Voltage Gain Enhancement for Step-Up Converter Constructed by KY and Buck-Boost Converters

SIMULATION DESIGN

POWER =60W
V_IN=12V
V_OUT=72V

· L_m =148μH, L_k = 0.3μH · the turns ratio of coupled inductor n = N_s/N_p =3 · OPERATING FREQUENCY OF THE SWITCH (MOSFET HERE) =100KHz · Gain formula of converter = ( (2-D) / (1−D) )+n OUTPUT CURRENT I_OUT = P_OUT / V_OUT I_OUT = 60W / 72V I_OUT = 0.833A INPUT CURRENT Assume that the converter efficiency is about 100% P_OUT = P_IN I_OUT = P_IN / V_IN I_OUT = 60W / 12V I_OUT = 5A VOLTAGE GAIN CALCULATION Gain = V_OUT / V_IN V_IN = 12V V_OUT = 72V Gain = 72V / 12V Gain = 6 DUTY CYCLE CALCULATION Voltage gain of converter = ( (2-D) / (1−D) )+n 6 = ( (2-D) / (1−D) )+3 3 = (2-D) / (1−D) 3(1−D) = 2-D 3−3D = 2-D 3−3D = 2-D 1= 2D D = 0.5 D = 50% Coupling coefficient calculation We have, The coupling coefficient of coupled inductor, k = L_m / (L_m + L_k) L_m =148μH, L_k = 0.3μH K = 148μH / (148μH + 0.3μH) = 0.997 COUPLED INDUCTOR DESIGN Here core used is etd-59.From the datasheet of ETD-59 core A_L=4.7uH We have, Mutual inductance = k √L_P * L_{S =} 148μH In paper winding ratio is given about 1:3 Let N be No. of turns in primary and 3N be No. of turns in secondary L_P=N²A_L L_S = (3N)²A_L L_S=9N²A_L M = k√9N²A_L * N²A_L M = k √9N⁴ * A_L² M= k * 3N² * A_L 148μH =.997 *3 N² *4.7uH 148μH =14.05 uH * N² N² = 148μH / 14.05 uH N² = 10.53 N=3.24 =3 No. of turns in primary = 3 No. of turns in secondary =3N =3* 3 No. of turns in secondary = 9 L_P= N_P² * A_L L_P= 9* 4.7 uH L_P= 42.3 uH L_S= N_S² * A_L L_S= 9² * 4.7 uH L_S= 81 * 4.7 uH L_S = 380 uH OUTPUT CAPACITOR VALUE FOR A CAPACITOR VOLTAGE CURRENT BASIC RELATION IS I = C * dV / dt dV is output ripple voltage. Assume that output ripple voltage is about 0.01% of output voltage dV = 0.01% * 72V dV = 0.0072 V C = I * dt / dV We have dt = duty ratio/frequency C = I * D / (F * dV ) C = 0.833A* 0.5/ (100000 Hz* 0.0072 V) C = 578 uF = 470uF (Standard value) Hardware

WAVE FORMS

s2-s1 gate signals

output (attenuation of 10 used)

See also

simple PWM - DSPIC30F2010

Vds2 PROGRAM (OPEN LOOP) //Micro controller -dspic30f2010 //compiler -mikroc //i have used crystal of 20 MHz //output at 50KHz // //duty_50% = (clock_frequency/ (output_frequency*4 *1)) -1 =99 //DEAD TIME = duty_50%/2 =45 void main() { unsigned int pwm_period, current_duty ; current_duty=99; //duty ratio 50% =99 pwm_period = PWM1_MC_Init(50000, 0, 0x11, 0); //enable 1L AND 1H pwm pins PWM1_MC_Set_Duty (current_duty, 1) ; PWM1_MC_Start(); DTCON1=10; //DEAD TIME CONTROL maximum 79 while (1); } PROGRAM (CLOSED LOOP) //used crystal of 20 MHz //output at 50KHz // //duty_50% = (clock_frequency/ (output_frequency*4 *1)) -1 =99 //DEAD TIME = duty_50%/2 =45 //feed back by 100k and 2.2k //adc value —295 for 67V //char g[5]; //void adctoascii (void); //declare globally int feedbackvoltage; void main() { unsigned int pwm_period, current_duty ; current_duty=99; //duty ratio 50% =99 pwm_period = PWM1_MC_Init(50000, 0, 0x11, 0); //enable 1L AND 1H pwm pins PWM1_MC_Set_Duty (current_duty, 1) ; PWM1_MC_Start(); DTCON1=10; //DEAD TIME CONTROL maximum 79 //UART1_Init(9600); // Initialize UART module at 9600 bps //Delay_ms(100); // Wait for UART module to stabilize //UART_Write_Text(“Start”); //UART_Write(0xd); TRISB.F0 = 1; while (1) { feedbackvoltage = ADC1_Read(0)*67/295; Delay_ms(10); //adctoascii ();UART_Write_Text(g);UART_Write(0xd); //Delay_ms(100); if(feedbackvoltage>70) { current_duty=current_duty-1; if(current_duty<1)current_duty=0; PWM1_MC_Set_Duty (current_duty, 1) ; } else if (feedbackvoltage<69 ) { current_duty=current_duty+1; if(current_duty>160)current_duty=160; PWM1_MC_Set_Duty (current_duty, 1) ; } } }

High Boost Ratio Hybrid Transformer DC-DC Converter for PhotovoltaicModule 24 TO 410VDC

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