Design On Power Supply Of Giant Magnetostrictive Actuator

Giant magnetostrictive material is a novel functional material. It has a series of significant advantages, such as strain large, high energy density, fast response compared to traditional magnetostrictive material. Micro-displacement actuator based on giant magnetostrictive material has wide applications in the fields of ultra-precision machining, fast positioning and adjustment, active vibration and noise reduction, fluid control and so on. During it works, magnetostrictive material change electromagnetic energy into mechanical energy, the energy size depends on the out put of the driving power. Static characteristics and dynamic characteristics of Giant magnetostrictive actuator lies on the performance of driving power for inductance coil. Therefore, the design of driving power is a key technology in research and application of giant magnetostrictive actuator.In this paper, based on the features of giant magnetostrictive actuator, through analyzing and comparing different types of constant current source circuits, a continuously adjustable current source circuit has been done and its control structure is analyzed. Through analyzing systematic error of the circuit system, it is obtained that voltage reference, sampling resistance, operational amplifier affect the output precision of current source mostly. Accordingly, methods have been proposed to restrain systematic error.Secondly, analyzing for input and output characteristics of power MOSFET used in the current source has is given in this paper. Accordingly, driving circuit of gate and over current protection circuit have been designed. In order to solve the heat dissipation problem of power MOSFET, a radiator is designed and assembled. Thirdly, hardware circuit of current source has been made, including constant current source circuit, DSP control system, figure model conversion circuit, temperature measuring module, keyboard module, LCD module, power module, PCB design and upper computer software.Finally, the performance index of giant magnetostrictive actuator driving power has been tested. Test results are output current stability is up to0.3‰, current ripple factor is up to 1%, load regulation is up to 0.3‰, voltage regulation is up to 0.6‰. It can meet the system requirements for the giant magnetostrictive actuator to provide a guarantee of precision positioning.