Research On Ultrasonic Power Based On DSP

Currently, the range of applications of ultrasonic machining technology is continuously expanded and the performance requirements of ultrasonic power is constantly improved. Therefore, the study of ultrasonic power is being payed colsely attention to by scholars at home and abroad. For the traditional ultrasonic power output resonant frequency is fixed with a single transducer; the matching network of ultrasonic transducer power and transducer can not be achieved dynamic matching during the transducer operation; ultrasonic power has certain defects in terms of the output power stability, And then, unable to realize the constant amplitude output of ultrasonic vibration system. For this reason, based on the three key technical problems of ultrasonic power supply as the research object, to build a new ultrasonic power based on DSP in this paper, the main research work are as follows:Firstly, the present research situation and development course of ultrasonic power is described, the research progress of the key technologies of ultrasonic power is analysised in this paper. Using the Mason equivalent circuit model of ultrasonic transducer, to analysis the Changes in impedance characteristics of the transducer, to establish the equivalent circuit model of the matching network; using a digital inductance to constitute the matching network to solve the power dynamic matching problem, and lay the foundation for the research of ultrasonic power work.Secondly, on the basis of analysis of the transducer and the matching network, to establish the overall scheme of power. Put forward the compound frequency tracking strategy which Based on the combining of digital phase-locked frequency tracking technology and variable step search current extremum method, to achieve multiresonant frequency band locking; Using the phase pulse width modulation technology(PS-PWM) to achieve power output stepless control, and enhances the stability of the output amplitude of ultrasonic system.Finally, the complete of hardware system and software system design of ultrasonic power supply. In the aspect of hardware system, Non-controlled rectifier was adopted to realize AC/DC conversion, with the bridge inverter circuit to constitutes a main power circuit power supply system, so that to complete the direct communication conversion,using digital matching inductance network to complete the electroacoustic converting,designing reasonable information feedback loop, building the hardware circuit of the control system based on DSP. In the aspect of software system, accordance with the requirements of the control strategy of the algorithm combining with the hardware system, to complete the design of the power with the main and each control module program. With the way that combination with software simulation and hardware debugging, to analysis and verify the design scheme of this paper, and provide the basis for further optimizing the system.The results prove that the ultraonic power which is introduced by the paper has the ability of multiple frequency band output, to achieve automatic frequency-tracking,stepless adjustment of output power and dynamic response characteristics of the transducer impedance changes, with the application of soft-swtiching technology, the power reduces the switching loss and enhances the efficiency of the whole machine.