An Accurate and Practical Core Loss Analysis for Compact High Step-Up Converters

A core loss analysis method is presented for compact converters generating a high output voltage. The proposed method focuses on analyzing the core loss of asymmetrical and discontinuous current to design compact converters with a high efficiency. Owing to the proposed method, an accurate core loss for asymmetrical and discontinuous current can be analyzed intuitively and practically, without additional measurement data in a wide frequency range. A compact high step-up converter is presented as an example to demonstrate the validity of the proposed analysis method through measurement results. This method can also be utilized for analyzing core losses in various compact switching mode power supplies that operate in discontinuous conduction mode.

I. Introduction

High step-up converters are widely used in plasma applications, battery power systems, fuel cell systems, and photovoltaic systems. To increase the step-up ratio and power efficiency, various topologies of high step-up converters have been reported [1]–[11]. For high efficiency, most topologies operate in continuous conduction mode (CCM) at maximum output power. Since CCM operation requires a large volume inductor, which is the most bulky component in a converter, these converters become considerably large. However, industry still needs much more compact converters to reduce production costs and increase portability [12]. In particular, as the effectiveness of plasma treatments on cells [13] and human skin [14]–[15] have been reported, the demand for portable plasma generators is increasing. In addition, previous papers have explained that higher dv/dt and higher voltage above several kV increase the effectiveness of such treatments [15]–[17] and prevent the excitation of muscle and nerve tissues [18]. Therefore, compact step-up converters with a much high step-up ratio are required for plasma treatments on human skin.