Trends in Power Electronics for High-Power Applications

Transcription

1 Trends in Power Electronics for High-Power Applications 1 Hirofumi (Hiro) Akagi November 5, 2018 IEEE PEAC, Shenzhen, China

2 Outline of Presentation Medium-Voltage, High-Power, High-Speed Motor Drives Bidirectional Isolated DC-DC Converters Using the Latest SiC-MOSFET Modules 2

3 Outline of Presentation Medium-Voltage, High-Power, High-Speed Motor Drives Bidirectional Isolated DC-DC Converters Using the Latest SiC-MOSFET Modules 3

4 A Real-Time Real-Power Emulator of a High-Power High-Speed Motor Drive K. Saito and H. Akagi, A Real-Time Real-Power Emulator of a Medium-Voltage High- Speed Induction Motor Coupled With a Mechanical Load, IEEE ECCE-USA, Sep. 2018, pp

5 Why are Real-Time Real-Power Emulators Useful? Real Inverters Under Test Real-Time Real Power Emulators Cables Converter + Controller Gate signals Gate signals Controller Whey are they useful in practice? 1. Easy to change motor-and-load parameters 2. No mechanical setup 5 [1] TEXAS INSTRUMENTS, [Online], Available: [2] Meidensha, [Online], Available:

6 Experimental System (200 V, 10 kw, and 300 Hz ) Two Modular Multilevel Double-Star Chopper-Cell (DSCC) Converters Inverter Under test Motor-load emulator 400 V 22% Common-mode inductor 6 Eight Chopper cells/arm Phase-shifted-carrier PWM V C * = 50 V C = 6.6 mf f sw = 1.5 khz Speed Motor Load x 1 +x 2 0 ~ 9000 r/min Squirrel-cage induction motor (four pole) Quadratic torque-to-speed 22% (leakage inductance) 200-V, 10-kW, 300-Hz base

7 Photo of the Downscaled Test Bench Inverter Under Test Motor-Load Emulator 7 Controller and Date- Acquisition Systems

8 Tested inverter : Current control Control of the Emulator i 1γ, i 1δ Emulator : Voltage control Auxiliary Inductor γ v con v con δ DSCC converter Reference voltages of the converter 8 γδ axis v con γ * * v δ con = Induction motor impedance matrix, considering voltage drop across the inductor i 1γ i 1δ i 2γ i 2δ Detected (Stator) Calculated (Rotor)

9 Startup Performance Speed rpm Reference ( = 300 Hz) 4500 [ rpm ] Load torque Motor torque [ N m ] Line-to-line voltage [ V ] Stator current [ A ] s 40% of static friction (0 ~ 300 r/min) 100% IEEE PEAC No Reprint Without Authorization 7.4% Acceleration torque

10 10 Stator currents [ A ] Magnetizing current [%] Torque current [%] i 2γ / I 1γ * (Rotor current) [%] -i 2δ (Rotor current) [%] Transient Performance (Step Response) ms Reference value (Step change) Theoretical waveform Time constant = 237 μs Time constant = 240 μs Calculated in the emulator

11 Outline of Presentation Medium-Voltage, High-Power, High-Speed Motor Drives Bidirectional Isolated DC-DC Converters Using the Latest SiC-MOSFET Modules 11

12 Bidirectional Isolated DC-DC Converters Using the Latest SiC-MOSFET Modules H. Akagi, Bidirectional Isolated DC-DC Converters Using 1.2-kV 400-A SiC-MOSFET Modules: A Success Story of Conversion-Efficiency Improvements, IEEE ECCE-USA, Sep. 2018, Special session 12

13 Conversion-Efficiency Improvements: Why? Higher conversion efficiency or lower power loss makes any power conversion system more compact in size and lighter in weight. This brings manufactures to cost reductions in their products unless IEEE they PEAC use 2018 platinum No or Reprint gold. Without Authorization 13 DeDoncker, Divan, and Khealuwala, IEEE Trans. IA, 1991.

14 Conversion Efficiency: Past and Present Switching Devices Core Material in Transformer Efficiency (DC to DC) khz (1) DeDoncker, Divan, and Khealuwala, IEEE Trans. IA, (1) 2005 (Tokyo Tech) 2018 (Tokyo Tech) Planar-Gate Si-IGBTs Ferrite Below kw, 50 khz Trench-Gate Si-IGBTs FINEMET TM * (18 μm) kw, 20 khz Latest Planer-Gate SiC-MOSFETs FINEMET TM * (14 μm) kw, 20kHz * Nano-crystalline soft-magnetic material from Hitachi Metals 14

15 Experimental System (750 Vdc, 100 kw, 20 khz) P loss P i dc 20 khz 750 V v ac1 i ac1 i ac2 v ac2 1 : 1 15 η = P out P loss + P out The Latest 1.2-kV 400-A SiC-MOSFET H-Bridge Modules IEEE Measurement PEAC 2018 Error No < Reprint 0.02% Without Authorization

16 SiC-MOSFET/SBD H-Bridge Module on the Market 16

17 Waveform Comparison at 750 Vdc, 100 kw, 20 khz Dual Module (2016) H-Bridge Module (2018) vac1 0 [kv] vac2 0 [kv] V (ΔV = 330 V) 890 V (ΔV = 140 V) 50 μs 50 μs iac1 0 [A] δ = δ = 27.8 η = 98.9% η = 98.3% IEEE PEAC 2018 No Reprint WithoutTokyo Authorization Institute of Technology No Change in Magnetics

18 Questions to the Optimum Operating Frequency Q1: Do the transformer and auxiliary inductors get smaller and lighter as the operating frequency gets higher? A1: The answer is theoretically YES, but practically NO. It depends strongly on the characteristics of the magnetic cores used for the transformer and the auxiliary inductors. Q2: Is the switching loss proportional to the operating frequency? A2: The answer is YES, without any exception. Q3: What is the optimum operating frequency? A3: In a range of 16 khz to 100 khz over a power rating of 50 kw. 18 The answer is decided mainly by the selection of magnetic cores from characteristics, as well as cost and availability on the market.

19 Active Devices and Passive Components Today s Main Player: Active Devices (Si-IGBTs, SiC-MOSFETs, and so on) Today s Supporting Players: Passive components (transformers, inductors, and capacitors), sensors, signal-processing devices, and so on Tomorrow s Main Players: Passive Components and Active Devices 19 Their Roles in Power Electronic Circuits and Systems for High-Power Medium-Frequency Applications Be careful of the two font sizes!

20 Thanks for your Attention! 20 was inaugurated in 1881.