電氣外文翻譯---基于dsp高速無刷直流電機控制使用直流環(huán)節(jié)電壓控制-電氣類-資料下載頁
2025-05-11 20:23本頁面
【導讀】1．外文文獻翻譯的內(nèi)容應與畢業(yè)設計/論文課題相關(guān)。成不少于2020漢字的二外文獻翻譯任務。學武昌分校本科畢業(yè)設計/論文撰寫規(guī)范》的要求撰寫。本附件為封面，封面上不得出現(xiàn)頁碼。不得選用相同的外文原文。壓控制方案被提出了。無刷直流電機的運行在一個高速度范圍、驅(qū)動系統(tǒng)可以有一。在現(xiàn)有的無傳感器控制方案,通常采用PWM(脈寬。然而,由于PWM技術(shù)和變頻變換不能履行獨立,明顯的。變換延遲存在于高速地區(qū)。與方波120°傳導速度控制是通過調(diào)節(jié)斬波直流環(huán)節(jié)逆變器的輸入電壓實現(xiàn)。由于傳感器可靠性降低高溫需要額外的導線。兩相PWM在高轉(zhuǎn)速傳感器控制計劃控制計劃都沒有得到解決。這激勵方案不需要死亡的時間電力設備的發(fā)。在單極開關(guān)的方法,PWM技術(shù)是疊加在那兩人中的一個主動開關(guān)在。國家,而其他開關(guān)仍在狀態(tài)。根據(jù)基于其使用的PWM調(diào)制方式,該控制技術(shù)可能導致減刑延遲或者一個。不規(guī)則的開關(guān)頻率的電力設備在高速度傳感器控制。
【正文】 enote the PWM switching period and frequency, respectively. Figure 1(a) shows a case of the ideal mutation. As can be seen in the gure, if the mutating instant is synchronized with the end of the PWM switching period, an ideal mutation can be obtained without any delay in the inverter sequence change. However,since the mutating instant depends on the rotor position, it does not usually coincide with the end of the PWM period. In this case, the mutation can be performed synchronized with the end of the present PWM period to start a next inverter sequence as Figure 1(b) , which is the normally used method. This results in an undesirable mutation delay and the maximum value of this delay bees the PWM switching period. If the switching frequency is chosen as 16 kHz,the maximum value of the mutation delay will be sec. Even though this mutation delay can be neglected for a medium speed range, it has significant in uences on the phase current response and drive performance at high speed since the 60degree interval that the mutation arises in is relatively small. For example, when a 2pole motor is rotating at 50,000 rpm, 60degree interval bees 200 sec. This mutating delay can be reduced by increasing the PWM switching frequency. In practice, however, the switching frequency cannot be increased without limit because of the increased switching loss. Also, the switching frequency of mercially available power devices is less than 20 kHz. Thus, to avoid an undesirable mutation delay, the next inverter sequence has to be applied as soon as the mutation signal interrupt occurs. Then, the present PWM period has to be terminated and the new PWM period synchronized with the mutation interrupt signal must be started. In the upper and lower switch PWM schemes,this may yield an irregular switching frequency much larger than f s under a high duty condition as shown in Figure 1(c) . In the ongoing and offgoing phase PWM schemes, this irregular switching frequency does not 6 occur since the phase executing the PWM is continually changed every 60176。interval. Thus, the ongoing and offgoing phase PWM schemes with the method in Figure 1(c) can be a preferred way for a high speed sensorless control. Nevertheless, there is still a problem. At high speed, only a few PWM pulses can be used for the speed control during a 60176。interval. Since a 60176。interval of a 2pole motor bees 200 sec at 50,000 rpm,if the switching frequency is chosen as 16 kHz, the number of PWM pulses during 60175。 is only , which results in an unequal number of PWM pulses 3 or 4 during a 60176。 interval. Unless the resolution of the pulse width is considerably high, this may result in a speed ripple at steady state and degrade the accuracy of the position signal detection. This problem is more serious at a higher speed region and can be effectively overe by controlling the voltage and frequency independently by the DC link voltage control scheme. 7 Figure 1. Relation between the PWM switching period and mutating instant:(a) Ideal mutation, (b) Case of mutation delay, and (c) Case of irregular switching frequency.
畢業(yè)設計相關(guān)推薦
鄂ICP備17016276號-1