**2. Transfer functions of the boost-type DC-DC converter**

In this study, a single-phase boost-type DC-DC converter was used as a plant. **Figure 1** shows the circuit diagram of the plant. To obtain the transfer function of this plant, a modeling method called the state-space averaging method was used. In this section, various transfer functions used for designing the control system of the DC-DC converter are described.

### **2.1 Derivation of the transfer function model using the state-space averaging method**

The switching converter is a time-varying circuit in which the state of the circuit can be set to either ON or OFF. Therefore, the state-space averaging method [11–13], which averages the circuit by a duty ratio, was used. The derivation for obtaining the transfer function of the switching converter using the state-space averaging method is shown below.
