General Purpose Power Electronic Converter

Background
Converters are a commonly used device within many electronic systems that allow the voltage of the device to operate in an area with a different voltage. This functionality is increasingly important in many technologies today since electronic devices often contain multiple sub-circuits where each circuit may have different voltage requirements than each other to include the main power supply. A well-known example of this is within portable electronic devices, such as a cellphones, tablets, and laptop computers.

Desired Goals
For our project, the design goal is to develop a converter system that utilizes 4 traditional converters and combines their outputs in order to push a higher, more efficient output while lowering the cost of high power converter system; ideally four, 60 kW converters as a single, .25 MW system.

Desired Specifications

 * •	input: ranged dependent on local power supplies available – 120 V - 400 V Direct Current or Alternating Current (DC or AC)
 * •	Output: fixed set value as established based on need. – 120 V, 240 V 400 V DC or AC
 * •	Must have at least 4 traditional converter modules
 * •	Efficiency must be greater than 90.0 %
 * •	Although size is not specified, a smaller system would be preferred.

Project Design Procedure

 * 1.	Investigate the different types of DC to DC (DC/DC) converters and their efficiencies.


 * 2.	Build a simulation model of the converter module


 * 3.	Build a simulation model of the combined converter modules.


 * 4.	Determine the optimal operating points of the combined converter modules.


 * 5.	Develop the software to automate the optimization function of the combined converter modules


 * 6.	Build the combined converter modules

Project Specifications
In order to implement the desired specifications into such a system, it was determined that by developing a lower power equivalent of the system, the control scheme of the system could be created and then scaled-up so that the desired goal could be attained. In agreeance with the client, the new project specifications are as follows:


 * •	Input: range dependent on available power sources – 12 VDC to 36 VDC
 * •	Output: fixed at a single voltage of 24 VDC
 * •	Must have at least 4 traditional converter modules
 * •	Efficiency must be greater than 90.0 %
 * •	Optional: Small System preferred.

Designs
Circuit of Forward Converter

V1 is input voltage source. L1 and L2 mean transformer. RB068L152 is the diode that design by our team(this is the key component to keep efficiency high) diode parameters: 1. BV=500 BV means breakdown voltage 2. N=0.35 N means emissive coefficient 3. Is=14.11n IS means saturation current 4. Rs= 2.2m Rs means series resistance 5. Cjo=40p Cjo means zero bias junction capacitance 6. M=0.5 M means Nodal gradient factor 7. tt=25n tt means crossing time 8. Iave=20 Iave means positive rated current 9. mfg means manufacturer 10. type means material, and we decide to use silicon Rload is a load resistor. R4 & R5 are feedback resistors R3 is Rsense R13, R14 and R15 are estimated values. UVLO and OVLO: the system undervoltage and overvoltage thresholds are programmed by a resistive voltage divider from Vin to UVLO and OVLO. Rt controls frequency. R1&C2 control duty cycle. C3 means soft-start input(this value is not very important) the secondary part is the same as our ECE 320 textbook, so there is no detailed description. However, their calculation equations are given in the next part.

Design Requirement

 * •	Minimum Input Voltage Value: Vinmin = 12 V
 * •	Maximum Input Voltage Value: Vinmax=36V
 * •	Output Voltage Value: Vout=24V
 * •	Pout=100W  Efficiency >=94%

Important values Calculation

 * •	Output Current: Iout=Pout/Vout=4.176 A Rload=Pout/Iout2 = 5.76Ω

Np-s= 1/3 Remarks: on the schematic, the ratio transformer is 300u : 2.7m. When we use set transformers in LTspice, (1:x) must be transformed into (1:x2). VOUT(TARGET) = 24V    Rset = 33333.33Ω Vset= Rset x 20uA= 0.6667V

Duty cycle
D=（12 x 0.6667V）/24V =  0.33335

Soft-start
Set tss= 2ms ,Css= 50nFx(tss/1ms)=100nF

Frequency
Set Rt= 49.9kΩ  Frequency =200KHz

Feedback
R4/R5 = (24V/1.6)-1= 14 : 1

Secondary Part Component Value
⊿Vc = 0.24V, ⊿ iIx = 8.352A Lx, min = 9.579uH minimum Inductor value Cx, min = 27.69uF Minimum Capacitor value

Other Components Values
CDFILT: Np/Ns=1/3,    L1 = 50uH,   CL=60uF  CDFILT,min=9.1287x1010F Set |Vref|=1.6V  Cc=4.7nF，Rsense= 0.0025 Ω    RZ,min = 3995Ω

Simulation Results
..........................................................................figure(1). simulation result value of every component.............................................................................................



the picture shows output voltage that the x-coordinate is time, and the y-coordinate is voltage,and it is almost getting close to 24V that is what we want to achieve purpose.

Pricing for Design
Budget

Document Archive

 * Gantt Chart

Other Documents

 * Other documents
 * Contract

Content of meeting

 * February 14 The First Meeting Minutes
 * February 21 The Second Meeting Minutes
 * March 1 The Third Meeting minutes
 * March 22 The Forth Meeting minutes
 * March 29 The Fifth Meeting Minutes
 * April 3 The Sixth Meeting Minutes
 * April 12 The seventh Meeting Minutes
 * April 23 The Eighth Meeting Minutes
 * August 23 The Ninth Meeting Minutes
 * August 30 The Tenth Meeting Minutes
 * Sept 6 The Eleventh Meeting Minutes
 * Sept 13 The 12th Meeting Minutes

Project Schedule
Project Schedule

Final Presentation
Presentation