Prof R T Kennedy 1 EET 423 POWER ELECTRONICS -2

Prof R T Kennedy2 BUCK CONVERTER CIRCUIT CURRENTS I fwd I ds E i n I i n ILIL I ds ICIC I fwd C R L ILIL I out a b V out

Prof R T Kennedy3 BUCK CONVERTER CIRCUIT VOLTAGES E i n V out V ds a b V L,a-b C R L V fwd

Prof R T Kennedy4 SUB INTERVAL EQUIVALENT CIRCUITS V ds = 0 a b V L,a-b = E in -V out E i n C R V out L MOSFET ON RECTIFIER OFF V fwd = -E in

Prof R T Kennedy5 SUB INTERVAL EQUIVALENT CIRCUITS E i n C R a b V out V fwd = 0 V ds = E in MOSFET OFF RECTIFIER ON L a b V L,a-b = -V out a b

Prof R T Kennedy6 E in =E ds + E fwd V L + V out = -V fwd E in VLVL V out V fwd V ds 0 V gs

Prof R T Kennedy7 E in =V ds - V fwd E in VLVL V out V fwd V ds 0 V gs - V fwd

Prof R T Kennedy8 SMPS OPERATION QUANTIZED POWER/ENERGY TRANSFER VOLTAGE REGULATION

Prof R T Kennedy9 VOLTAGE TRANSFER FUNCTION ANALYSIS ENERGY BALANCE ENERGY BALANCE POWER BALANCE POWER BALANCE VOLT-TIME INTEGRAL VOLT-TIME INTEGRAL

Prof R T Kennedy10 ‘IDEAL’ BUCK ANALYSIS ENERGY BALANCE APPROACH INDUCTOR CURRENT I L,M I L,m I L,av = I load 0

Prof R T Kennedy11 SUB-INTERVAL 1

Prof R T Kennedy12 SUB-INTERVAL 2

Prof R T Kennedy13 switching period

Prof R T Kennedy14 FARADAY’S VOLT-TIME INTEGRAL INDUCTOR VOLTAGE V1V1 t1t1 0 INDUCTOR CURRENT t2t2 V2V2 0 t t I m I M T current start and finish at same value EQUAL AREAS

Prof R T Kennedy15 BUCK and BOOST CONVERTERS VOLTAGE TRANSFER FUNCTIONS BOOST BUCK

Prof R T Kennedy16 BUCK-BOOST BOOST- BUCK CONVERTERS VOLTAGE TRANSFER FUNCTIONS INVERTED STEP DOWN (<1) INVERTED STEP UP (>1)

Prof R T Kennedy17 PRACTICAL SYSTEMS