Home - Blog

WellPCB PCB Assembly New Project #1:Wonderful Automatic Power Factor Correction

PCB Assembly New Project

I. WellPCB PCB Assembly New ProjectINTRODUCTION

Any motor that operates on alternating current requires apparent power, but apparent power is an addition of active power and reactive power. Dynamic control is the power that is consumed by the load. Reactive power is the power demanded by the amount and returned to the power source. The simplest way to specify power factor is ¯POWER FACTOR, the ratio between the sound (right) power whose unit is KW to the total (apparent) power whose unit is KVA consumed by A.C electrical equipment or motor‖. Power factor is a measure of how effectively electrical power is used to perform valuable work. The ideal power factor is unity or one. If the power factor is less than one, it means that excess energy is required to perform or achieve this Bill Of Materials (BOM) of a PCB get fitted onto aboard. PCB assembly project actual work.

A. Advantages of power factor improvement

Benefits that can be achieved by employing the proper power factor correction scheme are:

      1. Efficiency increases due to the reduction of power consumption.

      2. Due to reduced power consumption, there will be fewer greenhouse gases

      3. Reduction of electricity bills

      4. Extra KVA available from the same existing supply

      5. Reduction of I²R losses in transformers and distribution equipment

B. The idea to improve the power factor

The basic idea of this Bill Of Materials (BOM) of a PCB gets fitted onto aboard. PCB assembly project for power factor correction of a motor or circuits we have to connect a capacitor in parallel with the device with low power factor.

One of the traditional methods for power factor correction is static type compensation, in which fixed type capacitors are used for power factor correction. However, in this case, Care should be taken when applying power factor correction star/delta type control so that the capacitors should not be subject to rapid on-off conditions.

C. Working of Capacitors

By representing active power & reactive power at sides of the right angle, we can determine the apparent authority from the right triangle rule:

(KVA)² = ( KW)²+ (KVAR)²

To reduce the KVA, the total current requirement for any given load, one must shorten the line representing the KVAR. This is precisely what capacitors do. The ratio of actual power to apparent power is usually expressed in percentage and is called the power factor.

Fig-1. WellPCB PCB Assembly New Project #1.png

 Fig-1. Power Triangle


A. Static compensation

In this method for power factor improvement, static capacitors are connected in parallel with the device, which works on low power factors. These fixed capacitors provide a maximum current which eliminates the lagging component of load current and improves power factor.

B. Synchronous condenser

When a synchronous motor operates at no load and over-excited condition, it is called a synchronous condenser. A synchronous condenser is overexcited; it provides a maximum current and works like the capacitor of the PCB assembly project. When a synchronous condenser is connected across supply, it gives leading current and partially eliminates reactive component and thus improves power factor.


A. PCB Assembly project Main components

The main components used in this scheme for automatic power factor correction using a microcontroller include the following elements.

 1.Auxiliary Power Supply: Transformer

   Bridge rectifier

   Voltage regulator IC 7805


 3.LCD Display

 4.Capacitor Bank

 5.Potential transformer & current transformer

 6.Relay & relay driver IC

 7.Zero Cross Detector

B. Functional Block Diagram

This PCB assembly project detects zero crossings of voltage and current waveform from the line by ZCD from P.T and C.T, respectively. Depending upon the phase difference between voltage and an existing microcontroller sends out the signal to switch on the capacitor through relay driver IC and improves power factor.

WellPCB PCBA New Project #1.png

C.  Schematic Diagram

Fig-3 Schematic Diagram of Project.png

 Fig-3 Schematic Diagram of System

D. Description of Microcontroller: AVR AT mega 8L

The Atmel ATmega8 is a powerful microcontroller that provides a highly flexible and cost-effective solution to many embedded control applications. The ATmega8 is a low-power CMOS 8-bit microcontroller based on the AVR RISC architecture. By executing powerful instructions in a single clock cycle, the ATmega8 achieves throughputs approaching 1 MIPS per MHz, allowing the system designer to optimize power consumption versus processing speed. The AVR core combines a rich instruction set with 32 general purpose working registers. All the 32 entries are directly connected to the Arithmetic Logic Unit (ALU), allowing two independent records to be accessed in one instruction executed in one clock cycle. The ATmega8 AVR is supported with a full suite of program and system development tools, including C compilers, macro assemblers, program debugger /simulators, In-Circuit Emulators, and evaluation kits.


 1.8K bytes of In-System Programmable Flash with Read-While-Write capabilities.

 2.512 bytes of EEPROM, the 1K byte of SRAM.

 3.23 general-purpose I/O lines.

 4.32 general-purpose working registers.

 5.Three flexible Timers/Counters with compare modes. Internal and external interrupts.

 6.A serial programmable USART.

 7.A byte-oriented Two-wire Serial Interface.

 8.A 6-channel ADC (eight channels in TQFP and QFN/MLF packages) with 10-bit accuracy.

 9.A programmable Watchdog Timer with Internal Oscillator

E. Pin Configuration

4WellPCB PCB Assembly New Project #1.png

Pin Descriptions

 • VCC- Digital supply voltage.

 • GND- Ground.

 • Port B (PB7-PB0)-Port B is an 8-bit bi-directional I/O port with internal pull-up resistors (selected for each bit).

 • Port C (PC5-PC0) is a 7-bit bi-directional I/O port with internal pull-up resistors (selected for each bit).

 Note that the electrical characteristics of PC6 differ from those of the other pins of Port C. If the RSTDISBL Fuse is unprogrammed, PC6 is used as a Reset input. • PC6/RESET- If the RSTDISBL Fuse is programmed, PC6 is used as an I/O pin. A low level on this pin for longer than the minimum pulse length will generate a Reset, even if the clock is not running. Shorter pulses are not guaranteed to make a Reset.

 • Port D (PD7-PD0)-Port D is an 8-bit bi-directional I/O port with internal pull-up resistors (selected for each bit).

 • RESET-Reset input. A low level on this pin for longer than the minimum pulse length will generate a reset, even if the clock is not running. Shorter pulses are not guaranteed to make a reset.

 AREF- AREF is the analog reference pin for the A/D Converter. • AVCC-AVCC is the supply voltage pin for the A/D Converter, Port C (3-0), and ADC (7-6). It should be externally connected to VCC, even if the ADC is not used. If the ADC is used, it should be connected to VCC through a low-pass filter. Note that Port C (5-4) uses digital supply voltage, VCC. 9.

 • ADC7-6 In the TQFP and QFN/MLF package, ADC7-6 serves as analog inputs to the A/D converter. These pins are powered from the analog supply and serve as 10-bit ADC channels.

IV. WellPCB PCB Assembly New ProjectMETHODOLOGY

The methodology on which my paper-based is consisting of three main parts.

A. Auxiliary power supply

A bridge rectifier connected across the mainline converts AC signal to DC. A capacitor is attached to the output of the rectifier to get pure DC. The production of the bridge rectifier is +12V. Still, as the microcontroller works on +5V, this bridge rectifier’s output is further given to IC 7805(Voltage regulator IC), which offers a fixed output voltage of +5V. A capacitor is connected at IC 7805 to get pure DC voltage (remove unwanted ripples).

Fig-5. WellPCB PCB Assembly New Project.png

Fig-5. Auxiliary Power Supply


B. Zero cross detector (ZCD)

The current and voltage signal is measured from the main AC line using the current transformer and potential transformer, respectively. The output of these CT and PTs are given to Op-Amp LM 358. The combination of potential transformer and OP-Amp forms zero cross detector (ZCD V) also mix of current transformer, and OP-Amp styles zero cross detector(ZCD I).these zero-cross sensors individually convert both current and voltage waveforms to square wave and detects zero crossings of voltage and current.

WellPCB PCB Assembly New Project #1.png


C. Capacitor and relay matrix

Depending upon zero crossings of voltage and current wave microcontroller either switches on or switches off the required number of capacitors through electromagnetic relays. And the power factor is shown on the LCD for the various loads.

Fig-7 Connections of Capacitor Relay Matrix Circuit.png

Fig-7 Connections of Capacitor & Relay Matrix Circuit


D.  Flow Chart

 Fig-9. Flow Chart for system

The microcontroller first detects whether the first voltage edge is falling or the new side. Depending upon this logic, it detects whether the power factor is lagging or leading; accordingly, it switches on or off the number of capacitors to improve the power factor.

V.Interfacing of Microcontroller to LCD and Relay Driver ICE. PCB Assembly 3D View and PCB Design

WellPCB PCB Assembly New Project–PCB Assembly 3D view 

Fig-10 Proposed 3-D View of System.

PCB Design

Fig-11. PCB Design of System




VII. WellPCB PCB Assembly New ProjectCONCLUSIONS

This paper deals with the advanced method of power factor correction by using the microcontroller. As the Switching of capacitors is done automatically; hence, we get a more accurate result. Power factor correction techniques make the system stable, and due to the improvement in power factor, its efficiency also increases. Power factor correction scheme can be applied to industries, power systems as well as in household purposes. The use of microcontrollers reduces costs. Using a microcontroller, multiple parameters can be controlled, and the use of other hard wares such as the timer, RAM, ROM, and input-output ports reduces. Before APFC Circuit insertion


The automotive power factor correction using capacitive load banks is very efficient as it reduces the cost by decreasing the power drawn from the supply.

As it operates automatically, the workforce is not required, and this Automated Power factor Correction using capacitive load banks can be used for the industry’s purpose in the future. In the end, PWM techniques can be employed in this scheme. Along with power factor correction also speed control can be done in the future. In the future, Work can be done for harmonics reduction.

Designed by: Usman_Ali_khan

Hommer Zhao
Hi, I am Hommer, the founder of WellPCB. So far, we have more than 4,000 customers worldwide. If you have any questions, you can feel free to contact me. I really appreciate any help you can provide.