摘要
电流模式控制是实现双有源桥变换器(DAB)高动态功率调控的有效手段。但在高频高功率密度应用场合,现有的电流模式控制方案仍存在电流传感器带宽不足、“模拟+数字”混合控制器实现复杂的问题。基于“比较触发”机制,该文提出一种适用于高频DAB变换器(百kHz开关频率)的电流模式控制及实现方法,通过罗氏线圈实现高频电感电流的精确感知,并设计基于单一微控制器的模数混合电流模式控制器,简化了控制系统结构、降低了系统成本。采用该文提出的控制方案,可实现高频DAB变换器电感电流的高动态控制,进而实现变换器的快速功率调控和逐周期限流保护。实验结果表明:所提方法实现了200 kHz DAB变换器的电流模式控制,电感电流的动态响应时间仅为2.5μs,开关频率水平和动态响应远高于并优于已有研究成果。
The current mode control effectively achieves high dynamic response for dual active bridge (DAB) converters. However, for high-frequency and high-power-density applications, the existing control methods still face some limitations. On the one hand, the bandwidth of the commonly used current sensors, e.g., Hall-effect sensors, is not high enough to capture the complete information of the high-frequency inductor current. On the other hand, the existing implementation methods rely on analog comparators and digital triggers, which involve more discrete components and complex control logic than the traditional phase shift control. This paper proposes an analog-digital hybrid current mode control for high-frequency (hundreds of kHz) DAB converters. A high bandwidth (30 kHz~3 MHz) Rogowski current sensor is designed to accurately capture the inductor current, while the analog-digital hybrid current mode controller is implemented using a sole microcontroller, reducing system cost, complexity, and PCB layout area. Firstly, the operating principle of the analog-digital hybrid current mode control for DAB converters is detailed, and the inductor current reference value ±iref as a function of transmission power is derived. The theoretical analysis shows that the steady-state performance with the current mode control is equivalent to traditional phase shift control, and the inductor current shows an extremely fast dynamic response. Secondly, the feasibility and advantages of the Rogowski coil for sensing high-frequency inductor current are illustrated. Its operating principle, together with transfer characteristics, is analyzed. A Rogowski coil current sensor is fabricated to capture at least six harmonics of the inductor current of a 200 kHz DAB converter prototype. The bandwidth of the Rogowski coil current sensor is measured as 3.2 MHz using a vector network analyzer, which is sufficient for current mode control. An experimental comparison shows that Rogowski coil current sensors achieve higher accurate measurements of high-frequency inductor current than commercial Hall current sensors (ACS730). In addition, the implementation scheme of the analog-digital hybrid current mode control in a digital controller platform is described. The analog comparison and digital trigger functions are integrated using one microcontroller unit (MCU), which reduces system complexity and cost. Taking TMS320F28379D from Texas Instruments as an example, the implementation flow and register configuration are elaborated. A DAB converter prototype is designed with 1.4 kW-200 kHz, 150 V input, and 150 V output. The experimental results show that the inductor current of the DAB converter exhibits a swift dynamic response. The dynamic response time of the inductor current for the transient process, such as start-up, power step-up, and power step-down, is less than half of the switching period (2.5 μs). The response time is only 1/64 to 1/32 of the existing research. In addition, the inductor current is firmly restricted to current reference ±iref, which can be dynamically adjusted in the digital controller. Therefore, a cycle-by-cycle current limiting capability is simultaneously achieved. The following conclusions can be drawn. (1) The designed Rogowski coil current sensor can accurately capture the information of high-frequency inductor current, which is a prerequisite for current mode control. (2) The analog comparison and digital trigger functions are successfully integrated into a digital control to reduce system complexity and cost. (3) The DAB converter shows excellent dynamic performance using the proposed analog-digital hybrid current mode control method and implementation strategy.
作者
朱博阳
韩伟健
陈建良
辛振
Zhu Boyang;Han Weijian;Chen Jianliang;Xin Zhen(State Key Laboratory for Reliability and Intelligence of Electrical Equipment Hebei University of Technology,Tianjin 300401 China)
出处
《电工技术学报》
北大核心
2025年第6期1888-1899,共12页
Transactions of China Electrotechnical Society
基金
国家自然科学基金项目(52407201)
河北省高等学校科学研究项目(QN2023105)资助。
关键词
双有源桥变换器
电流模式控制
罗氏线圈
动态响应
Dual active bridge converter
current mode control
Rogowski coil
dynamic response
