上升等問(wèn)題。因此,在二十世紀(jì)末期,永磁同步電機(jī)的無(wú)位置傳感器技術(shù)應(yīng)運(yùn)而生。
根據(jù)擴(kuò)展卡爾曼濾波器理論,將狀態(tài)轉(zhuǎn)移矩陣進(jìn)行泰勒級(jí)數(shù)展開并忽略高次項(xiàng)得到系統(tǒng)在最優(yōu)點(diǎn)附近的近似線性化模型。當(dāng)濾波周期T足夠小時(shí),可將系統(tǒng)離散化,最后得到擴(kuò)展卡爾曼濾波器的離散化狀態(tài)轉(zhuǎn)移矩陣:
將式(3)~(5)代入擴(kuò)展卡爾曼濾波方程即為傳統(tǒng)擴(kuò)展卡爾曼濾波器模型,濾波分為兩個(gè)步驟。
預(yù)測(cè)階段:
校正階段:
從式(11)中可知該模型為非線性模型,為了將其線性化,可進(jìn)行如下變量代換[8]:
又因?yàn)楸碣N式永磁同步電機(jī)電感、電磁轉(zhuǎn)矩滿足如下關(guān)系:
將式(12)~(14)代入式(11)可得:
將式(17)、(18)代入式(19)可得:
從式(20)可知可觀、可控矩陣都為滿秩,即變換后的系統(tǒng)保留原有系統(tǒng)的可控性和可觀測(cè)性。于是當(dāng)濾波周期T足夠小時(shí),可將系統(tǒng)離散化,得到線性化擴(kuò)展卡爾曼濾波器的離散化狀態(tài)轉(zhuǎn)移矩陣:
本文利用matlab 7.1的Simulink工具箱搭建仿真平臺(tái)??刂葡到y(tǒng)結(jié)構(gòu)框圖如圖1所示,控制策略采用轉(zhuǎn)子磁場(chǎng)定向的電流、轉(zhuǎn)速雙閉環(huán)控制,控制方式采用空間矢量脈寬調(diào)制方法(SVPWM)。表1為永磁同步電機(jī)參數(shù)。
圖1 線性化EKF控制系統(tǒng)結(jié)構(gòu)框圖
表1 永磁同步電機(jī)參數(shù)
圖2 給定時(shí)轉(zhuǎn)速響應(yīng)波形
圖4 轉(zhuǎn)速、轉(zhuǎn)矩突變下系統(tǒng)動(dòng)態(tài)響應(yīng)波形
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Sensorless Control for PMSMs Based on Linear EKF
ZHU Lichao
(School of Mechatronics Engineering and Automation, Shanghai University, Shanghai 200072, China)
The traditional extended Kalman filter(EKF) theory used for PMSMs senorless control is analyzed. In allusion to its nonlinear and large amounts of calculation, a model of EKF in consideration of the effect of inertia in the rotating coordinate is created and a linear algorithm based on the method of substitution is presented. The new algorithm is compared with the traditional EKF algorithm by theoretical derivation and simulation analysis. The results show that the proposed algorithm has a small calculation and it can accurately estimate rotor position and speed with good static and dynamic performance.
EKF; PMSMs; sensorless control
TM341
A
1000-3983(2014)02-0010-04
2013-07-15
朱李超(1987-),2013年3月畢業(yè)于上海大學(xué)自動(dòng)化系電機(jī)與電器專業(yè),碩士,從事永磁同步電機(jī)控制技術(shù)研究。
審稿人:宮海龍