Abstract According to limited voltage gain of the standard step-up converters, cascade connection of the boost choppers can be employed to increase voltage gain. However, negative impedance instability problem due to converters constant power characteristic will complicate closed loop control of the cascaded converters. To cope with the problem, switched capacitor/switched inductor (SC/SI) circuits can be employed for voltage gain increment in transformerless DC–DC converters. High gain DC–DC converter model includes several state variables; hence multiple voltage and current sensors are required in closed loop applications. In this paper, a novel transformerless DC–DC step-up converter with very high voltage gain is proposed using SC/SI circuits which mitigates negative impedance instability problem. By modular extension, more improvements in converter gain and switch voltage stress can be obtained. In the developed circuit, inductors currents (and voltages of the capacitors) are equal during transient and steady-state conditions. Thus, model complexity is similar to standard DC–DC converters. Experimental response of the designed system is investigated in both continuous and discontinuous conduction modes of operation. Considering different performance parameters, proposed DC–DC converter is compared with recently reported methods. Closed loop response of the presented regulator is studied using two-loop control strategy under load and line changes.

中文翻译：

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具有极高电压增益和可调开关应力的模块化无变压器 DC-DC 升压转换器

摘要 针对标准升压转换器有限的电压增益，可以通过级联升压斩波器来提高电压增益。然而，由于转换器恒功率特性引起的负阻抗不稳定问题会使级联转换器的闭环控制复杂化。为了解决这个问题，开关电容器/开关电感器 (SC/SI) 电路可用于无变压器 DC-DC 转换器的电压增益增量。高增益 DC-DC 转换器模型包括几个状态变量；因此在闭环应用中需要多个电压和电流传感器。在本文中，提出了一种具有非常高电压增益的新型无变压器 DC-DC 升压转换器，该转换器使用 SC/SI 电路来缓解负阻抗不稳定问题。通过模块化扩展，可以获得转换器增益和开关电压应力的更多改进。在开发的电路中，电感电流（和电容器的电压）在瞬态和稳态条件下是相等的。因此，模型复杂度类似于标准 DC​​-DC 转换器。设计系统的实验响应在连续和非连续传导操作模式下进行了研究。考虑到不同的性能参数，将提出的 DC-DC 转换器与最近报道的方法进行比较。使用负载和线路变化下的双环控制策略来研究所提出的调节器的闭环响应。模型复杂度类似于标准 DC​​-DC 转换器。设计系统的实验响应在连续和非连续传导操作模式下进行了研究。考虑到不同的性能参数，将提出的 DC-DC 转换器与最近报道的方法进行比较。使用负载和线路变化下的双环控制策略来研究所提出的调节器的闭环响应。模型复杂度类似于标准 DC​​-DC 转换器。设计系统的实验响应在连续和非连续传导操作模式下进行了研究。考虑到不同的性能参数，将提出的 DC-DC 转换器与最近报道的方法进行比较。使用负载和线路变化下的双环控制策略来研究所提出的调节器的闭环响应。