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Current Monitoring for Power GaN Transistors-SenseGaN Technique

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A quick overview of the current sensing in power electronics converters is tested and analyzed. Then, SenseGaN technique along with the integration of semiconductors to monitor the power GaN module current without significant effects on power stage performance and opens a new era for smart devices in future power electronics. Various application for soft switching with this current measurement technique is also proposed.

Published in: Engineering

Current Monitoring for Power GaN Transistors-SenseGaN Technique

  1. 1. Current Mirroring of Power GaN Transistor- SenseGaN Technique By: Mehrdad Biglarbegian Team members: Namwon Kim, Shahriar Nibir Ph.D. adviser: Babak Parkhideh Electrical and Computer Engineering Department Energy Production and Infrastructure Center (EPIC) University of North Carolina at Charlotte Contact: mbiglarb@uncc.edu, bparkhideh@uncc.edu Phone: (704) 687-1959 January 12, 2018
  2. 2. 2/39Contact: mbiglarb@uncc.edu, Ph.D. adviser: bparkhideh@uncc.edu Contents • Motivations • GaN Transistors • Current Mirroring in GaN • Experimental Development • Application in Power Converters • Isolated-SenseGaN Measurement Technique • Conclusion
  3. 3. 3/39Contact: mbiglarb@uncc.edu, Ph.D. adviser: bparkhideh@uncc.edu Motivations Goals * Oak Ridge National Lab: Tolbert, et. al., “Power Electronics for Distributed Energy Systems and Transmission and Distribution Applications,” ➢ By 2030, 80% of all the electric power generated utilizes power electronics somewhere between point of generation to the end-use*. ➢ Let’s go toward lower loss, circuit miniaturization, and performance enhancement. Switching frequency is going high High power density, and efficiency Accurate & loss-less sensor Fact Demand Demand Options for accurate current sensors at high frequency converters are limited! Need to investigate alternative loss-less and wideband current sensing techniques Semiconductor and Gate Drive Circuits Control development Filter Design Sensing Thermal Management We need current sensing in Power Electronics: ➢ Advanced control ➢ Ultra-fast protection ➢ Diagnostics/prognostics
  4. 4. 4/39Contact: mbiglarb@uncc.edu, Ph.D. adviser: bparkhideh@uncc.edu Motivations Background ✓ Theoretically high BW. ✓ Topology dependent. ✓ Low accuracy @ high T. ✓ High loss. Current Sensors Non-Isolated Isolated Current Mirroring Filter- based Resistive- based Inductor- based Hall- Effect Current Transformer Rogowski Coil Magneto- Resistor
  5. 5. 5/39Contact: mbiglarb@uncc.edu, Ph.D. adviser: bparkhideh@uncc.edu Motivations Background Current Sensors Non-Isolated Isolated Current Mirroring Filter- based Resistive- based Inductor- based Hall- Effect Current Transformer Rogowski Coil Magneto- Resistor ✓ Accurate. ✓ Very bulky. ✓ Works only for AC.
  6. 6. 6/39Contact: mbiglarb@uncc.edu, Ph.D. adviser: bparkhideh@uncc.edu Motivations Background Current Sensors Non-Isolated Isolated Current Mirroring Filter- based Resistive- based Inductor- based Hall- Effect Current Transformer Rogowski Coil Magneto- Resistor ✓ Isolated ✓ Potentially high BW. ✓ Fast response. ✓ High current capability.
  7. 7. 7/39Contact: mbiglarb@uncc.edu, Ph.D. adviser: bparkhideh@uncc.edu Motivations Background • Even 2nH series inductance at high frequencies results in higher spikes across the switch. • Needs over-design considerations and knowing perfectly the EMI on converter power stage. SiLab sensors under 500kHz, 30V, 5A inverter: Top Switch in full bridge converter Bottom Switch in full bridge converter • Rogowski-based: SiLab sensors under 50kHz, 3A buck converter:
  8. 8. 8/39Contact: mbiglarb@uncc.edu, Ph.D. adviser: bparkhideh@uncc.edu Motivations Background Improved Inductor current with AKM-CQ3303 First porotype under 500kHz, 20A inverter. • Hall effect sensor:
  9. 9. 9/39Contact: mbiglarb@uncc.edu, Ph.D. adviser: bparkhideh@uncc.edu Motivations Background ✓ Loss-less ✓ Current Capacity ✓ No bandwidth limitations Current Sensors Non-Isolated Isolated Current Mirroring Magneto- Resistor Hall- Effect Current Transformer Rogowski Coil Filter- based Resistive- based Inductor- based
  10. 10. 10/39Contact: mbiglarb@uncc.edu, Ph.D. adviser: bparkhideh@uncc.edu Contents • Motivations • GaN Transistors • Current Mirroring in GaN • Experimental Development • Application in Power Converters • Isolated-SenseGaN Measurement Technique • Conclusion
  11. 11. 11/39Contact: mbiglarb@uncc.edu, Ph.D. adviser: bparkhideh@uncc.edu 11 Dielectric AlGaN GaN Substrate-Si S G D VGS 2DEG region (Previously was built on: Sapphire, SiC) GaN Transistors Architecture Gain egative • Higher Bandgap ✓ Potentially thinner and smaller device • Higher critical electric field ✓ Potentially lower R-ds(ON) • Lower capacitance charge ✓ Lower leakage current, and higher switching frequency • Enhancement Mode GaN ➢ Sensitivity to the gate source voltage (5V) ➢ Dynamic R-ds(ON) • High power switching frequency ➢ New techniques for control and measurement. ➢ System level reliability is still unforeseen.
  12. 12. 12/39Contact: mbiglarb@uncc.edu, Ph.D. adviser: bparkhideh@uncc.edu Contents • Motivations • GaN Transistors • Current Mirroring in GaN • Experimental Development • Application in Power Converters • Isolated-SenseGaN Measurement Technique • Conclusion
  13. 13. 13/39Contact: mbiglarb@uncc.edu, Ph.D. adviser: bparkhideh@uncc.edu Current Mirroring SenseGaN Technique 13 Dielectric AlGaN GaN Substrate-Si S G D 2DEG region Current input path Main Switch Sense Switch W/L=1W/L=n Gate Signal Vsense ImainIsense Vsense=Rsense*IsenseControl Unit Isense << Imain Current output path
  14. 14. 14/39Contact: mbiglarb@uncc.edu, Ph.D. adviser: bparkhideh@uncc.edu Current Mirroring System Description http://epc-co.com/epc/Portals/0/epc/documents/presentations/CompoundSemi2015-Ditching%20the%20Package.pdf http://www.mouser.com/pdfDocs/343654_GaNSystems__GN001_How_To_drive_GaN_EHEMT_Rev_20160426.pdf
  15. 15. 15/39Contact: mbiglarb@uncc.edu, Ph.D. adviser: bparkhideh@uncc.edu Current Mirroring Challenges ✓ Gate-Source voltage mismatching ✓ Suppression of voltage over-shoot ✓ Choosing proper resistor Gate Signal Vsense Main Switch Sense Switch W/L=1W/L=n
  16. 16. 16/39Contact: mbiglarb@uncc.edu, Ph.D. adviser: bparkhideh@uncc.edu Current Mirroring Proposed Solutions Virtual Grounding Circuit Isolated Gate Driver W/L=1W/L=n in Vout V Isolated Gate Driver L DSP + - - + - + + - Rsense 1Ω Si8271 Si8271 10kΩ 10kΩ 1Ω 4.7kΩ 10Ω 2Ω 10Ω 4.7kΩ 2Ω C R 6.8nF 1Ω 100kΩ 100kΩ Power GaN Sense GaN Power GaN 82pF 100kΩ 82pF 100kΩ 10pF 100kΩ 10pF 100kΩ 82pF 100kΩ 100kΩ 1nF Iref load LM6154 LM6154 LM6154 LM6154 S/H & Logic Circuits VoutVin 10Ω Ron(Q2) Rsense Ron(Q1) ID (b) (a) Q1 Q2 Delay on signal control path
  17. 17. 17/39Contact: mbiglarb@uncc.edu, Ph.D. adviser: bparkhideh@uncc.edu Current Mirroring Proposed Solutions Isolated Gate Driver W/L=1W/L=n in Vout V Isolated Gate Driver L DSP + - - + - + + - Rsense 1Ω Si8271 Si8271 10kΩ 10kΩ 1Ω 4.7kΩ 10Ω 2Ω 10Ω 4.7kΩ 2Ω C R 6.8nF 1Ω 100kΩ 100kΩ Power GaN Sense GaN Power GaN 82pF 100kΩ 82pF 100kΩ 10pF 100kΩ 10pF 100kΩ 82pF 100kΩ 100kΩ 1nF Iref load LM6154 LM6154 LM6154 LM6154 S/H & Logic Circuits VoutVin 10Ω Ron(Q2) Rsense Ron(Q1) ID (b) (a) Q1 Q2 𝑅 ሻ𝐷𝑆(𝑜𝑛 = 𝑅 ሻ𝐷𝑆(𝑜𝑛 25℃ 𝑒൫𝑇−25℃ Τሻ 𝑘 𝐼 𝑄_𝑃𝑜𝑤𝑒𝑟 𝐼 𝑄_𝑆𝑒𝑛𝑠𝑒 = 𝑘 + 𝑅 𝑠𝑒𝑛𝑠𝑒 𝑅 𝐷𝑆 𝑜𝑛 𝑄1 25℃ 𝑒 ቀ𝑇−25℃ Τሻ 𝑘 𝑄1 Better performance with GaN Delay on signal control path Virtual Grounding
  18. 18. 18/39Contact: mbiglarb@uncc.edu, Ph.D. adviser: bparkhideh@uncc.edu Current Mirroring Proposed Solutions Gate Signal Vsense 𝐼 𝑄1 𝐼 𝑄2 = 𝑘 + 𝑅 𝑠𝑒𝑛𝑠𝑒 𝑅 𝐷𝑆 𝑜𝑛 𝑄1 25℃ 𝑒 ቀ𝑇−25℃ Τሻ 𝑘 𝑄1 Ron(Q2) Rsense Ron(Q1) ID (b) 𝑅 𝑆𝑒𝑛𝑠𝑒 𝑅 𝑄2𝑅 𝑄1 𝑅 𝑆𝑒𝑛𝑠𝑒=1ΩInductor Current SenseGaN 𝑅 𝑆𝑒𝑛𝑠𝑒=1kΩInductor Current SenseGaN Time-µsec Time-µsec
  19. 19. 19/39Contact: mbiglarb@uncc.edu, Ph.D. adviser: bparkhideh@uncc.edu Current Mirroring Proposed Solutions 𝑂𝐹 = 𝑘1 𝑃𝑐𝑜𝑛𝑑𝑢𝑐𝑡𝑖𝑜𝑛 − 𝑉𝑠𝑤 2 𝑍 𝑠𝑒𝑛𝑠𝑒 + 𝑘2(1 + 𝑍 𝑠𝑒𝑛𝑠𝑒ሻ
  20. 20. 20/39Contact: mbiglarb@uncc.edu, Ph.D. adviser: bparkhideh@uncc.edu Contents • Motivations • GaN Transistors • Current Mirroring in GaN • Experimental Development • Application in Power Converters • Isolated-SenseGaN Measurement Technique • Conclusion
  21. 21. 21/39Contact: mbiglarb@uncc.edu, Ph.D. adviser: bparkhideh@uncc.edu Experimental Development Hardware prototype DC+ DC- Inductor Isolated Power Supply SENSE GaN Top Power GaN Bot Power GaN Load Connection DSP-micro Controller DC Supply for Control Signals • The prototype boost converter with GS66508T. [Qg = 6.5nC, Rds(on) = 55mΩ] Manufacture Part Number Description GS66508T GaN transistors SI8271GB-IS Gate driver LM6154BCM OpAmp 100MHz Bandwidth PHP02512E20R0BST5 20Ω 0.1% Sense resistor CL10C820FB8NNNC 82pF Filter capacitor
  22. 22. 22/39Contact: mbiglarb@uncc.edu, Ph.D. adviser: bparkhideh@uncc.edu Experimental Development SenseGaN results-150kHz, and 5A. Inductor Current SenseGaN Time-µsec Time-µsec Gate SignalsControl Signals
  23. 23. 23/39Contact: mbiglarb@uncc.edu, Ph.D. adviser: bparkhideh@uncc.edu Experimental Development SenseGaN results-50kHz, and 5A Blue: Inductor Current Time-µsec Orange: SenseGaN at 80% duty cycle Orange: SenseGaN at 20% duty cycle Blue: Inductor Current Time-µsec Time-µsec
  24. 24. 24/39Contact: mbiglarb@uncc.edu, Ph.D. adviser: bparkhideh@uncc.edu Contents • Motivations • GaN Transistors • Current Mirroring in GaN • Experimental Development • Application in Power Converters • Isolated-SenseGaN Measurement Technique • Conclusion
  25. 25. 25/39Contact: mbiglarb@uncc.edu, Ph.D. adviser: bparkhideh@uncc.edu Application in Power Converters SenseGaN for soft-switching ✓ Switching at Zero Current to reduce switching loss. ✓ There is no current sensor to achieve this possibility in the market.
  26. 26. 26/39Contact: mbiglarb@uncc.edu, Ph.D. adviser: bparkhideh@uncc.edu Application in Power Converters SenseGaN for soft-switching Inductor Current Average current for CCM and BCM DCM CCM SenseGaN Measurements Trigger Reference DCMCCM di dt Vth Tdelay Reference PWM Trigger Signal CCM BCM delay Reference PWM Trigger Signal delay delay no delay in CCM BCM BCM
  27. 27. 27/39Contact: mbiglarb@uncc.edu, Ph.D. adviser: bparkhideh@uncc.edu Application in Power Converters Proposed technique for ZCS Gate Drive in Vout V Gate Drive L = 33u DSP + - - + - + + - Rsense Ω Si8271 Si8271 10k 10k Ω 4.7k Ω Ω Ω 4.7k Ω C = 1u R 82pF 1k 100k 1k Power GaN Sense GaN Power GaN GS66508T 100k 10pF 100k 10pF 100k 82pF 100k load + - TLV3502 Comperator LM6154 LM6154 LM6154 LM6154 VThreshold Ω GS66508TGS66508T Q1 Q2 100k 100k Vout Vin ADC Trigger Virtual grounding and analogue signal processing Active Device Sensing Device Synchronous Device dDCM Operation Δf Δf TSW Region dBCM dCCM
  28. 28. 28/39Contact: mbiglarb@uncc.edu, Ph.D. adviser: bparkhideh@uncc.edu Application in Power Converters Closed loop ZCS control of a boost with SenseGaN Inductor Current Trigger- Delay SenseGaN Duty: 40% 60%
  29. 29. 29/39Contact: mbiglarb@uncc.edu, Ph.D. adviser: bparkhideh@uncc.edu Contents • Motivations • GaN Transistors • Current Mirroring in GaN • Experimental Development • Application in Power Converters • Isolated-SenseGaN Measurement Technique • Conclusion
  30. 30. 30/39Contact: mbiglarb@uncc.edu, Ph.D. adviser: bparkhideh@uncc.edu Iso-SenseGaN Proposing a new solution for improving the SenseGaN technique Drain Drain Source Source Gate Gate ▪ One of the drawback of current mirroring techniques (SenseGaN) is lack of galvanic isolation. ▪ Difficulties get severe where the active switch measurement is required for (>30V). ➢ Therefore, Iso-SenseGaN is proposed for …
  31. 31. 31/39Contact: mbiglarb@uncc.edu, Ph.D. adviser: bparkhideh@uncc.edu Iso-SenseGaN Proposing a new solution for improving the SenseGaN technique
  32. 32. 32/39Contact: mbiglarb@uncc.edu, Ph.D. adviser: bparkhideh@uncc.edu Iso-SenseGaN Proposing a new solution for improving the SenseGaN technique
  33. 33. 33/39Contact: mbiglarb@uncc.edu, Ph.D. adviser: bparkhideh@uncc.edu Comparator 60Hz 0 GB2 GB1 Comparator I_ref S1 A B A B ON OFF ON OFF GA1 Comparator I_ref S2 A B ON OFF GA2 If GB1 = ON If GB2 = ON Vload Iload IS1 IS2 Iso-SenseGaN Closed loop ZCS control of a DC-AC with SenseGaN Vs SB2 SA1 SA2 SB1 Current Sensing Unit Linv R1 Q3 Q1 Q2 Q4
  34. 34. 34/39Contact: mbiglarb@uncc.edu, Ph.D. adviser: bparkhideh@uncc.edu Iso-SenseGaN Closed loop ZCS control of a DC-AC with SenseGaN Vs GB2 GA1 GA2 GB1 Current Sensing Units Linv Load Q3 Q1 Q2 Q4 Vs GB2 GA1 GA2 GB1 Current Sensing Units Linv Load Q3 Q1 Q2 Q4 Vs GB2 GA1 GA2 GB1 Current Sensing Units Linv Load Q3 Q1 Q2 Q4 Vs GB2 GA1 GA2 GB1 Current Sensing Units Linv Load Q3 Q1 Q2 Q4 S2 S1 S2 S1 S2 S1 S2 S1
  35. 35. 35/39Contact: mbiglarb@uncc.edu, Ph.D. adviser: bparkhideh@uncc.edu Contents • Motivations • GaN Transistors • Current Mirroring in GaN • Experimental Development • Application in Power Converters • Isolated-SenseGaN Measurement Technique • Conclusion
  36. 36. 36/39Contact: mbiglarb@uncc.edu, Ph.D. adviser: bparkhideh@uncc.edu ➢ A novel current mirroring technique for GaN transistor is presented. ➢ The solutions are compatible with the lateral/vertical GaN structures. ➢ SenseGaN characteristics and implementation challenges were discussed in both the simulations and experimental results. ➢ The application of SenseGaN technique was verified in a DC-DC boost converter in closed loop control under quasi soft-switching. ➢ The new isolation is added externally on the sensing path to avoid common mode issues. ➢ This technique is also adaptable for other DC-DC buck converters as well as DC-AC converters (inverters), and many common typical power electronics topologies. Conclusion
  37. 37. 37/39Contact: mbiglarb@uncc.edu, Ph.D. adviser: bparkhideh@uncc.edu Publications from the presented work • Boundary Conduction Mode Control of a Boost Converter With Active Switch Current-Mirroring Sensing (IEEE Transactions on Power Electronics: Published on January-2018) Mehrdad Biglarbegian, Namwon Kim, and Babak Parkhideh-UNCC, USA • Characterization of SenseGaN Current-Mirroring for Power GaN with the Virtual Grounding in a Boost Converter (IEEE ECCE 2017: Published on September-2016) Mehrdad Biglarbegian, and Babak Parkhideh-UNCC, USA • Development of Isolated SenseGaN Current Monitoring for Boundary Conduction Mode Control of Power Converters (IEEE APEC: will be published) Mehrdad Biglarbegian, Namwon Kim, Tiefu Zhao, and Babak Parkhideh-UNCC, USA • Development of Current Measurement Techniques for High Frequency Power Converters (IEEE INTELEC 2016: Published on October-2016) Mehrdad Biglarbegian, Shahriar Nibir, Hamidreza Jafarian, and Babak Parkhideh-UNCC, USA • Current Monitoring for Power GaN Transistors (Application Patent: Filed on January-2017) Mehrdad Biglarbegian, Namwon Kim, and Babak Parkhideh-UNCC, USA • Demonstration on the YouTube: https://www.youtube.com/watch?v=42IQ_ZvXOQ4&t=33s
  38. 38. 38/39Contact: mbiglarb@uncc.edu, Ph.D. adviser: bparkhideh@uncc.edu Thanks! PV Integration Lab, EPIC, University of North Carolina at Charlotte, Charlotte, NC, USA

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