| In the recent 20 years, high linearity, high efficiency RF power amplifier(RFPA) has been the goal that were pursuited by the RF power amplifier technology at home and abroad. It also has been the key infrastructure which is behalf of the Multi-Carrier Linear Modulation that was represented by OFDM used in the fourth-generation mobile communication systems.Recently, Class-A and Class-AB power amplifier are maily used to meet the demand of high linearity and high efficiency at home and abroad. But the kinds of power amplifier are low efficiency naturely. Also, the amount of the time distribution of wireless communication data is uneven, the RF amplifier more often work in small load, this makes the efficiency of the power amplifier even worse. Take the advantages of high efficient switch-mode power supply and high linearity power amplifier, combined with the envelope following technology to supply the RFPA by amplified voltage. In this paper, we use parallel buck as the main topology, combined with interleave control method to design a dynamic voltage power supply which can track 300kHz envelope signal. The main research in this paper includes the following several aspects:Firstly, take the use of the strategy that were proposed, combined with the consideration of the difficult problems in the design, this paper decide to use the 3-phase parallel DC/DC converter as the main topology, this can meet the demand of working frequency of the switch device. Based on the analysis of the current control method, this paper choose interleave control method to satisfy the requirements,and then give the advantage of the method.Secondly, as the overall strategy was proposed, based on the analysis of the advantages and shortcomings of the DC/DC topologies that are used generally, we chose Buck converter as the main topology, and design its parameter. Then design the linear amplifier, control circuit, signal distribution circuit and their parameters. And then, do the controlling model about the main topology and control circuit, and analyze its dynamic performance by Bode plots based on its transfer function, then simulate it in simulink environment. Use the simulation result to optimize the parameter and reach the requirement at last.Finally, in order to understand the performance furtherly, the author use the device model to simulate the system in time domain in Saber and demonstrate that this stragety is feasible in some circumstance. And point out the shortcomings in the design , give the corresponding advice to improve the future work. |
