永磁交流伺服系統(tǒng)先進(jìn)控制策略研究

隨著國家重大專向“高檔數(shù)控機(jī)床與基礎(chǔ)制造技術(shù)”的實(shí)施，對永磁交流伺服系統(tǒng)的性能提出了愈來愈高的要求。本文首先通過對典型應(yīng)用案例的分析，揭示了交流伺服系統(tǒng)對應(yīng)用系統(tǒng)性能的影響，指出提高交流伺服系統(tǒng)性能的必要性。
永磁交流伺服系統(tǒng)參數(shù)的正確整定對系統(tǒng)的性能影響極大，設(shè)計(jì)者和用戶均難以實(shí)現(xiàn)這一目標(biāo)。因此，如何實(shí)現(xiàn)參數(shù)的自整定是這一領(lǐng)域的研究熱點(diǎn)問題。由于在多數(shù)應(yīng)用系統(tǒng)中慣量會經(jīng)常發(fā)生變化，且慣量變化對系統(tǒng)的動態(tài)性能影響很大，本文提出了一種轉(zhuǎn)動慣量在線辨識方法，能夠?qū)崿F(xiàn)慣量變化的自動辨識。在此基礎(chǔ)上，針對交流伺服控制器PI 參數(shù)自整定方法中，忽略了整定過程的周期性和所需的自學(xué)習(xí)能力，造成整定過程效率低、重復(fù)操作次數(shù)多、整定時間長問題,依據(jù)迭代學(xué)習(xí)控制，提出了一種交流伺服系統(tǒng)速度控制器PI 參數(shù)自整定控制方案，使控制器能夠進(jìn)行仿人操作，根據(jù)歷史控制經(jīng)驗(yàn)不斷地改進(jìn)學(xué)習(xí)增益。仿真和實(shí)驗(yàn)結(jié)果均驗(yàn)證了上述方法的有效性，且這些方法結(jié)構(gòu)簡單，易于實(shí)現(xiàn)，已在已研發(fā)的產(chǎn)業(yè)化項(xiàng)目中得到具體應(yīng)用。
用于伺服系統(tǒng)的永磁同步電機(jī)，一般具有較小的轉(zhuǎn)動慣量，這有可能使得電機(jī)的機(jī)械時間常數(shù)要小于電磁時間常數(shù)。面對這樣的機(jī)電時間常數(shù)的關(guān)系，電流環(huán)在動態(tài)過程中不能抑制速度環(huán)的擾動，電流的動態(tài)響應(yīng)明顯變差。對此本文加入一個反電動勢補(bǔ)償環(huán)節(jié)，以此來消除轉(zhuǎn)速在動態(tài)過程中對電流環(huán)的影響。理論分析并結(jié)合仿真研究，
對比有無補(bǔ)償環(huán)節(jié)的性能，提高了動態(tài)響應(yīng)，仿真結(jié)果驗(yàn)證了補(bǔ)償措施的有效性。
在永磁交流伺服系統(tǒng)中，電流環(huán)位于最內(nèi)環(huán)，其環(huán)寬對整個系統(tǒng)（速度環(huán)/位置環(huán)）的環(huán)寬具有制約作用。因此，在不提高功率器件開關(guān)速度的前提下如何提高電流內(nèi)環(huán)的寬度也是該領(lǐng)域的研究熱點(diǎn)。本文深入分析了傳統(tǒng)PWM 方式限制電流環(huán)寬度的原因，提出了新的改進(jìn)型PWM 方式，在不提高開關(guān)頻率的情況下，使電流環(huán)的帶寬得到了顯著
提高，從而擴(kuò)大了永磁交流伺服系統(tǒng)的頻帶，提高了動態(tài)響應(yīng)，實(shí)驗(yàn)結(jié)果均驗(yàn)證了該方法的有效性。
Abstract: With national significant expertise to the "high-quality CNC machine and basic manufacturing technology",
more and more demands are made for performance of the permanent magnet AC servo system. In this paper, through the analysis of typical applications, reveals the ac servo system influence on the performance of the system and the necessity to improve servo system performance.Permanent magnet AC servo system parameters in correct setting have a great impact on system performance. It is difficult to achieve this goal for designers and users. Therefore, how to achieve parameters self-tuning is of hot issues of this research field. In most applications inertia often changes. And the changes of inertia have a great influence on the system dynamic performance. A novel on-line identification method of inertia is put forward, and it can achieve automatic
identification of inertia changes. At present, most methods of self-tuning of PI controller for AC Servo drive cause various
problems, such as low efficiency, more iterative manipulation and more setting time, due to ignoring the periodic property
and the necessary self-study ability of setting process. This paper presents a novel self-tuning of PI speed controller for AC
servo drive based on iterative learning control. The proposed scheme make the controller improve learning gain according to
historical experiences like human being. The feasibility and validity of the proposed scheme has been verified with simulation and experimental result and the arithmetic is concise and apt to realize. PMSM used in servo system, generally has relatively small inertia, which could make the electrical mechanical time constant less than electromagnetic time constant. Face with such relationship between mechanical and electrical time constant, the current loop in a dynamic process can not curb the disturbance of speed loop, and dynamic response of current maybe bad. In this paper, add a link of speed compensation in order to eliminate the impact of speed on the current loop in dynamic process. Theoretical analysis and combine with the simulation studying, contrast the performance with and without the compensation link, simulation results show the effectiveness of compensation measures.
In permanent magnet AC servo system, the current loop located in the inner ring. The bandwidth of the entire system is restricted by current loop bandwidth. Therefore, how to expand the bandwidth of the current inner loop under not raising power device switching speed condition has been a hot research topic. Based on the analysis of current loop bandwidth restricted conditions using traditional PWM style, an improved version of PWM mode is proposed. Current loop bandwidth has been significantly improved without raising switching frequency. Thus increase the permanent magnet AC servo system bandwidth and improve the dynamic response. Experimental results verify the effect of the method.
關(guān)鍵詞：交流伺服系統(tǒng)；轉(zhuǎn)動慣量在線辨識；參數(shù)自整定；迭代學(xué)習(xí)控制；動態(tài)響應(yīng)
Keywords: AC servo system; inertia on-line identification; self-tuning; iterative learning control; dynamic response