本論文是針對直流無刷馬達做變負載模糊控制,利用無感測器位置偵測電路取代傳統的位置感測器,使用數位訊號處理器為控制器核心,並搭配周邊電路如:電氣隔離電路、控制電路、保護電路以及轉速顯示電路,以模糊邏輯控制法則來完成一個直流無刷馬達的速度控制。 因為無感測器位置偵測電路在低轉速下所得到的反電動勢太小,所以並無法有效地偵測出轉子位置,且隨著轉速不同會有非線性關係的相位差。本論文以實驗方法求得此相位落後之情況,並且依據此實驗結果做出相對應的相位補償,使得無感測器位置偵測電路所得到之訊號與真實位置訊號間的相位差縮小,而取代原本的感測器。控制器部分採用模糊邏輯控制理論,使用經驗法則設計出控制器參數,並與傳統之PID控制器作比較,由模擬結果可得知,模糊邏輯控制器有較佳的動態響應與強健性,且在控制器設計的過程中,不需要得知精確的系統數學模型,可藉由對系統輸入與輸出間之特性的了解,使用經驗法則設計歸屬函數之類型與決策之規則庫,即可完成控制器的設計,達到使系統穩定之目的。在另一方面為了減輕微處理器的運算負擔,我們將控制器的輸入與輸出建立一個對照表,以查表的方式求得控制器正確的輸出值,達到與模糊邏輯控制器相同的控制效果。
The research is about how to do fuzzy control for brushless DC motor drive under variable loading. By using position detection circuit to replace the original sensor, and collocating with other peripheral circuits to achieve the speed control by DSP. It's difficult to detect the position signal by the position detection circuit at low speed, furthermore, different speed would cause different non-linear phase-lag. Therefore we obtain the particular variation of the phase-lag by experiment, and design the phase compensation to reduce the difference between the detection signal and the real one. The controller is by using fuzzy logic control algorithm, and the parameters are designed by experience. Compared with the simulation results between fuzzy controller and PID controller, then we know there is the better response and robustness in fuzzy logic controller. And we don't exactly need the accurate mathematical model of the plant when we designed the controller. In order to reduce the calculation of fuzzy logic control algorithm, we build a look-up table to obtain the same output with the fuzzy controller.