Investigate Half Wave Uncontrolled Rectifier with Resistive Load

ABSTRACT

In this lab 1 and 2 we proposed to get result of single phase half-wave and full-wave rectifier uncontrolled. Additional, it also teach us how to calculate the RMS and average values of voltage,current and power for the half-wave and full-wave uncontrolled rectifier with resisitive load using theorical. To simulate we decide to use Multism software.This lab also prove the benefits of using reservoir capacitor in circuit to reduce the ripple in the circuit. Beside of that,the mean values also effect the wave form of each circuit that using capacitor. The bigger the mean values the more the wave will be rectify. According to this lab also the result of values for the circuit will be compare  between simulation and calculation theorically method that being used. From this lab,its prove that simulation result is more accurate compare to the calculation method. All of output circuit we show in waveform step by step. The supply rms value we take the 20V AC,frequency is 50Hz and the resistor is 10k Ohm.

METHODOLOGY

                        Methodology is generally a guideline system for solving a problem, with specific components such as phases, tasks, methods, techniques and tools. The first procedure for do this lab is simulate all the component on task 1 and task 3 . During the task 1 to measured mean voltage for the output, voltmeter and the resistance is should be connect in parallel. When Diode is connected series with the resistance and the voltage supply is 20v AC. Using the voltmeter tap the positive part on oscilloscope Y input and at the negative part, tap at the oscilloscope common. The volt that measurement using multisim is 8.673v . The output waveform showing on the oscilloscope is half wave. If need the wave look more particular, we have to adjust the scale. Don’t forget to put ground on the circuit because when we don’t have ground on the circuit the software will can’t simulate.

 From task 3 the circuit is the same with the task 1 the different is circuit add up by 2 different value capacitor. The value of the 2 capacitor which is 1µF and 22 µF. Now start with the 1 µF capacitor. Using the volt meter tap the positive part on oscilloscope Y input and at the negative part tap at the oscilloscope common. The volt that measurement using multisim is 15.726V.  The capacitor is connecting parallel with resistor and voltmeter. Using the 1uF capacitor the oscilloscope show the waveform will reduce ripple. For the 22 uF is show at the oscilloscope the waveform is more smooth and become straight line and the it just only a little bit ripple. The load voltage increase to the 26.484V. So we know the the capacitor function is to store the charge. When it operated. It will help to improve the circuit to the get more efficiency work.

Calculation theorical we use half wave formula to find the value of the average voltage. Before calculate the average voltage we need to find the maximum voltage first for the half wave. 

After get the value of the  maximum voltage (Vm), then we can continue to find the value of the average voltage (Vdc) , maximum current (Im) , RMS value of current (Vrms) and power (P) by using the formula given.

INTRODUCTION

Rectifier is a one device that used to convert Alternating Current (AC) to Direct Current (DC). The process is call it rectification. There are many uses of rectifier but are often found serving as component of DC power supplies and high voltage direct current power transmission system. Rectification may serve in roles other than to generate direct current for use as a source of power.

Figure 1 shown the sample of rectifier  such as Thyristor, SCR, power diode and diode rectifier.

Rectifier are largest class of products in the diode family. They are primarily used for blocking in one direction and conducting in the other. These include general purpose, standard, fast, ultra fast, signal/switching, high voltage and schottky rectifier.

Except for schottky rectifier, all are of p-n junction technology with different processing features to optimize parametric requirements for the variety of application implied by their titles.

Figure 2 shown diagram P-N Junction, and also symbol of diode.

In half wave rectification, either the positive or negative half of the AC wave is passed, while the other half is blocked. Because only one half of the input waveform reaches the output, it is very inefficient if used for power transfer. Half-wave rectification can be achieved with a single diode in a one-phase supply, or with three diodes in a three-phase supply. Half wave rectifiers yield a unidirectional but pulsating direct current.

Figure 3 Shown the waveform and circuit for half wave rectifier

ANALYSIS

In task 1, the analysis can be made is that we are required to make a theoretical calculation to find the rms voltage and current, voltage and current average value and power of the circuit Uncontrolled half wave rectifier with resistive load. Our purpose is to make the theoretical calculations is to make comparison with the values ​​taken by simulation. Using the calculation the average voltage get is 9v,for the average current is 0.9mA,for the maximum current is 2.83mA,for the RMS value of current is 1.414mA and for the power is 19.99kW. For the simulation the peak voltages that being get is 27.6v and for the mean value or the average voltage is 8.7v.

Figure 3 shown circuit half wave rectifier with resistor load.

Figure 4 shown the waveform Max Value (Vpk) before rectified. Max Value value is 28.3V and Time (T) is 20ms.

Figure 5 shown the waveform after rectified. This is call half wave half rectifer. The mean value for voltage (Vdc) is  8.7V.

In task 2, we are required to construct circuit half wave  rectifier uncontrolled use of software. Which of the software that can be used for this work such as multism, p-spice, micro sim, quartus II, matlab and others. However we choose to use multism as it is easier in use and user friendly.

During the the construct doing we find that the diode requested in question as not found in the software. The type is SY625/1.5 . It is replace by the diode type is virtual diode.Unfortunately it might will impact the mean value of the voltage required.

Beside that, the value for the mean value which is  average voltage from the calculation is 9v while the simulation is 8.7v is because of the tolerance in the component while using the simulation. But the different between the two value is just around 0.3v so its not a big deal. To obtain the negative result for the mean value is just connect the voltmeter to it opposite connection. A negative result will be obtain. From the task 2,its prove that simulation method is more accurate compare to the  calculation method.

            For task 3,it required to simulate the half wave uncontrolled rectifier with a reservoir capacitor. This is to study and observe the effect of using the  reservoir capacitor in the circuit. In this task, it required to use 2 differents values of the capacitor by separate. The first values of the capacitor used is 1uF, then the next one is 22uF.

Figure 6 shown the circuit half wave rectifier with Reservior Capacitor 1uF.

Figure 7 shown the waveform half wave rectifier before and after flowing capacitor 1uF and also value of mean voltage.

            For the task 4,the mean values and the ripple in the wave form by using 2 differents values of capacitor is observe and compare. When using 1uF of capacitor, the ripple is less rectify but its no more seen as the original half wave because the capacitor has act as the filter to stable the waveform and the values of the mean value is only 15.73v.

 But its differents when using the 22uF capacitor, because the wave form is almost rectify and the values of the mean value is increase to 26.28v. In this situation,the circuit is more stable because the ripple have lesses. And this prove that the greater the mean values the more stable the circuit and the less ripple will show.

    

Figure 8 shown circuit half wave rectifier with reservoir capacitor 22uF.

Figure 9 shown the waveform half wave rectifier before and after flowing capacitor 22uF and also value of mean voltage.

CONCLUSION

           

            After we finished completing these lab, what we can summaries is as the conclusion, when we talk about the half-wave rectifier, the circuit diagram should be only one diode. Other that, we also learn about the characteristics of diode which is  when it operated forward and reverse condition. Next is the circuit add up by reservoir capacitor. During construct the circuit using multisim and study the operation circuit we understand that, the capacitor function in circuit, why the waveform from ripple would become straight line. As the result, of the overall waveform, we provide the virtual image from multism. This experiment is almost totally success because we only found the problem when did the simulation using multism software because there have no type  SY625/1.5 of diode. To solve this problem the diode have being change with the virtual diode. Lastly, we hope that, our lab will archieve to the specification what the our lecturer need and answer the all question provided.

REFERENCE

^ Ashhfaq Ahmad. Power Electronics for Technology.

            Half-Wave Controlled Rectifier, 6,Page 151-157,175.

^ Shamsul Zahari, Chapter 2 Uncontrolled Rectifier.

            Half-Wave Controlled Rectifier,2,Page 2-8.

^ Andrzej M. Trzynadlowski, Introduction to Modern Power Electronics,

            Half- Wave Rectifier converter, Wiley-Interscience.

^ M.S Jamil Asghar, Power Electronics,

            Chapter 4, Half-Wave Rectifier Converter, Eastern Economy Edition.

^ Bose, Power Electronics and Motor Drives,

            Chapter 2 , Intro of Half-Wave Rectifier.

^ Rashid, Power Electronics, Circuit, Device and Applications,

            Second Edition, Prentice Hall.

^ Shepherd, Hulley, Liang, Power Electronics and Motor Control,

            Second Edition.