High Frequency And High Voltage Power Supply Based On Digital Control

The current high voltage power supply in many areas has been widely used. Medical treatment, communications, national defense and other fields are inseparable from the high voltage power supply. The high voltage power supply studied in this paper is mainly used in X-ray diffractometer to provide 10 KV ~ 60 KV voltage. The requirement of high voltage power supply used in the X-ray diffractometer is very high. The stability and control accuracy of the power supply directly affects the image quality of the X-ray diffractometer.The emergence of high frequency switching power supply to achieve high precision, high efficiency and high voltage power supply. It is suitable for X- ray diffraction, so this paper uses the design of high frequency switching power supply.This design is the high frequency high voltage power supply based on digital control. It not only realizes the power of high frequency, but also simplifies the complexity of the control circuit by using a digital-based control scheme.while improving the control accuracy of the output voltage. We take the conventional two-stage structure as the structure of the power supply. The first stage is the PFC(Power Factor Correction) circuit and the subsequent stage is the series and parallel resonant circuit. PFC circuit uses a single-cycle control strategy to achieve that the input current and the input voltage in the same phase, in order to improve the power factor. Series and parallel resonant circuit not only has the advantage of a series resonance and parallel resonance, while overcoming the disadvantages of the two circuits, and easy to achieve soft switching. The control strategy is based on digital phase shift control. By controlling the on-time of the MOS transistor to achieve a soft-switching, reducing losses on the switching. As a result of the digital control mode, the signal from the control chip can’t directly drive MOS. We design a driver circuit to control the switching of the tube. In addition each control chip and driver circuit requires low voltage to drive, an auxiliary power supply is designed to provide voltage. Taking into account the needs of low-voltage auxiliary power multi-output, we adopt a single-ended flyback topology. Through Analysis of the various parts of the circuit, the equivalent model of the circuit is given in this paper.The formula to choose the key elements that affect the performance of the circuit are deduced. The model of the power factor correction circuit and the series parallel resonant circuit is created, verified the correctness of the one cycle control theory. The circuit parameters were optimized according to the simulation results of some parameters on the circuit.In this paper, the various parts of the high-voltage power supply components were analyzed and calculated. A prototype based on the calculation results of the test was produced. After testing, the performance of each part meets the basic design requirements. Parameters should be further optimized in the future.