Research Of Transmitter Power Supply Based On Phase-shifted Full Bridge

Limited by the development of controllable power device, traditional transmitter power uses vacuum tubes as a concatenation of the adjustment tube to adjust the regulated power supply, which is of low efficency, huge volume and other shortcomings. As挺好widespread adoption of high frequency switch power supply technologies mature,Modern transmitters’ power supply need more stringent demands, such as efficiency,size,weight and so on. In this paper, phase-shifted full bridge ZVS PWM DC/DC converter is applied to the transmitter’ power supply.Firstly, this paper analyses phase-shifted full bridge ZVS PWM DC/DC converters switching mode in detail and discusses some certain working conditions of the converter, such as the realization of soft-switching condition, the duty losses and the current transformation of rectifier circuit. And then, it analyses the working principle of synchronous rectification.Secondly, according to the power supply indicators, the paper calculates the parameters and selects the devices of the main circuit devices, including the parameters’ calculation of transformer, resonant inductor, filter inductance, filter capacitor; the selection of power tubes, output synchronous rectifier tube, and clamping diode. By simulation, the calculation and the selection of parameters are correct.And then, it analyses the two types of control methods of the power supply:the voltage mode control and the peak current mode control. Peak current mode control is selected in this paper. Introducing the functional modules of the UCC28950, which is a phase-shifted full-bridge controller. It analyses and designs parts of the control circuit. It analyzes and designs various parts of the power supply’s control circuit. Then the power supply has been simulated. The simulation validates the rationality of the designing. It also proves that the power supply’s dynamic characteristics is good. It analyzes several parallel current-sharing methods’ working principle and advantages and disadvantages. The maximum current automatic current sharing method is simulated.At last, an experimental prototype of phase shifted full bridge ZVS PWM DC/DC converter has been researched and developed. The theory analysis is verified by the experiment. Experimental results show that the power supply is able to achieve soft switching. Some power supply indicators meet the requirements.