Study of Auxiliary Power Solution with High Input Voltage Presenter : Steel Huang Date: 6/8 04
Agenda Background Two Traditional Solutions Introduction Phase Cut Regulator Introduction
Smart Meter: Background - Application Area Industrial/Solar: Input Specification: ) Single Phase: 85V~450VAC ) Phases: 45V~70VAC
Background - Design Challenge () ) Bulk-cap: Must use or bulky cap and relevant balance circuit. ) Transformer design : The duty cycle is very small in high line. ) Startup circuit : Startup current is difficult to balance due to wide range input voltage. 4) HV switching circuit: Difficult to balance high switching loss and low conduction loss. 4
Background - Design Challenge () ) Big Space and Circuit Complexity a) Need or Bulk-caps and relevant balance circuit b) Complex transformer design ) Low Efficiency a) Need use HV MOSFET, big conduction loss and switching loss. b) High DC link voltage, small duty cycle setting, lower system efficiency. c) High DC link voltage, high VF secondary diode, big conduction loss. ) High Cost a) Device is expensive if adopting single MOSFET structure. b) Too many components if adopting Cascode FET or ESBC structure. 5
Background Two Traditional Solutions Introduction Phase Cut Regulator Introduction 6
Two Traditional Solutions for HV Application Single phase: DC input 0VDC-65VDC- Cascode FET Structure phase : DC input 6VDC-08VDC 4 5 ) Bulk caps ) Resistor balance circuit ) MOSFETs in series 4) Upper MOSFET driver circuit 5) Transformer 6) Feedback circuit 6 7
Advantage: Cascode FET Structure - Advantage and Disadvantage ) MOSFET could use popular ones. Disadvantage: ) Need or Bulk-cap and balance circuit. ) Must use MOSFETs. ) More components 4) The switching frequency could not be too high, suggest below 50KHz. Proposal Solution: ) FSL Series + discrete MOSFETs ) Three in one solution MOSFET controller MOSFET FSL Series + discrete MOSFET solution Integrated MOSFET solution 8
Two Traditional Solutions for HV Application - ESBC structure What s the ESBC device? ESBC (Emitter Switched Bipolar/MOSFET Cascode) device is actually a Emitter Switching, which stack a high voltage bipolar transistor with a low voltage MOSFET. Marriage of Bipolar High-Voltage with Low-Voltage MOSFET Negates weaknesses of both devices while taking advantage of their strengths Results in a higher breakdown voltage Minimum switching loss and conduction loss Easy to drive, allows use of standard controllers 9
ESBC Device s Structure ESBC Device s basic structure ESBC Device s on/off status 0
kinds of Driver Circuit of ESBC Bias supply drive Proportional drive For ESBC application, we must consider if the bipolar can provide a proper current gain Hfe,this Hfe not only guarantee the saturation conduction of the transistor at turn on, but also decrease the storage time of transistor at turn off. So, Proportional transformer drive is a good choice. It can guarantee the transistor s Hfe not changing at no load or high load. generally, we advice DC bias supply drive use under low power condition (such as <0Watt), for high power, adopting proportional drive is the best solution.
Advantage: ESBC Device s Structure - Advantage and Disadvantage ) Easy to drive big power Disadvantage: ) Also need or Bulk-caps and balance circuit. ) The driver circuit is a little bit complex. Proposal solution: ) FJAFS50A (550V,6A) + FDMA8655L(60V,7.5A)
Comparison of Two Traditional Solutions () - Efficiency Solutions Vin/Vout Devices Freq. Balance Circuits 60Vac 0Vac 80Vac 600Vac Cascode FET 45Vac-600Vac/ 5V/670mA FSL7MRIN+ FQP4N90C 67KHz Yes 6.4% 78.6% 76.9% 7.6% ESBC 45Vac-600Vac/ 5V/670mA FJBE60D+ FDC65N 67KHz Yes 67.% 79.56% 76.5% 65.68% From above efficiency data,we could see the different point is at the low line and high line, but In middle area, the efficiency is almost same.
Comparison of Two Traditional Solutions () - General Features ) For Cascode FET solution, there need two MOSFETs and upper MOSFET driver circuit, the switching loss is big. ) For ESBC solution, it just needs one bipolar transistor and a low side MOSFET, it can driver more big power, but the driver circuit is a little complex. This kinds of solutions all need or bulk-caps and relative balance circuit, this need more big space and more cost. So could we find some simple methods to solve these problems? Could we just use one bulk-cap? Could we adopt more simple driver circuit? 4
Background Two Traditional Solutions Introduction Phase Cut Regulator Introduction 5
What s Phase Cut Regulator? Input Bridge Phase cut regulator Bulk cap DC-DC High rectified sine DC voltage Low regulated DC voltage The phase cut regulator is circuit which insert between bridge and bulk-cap, which working in switching mode, it can regulate the high sine DC voltage from bridge to a low peak voltage DC voltage for bulk-cap. 6
Phase Cut Regulator Working Time Diagram As right pictures shown : T: SW on, bulk-cap not charge (Vline_on < Vref & Vline<Vbulk) T: SW on, bulk-cap charge (Vline_on <Vref & Vline>Vbulk) T:SW off, bulk-cap discharge (Vline_on >Vref) 7
Three Solution s Efficiency Comparison Solutions Vin/Vout Devices Freq. Balance Circuits 60Vac 0Vac 80Vac 600Vac Cascode FET 45Vac- 600Vac/5V/670mA FSL7MRIN+FQP4N90C 67KHz Yes 6.4% 78.6% 76.9% 7.6% ESBC 45Vac- 600Vac/5V/670mA FJBE60D+FDC65N 67KHz Yes 67.% 79.56% 76.5% 65.68% Pre-regulator 45Vac- 600Vac/5V/670mA FSL6+HGTDN0 67KHz No 77.84% 78.54% 75.% 66.49% 8
The Benefit of Phase Cut Regulator Just need one Bulk-cap,save cost and space. Don t need Bulk-cap balance circuit, more simple. Could use a low breakdown voltage MOSFET, more cheaper. As input DC voltage go down, the DC-DC part could set more big duty cycle, the efficiency will increase. 9
0 Schematic C0 05 D0 C 0 C 04 05VAC C 04 05VAC R70.9K C 04 05VAC VIN VOUT GND U7 NC + C77 NC CON +5V Vrr R4 00K R M D BAV99 C8 0 C7 47nF R6 K R74 4.7K CON +5V Vrr + C7 uf 5V L mh Q MMBT907A L mh L mh GND Vcc FB Ipk 4 Vstr 5 D 6 D 7 D 8 U70 FSL6MR C8 05 D4 MM5Z4V A Vsn L4 mh R 470K C 0 D7 N448WS D70 P6KE50A D D D5 D D0 D4 D9 D6 N RV 0D-6 R0 M B VB VA VC VH N C5 04 05VAC C6 04 05VAC 4 CON AC -In RV 0D-6 4 U7 FOD87C C4 04 05VAC RV 0D-6 R80 0K Q0 HGTDN0 R8 47 R0 R R R5 R C VccA R4 4 4 7 6 8 9 T70 EF0-4P Vsn D75 S0 + C79 470uF 5V R7 NC C78 NC R 0K D74 SS4 + C76 470uF 6V R7 NC C75 NC R7 47K + C70 68uF 400V D7 N448WS C80 04 R75 4K R76 4.7K U7 TL4 VR R79 4.7K D7 MM5Z68V R5 00K R78.K R6 00K R77 4.7K R7 00K R8 00K R9 00K D8 MM5Z68V Vcc D9 MM5Z68V D0 MM5Z68V R 47K D MMSZ550 R M R M R5 M Vcc R4 M C7 500V R6 M C74 C7 500V D N4007 VccA D7 ESJ R46 K Vrr A Q40 HGTDN0 R48 47 R40 R4 R4 R45 R4 VccA R44 R47 47K 5 6 7 4 - + U0B LM90A VR R K R4.M D 4 - + U0A LM90A VN R56 K Vrr R7 00K C Q50 HGTDN0 R58 47 R50 R5 R5 R55 R5 VccA R54 R57 47K 0 9 8 4 - + U0C LM90A VR D40 D4 R66 K Vrr B Q60 HGTDN0 R68 47 R60 R6 R6 R65 R6 VccA R64 R67 47K 4 4 - + U0D LM90A VR D50 D5 VR +5V L5 mh R8 M D D5 D7 D D4 D6 D D8 D60 D6 R9 M + C9 uf 5V R7 0 R0 K Q N7000 VccA Three phases smart meter power with phase cut regulator
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