Research On Large Power Transmitter Of High Density Resistivity Method Based On Bridge Circuit Cascade Technique

Mine sudden flooding is a multiple geology hazard. It has the characteristics of suddenly, large scale and has serious result. The negative influences of hazard result, such as mine sudden flooding, were exceeded economic category. When a accident occurred, it would arose wide attention from all over the world. The image of mining enterprises will suffered huge damage and the market affinity of the enterprise will weaken. These will severely influence the supervention develop motivity of mine enterprises. Because of the complexity and specificity of our mine hydro geologic condition, it makes high demands for survey and location methods. General conventional geophysical methods are hard to achieve the purpose of effective detection, not to mention accurate survey and location. High-density resistivity method is a improvement of general electricity resistivity method, it can select variety type of devices for combination observation. It has the characteristic of High density of measuring point . it can make up the shortcoming of lack of data and interpretation method for general resistivity method. Then the research item "Mine Old areas Detection and Prevention for Water Hazard Key Technique and Equipments" was proposed and the national scientific and technical supporting plain research project. was established. The project adopts high-density resistivity method, transient electro-magnetic methods and pseudo-random multi-frequency method for detection. The research contents of the paper are a subject of the project which is aim at research of large power launcher of high density resistivity method.The launcher of high-density resistivity method includes the transmitter and electrode transfer devices. The electric performance index of transmitters has direct influence on the detection efficiency and operating efficiency of the whole system. The distributed electrode transfer devices are the intermediate carrier by which the field source signal is transmitted into ground. It controls the operation mode of the system by switching electrodes. The stability and reliability of electrode transfer signal will direct influence the system detection work. The design of the launcher adopts standardization and modularization. Considering the influence of the electromagnetic interference between the modular circuits, design work assuring the equipment has the characteristics of portable,, intelligent and low power consumption. The whole logic control timing is finished by MCU MSP430F1611IPM which match large power driver mode DA102D4 and power device GT40T101,the MCU MSP430F123IPW controlling switching electrodes and the distributed communication RS-485 bus transceiver SN65HVD08D all of which achieve the transmitting and acceptance.The main contents of this thesis are as follows:1. Power conversion and isolation driving block which adopts H bridge cascade voltage-balance technique in order to achieve large power transmission by small power transmitting element. According to time control sequence, transmitting signal which is demanded by electrical method was generated. The electric isolation between the system information electronic circuit and power electric circuit was realized by optoelectronic technique which increased the system anti-interference ability. DA102D4 four digit driving board was used to driving power device.2. Current detection block. Using current transfomier. transmitting current signal was converted into voltage signal which measured and processed easily. After front-end processing, data collection was performed by the 12 bits AD of MSP430F1611IPM MCU. Converted data were stored in the transition memories. Then the system can read and calculate data and display the average absolute value of the transmitting current.3. The control section was based on MSP430F1611IPM MCU. According to the design demand of distributed high density electrical measuring device, the main work of control section are communicating with computers, generating driving signal and synchronizing signal and the controlling signal for electrode transition which communicated with RS-485.4. Constant-current source section. It is made-up by three-terminal adjustable constant-current source LM134 which produced by National semiconductor. It supplies a stable current for the system when it is measuring the ground resistance.5. Network bus adopts RS-485 communication bus and segmental structure model which guarantees stable and reliable system signal transmitting. 6. Using MSP430F123IPW MCU as electrode converter. The communication interface with RS-485 bus is made up with SN65HVD08 of RS-485 bus transceiver.Testing include performance tests and experiments. Performance index testing includes testing the magnitude of transmission voltage, the stability of transmission frequency and distributed bus communication. Test results showed that transmission voltage and frequency met the design requirement and 485 bus communications met the reliability requirement of instrument communication. Interior physical model experiments were carried out on March 20, 2009. It simulated the process of grounding resistance testing and verified the design of electrode converter met the instrument requirement.The main work and results of this thesis include the completion of high-density resistivity method transmitter, design of distributed electrode converter, key technique research and development of prototype.