Telecommunication Engineering

Abstract:

Here we are going to design Power Supply of Smart device Docking Station which will be able to plug into any type of single phase power system. This power supply system can supply the various parts of the docking station with the necessary quantities of power. In this case, to design the power supply system we have used uncontrolled bridge rectifier, buck and boost converter.

The uncontrolled bridge rectifier uses diode to rectify the input. Now as the diode is a unidirectional device, it only allows the current flow in one direction. This type of rectifier doesn’t allow the power to vary, based on the load as per required. In DC-DC buck converter the output voltage will be transformed to level less than the input voltage. In this buck converter the inductor resists the sudden variations in input current. When the switch is on the inductor stores the energy and discharges this energy when the switch will be closed. In boost converter, the input circuit resists sudden variation in input current. When switch is off the inductor stores energy in the form of magnetic energy and when the switch is on, the energy is discharged.

Part 1: Rectifier and Converter Design

a) Rectifier circuit:

The uncontrolled bridge rectifier uses diode for rectifying the single phase AC input in to DC output. Now as the diode is a unidirectional device, it allows the current flow in one direction. This type of rectifier doesn’t allow the power to vary based on the load as per required.

Circuit Diagram of Bridge rectifier is given below (Fig 1):

Fig: 1

The input waveform of the above circuit is given below (Fig 2):

Fig 2:

The output waveform of the above circuit is given below (Fig 3):

Fig 3:

b) Converter Circuit:

In DC-DC buck converter the output voltage will be transformed to level less than the input voltage. In this buck converter the inductor resists the sudden variations in input current. When the switch is on the inductor stores the energy and discharges this energy when the switch will be closed.

Circuit Diagram of the buck converter is given below (fig 4):

Fig 4:

Here we used buck converter to step down the voltage. The input voltage of the buck converter is 34 volt and the required output voltage is 24 volt. So we can obtain the duty cycle from the following equation.

When switch is closed for DT sec,

When switch is opened for (1-D)*T sec,

Since the average voltage across inductor is 0,

So the input output equation becomes,

Here, we select the switching frequency 54 KHz. So time period will be 18.51 μ-sec.

The output voltage waveform of the buck converter is given below (Fig 5):

Fig 5:

If we take the average of this voltage waveform which is given in Fig 6, we will get 24 volt.

Fig 6:

Peak to peak ripple voltage,

Part 2- Implement and Test Stage 2 Converters

The 2 stage converters are containing 5 volt and 34 volt respectively.

a) To implement 5 volt converter we need to use buck converter. In this case the buck converter circuit will be same as stage 1 buck converter circuit. In this case the input voltage is 24 volt and the output voltage is 5 volt. So we calculate the duty cycle by the following equation:

Here, we select the switching frequency 54 KHz. So time period will be 18.51 μ-sec.

b) To implement 34 volt converter we need to use boost converter. In boost converter, the input circuit resists sudden variation in input current. When switch is off the inductor stores energy in the form of magnetic energy and when the switch is on, the energy is discharged.

The boost converter circuit is given below (Fig 7):

Fig 7:

In this case the input voltage is 24 volt and the output voltage is 34 volt. So we need to step up the input voltage. There by we are using boost converter. So the duty cycle can be measured by the following formula.

When switch is closed for DT sec,

When the switch is opened for (1-D)*T sec,

Since the average voltage across inductor is 0,

So,

Here, we select the switching frequency 54 KHz. So time period will be 18.51 μ-sec.

The output voltage waveform is given below (Fig 8):

Fig 8

Peak to peak ripple voltage,

Part 3- Implement and Test Rectifier and Stage 1 converter

The combine circuit of bridge rectifier and stage 1 converter circuit is given below:

The voltage and current waveform is given below. To calculate power we need to multiply voltage with its corresponding current that is V*I.

Part 4- Join Rectifier/Stage 1 and three stage 2 converters and Test

After joining rectifier or stage 1 and three stage 2 converters the circuit is given below

After testing this we get the following wave form:

The above waveform is a combination of voltage and current waveform across the load of the stage 1 buck converter. In the wave form the blue color denotes the voltage and the red color denotes the current wave. If we multiply voltage corresponding to its current we will get the required power

2.

The above waveform is a combination of voltage and current waveform across the load of the stage 2 buck converter. In the wave form the blue color denotes the voltage and the red color denotes the current wave. If we multiply voltage corresponding to its current we will get the required power. The green curve denotes the variation in the input voltage of this converter.

3.

The above waveform is a combination of voltage and current waveform across the load of the stage 2 boost converter. In the wave form the blue color denotes the voltage and the red color denotes the current wave. If we multiply voltage corresponding to its current we will get the required power.

Conclusion:

Hence we have designed the Power Supply system of Smart device Docking Station. This docking station is requisite to be acquiescent to related power quality standards.