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 approach. The 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 = C∗V∗NPL

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

 

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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/

IMPROVING INTELLIGENT WIRELESS SENSOR FOR PREPAID METER BYPASS CONTROL

IMPROVING INTELLIGENT WIRELESS SENSOR FOR PREPAID METER BYPASS CONTROL

High quality prepaid meters are used to measure the amount of electricity supplied to a residential or commercial building. When the meter is tampered or bypassed, it will either stop functioning, under-register or even stop registering the amount of electricity been consumed. This is usually done by the consumers to avoid paying for the electricity that they use. Bypass causes huge revenue losses, affects our economy and development and affects lives and properties through fire outbreak, injury or even death by electrocution. It has being the major concern of the transmission and distribution losses in the supply of electricity. 

Due to poor maintenance, poor infrastructure, irregular regulation and monitoring of meters and so on by Nigerian Electricity Power Authority (NEPA), the national power grid was sold and a digital meter system was introduced against analog meters. Yet, Power Distribution Companies are still afraid to supply prepaid meter rather they prefer to bill their consumers based on estimation. They increase their tariff rate, increase cost of acquiring the digital meter and delay its installation may be to discourage people from getting prepaid meter or to remain in business. I  believe this is because prepaid meters are still being bypassed upon its implementation in the system.

Energy theft through illegal connection or bypass are being done using different techniques in Nigeria, that’s why the Federal Government through the Minister of Power, Works and Housing with some power distributors deployed a meter bypass trackers in order to reveal the culprits and have them punished. These trackers alone could not provide 100 percent protection. Therefore, to solve these problems, this project proposed for an intelligent wireless sensor for meter bypass control. 

The aim and objective of the newly improved intelligent wireless sensor for meter bypass control is for computerization of the prepaid metering system and to make electricity meter more sensitive to any bypass technique which will help in the provision of constant electricity in Nigeria. The intelligent wireless sensor for meter bypass control will acquire information related to the bypass techniques and activate a preventive measure as it notifies the authority using wireless sensor network (WSN). 

Through WSN, all meters are network nodes to harvest information, share information and give the sensor node long lifetime energy.  In this idea, we propose an intelligent algorithm to detect and send information when the meter is without load and there is power interruption, when the energy energy elapses and electricity is still available in the power line and so on. 

The system can monitor electrical parameters of the load such as voltage and current and subsequently calculates the power consumed. The novelty of this system is the implementation of the controlling mechanism of load in different ways. The developed system is a low-cost and flexible in operation and thus can save the load and the prepaid meter from surge.

 For more information on this project idea, feel free to call: +234803909203 or email: abldesigns@yahoo.com

CLIMATRONIC DEVICE FOR MONITORING GREENHOUSE EFFECT

Climatronic device for monitoring greenhouse effect is an electronic climate checker that Able Designs and Construction Company (ADACC) started developing for a long time now to monitor and control human activities in an environment which contributes to global warming or greenhouse gases like deforestation/burning of bushes, fossil fuels (coal, oil and natural gas), etc. Our aim is to monitor the adverse effects of climatic and weather conditions, then announce its consequences to the people in different regions and suggests adequate utilities they can utilize to be safe. The Government, Department of the Environment and Energy, Climatologist, Meteorological centers can utilize it to forecast the weather or climate change condition.
This is a multi-purpose smart climate checker to support the action to reduce the heat-trapping gas emissions. It can be used to monitor the rate of ozone layer depletion by determining the level of ultra violet radiation reaching the earth from the sun using UV Radiation sensor.  

The system consists of wireless sensor network (WSN) containing various weather sensors, micro-controller, transceivers and LCD. The micro-controller serves as a minicomputer in a chip that controls both the software and hardware operations.

More information and experimental result of this project concept will be uploaded in this site soon.  Greenhouse gas emission has caused significant increase in the number of premature deaths and other potentially catastrophic consequences in the earth. The problem of burning fossil fuels, burning of bush and land clearing are increasing the concentration of greenhouse gases which is contributing to warming of the Earth. This contributes to the high concentrations of heat-trapping “greenhouse gases” in the atmosphere. Climate change has the potential of claiming lives in thousands, properties and infrastructures are not left out of the possible destruction. Excessive heat or cold waves can cause death or sickness to those with inadequate utilities. Droughts can have adverse effect on water usage and destroy vegetation. Fog or exceptionally low ceiling can prevent many aircraft from landing and taking off safely. Turbulence and icing are also significant in-flight hazards in temperate regions. Thunderstorms are a problem for all aircraft because of severe turbulence due to their updrafts and outflow boundaries, strong winds, and lightning, all of which can cause severe damage to an aircraft in flight.

Benefit of solving the problem:

Global warming and climate changes seen today are being caused by the increase of carbon dioxide (CO₂) and other greenhouse gas emissions which pose threat to public health. This has continued to receive a clarion Call for engineers to model and develop device that can help human race. Heat wave which is another consequence of global warming can lead to thousands of heat-related deaths. Beyond that, there can be other troubling effects: decreases in crop yields, droughts, and dry conditions ripe for wildfires. Wildfires, in turn, lead to deforestation. Since trees absorb much of the excess carbon dioxide in the atmosphere, fewer trees mean higher levels of greenhouse gases in the atmosphere, thus perpetuating the cycle in which warmer temperatures wreak atmospheric havoc.

With the device we can monitor and stop activities that cause global warming, alert the people on the adverse effects of the climate change and suggest the right per-caution measures they can follow to run their daily activities.  Farmers and traders within commodity markets will known about the weather and decide on what to do on a particular day. For instance, they will know when prolong dryness, heat or rain fall will occur.  Prolonged periods of dryness can ruin cotton, wheat and corn crops while corn crops can be ruined by drought, their dried remains can be used as cattle feed substitute in the form of silage. Frosts and freezes play havoc with crops both during the spring and fall. For example, peach trees in full bloom can have their potential peach crop decimated by a spring freeze. Orange groves can suffer significant damage during frosts and freezes, regardless of their timing.

Wireless sensor network (WSN) techniques are to be used along with model-based design software tool known as Protues 8.3 professional, C programming language written in an algorithm in Mikro C pro. The design topology and WSNs are composed of a finite set of sensor devices geographically distributed in a given outdoor environment (usually predefined) to gather environmental data and the node devices placement may be known or unknown a prior. Network nodes can have actual or logical communication with all devices; such a communication defines a topology according to the application. 

Outline of our Objectives

1.     To design and simulate a smart climatronic device for the monitoring of adverse effects of climatic conditions and announce its consequences to the people at different regions.

2.     To forecast the possibility of the climate change and suggest adequate utilities for the people to perform their daily activities safely.

3.     To provide the National Meteorological Centers, Government bodies, Department of the Environment and Energy and other specialized bodies with a gadget to monitor the environment against burning of fossil fuels, and deforestation, etc. 

4.     To monitor the rate of ozone layer depletion in the earth station and determine the level of ultra violet radiation reaching the earth from the sun.

Broadcasting the possibility and impart of the climate change such as heat waves, cold waves, rainfall pattern and Ultra Violet Ray Radiation variations are very important especially when saving lives are involved. Heat waves, cold waves, flooding from torrential down pour have claimed so many lives in recent years. The proposed research will certainly help to save lives of populace if deployed in any area where any of these adverse effects of climate change occurs.

A microcontroller was programmed using an algorithm that collects information from UV sensor and weather sensors which comprises of pressure sensor, temperature and humidity sensors, etc. The information sourced or fetched from these sensors was compared with the climate condition data stored in EEPROM and used to forecast the present climate and weather condition. This also involves the transmission of information or results through a wireless communications channel using wireless sensor techniques.  Information can also be shown in LCD while a PV based SMP supply ensures a constant power supply. This was done to ensure or maintain a certain level of safety in the future environmental conditions, and to forecast weather conditions in a very simple and advanced method.

Proteus professional software was used to design and model a climatronic device using Peripheral interface controllers (PIC Microcontroller), UV radiation sensors and WSN techniques. Mikro C pro for Peripheral Interface Controller was used as the integrated development environment (IDE) and the generated hex file (machine language) was embedded into the micro-controller to carry out the system functions.  MATLAB code was used to analysis the final result produced from the model. A live experimentation was carried out in the work to ascertain the accuracy of the Proteus simulation and ensure that the system hardware can work if implemented in the future.  In the simulation program, the system monitors UV, temperature, relative humidity, pressure, wind direction and speed, etc. 

For more information, whatapp or call: +2348037909203. Email: abledesigns@yahoo.com