EET 423 POWER ELECTRONICS 2 POWER ELECTRONICS 2

EET 423 POWER ELECTRONICS -2 POWER ELECTRONICS 2 Prof R T Kennedy 1

SMPS OPERATION QUANTIZED POWER/ENERGY TRANSFER VOLTAGE REGULATION POWER ELECTRONICS 2 Prof R T Kennedy 2

BASIC COMPONENTS sw 1 Ein NON-ISOLATED C sw 2 L R sw 1 sw 2 ISOLATED SW 1 controllable Ein T C L R BJT MOSFET IGBT SW 2 non-controllable (RECTIFIER pn or Schottky) controllable (MOSFET) POWER ELECTRONICS 2 Prof R T Kennedy 3

COMPONENT INTERCONNECTIONS 1 2 sw 1 C sw 2 Ein R L 3 3 POWER ELECTRONICS 2 Prof R T Kennedy 4

SWITCHING CYCLE SUB INTERVALS L E in C R a E in C L R b E in L C R c POWER ELECTRONICS 2 Prof R T Kennedy 5

BASIC TOPOLOGIES & CONSTRAINTS SWITCH sw 1 1 2 L Ein 1 3 C R sw 2 L E in sw 1 C R 2 3 L L L Sw 1 Sw 2 ON OFF OFF ON ON POWER ELECTRONICS 2 Prof R T Kennedy PROBLEM inrush current short circuit source output capacitor voltage discharge J YES J L YES NO N 6

BASIC-1 BUCK CONVERTER L sw 1 Ei n C sw 2 R Ei n sw 1 on L C R a L Ei n c L C R Ei n sw 2 on POWER ELECTRONICS 2 Prof R T Kennedy C R Vout 7

BASIC-2 BOOST CONVERTER sw 2 L L C E in sw 1 on R sw 2 on R b L L E in C C R a POWER ELECTRONICS 2 Prof R T Kennedy 8

BUCK TOPOLOGY TERMINOLOGY • Step Down Converter output voltage input voltage • Direct Converter direct energy transfer from input to output (sw 1 on) • Forward Converter energy transferred forward supply load (sw 1 on) • Single Ended Converter common input-output rail • Non-Isolated Converter no transformer input – output isolation POWER ELECTRONICS 2 Prof R T Kennedy 9

BUCK TOPOLOGY TERMINOLOGY • Step Down Converter output voltage input voltage • Direct Converter direct energy transfer from input to output (sw 1 on) • Forward Converter energy transferred forward supply load (sw 1 on) • Single Ended Converter common input-output rail • Non-Isolated Converter no transformer input – output isolation POWER ELECTRONICS 2 Prof R T Kennedy 10

BOOST TOPOLOGY TERMINOLOGY • Step Up Converter output voltage input voltage • Indirect Converter no direct energy transfer from input to output • Single Ended Converter common input-output rail • Non-Isolated Converter no transformer input – output isolation POWER ELECTRONICS 2 Prof R T Kennedy 11

BOOST TOPOLOGY TERMINOLOGY • Step Up Converter output voltage input voltage • Indirect Converter no direct energy transfer from input to output • Single Ended Converter common input-output rail • Non-Isolated Converter no transformer input – output isolation POWER ELECTRONICS 2 Prof R T Kennedy 12

BUCK-BOOST COMBINED CONVERTER L E in C R POWER ELECTRONICS 2 Prof R T Kennedy C R 13

BUCK-BOOST COMBINED CONVERTER L E in C R POWER ELECTRONICS 2 Prof R T Kennedy C R 14

BUCK-BOOST COMBINED CONVERTER L L E in C R SWITCH SYNCHRONISATION POWER ELECTRONICS 2 Prof R T Kennedy 15

BUCK-BOOST COMBINED CONVERTER L Ein sw 1 on C R b L Ein C sw 2 on R c POWER ELECTRONICS 2 Prof R T Kennedy 16

BUCK-BOOST COMBINED CONVERTER Ein C L R Vout NOTE VOLTAGE INVERSION POWER ELECTRONICS 2 Prof R T Kennedy 17

BOOST-BUCK COMBINED CONVERTER L 2 L 1 E in C 1 R POWER ELECTRONICS 2 Prof R T Kennedy C 2 R 18

BOOST-BUCK COMBINED CONVERTER L 2 L 1 E in C 1 R POWER ELECTRONICS 2 Prof R T Kennedy C 2 R 19

BOOST-BUCK COMBINED CONVERTER L 2 L 1 E in C 2 C 1 SWITCH SYNCHRONISATION POWER ELECTRONICS 2 Prof R T Kennedy R 20

BOOST-BUCK COMBINED CONVERTER L 1 Ein L 2 C 1 C 2 R Vout NOTE VOLTAGE INVERSION POWER ELECTRONICS 2 Prof R T Kennedy 21

SMPS TOPOLOGIES POWER SUPPLIES SWITCHING LINEAR HARD SERIES SHUNT SWITCHED MODE SMPS SOFT RESONANT RPS HYBRID QRPS 2 BASIC TOPOLOGIES BOOST BUCK DERIVED BOOST DERIVED COMBINED SEPIC FORWARD PUSH PULL 1 or 2 Transistor BUCK-BOOST DERIVED BOOST –BUCK DERIVED BRIDGE FLYBACK HALF FULL CUK 1 or 2 Transistor POWER ELECTRONICS 2 Prof R T Kennedy BOOST -BUCK 22

SMPS TOPOLOGIES POWER ELECTRONICS 2 Prof R T Kennedy 23

RECAP SMPS APPLICATIONS POWER ELECTRONICS 2 Prof R T Kennedy 24

INDUCTOR CURRENT MODES Imax Iind 1 2 o Imin 2 1 CCM t Imax Iind 0 t BOUNDARY Imax Iind DCM o 1 2 1 3 t Prof R T Kennedy 2 3 Imin POWER ELECTRONICS 2 25

BUCK CONVERTER CIRCUIT CURRENTS Ii n Ids a IL Ifwd IL b Iout L IC Ids Ei n Ifwd C POWER ELECTRONICS 2 Prof R T Kennedy R Vout 26

Vgs BUCK CONVERTER CIRCUIT CURRENTS CCM 0 Iout 0 IC, av= 0 0 IL, av=Iout 0 Ids, av 0 Ids Iin, av Iout IL=Ids+Ifwd 0 0 Ifwd 0 IL=Iout+IC 0 Iout Ifwd, av POWER ELECTRONICS 2 Prof R T Kennedy 27

Vgs BUCK CONVERTER CIRCUIT CURRENTS CCM 0 Iout 0 IC, av= 0 0 IL, av=Iout 0 Ids, av 0 Ids Iin, av Iout IL=Ids+Ifwd 0 0 Ifwd 0 IL=Iout+IC 0 Iout Ifwd, av POWER ELECTRONICS 2 Prof R T Kennedy 28

Vgs Iout IC BUCK CONVERTER CIRCUIT CURRENTS DCM 0 0 IC, av= 0 0 IL=Iout+IC IL, av=Iout IL 0 Ids, av Iin, av 0 IL=Ids+Ifwd, av 0 POWER ELECTRONICS 2 Prof R T Kennedy 29

BOOST CONVERTER CIRCUIT CURRENTS Iin IL L Ids Ifwd C POWER ELECTRONICS 2 Prof R T Kennedy b Iout IC Ids Ei n Ifwd a Ifwd R Vout 30

Vgs 0 Iout 0 IC BOOST CONVERTER CIRCUIT CURRENTS CCM IC, av= 0 0 Ifwd=Iout+ IC IL, av=Iin, av Ifwd 0 Iout Ifwd, av Ids IL, av IL=Ids+ Ifwd 0 IL, av IL 0 POWER ELECTRONICS 2 Prof R T Kennedy 31

Vgs 0 Iout 0 IC 0 Ifwd BOOST CONVERTER CIRCUIT CURRENTS DCM IC, av= 0 Ifwd=Iout+ IC Ifwd, av = Iout 0 Ids, av IL=Ids+ Ifwd 0 IL, av = Iin, av IL 0 Prof R T Kennedy POWER ELECTRONICS 2 32

WAVEFORMULAE C DC- average AC- rms total- rms 0 DT ( 1 - D) T B C k. C A 0 DT (1 - D) T 0 POWER ELECTRONICS 2 Prof R T Kennedy 33

WAVEFORMULAE DC- average AC- rms total- rms C 0 D T (1 -D) T POWER ELECTRONICS 2 Prof R T Kennedy 34

TRAPEZOIDAL-SQUAREWAVE RMS COMPARISON B k. C C A 0 D T (1 - D) T rms, trap rms, sq square wave POWER ELECTRONICS 2 Prof R T Kennedy CCM-DCM boundary 35

PARASITICS PARASITIC EFFECTS LOSSY RESISTIVE SOURCE RS INDUCTOR r. L MAGNETICS core loss winding loss CAPACITOR esr LOSSLESS CAPACITOR esl SEMICONDUCTORS RECTIFIER VF I rev rec TRANSISTOR ON Loss BJT /IGBT ce BJTV/IGBT Vce POWER ELECTRONICS 2 Prof R T Kennedy INDUCTOR TRANSFORMER leakage L stray capacitance SWITCHING loss MOSFET rds, on MOSFET turn on turn off rds, on 36

POWER and POWER LOSSES MOSFET IM 0 Dmos. T T IGBT IM 0 Digbt. T T BJT IM 0 Dbjt. T T POWER ELECTRONICS 2 Prof R T Kennedy 37

POWER and POWER LOSSES RECTIFIER IM 0 Drect. T T RESISTOR IM 0 R DT T POWER ELECTRONICS 2 Prof R T Kennedy 38

SYSTEM POWERS and EFFICIENCY POWER ELECTRONICS 2 Prof R T Kennedy 39

SYSTEM POWERS and EFFICIENCY POWER ELECTRONICS 2 Prof R T Kennedy 40

VOLTAGE TRANSFER FUNCTION ANALYSIS • ENERGY BALANCE • POWER BALANCE • VOLT-TIME INTEGRAL POWER ELECTRONICS 2 Prof R T Kennedy 41

FARADAY’S VOLT-TIME INTEGRAL IM INDUCTOR CURRENT Im current start and finish at same value 0 t V 1 INDUCTOR VOLTAGE 0 t 1 t V 2 t 2 T EQUAL AREAS POWER ELECTRONICS 2 Prof R T Kennedy 42

BUCK and BOOST CONVERTERS VOLTAGE TRANSFER FUNCTIONS BOOST BUCK POWER ELECTRONICS 2 Prof R T Kennedy 43

BUCK-BOOST- BUCK CONVERTERS VOLTAGE TRANSFER FUNCTIONS INVERTED STEP DOWN (<1) INVERTED STEP UP (>1) POWER ELECTRONICS 2 Prof R T Kennedy 44

PRACTICAL SYSTEMS POWER ELECTRONICS 2 Prof R T Kennedy 45