外文翻譯-基于dsp高速無刷直流電機控制使用直流環節電壓控制-資料下載頁

【導讀】無刷直流電機的運行在一個高速度范圍、驅動系統可以有一個比較輕體積小,在同一輸出。PWM技術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。另一方面，使用的直流母線。電壓控制方案，變頻器操作與方波120°傳導速度控制是通過調節斬波直流環節逆變器的輸入電壓實。此外，以有一個波形相位目前類似的矩形波和終端電壓更有效率的處理在位置檢測電路。際應用變換議題延遲的一個高速度的無傳感器控制進行了討論。整個控制系統的實施應用DSP芯。片的無刷直流電機TMS320C240和有效性的比較驗證了仿真和實驗。個絕對速度傳感器通常限于大約6000轉速與旋轉需要一個特殊的外部電路。會受到安裝的準確性。在該方案中,逆變頻率控制供應電流有三相矩形脈沖寬度。120度及馬達速度控制電壓調節采用降壓斬波器作為降壓轉換器。超過傳統的兩相PWM在高轉速傳感器控制計劃控制計劃都沒有得到解決。代表示PWM技術轉換期間和頻率,分別。它具有重大影響的相電流響應和驅動器的性能在高速度。

　　

【正文】 on. 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 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. 4 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.