A Novel High Step-Up DC–DC Converter for a Microgrid System-SIMULATION IN MATLAB (SIMULINK )

CIRCUIT

Design
Note
  • These designs are according my ideas.There may be errors in design
  • I have done simulation only.Hardware will be done march 2016
Datas given in this IEEE paper
  • POWER =400W
  • VIN=24V 
  •  IIN=16A
  •  VOUT=400V ,
  • IOUT =1A
·        Lm =48μH, Lk =0.25μH
·        the turns ratio of coupled inductor n = Ns/Np =4
·        OPERATING FREQUENCY OF THE SWITCH (MOSFET HERE) =50KHz
·        Gain formula of converter = ( (1+n) / (1−D) )+n

VOLTAGE GAIN CALCULATION

 Gain = VOUT  / VIN
  • VIN = 24V 
  •  VOUT = 400V
Gain = 400V /  24V  =16.6

DUTY CYCLE CALCULATION

Voltage  gain of converter = ( (1+n) / (1−d) )+n
16.6  = ( (1+4) / (1−d) )+ 4
16.6 = ( 5 / (1−d) )+ 4
12.6 S= 5 / (1−d)
(1−d)  = 5 / 12.6
(1−d)  = 0.396
D = 1− 0.396
D = 0.604

Coupling coefficient calculation

We have,
The coupling coefficient of coupled inductor, k = Lm / (Lm + Lk)
Lm =48μH, Lk =0.25μH
K = 48μH / (48μH + 0.25μH) = 0.995

COUPLED INDUCTOR DESIGN

Here core used is etd-59.From the datasheet of ETD-59 core
AL=1.5uH
We have,
M=k √LP * LS = 48μH
In paper winding ratio is given about 1:4
Let N be No. of turns in primary and 4N be No. of turns in secondary
LP=N2AL
LS=16N2AL
M = k√16N2AL * N2AL
M =  k  √16N* AL2
M= k * 4 N* AL
48μH =.995 * 4 N*1.5uH
48μH =5.97 uH * N2
N2 = 48μH  / 5.97 uH
 N2 = 8
N=2.83 =3
No. of turns in primary = 3
No. of turns in secondary =4N =4 * 3
No. of turns in secondary = 12

LP= NP* AL
LP= 9* 1.5 uH
LP= 13.5 uH
LS= NS* AL
LS= 12* 1.5uH
LS= 144  * 1.5 uH
LS= 216 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 0.02% of output voltage
dV = 0.02% * 400V
dV =  0.08 V
C = I * dt / dV  
We have dt = duty ratio/frequency
C = I * D /  (F * dV )
C = 1A* 0.604/ (50000 Hz* 0.08 V)
C = 151 uF =180uF (Standard value)