Eidgenössische Technische Hochschule Zürich Laboratory for High Swiss Federal Institute of Technology Zurich Power Electronic Systems
Solid State Modulators – Efficiency Considerations focussing on SiC Devices –
J. Biela, S. Stathis, M. Jaritz, and S. Blume www.hpe.ee.ethz.ch / [email protected] Typical Topology of Solid State Pulse Modulator Systems
AC/DC rectifier unit DC/DC converter for charging C-bank / voltage adaption Pulse generation unit Load e.g. klystron
Constant Power Pulsed Power
AC DC Energy Storage
Pulse Klystron Modulator Load DC DC Grid Medium Voltage ⎧⎪⎪⎪⎨⎪⎪⎪⎩ Sometimes integrated V V V V
t
Pulse t t t Pulse 400V or MV Intermediate Buffer Capacitor Bank Pulse Voltage
High Power 2 33 Electronic Systems Typical Topology of Solid State Pulse Modulator Systems
Grounded klystron load I Isolation with 50Hz transformer or I Isolated DC-DC converter
Typical Isolation
AC DC Energy Storage
Pulse Klystron Modulator Load DC DC Grid Medium Voltage
V V V V
t
Pulse t t t Pulse 400V or MV Intermediate Buffer Capacitor Bank Pulse Voltage
High Power 3 33 Electronic Systems 29 MW(35MW)/140 µs Modulator for CLIC – System Efficiency –
High Power Electronic Systems CLIC System Specifications
Output voltage 150...180 kV Settling time <8 µs Output power (pulsed) 29 MW (- 35 MW) Repetition rate 50 Hz Flat-top length 140 µs Average output power 203 kW (- 245 kW) Flat-top stability (FTS) <0.85 % Pulse to pulse repeatab. <100 ppm Rise time <3 µs
819 klystrons 819 klystrons 15 MW, 142 µs circumferences 15 MW, 142 µs delay loop 73 m drive beam accelerator CR1 293 m drive beam accelerator (c)FT 2.4 GeV, 1.0 GHz CR2 439 m 2.4 GeV, 1.0 GHz 2.5 km 2.5 km delay loop delay loop CR2 CR2 Drive Beam CR1 CR1 decelerator, 24 sectors of 878 m
BC2 BC2 BDS BDS 2.75km 2.75km – IP + TA e main linac, 12 GHz, 100 MV/m, 21 km e main linac TA
48.3 km CR combiner ring Main Beam TA turnaround DR damping ring PDR predamping ring booster linac BC bunch compressor 2.86 to 9 GeV BDS beam delivery system IP interaction point BC1 dump e– injector, e+ injector, 2.86 GeV e– e– e+ e+ 2.86 GeV PDR DR DR PDR 389 m 427 m 427 m 389 m
High Power 5 33 Electronic Systems CLIC Solid State Modulator – System Overview
AC/ DC Unit Interleaved Boost Converter Switching Unit
750V 3kV 3kV 400V -180kV 3kV AC 750V DC -180kV 400V Klystron Voltage Load Grid DC DC
0-300V DC 3kV 450V
DC Active 0V Bouncer 300V
Matrix Transformer
High Power 6 33 Electronic Systems CLIC Modulator – Grid/Isolation Transformer
Voltage 3×400 V to 3×400 V @ 250 kVA Core material Silicon steel Winding material Aluminium Weight 890 kg Efficiency 98.8 % (PCore = 700W & PWdg = 2.3kW)
Higher efficiency
I Better core material E.g. Amorphous (PCore − 60%) I Copper winding Higher conductivity (PWdg − 35%) I Efficiency ¬ ≈99.2 % (Estimated) (Larger volume ¬ Higher efficiency)
AC DC
DC Grid
DC DC DC Isolation PFC Boost Converter Bouncer Switching Unit Pulse Transformer Rectifier (Droop Compensation) Transformer
High Power 7 33 Electronic Systems +
CLIC Modulator – AC/DC Converter Efficiency
Type (B&R) ACOPOSmulti 8BVP1650 Topology 2-level PFC-rectifier Switches 1.2 kV Si IGBTs Voltage conversion 400 VAC → 750 VDC (620 V – 800 V) Efficiency 97.47 %
Higher efficiency
I 1.2 kV SiC MOSFETs Lower PCond & PSW I Optimised design E.g. higher volume / lower fSW I Efficiency ¬ ≈99 %
+
AC DC
DC Grid
DC DC DC Isolation PFC Boost Converter Bouncer Switching Unit Pulse Transformer Rectifier (Droop Compensation) Transformer
High Power 8 33 Electronic Systems CLIC Modulator – Boost Converter Basic Operation
Input voltage 600 V – 800 V Output voltage 3 kV Switching frequency 70 kHz – 240 kHz T1 T2 T3 T4 T5 Output power 40 kW
I L L ... Imax 650 V Si MOSFETs 8 in series I ¬ Cs/R for balancing L Boundary cond. mode t Sn Imin 6-fold interleaving ¬ 6 × 40 kW ...
vCd,tot vCs,tot VDC
S1 ZVS ZVS off on t
AC DC
DC Grid
DC DC DC Isolation PFC Boost Converter Bouncer Switching Unit Pulse Transformer Rectifier (Droop Compensation) Transformer
High Power 9 33 Electronic Systems CLIC Modulator – Boost Converter Efficiency
Nom. voltages 750 V → 3 kV ... Output power 40 kW Switching frequency 70 kHz – 240 kHz Sn 8×650 V Si MOSFETs 2× Infineon IPZ65R019C7 ... 4×1.2 kV diodes Microsemi APT75DQ120B Efficiency 97.2 %
S1
Fans Inductor Output capacitors Snubber Capacitor 2% HV output Boost Diode Inductor Switching 11% Power 3% input MOSFET Diode Conduction Conduction 58% Input fuse 20%
MOSFET Switching 6% Input capacitors PCB with isolated gate drives
High Power 10 33 Electronic Systems CLIC Modulator – "SiC" Boost Converter
Voltages 750 V → 3 kV ... Switching frequency 70 kHz – 240 kHz Higher efficiency Sn I 4×1.2 kV SiC MOSFETs 2×C3M0016120K ... I 4×1.2 kV SiC Diodes 2×IDW40G120C5B I Efficiency ≈ 98.6 % (Old: 97.2 %)
S1
Snubber Capacitor 4%
700 W Si-based Converter 600 W MOSFET SiC-based Converter Boost Conduction 500 W Inductor 25% 46% 400 W
300 W
200 W Diode Conduction 100 W 22% W MOSFET MOSFET MOSFET Diode Diode Switching 3% Conduction Switching Conduction Switching
High Power 11 33 Electronic Systems Conduct. Losses 13%
Switching Losses 87%
CLIC Modulator – Switching Unit
ABB StakPak 4.5 kV / max. 3 kA (pulsed) (5SNA1250B450300) Active reset switch 4 units in parallel Pulse current 4 × 2.4 kA (@ PP = 29 MW ) Efficiency 98.6 % (Switching losses: 87% of Ptot)
Higher efficiency I Semiconductors SiC MOSFETs (assumption: 1.2 kV devices) (4 in series / 3 parallel) I Efficiency ¬ 99.5 %
AC DC
DC Grid
DC DC DC Isolation PFC Boost Converter Bouncer Switching Unit Pulse Transformer Rectifier (Droop Compensation) Transformer
High Power 12 33 Electronic Systems CLIC Modulator – Bouncer
Output voltage 0...300 V (10 % droop) Input voltage 450 V 24-fold interleaving Ultra low ripple Semiconductors IGBTs
3kV DV=300V V main Vtotal
+ S DHS HS Cmain L 300V b
SSC Vb,out SLS DLS Active Bouncer Module
AC DC
DC Grid
DC DC DC Isolation PFC Boost Converter Bouncer Switching Unit Pulse Transformer Rectifier (Droop Compensation) Transformer
High Power 13 33 Electronic Systems CLIC Modulator – Bouncer Operating Principle
Output voltage 0...300 V Input voltage 450 V
S DHS Output current (pulse) >600 A HS Cmain L (per module) b
SSC SLS DLS Active Bouncer Module
Wait for trigger VBout shortened } } 625A i b V 3.0kV main 2.7kV V 450V Bin
VBout
Wait tk Pre- Interpulse for next Pre- charge Pulse Resonant Recharging pulse charge
High Power 14 33 Electronic Systems CLIC Modulator – Bouncer Components
Output voltage 0...300 V Input voltage 450 V
S DHS 4×6-fold interleaving HS Cmain L Switching frequency 100 kHz b Per module: SSC SLS DLS I SLS-IGBTs 2×IGW50N65H5 Active Bouncer Module I DLS-Diodes 4×IDW40E65D1 I SHS-IGBTs (w. diode) 6×IKW50N65F5 I SSC-IGBTs (w. diode) 6×IKW50N65F5 I Inductor Lb = 26 µH 4×Metglas AMCC32
Control board
Buck-boost switch Short circuit switch
High Power 15 33 Electronic Systems CLIC Modulator – Bouncer Efficiency
With IGBTs I Total AVG losses 1.56 kW
I Module efficiency 91.0 % Bouncer-Level S DHS HS Cmain ¬ Efficiency 99.4 % System-Level Lb
SSC SLS DLS Active Bouncer Module
HS IGBTs conduct. 7%
Inductor 625A losses 18%
HS IGBTs switching HS diodes 3% 51%
SC IGBTs 3% ib
LS IGBTs 4% LS diodes 14%
tk
High Power 16 33 Electronic Systems CLIC Modulator – SiC Bouncer Efficiency
With IGBTs I Total AVG losses 1.56 kW
I Module efficiency 91.0 % Bouncer-Level S DHS HS Cmain ¬ Efficiency 99.4 % System-Level Lb
SSC SLS With SiC MOSFETs DLS I Total AVG losses 0.79 kW Active Bouncer Module I Module efficiency 95.2 % Bouncer-Level ¬ Efficiency 99.7 % System-Level
Inductor losses 35%
800W Si-based converter HS diodes HS SW 600W 5% conduction 12% SiC-based converter SC SW 4% 400W LS SW HS SW switching 200W 9% 8%
W LS diodes HS switch HS switch LS diodes LS switch SC switch 27% conduction switching
High Power 17 33 Electronic Systems CLIC Modulator – Pulse Transformer
Matrix transformer 2 cores / 4 primary windings Turns ratio 62 ¬ 4:(2×124) Core material SiFe / 50 µm
Vsek RLoad
I Ipri,1 pri,3 S M,1 SM,3 Df,1 Df,3
I Ipri,2 pri,4 S M,2 SM,4 Df,2 Df,4
AC DC
DC Grid
DC DC DC Isolation PFC Boost Converter Bouncer Switching Unit Pulse Transformer Rectifier (Droop Compensation) Transformer
High Power 18 33 Electronic Systems CLIC Modulator – Pulse Shape/Transformer Efficiency
Rise + settling time 4.6 µs Fall time <3 µs Flat top 140 µs Efficiency 96.7 % (Trafo + Pulse shape)
Reverse voltage Time to Fall flat top Time
t “Dissipated” pulse “energy” Pulse Shape Winding Losses 88% 4% Core Losses 8% Flat top (Used pulse “energy”)
Allowed droop
High Power 19 33 Electronic Systems CLIC Modulator – Higher Transformer Efficiency
Core material SiFe 25 µm lamination Amorphous material Insulating oil Ester 7131 εr = 3.2 ¬ Mineral oil εr = 2.2 Shorter load cable Transformer design Critical damping (slightly underdamped) Larger volume / Core splitting
Estimated efficiency ≈ ≥97.5 %
0.98 Mineral oil CLIC trafo @12kV/mm 1.5m cable 0.975 Mineral oil @10kV/mm 1.5m cable 0.97 Natural ester @10kV/mm 1.5m cable 0.965
Efficiency (%) 0.96 Mineral oil @10kV/mm 5m cable Natural ester @10kV/mm 0.955 5m cable
1.05 1 0.95 0.9 0.85 0.8 0.75 0.7 0.65 Transformer volume (m3)
High Power 20 33 Electronic Systems CLIC Modulator – System Efficiency
Original System Improved System
Grid Trans- Pulse Shape/ Pulse Shape/ former 10% Transformer Transformer 39% 28% Grid Trans- former PFC 12% Bouncer 21% Bouncer 5% 5% Switching Switching Unit 8% Unit 12% PFC 24.8kW 15%
Booster Booster 21% 24% 13.4kW
Conventional SiC-based
88.7% Original 98.8% 97.5% 97.2% 99.4% 98.6% 96.7% Improved 99.2% 99.0% 98.6% 99.7% 99.5% 97.5% 93.6% AC DC
DC Grid
DC DC DC Isolation PFC Boost Converter Bouncer Switching Unit Pulse Transformer Rectifier (Droop Compensation) Transformer
High Power 21 33 Electronic Systems SwissFEL Modulator – Pulse Efficiency @ Short Pulses
Free electron laser ¬ X-Rays Electron beam energy 5.8 GeV Wavelength range 1 Å – 70 Å Output voltage 370 kV Output power (pulsed) 127 MW Flat-top length 3 µs Rise time <1 µs Repetition rate 100 Hz
High Power 22 33 Electronic Systems SwissFEL – Pulse Transformer
Matrix transformer 6 cores / 12 primary Turns ratio 1:21 × 6 ¬ 1:126 Core material SiFe / 50 µm Rise time ≈ 1 µs Fall time ≈ 0.9 µs ¬Pulse shape ≈ <82 %
High Power 23 33 Electronic Systems Solid State Modulators 2.88 MW / 3.5 ms Modulator for European Spallation Source (ESS)
High Power Electronic Systems ESS Modulator Specifications
Pulse power 2.88 MW Pulse voltage 115 kV Pulse width 3.5 ms Rise/fall time ≤ 150 µs Repetition rate 14 Hz
RF powering cell #1
Electrical pulsed Klystron SC cavity power RF power A #A Klystron modulator (Power Supply) Klystron RF power SC cavity
B Beam #B Electrical Network RF powering cell #N
Similar to RF powering cell #1
High Power 25 33 Electronic Systems ESS Modulator – Basic Configuration
Pulse power 2.88 MW DC Pulse voltage 115 kV Pulse width 3.5 ms Rise/fall time 150 µs ≤ DC Repetition rate 14 Hz
DC
DC
DC
Energy DC Storage R 400 V AC DC S 3-phase 50 Hz T DC Parallel DC Series connection connection
High Power 26 33 Electronic Systems ESS Modulator – Basic Configuration
Pulse power 2.88 MW Pulse voltage 115 kV Pulse width 3.5 ms Rise/fall time ≤ 150 µs
Repetition rate 14 Hz Balancing Circuit
CP Switching frequency 105 kHz DC-B1 S1 S2 CS LS 1 : n 12.5 A C C I CDL1 P P O1 Modules: 2 parallel / 9 in series S VDL1 B1 Iprim V 400 V sec Cf VO1
S3 S4 LDL 12.8 kV SPRC-Bm1 CP
CDL2 SB2 V DL2 SPRC-Bm2 12.8kV 400 V 2 SPRC-Bms ISOP stack
V DL3 SPRC-Bm3
400 V Klystron/IOT DC-B2 VO2 V DL4 SPRC-Bm4 400 V Vout 2 SPRC-Bms ISOP stack 115kV
AC V DL17 SPRC-Bm17 400 V 800 V 400 V
3-phase DC-B9 VO9 50 Hz Grid V DL18 SPRC-Bm18 DC 400 V PFC Rectifier 2 SPRC-Bms ISOP stack SPRC IPOS modulator system
High Power 27 33 Electronic Systems ESS Modulator – Series-Parallel Resonant Converter Module
H-bridge 650 V MOSFETs (STY139N65M5) Module loss distribution:
I H-bridge 221 W (179 W PCond) CP I Rectifier diode 78 W (APT60DQ120SG) S1 S2 1 : n 12.5 A I Series inductor 132 W (Air core with litz) CP CP I Series capacitor 56 W (NP0 / 896 pieces) 400 V I Parallel capacitor 18 W (NP0 / 864 pieces) Cf Σ 505 W (per module) S S 3 4 12.8kV SPRC-Bm1 CP
H-bridge: 6 x 650V MOSFETs in parallel Diodes LS
CS
CP
High Power 28 33 Electronic Systems ESS Modulator – Step-up Transformer/Pulse Shape
Transformer 2:40 / Midel 7131 trise Losses (per module) 0 I Core 73.4 W (2×4× UU126/20 / N87 ferrite) -20 I Primary winding 12.9 W (405 × 0.071mm / 18 parallel)
I Secondary winding 11.1 W (1125 × 0.071mm) -40 K1 V Rise time 107.8 µs (0→99%) -60 out Fall time 83.5 µs (100→10%) -80 Pulse shape (total) 97.8 % Falling Edge -100 -113.85 = 99 % of Vout -115 -120-0.05 0 0.05 0.1 0.15 Output voltage (kV) Time (ms) 20 20 10 % of V Primary-secondary Secondary out tfall t Primary bobbins fastening plate bobbin (POM) 2 t t 0 0 1 2 K -11.5 K 2 -20 1 -20
K2 -40 -40
22cm V out V -60 -60 out Secondary Primary bobbin -80 -80 Rising Edge -100 -100 22cm -115 -115 27.3cm -120 -120 0 0.5 1 1.5 2 2.5 3 3.5 4 3.45 3.5 3.55 3.6 3.65 3.7 Time (ms) Time (ms)
High Power 29 33 Electronic Systems ESS Modulator – Module Loss Distribution
Resonant converter 92.9 % (incl. transformer) (without pulse shape)
Parallel Rectifier Capacitor Diodes 2.9% 13.0%
Series Capacitor H-Bridge 9.2% 37%
CP S1 S2 1 : n 12.5 A Series Inductor CP CP 21.9% 400 V Transformer Cf 16% S S 3 4 12.8kV SPRC-Bm1 CP
High Power 30 33 Electronic Systems ESS Modulator – Converter with SiC
Improved efficiency I 1.2 kV SiC MOSFETs No balancing / Lower conduction losses I 1.7 kV SiC Diode Lower losses in rectifier 1 1 I Ls ⇒ 2 × Ls@ 2 I 2 × volume / 2 losses I New core material N97 instead of N87 ¬ New efficiency ≈ 94.4 % (+1.5% / Old: 92.9 %)
Further improvements I More parallel devices C I Higher f ¬ Shorter t /t P SW r f S1 S2 CS LS 1 : n 12.5 A C C I I Higher overrating ¬ Shorter tr/tf P P O1 800 V Iprim V sec V ¬ Cf O1 New system optimisation VO1 S S 3 4 12.8kV 2 x SPRC-Bm1 12.8 kV C IPOP P
250 W
Si-based Converter Klystron/IOT 2 x SPRC-Bm2 V 200 W 800 V O2 SiC-based Converter IPOP
150 W Vout 115kV
100 W
800V 50 W 2 x SPRC-Bm8 800 V IPOP VO9 W H-Bridge Transformer Series Series Parallel Rectifier Inductor Capacitor Capacitor Diodes SPRC IPOS modulator system
High Power 31 33 Electronic Systems ESS Modulator – System Efficiency & Loss Distribution
Si-based SiC-based I Resonant converter 92.9 % 94.4 % I PFC charging 97.5 % 99.0 % ⇒ Electrical system 90.5 % 93.5 %
I Pulse shape 97.8 % 97.8 % ⇒ Total efficiency 88.5 % 91.4 %
PFC Pulse Shape PFC Charging Charging 11.4% 17.8% Pulse Shape 20.3% 25.4% H-bridge Rectifier 19.2% 9.9%
Transformer H-bridge Rectifier 10.0% 22.7% 14.0% Resonant Resonant Tank Tank 19.3% Transformer 17.8% 12.1%
High Power 32 33 Electronic Systems Conclusion
Efficiency gain (Assuming "drop-in" replacement) I CLIC Modulator ∆η = +≈4.9 % ¬ ηSiC = 93.6 % I ESS Modulator ∆η = +≈2.9 % ¬ ηSiC = 91.4 %
Higher Efficiency I Switches/diode Wide band gap devices (parallel SIC MOSFETs...) I Core material SiFE 25 µm lamination or Amorphous Use of uncut cores I Insulating oil Ester 7131 εr = 3.2 ¬ Mineral oil εr = 2.2 I Transformer design Critical damping (slightly underdamped) Larger volume / Core splitting I Short load cable I Fix operating point η Efficiency Limit Power Density η-ρ-Pareto-Front Limit Efficiency Power Density ρ
High Power 33 33 Electronic Systems