Tuesday 6 August 2019

PRODA In-House Training on Power Inverter Design.


Able Designs and Construction Company (ADACC) and Dr. Ericsson Eguriase Otavboruo presents here a snippet of what was taught  at the Project Development Institute (PRODA) in-house training on power inverter designed by Engr. Dr. Fabian C. Okonkwo to impart specific skills and practical knowledge to the staff of EPED. 


What is a Power Inverter?
A power inverter is an electronic device that converts direct current (DC) from battery or solar panel to alternating current (AC) which can power an electric iron, air conditional, television,  mobile phone, computer and other domestic or industrial appliances. The generated AC power can carry these loads with the energy stored in the battery. 
The inverter power is rated in VA or KVA.
Power in VA = AC Voltage x AC Current in Amps
Power in KVA = AC Voltage x AC Current in Amps/1000
Power in Watts = AC Voltage x AC Current in Amps x PF
Where PF = power factor 
Power in KW = AC Voltage x AC Current in Amps x PF/1000
Also  Power in W = Power in VA x PF
Power in KW = Power in KVA x PF
A simple power inverter consists of the units  in the black box design shown below using top-down approach  also known as step-wise design.
                                                    Block Diagram of a Power Inverter


                                    A Simple Square wave Power Inverter Circuit
                             Protues Version of the Square wave Power Inverter Circuit




According to Pst. Engr. A. A Ndubuisi, one of the critical test for graduate engineers is in the application of technical knowledge in a way to solve engineering problems and to implement ideas in a cost effective and practical approachThe ability to take a thought or idea and translate it into a physical and workable product is what separates an engineer from other fields of science and mathematics. 
EPED staff are trained by ADACC to think innovatively in order to design and develop electronic products from the initial vague concept to commercial production. Through the in-house training/workshop on COMPUTER AIDED DESIGN, PRINTED CIRCUIT BOARD PRODUCTION AND PROCESSING, SOFTWARE DEVELOPMENT, CIRCUIT DESIGN, MATLAB WORKSPACE AND SIMULINK, etc a lot of improvement has been done in EPED. 
Thanks to Engr. Onyebuwa Ugochukwu. E who contributed immensely in the PCB production and processing during the 10th to 14th June 2019 training .






Oscillator: The oscillator unit in the above design is where the power conversion takes place.  
An oscillator is simply an electronic circuit that produces a periodic or alternating signal. In the design, CD4047 is used to design the oscillator unit with good frequency stability. 
The CD4047 is a multivibrator chip with very low power consumption designed by TEXAS INSTRUMENTS. It can operate as a monostable and astable circuit. It is one of the tricks that can generate 50% duty cycle which creates the pulse applied in the above circuit.
Buffer: The primary purpose of the buffer circuit in the design is to boost the current from the oscillator unit.
A buffer circuit is mainly used where a signal has a very low current which needs to be increased. It can also maintain the same voltage level. The buffer circuit draws current from the power supply unit and adds it to the signal.
Power Unit: The power unit consists of a step up transformer and power transistors mostly MOSFET mounted on a heat sink.
This unit can use H-Bridge topology. It determines the output power rating of the inverter.  The battery supply is given to the MOSFET to deliver the resulting AC signal to the step up transformer in order to produce 220v AC at 50 Hz. The MOSFET can be IRF540 which is a N-channel enhanced mode silicon gate field effect transistor.

Power Inverter system plays a prominent role in ensuring uninterruptible power to sensitive loads in PRODA. The waveform below is the simulated result of the square wave inverter. 




The power inverter system also has a battery charging unit that charges the battery during utility power. During utility power, the battery of the inverter is charged and at the same time power is supplied to the loads. When utility power fails, the battery system begins to supply power via the inverter to the loads. 
The backup time depends on the number of batteries as well as the capacity of the batteries in Amp-hours.
To calculate the inverter battery backup time
It is calculated as:
Back up time = Battery Power in Watt hour (Wh)/Connected Load in Watts (W)
Battery Power in Wh = Battery Capacity in AH x Battery Voltage (V) x Number of Batteries.
Let us shorten the formula by using the following Symbols:
 Let  ABLE = battery backup time in hours
C = battery capacity in AH 
V = battery voltage in volts
N = Number of batteries in series or parallel as the case may be.
PL = connected load in watts (W)
Now
ABLE = CVNPL
Suppose we will selected a 24V, 1.5KVA inverter system that is to use two 12V batteries in series connection and suppose the capacity of our batteries are 200AH each, 
then :
C = 200AH
V = 12V
N = 2
PL   = 1,060W 
ABLE = 200 12 21060 = 4.53hrs


DR. ERICSSON EGURIASE OTAVBORUO can be contacted for MATLAB designs through the Director of EPED in PRODA. We shared IET journals and electronic magazines to all the participants and IT students in EPED because we discovered that some design secrets and ideas are hidden in application notes, engineering journals and hard to get data books. Therefore, the vital information including job opportunities and advert for professional development courses can be found there. To get more journals and magazines visit:  www.theiet.org/magazine.  These magazines should be considered required reading to keep up with the latest electronic products and circuit ideas. The advertisements are as important as the articles
 
...................................................................................................................................................................
THE IN-HOUSE TRAINING AND WORKSHOP TEST ON CAD AND ELECTRONIC DESIGN
Conducted by Able Designs (A member of Schoolnet and business partner of IET, U.K).
Instructions: Answer all questions in part one.                                                    
Part One: Questions and Answers.                                       Time: 30 minutes
1.     What is CAD?
2.     Describe the features in Proteus 8 as CAD software?
3.     What is the correct and full meaning of the following acronym in Protues 8 CAD suite?  
A.   ISIS
B.   ARES
4.     Use the CD4047 oscillator formula given during the training programme to get a 50 Hz frequency output for the inverter?
NOTE: Kindly show all the mathematical steps used to achieve the answer.
5.     Design and draw a complete schematic circuit diagram of the CD4047 power inverter and determine its component values for 1 KVA, 220v AC, 50 Hz and 24v DC Design specification.
6.     Name the three main type of PCB?
7.     What is the four parts of PCB?
8.     What are the basic steps to develop a product idea?
9.     Explain the following in Protues 8 and their uses
a.     Board Edge
b.     Selection Mode
c.      Component Mode
d.     Package Mode
e.      Track Mode
f.       Via Mode
g.     2D graphics box mode
h.     2D graphics text mode
i.       Dimension Mode
Part Two: Practical.                                                      Time: 1 Hour only 
Please do the hardware or software implementation and present the work for confirmation.   
1.     Identify all the physical components used in the inverter design and use them to build a working prototype of the product on a breadboard or veroboard?
2.     Design and simulate the prototype of the inverter design in Protues 8 software without using any of the component values (except the IC) used during the training. The design must be accurate and simulates with the with the waveform showing on an oscilloscope? 


For more information: Contact the Director, EPED Department PRODA, Enugu or ADACC on +2348037909203, abledesigns@yahoo.com 
You can also join IEE which is now IET from https://www.theiet.org/

2 comments:

Able Designs said...

The training was so great...... Thank God

Networking said...

That’s good. We love to attend the next training Sir