An improved approximation method with adjustable zero and pole distributions for fractional order systems

摘要

With the gradual development of research on approximating fractional order systems, more precise methods are needed to approximate fractional order systems using integer order elements. This paper provides a new approximation algorithm which improves the approximation accuracy by adjusting the distribution of the zeros and poles of the approximation system. In a predefined frequency range, this method can accurately approach fractional order controlled objects. Especially at the boundary of low frequency and high frequency, the accuracy is greatly improved than other methods. This method also guarantees that the approximate system is strictly proper. Numerical examples in both time and frequency domains prove the effectiveness and advantages of the method.