Soft-Switching Technology for Three-phase Power Electronics Converters. Rui Li

in space complex plane.Figure 6.5 The voltage and current waveforms in a utility cycle.Figure 6.6 Sectors in space vector diagram.Figure 6.7 Three‐phase main bridges’ equivalent circuits of four vectors in ...Figure 6.8 The dendrogram analysis of switching commutation sequences betwee...Figure 6.9 Three kinds of space vector sequences with one Type 2 commutation...Figure 6.10 Driving logic waveform in Sector 1‐1.Figure 6.11 Voltage and current waveforms, current polarity regions, and sec...Figure 6.12 Voltage and current waveforms, current polarity regions, and sec...Figure 6.13 Synthesis of v_ref in Sector 1‐1 when π/6 <φ < π/2.Figure 6.14 State transitions with preferred vector sequence in Sector 1‐1 w...Figure 6.15 Key waveforms in Sector 1‐1.Figure 6.16 Equivalent circuit of stage 1:

stage.Figure 6.17 Equivalent circuit of stage 2: the first resonance stage.Figure 6.18 Equivalent circuit of stage 3: the diode freewheeling stage.Figure 6.19 Equivalent circuit of stage 4: the diode reverse recovery stage....Figure 6.20 Equivalent circuit of stage 5: the second resonance stage.Figure 6.21 Equivalent circuit of stage 6:

stage.Figure 6.22 Equivalent circuit of stage 7: the first Type 1 commutation stag...Figure 6.23 Equivalent circuit of stage 8:

stage.Figure 6.24 Equivalent circuit of stage 9: the second Type 1 commutation sta...Figure 6.25 Equivalent circuit of stage 2 (t₁–t₂): the first resonance stage...Figure 6.26 Equivalent circuit of stage 5 (t₄–t₅). (a) Circuit state of the ...Figure 6.27 Gate signal derivation in Sector 1‐1.Figure 6.28 Control block diagram of the MVAC inverter.Figure 6.29 Topology of the ZVS inverter.Figure 6.30 T _r1 versus resonant parameters.Figure 6.31 λ ₇ versus Z_r..Figure 6.32 i _res /I_m versus resonant impedance Z_r..Figure 6.33 Resonant impedance Z_r versus resonant parameters.Figure 6.34 CM200DU‐24NFH IGBT turn‐off loss under ZVS conditions.Figure 6.35 Recommended resonant parameters area.Figure 6.36 Experimental circuit.Figure 6.37 Output current and grid voltage.Figure 6.38 Voltage and current waveforms of the bridge switch.Figure 6.39 Voltage and current waveforms of the auxiliary switch.Figure 6.40 The resonant branch current and auxiliary switch voltage.Figure 6.41 Voltage across C_Cl and current through L_r.Figure 6.42 Measured efficiency.

      7 Chapter 7Figure 7.1 Topology of the CAC ZVS three‐phase inverter.Figure 7.2 Sectors of space vector diagram.Figure 7.3 Equivalent circuits of four vectors in sector 1‐1: (a) vector 111...Figure 7.4 Vector sequences with four vectors: starting with (a) 111, (b) 00...Figure 7.5 Vector sequences with two nonzero vectors and zero vector 000: st...Figure 7.6 Vector sequences with two nonzero vectors and zero vector 111: st...Figure 7.7 Driving sequence of ZVS‐SVM in sector 1‐1 within one switching pe...Figure 7.8 Key waveforms in sector 1‐1.Figure 7.9 Equivalent circuit of the first steady stage.Figure 7.10 Equivalent circuit of the first resonant stage.Figure 7.11 Equivalent circuit of diode freewheeling stage.Figure 7.12 Equivalent circuit of Type 2 commutation stage.Figure 7.13 Equivalent circuit of short-circuit stage.Figure 7.14 Equivalent circuit of the second resonant stage.Figure 7.15 Equivalent circuit of the second steady stage.Figure 7.16 Equivalent circuit of the first Type 1 commutation stage.Figure 7.17 Equivalent circuit of the third steady stage.Figure 7.18 Equivalent circuit of the second Type 1 commutation stage.Figure 7.19 Simplified equivalent circuit of the first resonant stage.Figure 7.20 Simplified equivalent circuit of the second resonant stage.Figure 7.21 Modification of short circuit pulse: (a) previous driving sequen...Figure 7.22 Driving sequences derivation: (a) sector 1‐1 and (b) sector 1‐2....Figure 7.23 Control block diagram of CAC ZVS three‐phase inverter.Figure 7.24 Turn‐off loss with paralleled buffer capacitor C_b.Figure 7.25 Region for selecting resonant parameters.Figure 7.26 30 kW ZVS inverter prototype.Figure 7.27 Bus bar and structure 30 kW ZVS inverter prototype.Figure 7.28 Prototype of resonant inductor.Figure 7.29 Filter inductor.Figure 7.30 Experimental circuit.Figure 7.31 Output current and grid voltage.Figure 7.32 Voltage and current waveforms of the bridge switch.Figure 7.33 Voltage and current waveforms of the auxiliary switch.Figure 7.34 Voltage across C_cl and current through L_r.Figure 7.35 Measured efficiency vs. output power.

      8 Chapter 8Figure 8.1 Topology of the CAC ZVS three‐phase grid inverter.Figure 8.2 Sectors of space vector diagram.Figure 8.3 Key waveforms in sector 1‐1.Figure 8.4 Equivalent circuit of the first steady stage.Figure 8.5 Equivalent circuit of the first resonant stage.Figure 8.6 Equivalent circuit of the diode freewheeling stage.Figure 8.7 Equivalent circuit of the Type 2 commutation stage.Figure 8.8 Equivalent circuit of the short‐circuit stage.Figure 8.9 Equivalent circuit of the second resonant stage.Figure 8.10 Equivalent circuit of the second steady stage.Figure 8.11 Equivalent circuit of the first Type 1 commutation stage.Figure 8.12 Equivalent circuit of the third steady stage.Figure 8.13 Equivalent circuit of second Type 1 commutation stage.Figure 8.14 Demonstration of conduction loss models.Figure 8.15 Turn‐off loss measurement circuit and key waveforms.Figure 8.16 Fitted turn‐off loss function of device 1.Figure 8.17 Definitions of the unified inductor model.Figure 8.18 Measurement setup of magnetic core loss.Figure 8.19 Core losses per volume under different frequencies.Figure 8.20 Demonstration of the filter inductor.Figure 8.21 Average value of the volume over capacitance.Figure 8.22 Shape and dimensions of selected heat sink.Figure 8.23 Thermal model of the heat sink.Figure 8.24 3D model of the heat sink with IGBT devices.Figure 8.25 Procedures of optimization design.Figure 8.26 Optimization results of different switching modules.Figure 8.27 Prototype of the improved resonant inductor.Figure 8.28 Prototype of the improved filter inductor.Figure 8.29 Prototype of the improved clamping capacitor.Figure 8.30 Experimental circuit.Figure 8.31 Measured conversion efficiency.Figure 8.32 Measured efficiency and power density.

      9 Chapter 9Figure 9.1 Current and voltage waveforms of the resonant inductor.Figure 9.2 Inductor with air gap.Figure 9.3 Equivalent magnetic circuit model.Figure 9.4 Window area A_e and cross‐section area A_c.Figure 9.5 Triangular inductor current.Figure 9.6 Design flowchart.Figure 9.7 EE55A shape size.Figure 9.8 Sinusoidal components of different frequencies.Figure 9.9 The barrel winding structure.Figure 9.10 Winding loss of different frequencies.Figure 9.11 The definition of the winding.Figure 9.12 Winding loss of each turn in the first order AC component.Figure 9.13 Distribution of winding loss and magnetic field lines.Figure 9.14 The position definition in the core window: (a) 0%; (b) 100%.Figure 9.15 Winding loss in different positions.Figure 9.16 Distribution of winding loss in different positions.Figure 9.17 Winding loss under different winding thickness.Figure 9.18 Distribution of winding loss under different winding thickness....Figure 9.19 Flat winding structure.Figure 9.20 Different structures: (a) structure 1: laminated structure; (b) ...Figure 9.21 Winding loss in different structures.Figure 9.22 Distribution of winding loss in the laminated structure.Figure 9.23 Distribution of winding loss in the interleaved structure.Figure 9.24 Distribution of winding loss and magnetic field lines.Figure 9.25 The position defined in the core window: (a) 0%; (b) 100%.Figure 9.26 Winding loss in different positions.Figure 9.27 Winding loss under different winding thicknesses.Figure 9.28 Distribution of winding loss under different winding thicknesses...Figure 9.29 Comparison of the different winding structures: (a) winding loss...Figure 9.30 Simulation results in a switching period.Figure 9.31 Structure of the resonant inductor.Figure 9.32 Experimental prototype of the resonant inductor.Figure 9.33 Voltage and current of the resonant inductor at 30 kW.Figure 9.34 Experimental tests of winding and core temperature.

      10 Chapter 10Figure 10.1 Topology of traditional hard‐switching SiC three‐phase grid inve...Figure 10.2 Grid voltages and grid currents waveforms of unity power factor ...Figure 10.3 Voltage space vector diagram with 12 subsectors.Figure 10.4 Switching patterns of SVM 12: (a) sector 1‐1 and (b) sector 1‐2....Figure 10.5 Topology of soft‐switching SiC three‐phase grid inverter.Figure 10.6 Switching patterns of ZVS‐SVM in sector 1‐1.Figure 10.7 Waveforms of the key components in one switching period in secto...Figure 10.8 Equivalent circuit of the resonant stage for ZVS of the main swi...Figure 10.9 Equivalent circuit of the three‐phase bridges' short‐circuit sta...Figure 10.10 Equivalent circuit of the resonant stage for ZVS