Research On Hardware Circuit For Magnetic Bearing

Electromagnetic power was used in magnetic bearing to make the rotor suspended in space with non-contact in axis, with no friction, no lubrication, no oil pollution, low energy consumption, low noise, long lifespan, etc. And it is the main direction of development in high-speed rotating mechanism steady bearing in the future.A complete set of driving system for magnetic bearing, including at least two radial magnetic bearings, an axial magnetic bearing and an electric motor; the system of hardware circuit include sampling, power driving, peripheral protection and power module. the structure is quite complex. Moreover, if the inverter is used in electric motor to control independently, the system of hardware is scattered, the communication between the controllers is inconvenient and antijamming ability is bad. The design of integrated circuit is carried on in order to decrease volume, lower the cost of objective and increase the precision, the stability and antijamming ability of the magnetic bearing further.This paper take the radial load for 800N, axial load for 1000N and motor power for 550W as the studying object in magnetic bearing, the majority of controller of hardware circuit structure was designed based on TMS320LF2407A. According to the requirement of actual working voltage to design DSP sampling circuit which based on the analysis of the parameters in displacement, current, voltage, speed, parameters of real-time detection principle foundation.. Then use PSPICE simulation software to conduct the simulation research and the improvement of the designed circuit.IGBT and IPM were selected as core components both in magnetic levitating bearing and motor power driver module. This paper analyze their characteristics and working principle, then design the related isolation, driving and protecting circuits, etc. For IPM driving unit, the 15V power source which is different, has been designed to four groups, and attached functions such as isolation protection, filter as well as constant voltage. The experimental result demonstrated that uses the filter and the constant voltage can eliminate harmonic effectively, improve the precision of output.Suppose the speed for magnetic bearing is 10000r/min and actual output based on the displacement, velocity, current, voltage, etc, according to the design of the circuit of sampling which based on the analysis of the testing frequency signal interference and components, combined with simulation magnetic bearing systems that fit the filtering structure of circuit and parameters.Finally, the overall planning has been carried on to the system of electric circuit in hardware, and makes the printed wiring board (PCB), and take sharpening the system antijamming ability as the goal, improving the layout and the wiring,then it discussed the electromagnetic shielding and other anti-jamming measures further.