Research On The Key Technology Of Series High Power Electrical Transmitter

According to the investigation results of the Ministry of Land and Resources, among the mines we are exploiting now, more than 60% of the mines appear crisis on lack of minerals and more 30% of them appear serious crisis. Now we are facing a serious situation of lacking minerals. Now the natural resources exploration and extraction depth of our country are mainly less than 500 meters, while in other countries the depth has been more than 4800 meters. Comparing the detecting depth of our country to the others, we can see that we are under-developed in both the exploration and physical geography instruments. According to the new physical geography theory, we have lots of mineral examples between 500~1500 meters underground, and we have an exciting second minerals latent capacity. So it's an effective way to ease the crisis of minerals by developing the detecting theory and physical geography instruments. Though we have had lots of achievements on physical geography instruments, our instruments are mainly working less than 500 meters. Now there many famous instruments in the world, such as the V5/V8 system developed by Canada and the GDP32 system of America. All these systems have had a lot of applications.This article mainly studies the key technology of large depth transmitter source. The Controlled Source Audio-frequency Magnetotelluric (CSAMT) is a widely used method on large depth minerals detecting. This article studies the basic theory of CSAMT and designed a transmit system which can be used on the 500~1500 meters detecting. The CSAMT method enlarges the exploration depth by reducing the output frequency or increasing the output current. In order to raising the work efficiency, the transmitter should have the ability of creating imitative-random waves. In this design we use the multi-powers technology, according to the series connection of these power sources, the system has a very high-voltage output. The current output of the powers changes by the H-Bridges. To ensure that the H-Bridge works safely, we design the IGBT driver circuit and the protection circuit. The main controller of the system is MSP430F1611, which is produced by TI. It has a very powerful PWM output module which can create kinds of PWM waves by setting its register correctly. The output current is detected by the Hall sensor CS100B/4V. The sensor voltage is converted by the ADC inside the MSP430. The detected signal is transformed to current value and send to the LCD. Also the MSP430 contrasts the output current with the Max-current, when there is over current, the controller will stop the output and alarm.The article mainly works on the following three technologies, the simulation of CSAMT, the calculation of the large power transformer in the Switching Power Supply, the IGBT driver circuit and protection circuit. The Switching Power is based on Half-Bridge Topology, the transformer is designed using a few EC-70 cores, and its parameter is calculated accurately. The H-Bridge is designed using PGL60N100D, and its driver circuit is designed on the Push-Pull topology. The driver circuit is isolated using high-voltage transformer and coupler to ensure its safe. Also the protect circuit is designed to set Dead-Time between the two control waves. The Dead-Time is created by RC delay, and there is multi-comparator circuit which can ensure that the H-Bridge can't conduct directly.According to the simulated results, to achieve the depth to frequency detecting, the transmitter should has the ability of creating kinds of mode and frequency waves. In this system, the main controller MSP430F1611 has a powerful ability to produce PWM waves. The input and display system is achieved by a 4*4 keyboard and a 20*2 LCD.After the design of the system, we carried on many experiments. According the results, we find out the existing problem and give some suggestions to improve the system.