Study Of Numerical Control DC Power Supply Base On One-cycle Control

The switches are the main components in numerical control DC power supply, in order to convert AC power into DC power, the turn-on time of the switches must be modulated. The numerical control DC power supply is one kind of switching power supply, and the DC/DC converter is the main topology of it. There are some inherent defects in circuit structure and control method of the switching power supply: in the low-voltage and high-current situation, since there is a large voltage-drop of rectifier diode on the DC/DC conversion, the efficiency of the switching power supply is much lower; the switching power supply is one kind of nonlinear system, if the traditional linear control method is used, the dynamic response will be slow, and it will have bad stability and poor capability for rejection of input disturbance. In order to improve the deficiencies of switching power supply and obtain high quality waveform of DC output voltage, the synchronous rectification and one-cycle control (OCC) are used in this system.In this thesis, the background of the topic and the technique data of the device are introduced; the overall structure of numerical control DC power supply is designed, and the forward converter is selected to be the main topology of the device; furthermore, the method of synchronous rectification is introduced, the dead-zone control of synchronous rectification circuit is discussed and the driver module of synchronous rectifier is chosen; next, the principle of OCC is described, and the continuous time mode of DC/DC converter is built on it; finally, an OCC-PID controlled system is designed, and a simulation research of the system is done by using Matlab7.0.On the basis of the theoretical analysis and simulation, the main circuit of system and hardware circuit of controller based on DSP are designed and the software flow chart is also finished. In this paper, the test data of the experiment is analyzed. The result shows that the device adapts the design requirement and it is valuable to project.At the end of this paper, a conclusion is summarized, and the main problems which need to improve are proposed.