全桥隔离DC/DC变换器的直接功率控制方法

以无工频变压器电力牵引传动系统为应用背景,对其中的全桥隔离DC/DC变换器开展研究。在电力牵引传动系统中,单相网侧脉冲整流器直流输出电压中含有二倍电网频率的电压脉动,该二倍频脉动可能会引起电机中的拍频现象。因此,为减小该二倍频电压脉动对DC/DC变换器输出电压的影响,研究全桥隔离DC/DC变换器在输入电压动态变化时的高性能控制方法非常必要。为提高全桥隔离DC/DC变换器在输入电压脉动以及突变情况下的动态响应性能,基于单相移控制方法,提出了一种直接功率控制方法,并进行了详细的分析。最后,基于RT-LAB和赛灵思XC3S500E的半实物仿真平台和基于TMS320F28335控制器的实物实验平台对所提出的控制方法进行验证,半实物仿真和实物实验结果表明:在输入电压突变、输入电压含有脉动和波动的情况下,该直接功率控制算法能有效提高输出电压的动态性能,减小输入电压扰动对输出电压的影响。

Direct Power Control Scheme of Full-bridge Isolated DC/DC Converters

This paper focuses on the full-bridge isolated DC/DC converter, which is a part of transformerless AC traction drive system in railway application. In the AC transformerless traction drive system, there are twice-grid-frequency ripple in DC-link voltage of single phase grid-side pulse-width modulation converters, which can lead to the motor beat frequency phenomenon. Thus, in order to reduce the effect of twice-grid-frequency ripple on the output side of the full-bridge isolated DC/DC converter, an appropriate control method is necessary in the input voltage variation application. In order to improve the dynamic response of the full-bridge isolated DC/DC converter in the input voltage fluctuation and mutation conditions, a direct power control scheme in the single-phase-shift mode is proposed and analyzed in detail. Finally, the proposed control scheme is verified on a hardware-in-loop(HIL)simulation platform with RT-LAB simulator and XC3S500E controller of Xilinx, which is also tested on the experimental platform with TMS320F28335 controller. The HIL simulation and experimental results show that the adopted direct power control can significantly improve the dynamic response of the output voltage in the input voltage step change and fluctuation conditions, while reducing the effect of input voltage disturbance on the output voltage of the full-bridge isolated DC/DC converter. This work is supported by National Natural Science Foundation of China(No. 51577160).