Automatic Power Factor Correction Systems

The power factor is one of the problems in electric power quality improvement. In many cases, low power factor causes the waste of electrical energy. In large commercial and industrial sectors, usually used in a centralized system of capacitors in a room for power factor correction. However, changes in the electric power consumed by electrical equipment operated at any time require changes in the capacity of capacitors which must compensate for the inductive nature of the electrical equipment is being operated. A value system that can provide appropriate capacity of capacitors to improve power factor is needed on systems with dynamic changes in electrical load.
Ideally, all customers of electric energy should have a good power factor (close to the value 1) to reduce the cost of electrical energy production. However, power factor corrections should be done the right way for any equipment used. This raises a new problem: how to design a power factor correction systems that can be used for all electrical equipment used. And how for power factor correction systems can also be operated for a variety of electrical load, so it does not need to be plugged at any existing electrical equipment. With this system, the expected power factor can be fixed easily and the system can be used for every electricity customer. With the corrected power factor, the electricity companies no longer must be generated electrical energy that is greater than the needs of customers.
Power factor is one parameter determining the quality of electric power. A good quality electrical power will increase efficiency in the electricity system. With the same production at the customer side, the total electrical energy consumed by customers will be reduced. This will be followed by a decrease in the voltage loss in the distribution system, thus decreasing the voltage drop on the customer side. On the generation of electrical energy, without reducing the electrical energy dollars are sold, the total energy generated will be smaller so that the operational costs of electricity generation will be reduced. With the increased efficiency of electric power, rising power demand next few years can still be supplied by the current generator, so the electricity deficit in this country for a while can be forgotten and needs additional power plant may be delayed.

Using ATmega8535 AVR Microcontroller
Heaviest Electrical Loads for the System 
Modeling using MATLAB
The Performance of the APFC

Using ATmega8535 AVR Microcontroller

APFC system uses AVR microcontroller family as the main component that has an internal ADC. ATmega8535 microcontroller is used here. To be able to record voltage and current signals, we use a voltage-to-voltage converter and current-to-voltage. A signal conditioning is used to make the both output signal voltage of the converter in accordance with the characteristics of the ADC inputs. This system uses a capacitor bank (C-bank), which consists of four capacitors. These capacitors are used for power factor correction.

The need for Automatic Power Factor Correction (APFC) Systems
Heaviest Electrical Loads for the System  
Modeling using MATLAB
The Performance of the APFC

Heaviest Electrical Loads for the System

For this system, the greater the power used, effort should be made for power factor correction is also more severe. Capacitor capacity value should be used for power factor correction will be even greater.
At the same apparent power, the lower the power factor, power factor correction efforts are also increasingly heavy. Attempts to raise the power factor will require a capacitor with larger capacity as well. Low power factor due to the large value of phase difference between voltage and current.
Heaviest electrical loads for the system occurs when the load has largest apparent power and smallest power factor. All capacitors in the C-bank should be able to correct this condition so that the value of power factor becomes one.
Modeling using MATLAB
This model is created using Simulink in MATLAB version 6.5.1. Models of automatic power factor correction systems can be seen in the following figure. This model consists of several subsystems and the S-Function. This system is also equipped with input devices that can retrieve data from a file and the output device (data logger), which can save data to multiple variables in a workspace that can be saved to a file for further processing. Listing program written in C language.

The need for Automatic Power Factor Correction (APFC) Systems
Using ATmega8535 AVR Microcontroller
Modeling using MATLAB
The Performance of the APFC

Modeling using MATLAB

This model is created using Simulink in MATLAB version 6.5.1. Models of automatic power factor correction systems can be seen in the following figure. This model consists of several subsystems and the S-Function. This system is also equipped with input devices that can retrieve data from a file and the output device (data logger), which can save data to multiple variables in a workspace that can be saved to a file for further processing. Listing program written in C language.




The need for Automatic Power Factor Correction (APFC) Systems
Using ATmega8535 AVR Microcontroller
Heaviest Electrical Loads for the System 
The Performance of the APFC

The Performance of the APFC

Assuming the capacitor value of automatic power factor correction systems can be any, or in other words the number of variations of the value of the capacitor capacity is infinite, the higher the apparent power of load or the lower the power factor of load, power factor correction efforts will be heavier and value output power factor can still be worth far below one.
But with the limited number of variations in the value of the capacitor capacity, as long as the maximum limits of correction, the higher the load apparent power, power factor corrected values would be guaranteed getting closer to one and have a fairly small fluctuations.
In order to achieve the value of power factor as close to one, the determination of the total capacity of capacitors in the C-bank should be based on the largest electrical load that happens, both electrical load with the greatest apparent power and the smallest power factor, and not based on installed power capacity.
In conditions with heavier loads than specified, the system will perform power factor correction by using all of available capacitors and there is the possibility of power factor corrected still much smaller than one.
With the same power factor value, the lower the load apparent power, power factor corrected values will be more varied and this value can be far below the value of one. The low power factor at low power will not be harmful because the reactive current that occurred only a little.
The model has been developed can be implemented into a prototype of automatic power factor correction that can be used for many consumers.
For overall power factor correction, should be considered the harmonic components. This research can proceed with efforts to correcting harmonic component.

The need for Automatic Power Factor Correction (APFC) Systems
Using ATmega8535 AVR Microcontroller
Heaviest Electrical Loads for the System 
Modeling using MATLAB