Title Page
Contents
ABSTRACT 10
Ⅰ. Introduction 12
1.1. Background 12
1.2. Chapter description 14
Ⅱ. Three-Phase common mode inductor introduction 15
Ⅲ. Analytical model of a dual-winding three-phase common-mode inductor 22
3.1. CM inductor 23
3.2. Losses and associated resistance 25
3.2.1. Core loss 25
3.2.2. Winding equivalent resistance 26
3.3. Parasitic shunt capacitance 28
3.4. Leakage and saturation issues 34
Ⅳ. Inductor winding capacitance elimination for EMI suppression 36
4.1. Common mode inductor equivalent circuit 38
4.2. Elimination of parasitic capacitance 39
Ⅴ. Model and experimental verification and analysis 43
5.1. Inductive impedance verification 43
5.2. Winding leakage and core saturation verification 50
5.3. Common mode inductor wirewound capacitance elimination designs 53
5.4. Applications to EMI filters 59
5.5. Filter verification 61
Ⅵ. Summary of the paper 65
References 69
Appendix 74
Abstract (in Korean) 76
TABLE 5-1. Specifications of HF three-phase CM inductor 45
TABLE 5-2. Leakage inductances measured at 10kHz 50
〈Figure 2-1〉 Construction of a three-phase CM inductor 15
〈Figure 2-2〉 Circuit diagram of three-phase CM inductor models: (a) three coupled inductors; (b) three-winding transformer 17
〈Figure 2-3〉 Distributions of the magnetic field (Hcm) and flux density (Bcm) for the CM currents[이미지참조] 19
〈Figure 3-1〉 Single-phase common-mode (CM) equivalent circuit model of the three-phase CM inductor 22
〈Figure 3-2〉 Typical permeability versus frequency curves 24
〈Figure 3-3〉 Stray capacitance network for single-layer winding inductors 28
〈Figure 3-4〉 The analytical model for calculating the stray capacitance in winding is described in reference 29
〈Figure 3-5〉 The winding stray capacitance as functions of α=p/φo (φo :0.53 mm, φw : 0.50 mm, lT : 33.8 mm, and εɤ : 3.3)[이미지참조] 30
〈Figure 3-6〉 The winding stray capacitance of a three-phase CM inductor for high frequency consists of the turn-to-turn capacitance... 32
〈Figure 3-7〉 Stray capacitance networks for high frequency three-phase CM inductor 33
〈Figure 3-8〉 Simplified magnetic field path for the leakage field 34
〈Figure 4-1〉 Actual toroidal inductor model 36
〈Figure 4-2〉 Parasitic common mode inductor model 37
〈Figure 4-3〉 Typical equivalent circuit for coupled CM inductors: (a) equivalent circuit and (b) the decoupled circuit 38
〈Figure 4-4〉 Winding capacitance cancellation for CM inductors: (a) two capacitors connected to the centre taps of both windings... 40
〈Figure 4-5〉 Cα canceled network[이미지참조] 42
〈Figure 5-1〉 Pictures of HF three-phase CM inductors: (a) CM1. (b) CM2. (c) CM3. (c) CM4 45
〈Figure 5-2〉 The CM impedance and the phase curves of CM-1 and CM-2 derived from the measurement and the analyses 47
〈Figure 5-3〉 The CM impedance and the phase curves of CM-3 and CM-4 derived from the measurement and the analyses 49
〈Figure 5-4〉 Inductance measurements for evaluating the leakage inductance of three-phase CM inductors 51
〈Figure 5-5〉 Simulation topology diagram 53
〈Figure 5-6〉 Insertion voltage gain for two different inductors 54
〈Figure 5-7〉 Conventional common mode inductor winding structure does not have high enough coupling coefficient 55
〈Figure 5-8〉 Cα Bad cancellation at high frequencies due to leakage inductance of conventional winding structur[이미지참조] 55
〈Figure 5-9〉 A winding strategy to increase the coupling coefficients of the three half-windings is proposed 57
〈Figure 5-10〉 Improved inductor performance through winding capacitance elimination 58
〈Figure 5-11〉 Build L type EMI filters 60
〈Figure 5-12〉 Eliminating Cα improves CM filter performance at high frequencie[이미지참조] 60
〈Figure 5-13〉 LCR circuit topology 61
〈Figure 5-14〉 Experimental graphics 62
〈Figure 5-15〉 Comparison of filtering results 64