클램핑 전압원 회로 기반 위상천이 풀-브릿지 컨버터의 고효율·고전력밀도 달성을 위한 하이브리드 스위칭 기법 = Hybrid Switching Technique for High Efficiency and High Power Density Phase-Shifted Full-Bridge Converter Using Clamping Voltage Source Circuit

다국어 초록 (Multilingual Abstract)

This paper proposes a novel hybrid switching technique to improve the limitations of clamping voltage source circuit under low effective duty-ratio conditions. In phase-shifted full-bridge (PSFB) converter employing clamping voltage source circuit, operation under low effective duty ratio causes an extended discharging interval of the clamping capacitor. As a result, increased clamping capacitor requirements, increased primary-side peak and RMS current, the requirement for small magnetizing inductance, and still-large output inductor are observed.
To overcome these limitations, a hybrid switching technique combining pulse-width modulation (PWM) and pulse-frequency modulation (PFM) is proposed. Unlike the conventional method, which operates solely based on phase-shifted PWM, the proposed method applies both PWM and PFM schemes. The proposed technique is experimentally validated using a 1.6 kW prototype designed for an input voltage range of 240-410 V and an output specification of 48 V / 33.4 A. At an input voltage of 410 V and an output condition of 48 V / 33.4 A, the proposed method improves the efficiency from 92.5% to 94.1%, achieving an efficiency enhancement of approximately 1.6%. In addition, the reduced burden on the clamping capacitor and the output inductor confirms an improvement in power density.

목차 (Table of Contents)

• 1. Introduction 1
• 1.1 Research Background 1
• 1.2 DC-DC Converters Used in EVs 3
• 1.3 Previous Research on PSFB Converter 5
• 1.4 PSFB Converter Using CDD Clamping voltage Circuit 6
• 2. Concept and Operational Principle of the Proposed Method 11
• 2.1 Concept of the Proposed Method 11
• 2.2 Operational Principle of the Proposed Method 14
• 3. Steady-State Analysis 21
• 3.1 Voltage Gain 21
• 3.2 Clamping Capaciotor Cc 24
• 3.3 Filter Requirement 26
• 3.3 ZVS Conditions 28
• 4. Experimental Verification and Analysis 31
• 4.1 Experimental Setup 31
• 3.2 Experimental Results 34
• 5. Conclusion 43
• References 44
• Summary (Korean abstract) 50