使用多率濾波器脈波寬度調變於 切換式磁阻馬達控制

Abstract

本論文針對切換式磁阻馬達的電流控制策略提出了多率濾波器脈波寬度調變 (Multi-rate Pulse Width Modulation, MRFPWM) 的方法，以改善目前廣泛使用的脈波寬調變 (Pulse Width Modulation, PWM) 的效能。本論文利用濾波器來作電流誤差的補償使得降低量化誤差同時利用多率系統將兩個PWM訊號合併製作一個非對稱脈波寬度調變來降低功率電晶體之切換次數及降低功率級的損失，因此能夠有效地降低功率開關元件的溫度並增加其壽命。此外，本論文也發展了高效率角度控制策略，以降低額外產生之銅損為目的，調整最佳化切換角度，同時能夠達到定轉矩控制的條件，爲了證實此方法之可行性也以用理論運算為基礎，透過系統分析驗證此方法在某種條件下能夠發揮最高效率。本論文是採用低成本的32位元控制器與三相非對稱控制器，透過實驗來比較幾個不同的電流控制策略；包括 PWM、非對稱脈波寬調變 (Asymmetric Pulse Width Modulation, APWM)、具濾波器脈波寬度調變 (Filter Pulse Width Modulation, FPWM) 以及 MRFPWM。實驗結果顯示，在相同的負載下比較不同轉速，其 MRFPWM 之效率都優於其他控制策略，且切換次數降低一倍使得功率電晶體之表面問題也相對的減少，這不僅能夠提高功率電晶體的效率且增加使用壽命。

This thesis proposed a novel scheme for current control of switched reluctance motor by using multi-rate filter pulse width modulation to improve the efficiency of traditional pulse-width modulation. We utilized a filter to compensate the error current for reducing the error current and generating an asymmetrical pulse width modulation, which is the combined by two PWM signals produced by multi-rate system. This method can reduce the switching loss of power transistor and decrease power consumption. Thus, the temperature of the power switching element will be reduced and provide a long life span. In addition, we also developed a high efficiency angle control strategy, the purpose is to lower extra copper loss, simultaneously able to achieve constant torque controlled conditions. In order to verify the feasibility of this method are used as the basis of theoretical operations, through systematic analysis of verification under certain conditions, this method can play a maximum efficiency. The implementation of our system is using a low-cost 32-bits controller and a three-phase asymmetric half bridge inverter. In our experiment, we compared the various speeds in the same load with different current control strategies such as PWM, APWM, FPWM and MRFPWM. The results showed that the efficiency of MRFPWM is better than other control strategies, it also lowered the number of switching doubled for protecting the surface of power transistor and increased the efficient of power transistor.