Research And Development Of HVDC Power Transmission System Based On Ocean Controlled Source Electromagnetic

Marine controllable source electromagnetic method is a part of marine electromagnetic method,which is widely used in marine geological structure survey,seabed oil and gas and gas hydrate exploration.Marine controllable source electromagnetic transmitter is an important part of marine controllable source electromagnetic detection system Among them,the size of the emission current is related to the quality of underwater anomalous resistivity imaging and the depth of detection.At present,many related detection equipment use AC power to directly supply underwater transmitters to work.Because of the large AC power transmission loss on longdistance cables and the small carrying power of the cables,it is impossible to carry out larger current transmission tasks.Therefore,this paper proposes a marine controllable source electromagnetic transmitter using high-voltage direct current transmission scheme,aiming to achieve greater emission current.Relying on the national key research and development project-the research and development of the deep-water dual-ship towed marine electromagnetic exploration system,this thesis mainly focuses on the power transmission system of the marine controllable source electromagnetic transmitter,and the design of the nearly 3000 V high-voltage high-power rectifier unit,400 Hz three-phase The three main parts of fixed frequency inverter unit design and status monitoring unit design are carried out.Among them,the high-voltage and high-power rectifier unit is composed of a bridge rectifier circuit and a filter circuit.The booster power supply boosts 380 V AC power,and performs AC-DC conversion through the bridge rectifier circuit,and uses smoothing reactors and filter capacitors for filtering to reduce DC Ripple,and finally get nearly 3000 V DC high voltage for the electric power supply of the electromagnetic transmitter.The 400 Hz fixedfrequency three-phase inverter unit uses the LPC2368 microcontroller and CPLD to jointly control6 groups of IGBT modules.The IGBT modules form 3 H bridges for three-phase inverters.By controlling the inverter waveforms,the phase difference of each phase is 120°.The modules are electrically connected through stacked busbars,which effectively reduces the stray inductance.At the same time,the overall structure design and related simulation of the inverter unit are carried out with the help of Solid Works three-dimensional modeling software to ensure the stability and reliability of the system.The state quantity acquisition unit mainly includes the monitoring of the input and output voltage and current of each phase of the high-voltage power supply,and the temperature and humidity of the surrounding environment of the power supply.The output signal of each sensor is transmitted to the STM32 single-chip microcomputer for data acquisition and processing through the conditioning circuit,and then the RS-485 communication transmits the real-time status measurement data to the PC to realize real-time monitoring and prevent the risk of over-current and overload in the equipment.The overall power transmission system has been tested indoors.The test content includes: the rectified output voltage is nearly 3000 V,the rectified voltage ripple is less than 5%,the inverter output waveform is normal,and the maximum temperature of each module is within 50?.The test results show that the data of the entire power transmission system is normal and stable,providing technical support for the transmitter to achieve ultra-high current transmission tasks in the future.