Research On High-Precision Microwave Power Control Technology

Microwave has widely used in industry, agriculture, medical, health and other fields, for its unique thermal effect of endogenous. With the constantly development of microwave technology, the precise control and accurate measurement techniques of microwave output power in microwave technology has became the key technologies for further promote the microwave technology application.Current, the problem of low precision and poor stability will exist when microwave output power in control process, this paper presents a new method which take the use of DSP technology and a combination of SCR control technology to control the microwave output power. To make the use of DSP hardware timer, which produce a delay trigger pulse signal to SCR for high precise control of thyristor conduction angel; to realize precise control of high-voltage anode magnetron by changing the high-voltage transformer primary voltage. To achieve the precise control of microwave output power, A/D converter and digital temperature sensor was used to actualize the real-time monitoring of microwave output power and its heating effect, and achieve closed-loop control of this system, which make the further improve of the stability and reliability to system. Precise control of microwave output power has mainly depends on DSP hardware timer and external relevant circuit in system.Frequency of crystal oscillator in external is 10MHz, the operating mode of frequency was 10 times in internal PLL, which can produce 100MHz operating frequency, and make this form of the SCR conduction angle regular controller timing error reach 10ns, this precise can not be realized in tradition SCM system, so, control precise by the DSP control system consisting of microwave power is more than microcomputer control system consisting of microwave power. And this so by the DSP control system consisting of microwave power is more than the precision of its control by the microcomputer control system consisting of microwave power. Through experimental analysis, temperature and microwave power control is stable and adjustable when material was heated in control system, overall performance is stable and reliable, and the output microwave power control accuracy can reach 1%.