Bruce Carsten: Lifetime Achievement Award Winner

Sep 1, 2006 12:00 PM
By David Morrison, Editor, Power Electronics Technology

Steam-Powered Inspiration

When Bruce Carsten was born in 1943 in Reedly, Calif., his father, Henry, was half a world away, a sergeant in the U.S. Army serving in the Pacific theater. On his return, Carsten’s father moved the family north to Camino, a sawmill town in the Sierra Nevada foothills.

In this town, the sight of steam-powered trains on the railroad or Shay engines moving lumber around at the sawmill could fuel a young boy’s interest in the mechanical world, particularly since Carsten’s father (who later became a lumber grader) worked at the sawmill. But as Carsten relates, a very early childhood experience may have helped put him on course to eventually become an engineer.

“I seem to have been born with a fascination in things mechanical,” says Carsten.

“One of my early and clearest memories (from about age 2) is of a ride on a steam-powered side-wheeler ferry boat in San Francisco Bay with my mother and grandmother,” Carsten recalls. “As we were leaving the dock one of them mentioned to me that the engine could be viewed through some internal windows.

“I climbed up on a wood slat bench to peer in, and beheld a most wondrous sight! There was a double-acting single-cylinder steam engine overhead, driving the crankshaft underneath through a long connecting rod,” says Carsten. “Two pushrods from the crankshaft operated valves in the steam chest on the cylinder, and the whole thing huffed and chuffed along at about 15 or 20 RPM.

“It was great theater, and I was awestruck, even though I did not fully understand what I saw at the time,” Carsten explaines. “Almost instantaneously my mother was pulling on my arm saying, ‘Come on! We want to go outside and see the sights!’ when the most beautiful sight in the world was right here!”

As he grew up, there were plenty of activities at home to encourage Carsten’s interest in the mechanical world. He helped his father work on cars, learning that it was OK to take machines apart, so long as you noted how they came apart, which allowed you to put them back together. And at a young age, Carsten learned to use the tools in his father’s workshop. Learning how to use power tools responsibly provided Carsten with a background that would prove helpful in his professional career when he would be required to work with potentially lethal voltages in industrial power settings.

Carsten relates how his mechanical interests led him to take apart all types of appliances to see how they worked. Family and friends encouraged Carsten’s interests by giving him items such as broken alarm clocks to disassemble.

Then, as an eighth grader, a story about Marconi sparked Carsten’s interest, so to speak, in electronics. Once again, the family members helped Carsten satisfy his curiosity with unusual presents. “The principle gift was old tube-powered radios,” Carsten recalls. “These were carefully disassembled in stages. Ultimately, I had unwound the transformers and speaker electromagnets, unrolled all the capacitors, and broken open the glass envelopes on the tubes, and separated the plate, grids and filaments. I learned how everything was built before fully understanding how it all worked.”

Carsten notes that his father and mother encouraged their children to pursue whatever interests caught their imaginations. They also instilled a love of books and reading in their home, with Carsten’s father, setting an example as a voracious reader. And though life during the Great Depression had discouraged Carsten’s father from going to college, he was, by nature, “intellectually curious” and “skeptical,” says Carsten, and instilled these traits in his son. As an engineer, both of these traits would come to bear in Carsten’s work. When confronted with engineering challenges, Carsten’s intellectual skepticism caused him to question all assumptions, eschewing a false sense of certainty when looking for answers, and when making decisions, keeping his mind open to conflicting evidence.

Advances in Magnetics Design

When Carsten began investigating the high-frequency effects on magnetics, the only work he could find on the subject was an old multigenerational copy of P.L. Dowell’s “Effects of eddy currents in transformer windings.”[2] “Dowell goes through the whole thing, which has a mathematical derivation, but it only applied to sinusoidal current,” explains Carsten. “I’m thinking it through and I realized that the losses at the different frequencies were orthogonal. In other words, the losses at one frequency did not have any impact on the losses produced by a current at a different frequency, whether harmonically related or not. And I further realized that what you’ve got to do is calculate the loss at every frequency independently, which is going to depend on both the magnitude of the current at that frequency—the harmonic amplitude—and the resistance at that frequency, which has to be calculated separately.

“In order to do the calculations for the single-ended converter used in the switchmode telecom rectifier, I had a programmable calculator running for about six weeks to get the information, 24 hours a day by and large, and printing intermediate results and going back and adding in more harmonics and printing it out for fast rise and fall times. And I just sort of assumed that this was already known and I just couldn’t find the reference.
“Then, at Powercon, P.S. Venkatramen[3] published an analysis of this in which you had to combine the effects of three different graphs to get the results, but everybody was absolutely thrilled. Nobody has ever done this before.” Carsten says he had done a smiliar analysis several years ago, but didn’t think it was worth publishing because he believed, wrongly, that it was already known.

“Well it turned out it wasn’t, so in 1986, I published my results[4], which were similar to Venkatramen’s, but I also had a more intuitive method of combining the results, what I call Kr, the loss resistance factor—a normalization that made it very easy to use the information,” says Carsten.

Others then used Carsten’s methods to push the field further. “Dowell’s analysis wasn’t the most general because you couldn’t apply it to noncurrent carrying shields or noncurrent carrying windings, or other merged windings or multiple secondaries, where a winding is not only producing its own field but also immersed in the field produced by another winding, etc,” explains Carsten. “Apparently, a researcher called Perry did a more general analysis. Then J.P. Vandelac and P. Ziogas applied my ‘toolkit’ to adapt Perry’s analysis to nonsinusoidal current, and that’s sort of become the industry norm for the basic one-dimensional analysis[5]. But it was sort of the formal way of calculating what the loss would be for any wave shape, and the loss normalization factor that was applied, that was my contribution.

“It was very much a community effort,” Carsten points out. “I worked with the results of others. Others took what I did and carried them into more fruitful areas.”

References

1.In 1981, Carsten presented a paper titled, “High Power SMPS Require Intrinsic Reliability” at the Power Conversion International Conference (PCI 1981) in Munich, Germany. This paper described a number of the innovations he conceived in the 1970s, such as his “bulletproof” emitter drive, current-limiting technology and hot-swap power modules. Another concept, polyphase switching, was alluded to in the paper, but not described in detail because Carsten’s employer considered it too proprietary.
2. Dowell, P.L. “Effects of Eddy Currents in Transformer Windings,” Proc. Institute Elec Eng., vol. 113, no.8, pp. 1387-1394, August 1966.
3. Venkatramen, P.S. “Winding Eddy Current Losses in Switch Mode Power Transformers Due To Rectangular Wave Currents,” Powercon 11, 1984.
4. Carsten, Bruce. “High Frequency Conductor Losses in Switchmode Magnetics,” High Frequency Power Conversion Conference proceedings, 1986, pp. 155-176.
5. Vandelac, J.P., and Ziogas, P. “A novel approach for minimizing high frequency transformer copper losses,” IEEE Power Electronics Specialists Conference proceedings, 1987, pp.355-367.

Technical Papers

1. "HIGH POWER SMPS REQUIRE INTRINSIC RELIABILITY"
PCI '81 Proc., Munich, West Germany
PCI '82 Proc., San Francisco, CA (Slightly revised)

2. "DETHRONING THE SINE WAVE” (DC-AC inverter output waveforms)
PCI '84 Proc., Atlantic City, NJ

3. "DESIGN TECHNIQUES FOR THE INHERENT REDUCTION OF POWER CONVERTER EMI"
Powercon 11 Proc., 1984, Dallas, TX

4. "A LOW VOLTAGE SCHOTTKY FOR HIGH EFFICIENCY VLSI POWER SUPPLIES"
PCI '84 Proc., Paris, France

5. "RADIO FREQUENCY POWER CONVERSION: FAD OR THE FUTURE?"
PCIM Magazine, January '86

6. "REVERSE RECOVERY CHARACTERISTICS OF HIGH SPEED RECTIFIERS"
PCIM Magazine, February '86

7. "FAST, ACCURATE MEASUREMENT OF CORE LOSS AT HIGH FREQUENCIES"
PCIM Magazine, March '86

8. "CURRENT MODE CONTROL FOR HIGH FREQUENCY SWITCHMODE"
PCIM Magazine, April '86

9. "SWITCHMODE DESIGN TECHNIQUES ABOVE 500 KHz" (tutorial)
1st HFPC Conf. Proc., 1986, Virginia Beach, VA

10. "HIGH FREQUENCY CONDUCTOR LOSSES IN SWITCHMODE MAGNETICS"
1st HFPC Conf. Proc., 1986, Virginia Beach, VA
PCI '86 Proc., Munich, West Germany
PCIM Magazine, November '86 (revised version)

11. "VLSI & VHSIC POWER SYSTEM DESIGN CONSIDERATIONS"
PCI '86 Proc., Boston, MA

12. "DISTRIBUTED POWER SYSTEMS OF THE FUTURE UTILIZING HIGH FREQUENCY CONVERTERS"; 2nd HFPC Conf. Proc., 1987, Washington, DC

13. "A HYBRID SERIES-PARALLEL RESONANT CONVERTER FOR HIGH FREQUENCIES AND POWER LEVELS"; 2nd HFPC Conf. Proc., 1987, Washington, DC

14. "DESIGN TRICKS, TECHNIQUES, AND TRIBULATIONS AT HIGH CONVERSION FREQUENCIES" (Tutorial) 2nd HFPC Conf. Proc., 1987, Washington, DC;
PCI '87 Proc., Munich, West Germany

15. "ON THE FUNDAMENTAL PERFORMANCE SIMILARITIES OF FLYBACK AND FORWARD CONVERTERS AT HIGH FREQUENCIES": PCI '87 Proc., Long Beach, CA

16. "HIGH SPEED CONTROL OF SINUSOIDAL INPUT CURRENT CONVERTERS FOR MINIMAL ENERGY STORAGE REQUIREMENTS"; PCI '87 Proc., Long Beach, CA

17. "THE POTENTIAL OF SUPERCONDUCTORS AND SYNTHETIC METALS IN SWITCHMODE POWER SUPPLIES OF THE FUTURE"; 3rd HFPC Conf. Proc., 1988, San Diego, CA

18. "TOPOLOGIES FOR INCREASING OUTPUT VOLTAGES WITH SCHOTTKY DIODES"
3rd HFPC Conf., 1988, San Diego, CA

19. "TRENDS IN HIGH FREQUENCY POWER CONVERSION"; (Co-Authored With K. Kit Sum)
3rd HFPC Conf. Proc., 1988, San Diego, CA

20. "CONVERTER COMPONENT LOAD FACTORS; A PERFORMANCE LIMITATION OF VARIOUS TOPOLOGIES"; PCI'88 Proc., Munich, West Germany

21. "COMPATIBLE POWER CONVERTERS FOR LITHIUM BATTERY SYSTEMS"
4th International Meeting on Lithium Batteries
May 24-27, 1988, Vancouver, BC

22. "THE PROXIMITY CURRENT PROBE; OBTAINING WIDEBAND CURRENT WAVEFORMS IN THICK FILM AND PRINTED CIRCUIT CONDUCTORS"
4th HFPC Conf. Proc., 1989, Naples, FL.
PCIM'89 Conf. Proc, June 6-8, 1989, Munich, Germany

23. “DESIGN TECHNIQUES FOR TRANSFORMER ACTIVE RESET CIRCUITS AT HIGH FREQUENCIES AND POWER LEVELS";
5th HFPC Conf. Proc., 1990, Santa Clara, CA

24. “AC MAINS COMPATIBILITY BOX";
PCIM/PQ Conf. Proc., 1990, Philadelphia, PA

25. “SLOW WAVE" TRANSMISSION LINE RESONANCE PHENOMENA IN MONOLITHIC CERAMIC AND STACKED FOIL PLASTIC CAPACITORS"
6th HFPC Conf. Proc., 1991, Toronto, ON

26. “ISOLATION OF FAULTED POWER MODULES IN LOW VOLTAGE DC DISTRIBUTED/REDUNDANT POWER SYSTEMS"; PCIM/PQ Conf. Proc., 1991, Universal City, CA.

27. “POWER CONVERTERS FOR LAPTOP COMPUTERS"; (Tutorial)
PCIM/PQ Conf. Proc., 1991, Universal City, CA.

28. “LOW PROFILE MAGNETICS, GEOMETRY SELECTION AND OPTIMIZATION"
Seminar 8, APEC '92 Conference, Boston MA

29. “DESIGN OF MULTI-STAGE FILTERS FOR USE WITHIN WIDEBAND CONTROL LOOPS"
7th HFPC Conf. Proc., 1992, San Diego, CA

30. “SIMPLIFIED CALCULATION OF MAGNETIC AND ELECTRICAL LOSSES IN UNITY POWER FACTOR BOOST PREREGULATORS"
PCIM/PQ Conf. Proc., 1992, Irvine, CA.

31. “ACHIEVING 80-90% EFFICIENCY OVER A 100:1 LOAD RANGE AT 3.3V WITH SYNCHRONOUS RECTIFICATION AND A CYCLE-BY-CYCLE CONTROL ALGORITHM"
8th HFPC Conf. Proc., 1993, Vienna, VA.

32. “CROSS REGULATION EFFECTS IN MULTIPLE "BATCH REGULATED" OUTPUTS"
8th HFPC Conf. Proc., 1993, Vienna, VA.

33. “THE BIPOLAR TRANSISTOR IS DEAD. LONG LIVE THE BIPOLAR TRANSISTOR"
PCIM/PQ'93 Conf. Proc., 1993, Irvine, CA.

34. “DESIGNING HIGH FREQUENCY CURRENT SHUNTS AND CURRENT TRANSFORMERS"
9th HFPC Conf. Proc., 1994, San Jose, CA.

35. “MEASUREMENT OF POWER LOSSES IN SEMICONDUCTOR CASES WITH KOVAR-GLASS HERMETIC SEALS"; Proc. of PCIM'94; June 28-30, 1994; Nurnberg, Germany

36. “DESIGNING FILTER INDUCTORS FOR SIMULTANEOUS MINIMIZATION OF DC AND HIGH FREQUENCY AC CONDUCTOR LOSSES"
Proc. of PCIM/PQ '94; Sept. 18-22, 1994, Dallas, Texas

37. “LOW PROFILE MAGNETICS"; Proceedings of the Soft Ferrite Users Conference '94; October 24-25, 1994, Rosemont, IL.

38. “WHY THE MAGNETICS DESIGNER SHOULD MEASURE CORE LOSS; WITH A SURVEY OF LOSS MEASUREMENT TECHNIQUES AND A LOW COST, HIGH ACCURACY ALTERNATIVE"
Proc. of HFPC'95; May 7-11, 1995, San Jose, CA.
Proc. of PCIM'95; Nurnberg, June 20-22, Germany

39. "OPTIMIZING OUTPUT FILTERS USING MULTILAYER POLYMER CAPACITORS IN HIGH POWER DENSITY LOW VOLTAGE CONVERTERS"
Proc. of HFPC'95; May 7-11, 1995, San Jose, CA.

40. "A 'CLIPPING PRE-AMPLIFIER' FOR ACCURATE SCOPE MEASUREMENT OF HIGH VOLTAGE SWITCHING TRANSISTOR AND DIODE CONDUCTION VOLTAGES"
Proc. of PCIM/PQ'95, September 9-15, 1995, Long Beach, CA.

41. “FET SELECTION AND DRIVING CONSIDERATIONS FOR ZERO SWITCHING LOSS AND LOW EMI IN HF "THYRISTOR DUAL” POWER CONVERTERS"
Proc. of PCIM'96, May 21-23, 1996, Nurnberg, Germany
Proc. of PowerSystems World, Sept. 7-13, '96, Las Vegas, NV

42. "CALCULATING THE HIGH FREQUENCY RESISTANCE OF SINGLE AND DOUBLE LAYER TOROIDAL WINDINGS"; Proc. of PCIM'97, June 10-12, 1997, Nurnberg, Germany

43. "POTENTIAL FUTURE ALTERNATIVES FOR THE GENERATION OF LOGIC VOLTAGES BELOW 3V"; Proc. of HFPC'97, Sept. 6-12, 1997; Baltimore, MA.

44. "SPACED ROUND WIRE TO EQUIVALENT FOIL TRANSFORMATION FOR CALCULATING HF LOSSES IN SOLENOIDAL WINDINGS"
Proc. of HFPC'97, Sept® 6-12, 1997; Baltimore, MD.

45. "THE NORMAL MODE INDUCTANCE OF COMMON MODE INDUCTORS"
Proc. of PWS'98, Nov. 8-13, 1998; Santa Clara, CA.

46. "STACKED FLYBACK CONVERTERS FOR LOW POWER OUTPUTS WITH INPUT VOLTAGES OVER 500V"; (co-authored with Paul Greenland, Allegro Microsystems)
Proc. of HFPC'99, Nov. 9-11, Chicago, IL.

47. "HINTS AND KINKS ON PATENTING YOUR INVENTION"
Proc. of HFPC 2000, Oct. 3-5, 2000, Boston, MA.

48. "THE LOW LEAKAGE INDUCTANCE OF PLANAR TRANSFORMERS; FACT OR MYTH?";
Proc. of APEC'01, March 6, 2001, Anaheim, CA.

49. "THE ADVANTAGES OF BJTs OVER FETs FOR SYNCHRONOUS RECTIFICATION BELOW 3 VOLTS"; Proc. of PCIM 2002, May 14-16, 2002, Nuremberg, Germany.

50. "CURRENT CAPABILITIES OF CONDUCTORS ON INSULATED METAL SUBSTRATES, INCLUDING FREQUENCY EFFECTS"; (co-authored with Herb Fick, Bergquist)
Proc. of PCIM 2002, May 14-16, 2002, Nuremberg, Germany

51. "FINDING AND FIXING SMPS RINGING WAVEFORM EMI"; Proc. of PowerSystems World Conference, October 29-31, 2002, Rosemont, IL

52. "THE APPLICATION OF CURRENT MULTIPLYING RECTIFIERS TO NON-ISOLATED BUCK REGULATORS"; Proc. of PCIM 2003, May 20-22, 2003, Nuremberg, Germany

53. "CURRENT MULTIPLYING RECTIFIERS FOR HIGH CURRENT OUTPUTS"; Proc. of PowerSystems World Conference, November 4-6, 2003, Long Beach, CA

54. "THE CONTROL ALGORITHM AS A HIGH PERFORMANCE ALTERNATIVE OR SUPPLEMENT TO LINEAR/ANALOG FEEDBACK CONTROL"
Proc. of PCIM 2004, May 25-27, 2004 Nuremberg, Germany

55. "A NEW HIGH SATURATION FERRITE INCREASES SWITCHMODE INDUCTOR ENERGY DENSITY"; Proc. of PCIM 2006, May 30 - June 1, 2006, Nuremberg, Germany

Other Articles:
"Surface Mount Technology Aids Portable Equipment Designs"; PCIM magazine, December 1991

"Clipping Preamplifier Provides Accurate Measurement of Transistor Conduction Voltages" PCIM magazine, August 1996

“Finite Element Analysis Software Generates formulas for Calculation of High Frequency toroid Resistance”; PCIM Magazine, April 1997

“Sniffer Probe Locates Sources of EMI”; EDN magazine, June 4, 1998

"Stacked Flyback Converters Allow Lower Voltage MOSFETs for High AC Line Voltage Operation" by Paul Greenland, Allegro Microsystems Inc. and Bruce Carsten, Bruce Carsten Associates. PCIM magazine, March 2000

“H-Field Probes Spot Switchmode Supply EMI”; PCIM magazine, September, 2001

”CURRENT SHUNTS”; Wiley Encyclopedia of Electrical and Electronic Engineering, John Wiley & Sons, Inc., 1999, Vol.4, pp. 452-458.

“CURRENT TRANSFORMERS”: ibid, pp. 459-466

“Carsten’s Corner” Columns in PCIM Magazine
1. “Will the Real R&D Lab Please Stand Up?”; June 1988, p.39

2. “Why Are Breakthroughs So Much Work?”: July 1988, p.77

3. “How About a Conference Paper from You?”, August 1988, p.96

4. “The Engineer’s Lament”; October 1988, P. 59

5. Untitled in the magazine; the intended title was “Will the U.S. Lose its Technological Lead to Japan?”; November 1988, p.12

6. “Can a FET be Damaged by Switching Too Fast?”; December 1988, p. 47

7. “Capital Equipment and Personnel”; January 1989, p.86

8. “Things we’d Like to See: More Application Specific Components for SMPS”; February 1989, p.78

9. “Why is There No “Electrostatic” Dual to the Transformer?” March 1989, p.36

10. “Why do Most Innovations Seem to Come From Smaller Companies?”, April 1989, p.94

11. “More on the Electrostatic Dual to the Transformer” (In response to reader’s comments) May 1989, p. 79

12. “The Role of the Consultant”; June 1989, p.51

13. “STILL More on the “Electrostatic” Transformer”: August 1989, p.67

14. “They Oughta Make a Safe “Yankable” Power Cord”; September 1989, p.109

15. “”Work” vs ‘”Play” as a Learning Experience”; October 1989, p.90

16. “Let’s Define a Few Terms”, November 1989, p.38

17. “Can There be a Simple Solution to Every Problem?”; December 1989, p. 45

18. “You Can’t Solve an Undefined Problem!” February 1990, p.57

19. “Where Are Our Future Innovators to Come From?”; March 1990, P. 124

20. “Distributed Power Systems”; May 1990, p.63