Design Of Control Circuit For Continuous Wave Mud Pulser

At present,MWD is an important technical means to obtain downhole data.With the increasing difficulty of oil exploitation,more and more downhole data need to be transmitted,and the requirement of data rate is higher and higher.Continuous wave mud pulser has high transmission rate,excellent reliability,and good interference rejection ability,so it becomes the latest mud pulse MWD data transmission technique.The rotary valve of the continuous wave mud pulser is driven by the permanent magnet synchronous motor.This thesis is mainly about the design of control circuit for permanent magnet synchronous motor used in continuous wave mud pulser.Firstly,the working principle of the continuous wave mud pulser is introduced,and field-oriented control method of permanent magnet synchronous motor is expounded with the space vector pulse width modulation algorithm,these provides a theoretical basis for implementation of the control of permanent magnet synchronous motor.Secondly,the design of permanent magnet synchronous motor control circuit is presented in detail,which consists of control circuit board and drive circuit board,control circuit board includes TMS320F2812 as the MCU of control system hardware design,and LM2576 HV,LM2576,TPS73HD318 PW give three stage power supply,AD2S1200 for decoding signals for resolver which connected on rotor of the permanent magnet synchronous motor to detect rotor speed and position.The drive circuit board includes power stage three-phase inverter circuit of IRFR2907 and its driving circuit designed with IR2130.Current detection circuit and dc bus voltage detection circuit are also designed in rive circuit board to realize overvoltage,under voltage,overcurrent protection and other protection functions.At last,the slave computer software for controlling permanent magnet synchronous motor and software to communicate with host computer were developed in the CCS,then the host computer monitoring software is developed using LabVIEW,which can monitor stator current,rotor speed,quadrature axis and direct axis current of permanent magnet synchronous motor in FOC control by communicating with slave computer.On the basis of above software and control circuit design,a experiment system was built to test designed control circuit of continuous wave mud pulser.Several tests were carried out and the experimental results show that the designed hardware and software are functional proper,and can be adopted in controlling permanent magnet synchronous motor used in rotary valve of continuous wave mud pulser.