Digital Control Of Phase-shifted Full-bridge Soft-switching Converters

Currently, the miniaturization and integration is the direction of electronic systems'development, this prompt the power system to reduce its own volume. Improve the switching frequency is an important way to reduce the volume, but at the same switching losses continue to rise with the increasing of switching frequency, which significantly affects the power system's miniaturization. To solve this problem, the soft-switch technology is used in the high frequency switching power supply. Communication system is a major application for switching power supply, with the digital technology used widely in communication system, if the power supply system is also under the control of the digital control system, it is undoubtedly that the whole system will achieve self-management, fault diagnosis and even auto repair and other functions.Based on these reasons, this paper is mainly focused on the realization of digital control for soft switching converters. Because the phase-shifted ZVS full-bridge topology is a mature technology and widely used in many systems, this paper use this topology, and its working principle is analyzed, then, the converter main circuit hardware is designed. Control system hardware design is the key to the entire design, this section contains the main control IC, the control signal drive circuit and the output voltage sampling circuit. In order to ensure the safe operation of the system, we also added a lot of protection circuit in control system, and use the flexibility of digital systems to achieve the continuous monitoring of the system.As the core of the control system, the DSP TMS320F28335 produced by TI was used in this paper, it has a very high computing performance. because of its very high computing performance, we not only use the PID algorithm, but also use the genetic algorithm to optimize the performance of digital PID algorithm. The main role of the genetic algorithm is finding the optimal solution for the PID regulator, it can help the system to find the optimal parameters, and can also tracking parameters change on the main circuit, and ensure the system stability and durability under harsh conditions. After Complete hardware and software design of the system, we create a prototype to validate the overall design.