Research And Realization Of Energy Supply System For Wireless Medical Endoscope

The energy supply is the most important problem in the capsule endoscope system. The existing capsule endoscope systems can only be moved by the wriggle of the stomach. To get higher-megapixel performance, more clear pictures and the abilities such as directional movement, arranging medicine even operation the capsule endoscope systems must be afforded enough energy. Nowadays, The charge-coupled device (CCD) is the most mature imaging technology. But the CCD imaging technology rely too much on the power supply. The traditional battery can't afford the enough energy for the system. Through a lot of research the wireless power transmission (WPT) has a complete theory system It is feasible to bring the WPT into the capsule endoscope system.Firstly, the stabilities of position, posture and frequency are researched in this paper. This is due to the position and posture of receiving coil is changing all the time when the capsule endoscope system is swallowed and it is easy to detuning in transmitting terminal. In order to solve these problems helmholtz coil the 3-D receiving coil and switched capacitor are designed.Secondly, the transfer efficiency of system is broken down into 3 parts.There are transmitting terminal efficiency, the coupling efficiency and receiving efficiency. All the parts are researched in this paper. Because the wireless power system of the capsule endoscopy system has extremely small transfer efficiency The efficiency is a impront factors when designing all the part. Each part needs to promote efficiency as far as possible, so that the efficiency of all the system will get a peak. Through analyze and test the frequency characteristics of coils The optimization of coils is put forward. The value of Q is the principal factor to transfer efficiency. Using the electromagnetic simulation in COMSOL the feasibility of this design is verified.Finally, the prototype of the wireless power system is realized. The whole system is included by transmitter module receiving module and coils. In the transmitter module the transmitter coil is driven by full bridge inverter circuit and a energy absorption circuit is designed to protect MOSFET. The circuit of switch capacitance is used to compensate the frequency. In the receiving module the whole bridge rectifier circuit is used. After the rectifier there are two voltage stabilizers. The one is DC-DC and the other one is LDO. The experimental results show that the two voltage stabilizers have the ability to improve the efficiency and improve the voltage quality. In this prototype of the wireless power system the transmission power can be reached 30W and received power can be reached 20mW. So the system has the practical value.