直流無刷馬達無感測驅動之分析

Abstract

隨著科技的進步與發展，馬達在日常生活中開始扮演著重要的角色。憑藉著它的高效率與小尺寸的優勢，現今三相無刷直流馬達已被廣泛地應用於家電設備及多種裝置之中。但大部分的傳統三相無刷直流馬達必須使用霍爾位置感測器來偵測轉子與定子之間的相對位置，其缺點除了增加成本，減少馬達的壽命之外，霍爾感測器易受干擾且不耐高溫，而且在馬達上擺放感測器時，必須擺放在精確的位置才能得到準確的轉子位置。因此，可以改善以上缺點的無感測驅動技術便越來越受到重視。

本論文為探討在不同導通角度之下的無感測驅動方式與特性的分析，其中無感測驅動的技術為使用數位式相位移器與遮罩來偵測由感應電動勢訊號所得到的零交越點，並且藉由判斷這些零交越點來得到準確的馬達換相位置。在驅動實現方面，藉由馬達的電壓回授訊號來獲得零交越點訊號，進而達到驅動與控制的目的，並且利用場效型可規劃邏輯陣列元件 (FPGA) 與硬體描述語言(VHDL) 進行無感測驅動控制系統的模組化設計。本文採用 FPGA 內部晶片運算設計與搭配外部的驅動電路完成三相無刷直流馬達的無感測控制系統，最後將不同角度的驅動實驗結果做速度、電流與震動等特性的分析與比較，並且在其中得到一最佳的無感測驅動方式。

With the progress and development of technology, motors have become more and more important in our life. Because three-phase brushless direct current motors (BDCMs) possess high efficiency, high reliability and small sizes, they have been applied extensively in various home electrical appliances and devices now. But most of traditional three-phase BDCMs have to use Hall sensors to detect the corresponding position of the rotor and the stator. Besides increasing cost and reducing life of motors, using Hall sensors has many defects, because Hall sensors are interfered easily and cannot endure high temperature. Moreover, Hall sensors must be located precisely so that we can exactly acquire the present state of the rotor, when we place sensors in the motor. Therefore, people pay much more attention to using the sensorless drive schemes which can improve various drawbacks mentioned above.

This thesis discusses methods of the sensorless drives with various conduction degrees and characteristic analyses. We implement sensorless drive scheme by using the digital phase shifter and the mask to detect zero-crossing points obtained by the signal of the induced electromotive force, besides we can acquire accurate commutation positions with these zero-crossing points. The experiment achieves drive and control purposes because using voltage feedback to get zero-crossing signal, and using field programmable gate array (FPGA) and very high speed integated circuit hardware description language (VHDL) to design modular function of the sensorless drive control system. This thesis uses the interior operations of the FPGA chip and the drive circuit to accomplish sensorless drive control system of three-phase BDCMs. We last analyze and compare rotational speeds, currents and vibrations of results of different degree drives, and accurate a optimum sensorless drive scheme.