Week 9 : Wireless mobile charger in market

Objectives:

1. To make research more on the devices that already had been on market
2. To study the construct of the wireless mobile charger 

Methods:

1. Bought (online) the wireless mobile charger that already on market 
2. Test if the wireless charger would function with mobile phone
3. Open the wireless charger to observe its parts

Results:

 

Figure 1: Wireless QI charger

 

 Figure 2: The wireless charger been plugged on to USB laptop

 

Figure 3: Phone being charged as soon as the charger being plugged

 

Figure 4: The construction of the wireless charger receiver

 

Figure 5: The construction of the wireless charger transmitter

 

Figure 6: The wireless charger transmitter circuit

Conclusion:

For this week, I have decided to bought my own wireless mobile charger online. The product is originality from China. It cost me about RM60 for this device. As we can see, the construction of the wireless mobile charger is quite simple. The circuit is quite small. It is made to fit into its body which is also quite small. It's just as big as a man's palm. As for the receiver and the transmitter, it is made of a coil. Its using a concept as a transformer which has been discussed in my previous blog. Meanwhile, the transmitter circuit is quite complicated. It is because the circuit has to be small to be fitted to its body. All its components is integrated into one small circuit. This week, my progress is on the observation of the wireless charger construction which has been on market is achieved as I already dismantle or disassemble all the wireless charger that I have bought. Only the physical construction that already been observed. The circuit is quite complicated but will be studied by me later.

Week 8 : Another comparison of wireless power transfer

Objectives:

1. To get the idea by making comparison of others project
2. To determine whether the size of the transmitter coil would affect the range of wireless power transfer

Methods:

1. By making some research on internet
2. By comparing others project on wireless power transfer
3. Attachment below shows on the project

Results: 
 

Figure 1: Wireless power transfer powered up a small bulb

Figure 2: Circuit diagram for the wireless power transfer transmitter 

Figure 3: Video showing on the commissioning of the wireless power transfer 

Conclusion:

As for conclusion, I found that with increase the size or diameter of the coil, the range of the wireless power transfer also increase. Also, with the increment of the coil loop, will make the range increase. This is because, by increasing these two factors, the resonant frequency for receiver and transmitter also will be decrease, but to achieve this, both of the circuit should resonate at the same frequency which means that the loop should on the same size. Larger loop with the same capacitance value will  lower the resonant frequency. The best way to increase the range is by lowering the resonant frequency. There are also another way to increase the range of the wireless power transfer such as by inserting ferrite core into a loop which will decrease the resonant frequency. The research on this factor to increase the range of the wireless power transfer still in progress.

Week 7 : My own design of the wireless mobile charger

Objectives:

1. To proposed my own design for the wireless mobile charger
2. To design the wireless charger (transmitter) using designer software

Methods:

1. By comparing other wireless mobile charger that available in market
2. Designing the transmitter platform using SketchUp software
3. Attachment below are some of my design on the wireless mobile charger

Results: 
 

Figure 1: Front Side View

Figure 2 : Back Side View

Figure 3: Bottom View

Figure 4 : On/Off Button



Conclusion:

As for this week, my progress on the development of the wireless mobile charger is more on the design that I want to propose to my supervisor. The design is quite compatible for any type of mobile phone. Even, the deck or platform for the mobile charger can charge more than one mobile phone at one time. The mobile phone must be place on the platform along with a receiver which I will develop after this. I propose that the platform should be made of plastic and also a little bit of rubber to prevent the mobile phone from slipped off from the platform. The platform will use power source from USB plug cable that can be plugged at socket outlet or any USB source such as PC or laptop. Also, it has a ON/OFF button at the back side of the platform. This is only the platform design of the wireless mobile charger, it is not including its circuit design yet.

Week 6 : Comparison with other wireless charger

Objectives:

1. To compared the previous design of wireless charger with other design
2. To compared the range of the power that being transferred by these two devices

Methods:

1. By making research on internet
2. Comparing the previous design with a product that has been marketed

Results:

Figure 1: transmitter circuit  or platform which contain coils inside it

Figure 2: the receiver

Figure 3: As we can see, the receiver also contain with coils.

Conclusion:

As for conclusion, I found that the design that being used is much more attractable and much more effective than the previous design that looked quite clutter or unmanaged. This design also shows that the range that the wireless power can be transmitted is quite better than the previous design. This technology also known as Qi (pronounce as chi).  This technology also using the same working principle as previous project, which is using inductive coupling method. The coupling method is the principle on how the transformer work when there is an air gap between the transformers. The primary coil and the secondary coil are not directly connected each other. Each coil has their own circuit. Energy transfer took place through a process known as mutual induction.

Week 5 : The design

Objectives:

1. To design the wireless charger by compared with design that has been create by others
2. To study the method that being used in built up the wireless charger

Methods:

1. By making research on internet
2. Comparing other person that has create the wireless charger
3. Attachment below shows the design and the block diagram of the project

Results:

Figure 1: design for the wireless charger

Figure 2: block diagram for the wireless charger

Conclusion:

On my observation through this person project, my find out is that the wireless charger is consists of two portable platform that can be easily moved each other but there are some distance that these two platform must be keep so that the power can be transferred wirelessly. Otherwise, the power cannot be transferred. The distance that this two portable platform must be keep is around 3 cm. The working principle of this project is in this wireless charging system there are two circuits, a transmitter circuit and a receiver circuit (as being mention as two portable platform).

• The transmitter circuit consists of step down transformer of 230/12V. This transformer steps down 230V AC from main supply to 12V AC. Then that 12V AC is converted into 12V DC with the help of bridge rectifier. After that a 2200/25V capacitor is used to filter the ripples and pure DC is supplied. Then the oscillator circuit oscillates at 10MHz and with the help of transmitting coil it transmits the wireless power.
• The receiver circuit receives the power through receiving coil and passes through voltage multiplier circuit (consisting of diode and capacitor voltage multiplier) and through that voltage the mobile charging is achieved.

Week 4 : Introduction of my FYP

Objectives:

1. To give an overview on my final year project
2. To make an introduction to my FYP

Methods:

1. By making research on internet
2. By comparing to other device that using this wireless power transfer technique
3. Here are the attachments about my introduction on my FYP

Results:

Video : Showing how wireless power transfer works

Conclusion:

This week I am going to give an overview on my final year project. My final year project title is the development of wireless charger for mobile phone. As the term ‘wireless’ has been mention it is mean that the mobile phone is going to be charge without using any wire or solid conductor. As being mention in my last blog, this wireless charger has 3 different methods of transferring the energy, but for my project I am going to use the inductive coupling method. This is because inductive method is a simple power transmission that uses a technique as same as transformers. It consists of two coils that being separated by air and air is being used as a medium for transmit the power. Every substance can be used to transfer power because of its permeability. Air also has its own permeability. Permeability is a quantity measuring the influence of a substance on the magnetic flux in the region it occupies. Therefore, air also can be a medium for electromagnetic field to exist. The existence of magnetic field will make the power from primary coil to be transferred to secondary coil.

Week 3 : Wireless Power Transfer (non-radioative technique)

Objectives:

1. To study on wireless power transfer 
2. To investigate non-radioactive technique wireless power transfer
3. To differentiate types of non-radioactive wireless power transfer

Methods:

1. By making some research on internet
2. Get assist from lecturer
3. Below are the attachment detail on non-radioactive wireless power transfer

Results:

Conclusion:

For this week, I more focused on the non-radioactive wireless power transfer technique, because it is the method that I will be using in my final year project. Non-radioactive wireless power transfer are consist of three methods of coupling which are inductive coupling, capacitive coupling and also magnetodynamic coupling. Inductive coupling or electrodynamic induction is the near field wireless transmission of electrical energy between two magnetically coupled coils that are part of resonant circuits tuned to resonate at the same frequency. This process occurs in a resonant transformer, an electrical component which consists of two high Q coils wound on the same core with capacitors connected across the windings to make two coupled LC circuits. Resonant transfer works by making a coil ring with an oscillating current. This generates an oscillating magnetic field. Because the coil is highly resonant, any energy placed in the coil dies away relatively slowly over very many cycles; but if a second coil is brought near it, the coil can pick up most of the energy before it is lost, even if it is some distance away. Meanwhile capacitive coupling is the transfer of energy within an electrical network by means of the capacitance between circuit nodes. This coupling can have an intentional or accidental effect. Capacitive coupling is typically achieved by placing a capacitor in series with the signal to be coupled. Lastly, magnetodynamic coupling is a power that being generated by two motors that rotate synchronously paired by a magnetic field that being generated by permanent magnet. The receiver armature is turned by the existence of the transmitter magnetic field. The magnetic field acts as a mechanical coupling between armatures. The receiver armature then produces power as it is being turn by the transmitter armature.