Development Of Magnetic Resonance Sounding Instrument Switching Power Supply For Detecting Groundwater

Magnetic Resonance Sounding (MRS) for detecting groundwater is the only nonintrusivegroundwater detection method, which has a lot of advantages including high precision, highefficiency, abundant information and unique solution etc. Recently, MRS is widely applied in thefields of groundwater detection, dam seepage prevention and mine/tunnel disaster waterprediction etc.As an important part of the whole system, stable switching power supply is directly relatedto the precision of current emission and signal acquisition, and impacts the accuracy of thedetecting results. Therefore, the development of secure and reliable high-speed switching powersupply is the key to making MRS instrument for groundwater detection efficient and reliable.Since the old switching power supply of the instrument is provided by suppliers, designers donot understand the principle and internal structure of the instrument, so it cannot work well withthe instrument and only has a single boosting function. With the development of MRS and theapplications in mine/tunnels and other confined space, the instrument has new requirements forswitching power supply. Through conducting a series of analyzes and comparison and combiningMRS instrument work principle and internal structure, this paper designs a new switching powersupply to solve the problems and satisfy the requirements.According to the principle of MRS groundwater detection and the characteristics ofinstruments, the new switching power supply adopts a series of key technologies，such asselecting the full bridge topology as inverter circuit, using power MOSFET as a switching device,adopting IR2110to drive switches, choosing integrated PWM control chip SG3525as the core ofcontrol circuit, calculating the related parameters and so on. Based on this, the new switchingpower supply considers the stability, reliability, and compatibility with the MRS instrumentsystem, and makes distribution of the structure rationally. In addition, according to the specialneeds of MRS groundwater detection instrument, the paper adds auxiliary function circuit intothe power supply module, including high-voltage linear regulator, discharge circuit with constantcurrent, voltage detection circuit, high current switching control circuit and over-current protection circuit.The paper includes the test results of the waveform of key nodes, efficiency, stability andother parameter after the design. Test results show that the circuit design is reasonable, theparameter selection is appropriate, output waveform is stable, entire system is safe and reliable,all parameters and performances meet the new needs and requirements perfectly.