In the renewable energy system, generally, the output voltage of renewable sources, such as photovoltaic (PV) and the fuel cell is relatively low and should be boosted to a high voltage first. However, there will be a large amount of second harmonic current (SHC) on the dc bus when powering the ac load. This article aims for suppressing the SHC in the front-end converter with a high-gain dc_dc converter. The accurate small-signal model of the high-gain converter considering leakage and magnetic inductance of the coupled inductor is proposed. Then, the impedance editing method is proposed to establish a second harmonic impedance in the control loop, which brings little influence on the system dynamic performance during the load transient. Even, the system dynamic performance will be improved due to the feedforward of the input current. Meanwhile, considering the system stability and SHC reduction, the detailed design method of optimal parameters for both controller and converter is presented. Importantly, zero-voltage switching (ZVS) of all dc_dc converter switches can be realized after SHC suppression. Hence, when the SHC is reduced, the system efficiency is improved as well. Finally, a 500 W two-stage single-phase inverter is fabricated and tested to verify the effectiveness and feasibility of the proposed SHC suppression methods.

中文翻译：

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线性发电机驱动器基于电流调制的在线谐振调节策略


在可再生能源系统中，一般来说，可再生能源，例如光伏(PV)和燃料电池的输出电压较低，需要先升压至高电压。然而，在为交流负载供电时，直流母线上会产生大量的二次谐波电流（SHC）。本文旨在通过高增益 dc_dc 转换器抑制前端转换器中的 SHC。提出了考虑耦合电感漏感和磁感的高增益转换器的精确小信号模型。然后，提出了阻抗编辑方法，在控制环路中建立二次谐波阻抗，在负载瞬态期间对系统动态性能影响很小。甚至，由于输入电流的前馈，系统的动态性能也会得到改善。同时，考虑系统稳定性和SHC降低，提出了控制器和变换器优化参数的详细设计方法。重要的是，所有dc_dc转换器开关的零电压开关（ZVS）都可以在SHC抑制后实现。因此，当SHC减少时，系统效率也会提高。最后，制作并测试了500 W两级单相逆变器，以验证所提出的SHC抑制方法的有效性和可行性。