Order Reduction of Zeta Converter Using Direct Truncation and Routh Approximation Method

Zeta converter is a buck-boost converter with a noninverting output of order four. In this paper, the zeta converter model is developed utilizing the state-space averaging technique. A fourth-order test system is considered which is converted into an interval system by assuming a variation of ±10% in equivalent series resistances (ESRs) of inductances and capacitances due to temperature variations. This modeled interval system is then converted to a lower order system, by reducing the numerator using the direct truncation method and the denominator is reduced using the Routh approximation method with the help of interval arithmetic rules. The step, impulse, and frequency responses are plotted for proposed reduced models.