Rectifier Research Paper

Rectifiers:

A rectifier is an electrical device that converts the Alternating Current "AC" to Direct Current “DC ". This process called rectification. Rectifier can take many different physical forms for example: solid-state diodes, vacuum tube diodes, mercury arc valves, silicon-controlled rectifiers and various other silicon-based semiconductor switches.

Rectifier Circuits:

Rectifier Circuits can be either single phase, three phase or six phase. Single phase and three phase are mostly common used. Single phase rectifiers can be used for house equipment and three phase for important industrial applications and others.

Single phase Rectifiers:

Half Wave Rectifiers:

In half wave rectifiers either the positive or the negative wave passes and

The DC output of the rectifier V_dc can be calculated using this equation: V_dc= V_peak/π and the root mean square value of the output can be also calculated using this formula: V_rms= V_peak/2 . Figure 1 : The output of a half wave rectifier

Full Wave Rectifiers:

In Full wave Rectifiers the negative and positive wave of the input passes through the diode unlike the half wave rectifier as we can see that in Fig 2. The output of the full wave is much higher than the half wave because it converts both waves of the input. Also a smooth capacitor can be used to converts the ripple output to smooth DC output. The DC output of the rectifier V_dc can be calculated using this equation: V_dc= (2V_peak)/π and the root mean squre value of the output can be also calculated using this formula: V_rms= V_peak/√2 . Figure 2 : The output of a Full wave

During the positive the cycle D1 and D2 are conducting while D3 and D4 are reverse biased, then the current will flow through the load as shown below in Fig 6. Figure 6 : Positive Cycle of Bridge rectifier.

The Negative Cycle:

During the negative cycle D3 and D4 are conducting while D1 and D2 are reversed biased and the current will flow in the same direction as in the positive cycle as we can see in Fig 7. Figure 7 : Negative Cycle of Bridge Rectifier.

The Current flow in the rectifier is unidirectional, which means that the voltage across the load is also unidirectional. But in Reality the current flow in the two conducting diodes in each cycle instead of one diode like in the figures above. This means that the ripple frequency is doubled for example if the supply frequency is 50Hz it will be 100Hz.

Inverters:

Inverter is a device that transform the electrical energy from it is DC form to it is AC form.

There are many reasons behind going for AC rather than DC. One of the problems with direct current (DC) that transmitting it through long distances will cause a lot of power losses Also it has a low voltage since it cannot be stepped