Objective For the inverters used in UPS, it is important to maintain the pure sinusoidal AC output voltage waveform over all loading conditions and transients. Methods A novel sinusoidal output voltage control strat...Objective For the inverters used in UPS, it is important to maintain the pure sinusoidal AC output voltage waveform over all loading conditions and transients. Methods A novel sinusoidal output voltage control strategy is pregented in this paper. The output voltage is controlled by introducing filtering eapacitor current feedback. Two simple PI regulators are used for the current and voltage control loops. Results With the new control strategy, the inverter achieves very low output voltage distortion, good output voltage regulation and strong perturbation rejection, fast dynamic response, and good performance under nonlinear loads. The THD under capacitance rectifying load is better than 0.2%, the output voltage regulation within 0 to full load is less than 0.1%. The resting time under load transient is within 200?μ s . Conclusion The merits of the new control strategy include rapid response and good steady state stiffness.展开更多
To miniaturize a very low level dc current amplifier and to improve its output response speed, the switched capacitor negative feedback circuit (SCNF), instead of the conventionally used high-ohmage resistor, is prese...To miniaturize a very low level dc current amplifier and to improve its output response speed, the switched capacitor negative feedback circuit (SCNF), instead of the conventionally used high-ohmage resistor, is presented in this paper. In our system, a switched capacitor filter (SCF) and an offset controller are also used to decrease vibrations and offset voltage at the output of the amplifier using SCNF. The theoretical output voltage of the very low level dc current amplifier using SCNF is obtained. The experimental results show that the unnecessary components of the amplifier’s output are much decreased, and that the response speed of the amplifier with both the SCNF and SCF is faster than that using high-ohmage resistor.展开更多
基于单移相控制(Single Phase Shift,SPS)的双有源全桥(Dual Active Bridge,DAB)变换器在工业领域中应用广泛。然而当输入、输出电压不匹配时,存在输出电容纹波电流过大的问题,其输出电容所能承受的纹波电流与DAB输入、输出电压的范围...基于单移相控制(Single Phase Shift,SPS)的双有源全桥(Dual Active Bridge,DAB)变换器在工业领域中应用广泛。然而当输入、输出电压不匹配时,存在输出电容纹波电流过大的问题,其输出电容所能承受的纹波电流与DAB输入、输出电压的范围有很大关系。首先介绍了基于SPS控制的DAB工作原理,详细分析了DAB变换器的模态,推导了DAB各模态下电感电流、副边H桥输出电流的数学表达式以及DAB功率传输模型。其次提出了DAB输出电流利用率的概念,推导了输出电容纹波电流与输出电流利用率、电压传输比以及各电路参数的数学关系,从数学理论上揭示了输入、输出电压不匹配时,输出电容纹波电流过大的原因,为DAB电路的电容以及宽电压输出的设计提供了理论支撑;然后基于实际设计的电容纹波电流的允许范围,推导了DAB输出电压范围的数学公式;最后通过仿真和试验验证了理论分析的正确性。展开更多
文摘Objective For the inverters used in UPS, it is important to maintain the pure sinusoidal AC output voltage waveform over all loading conditions and transients. Methods A novel sinusoidal output voltage control strategy is pregented in this paper. The output voltage is controlled by introducing filtering eapacitor current feedback. Two simple PI regulators are used for the current and voltage control loops. Results With the new control strategy, the inverter achieves very low output voltage distortion, good output voltage regulation and strong perturbation rejection, fast dynamic response, and good performance under nonlinear loads. The THD under capacitance rectifying load is better than 0.2%, the output voltage regulation within 0 to full load is less than 0.1%. The resting time under load transient is within 200?μ s . Conclusion The merits of the new control strategy include rapid response and good steady state stiffness.
文摘To miniaturize a very low level dc current amplifier and to improve its output response speed, the switched capacitor negative feedback circuit (SCNF), instead of the conventionally used high-ohmage resistor, is presented in this paper. In our system, a switched capacitor filter (SCF) and an offset controller are also used to decrease vibrations and offset voltage at the output of the amplifier using SCNF. The theoretical output voltage of the very low level dc current amplifier using SCNF is obtained. The experimental results show that the unnecessary components of the amplifier’s output are much decreased, and that the response speed of the amplifier with both the SCNF and SCF is faster than that using high-ohmage resistor.
文摘基于单移相控制(Single Phase Shift,SPS)的双有源全桥(Dual Active Bridge,DAB)变换器在工业领域中应用广泛。然而当输入、输出电压不匹配时,存在输出电容纹波电流过大的问题,其输出电容所能承受的纹波电流与DAB输入、输出电压的范围有很大关系。首先介绍了基于SPS控制的DAB工作原理,详细分析了DAB变换器的模态,推导了DAB各模态下电感电流、副边H桥输出电流的数学表达式以及DAB功率传输模型。其次提出了DAB输出电流利用率的概念,推导了输出电容纹波电流与输出电流利用率、电压传输比以及各电路参数的数学关系,从数学理论上揭示了输入、输出电压不匹配时,输出电容纹波电流过大的原因,为DAB电路的电容以及宽电压输出的设计提供了理论支撑;然后基于实际设计的电容纹波电流的允许范围,推导了DAB输出电压范围的数学公式;最后通过仿真和试验验证了理论分析的正确性。
