Virtual Impedance based Second Order Ripple Control For Non-Inverting Buck-boost Converter
10 Oct 2020-pp 1-6
TL;DR: In this article, a dual loop control with inverted notch inductor current feedback based impedance control methodology is proposed to increase the impedance in series with the inductor, virtually This leads to significant reduction in ripple currents propagating through the buck-boost converter to the source.
Abstract: The second order ripples are reflected at the input terminals of the inverters during dc-ac conversion This leads to oscillations in current and voltages at twice the ac supply frequency The oscillations are more dominant in dc to single phase ac conversions The second order ripple current propagates to the source and leads to failure of heating issues A dual loop control with inverted notch inductor current feedback based impedance control methodology is proposed to increase the impedance in series with the inductor, virtually This leads to significant reduction in ripple currents propagating through the buck-boost converter to the source This however leads to the degradation of dynamics An integral sliding mode control is proposed to improve the dynamic performance and also mitigate uncertainties As a result the objective of achieving variable ac voltage without ripple propagation to the source, without adding any extra component is fulfilled The proposed control is verified through simulations and experiments on a buck-boost feeding a single phase ac load
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11 Dec 1996
TL;DR: The paper generalized a new sliding mode design concept, namely integral sliding mode (ISM), and removes the discontinuous control action from the real control path and inserts it to an internal dynamic process for generating the sliding mode to alleviate chattering.
Abstract: The paper generalized a new sliding mode design concept, namely integral sliding mode (ISM). The order of the motion equation in ISM is equal to the order of the original system, rather than reduced by the number of dimension of the control input. As the result, robustness of the system can be guaranteed throughout an entire response of the system starting from the initial time instance. Uniform formulations of the ISM design principle are developed in the paper. It is shown through examples that our generalized ISM scheme enables a wide scope of application areas. In the case that the given control matrix can not be used directly for generating the sliding mode, the associated decoupling problem was also discussed based on the concept of sliding mode transformation. To alleviate chattering, we remove the discontinuous control action from the real control path and insert it to an internal dynamic process for generating the sliding mode.
838 citations
TL;DR: In this article, an average-current-mode noninverting buck-boost dc-dc converter is proposed, which is able to use the full output voltage range of a Li-ion battery, but it also features high power efficiency and excellent noise immunity.
Abstract: With the rapid growth of battery-powered portable electronics, an efficient power management solution is necessary for extending battery life. Generally, basic switching regulators, such as buck and boost converters, may not be capable of using the entire battery output voltage range (e.g., 2.5-4.7 V for Li-ion batteries) to provide a fixed output voltage (e.g., 3.3 V). In this paper, an average-current-mode noninverting buck-boost dc-dc converter is proposed. It is not only able to use the full output voltage range of a Li-ion battery, but it also features high power efficiency and excellent noise immunity. The die area of this chip is 2.14 × 1.92 mm2, fabricated by using TSMC 0.35 μm 2P4M 3.3 V/5 V mixed-signal polycide process. The input voltage of the converter may range from 2.3 to 5 V with its output voltage set to 3.3 V, and its switching frequency is 500 kHz. Moreover, it can provide up to 400-mA load current, and the maximal measured efficiency is 92.01%.
113 citations
TL;DR: In this paper, a two-stage single-phase inverter with a boost-derived front-end converter was designed to reduce the second-harmonic current (SHC) by using virtual series impedance.
Abstract: The instantaneous output power of the two-stage single-phase inverter pulsates at twice the output frequency $(2f_{{\rm{o}}})$ , generating notorious second-harmonic current (SHC) in the front-end dc–dc converter and the input dc voltage source. This paper focuses on the SHC reduction for a two-stage single-phase inverter with boost-derived front-end converter. To reduce the SHC, a virtual series impedance, which has high impedance at $2f_{{\rm{o}}}$ while low impedance at other frequencies, is introduced in series with the boost diode or the boost inductor to increase the impedance of the boost-diode branch or boost-inductor branch at $2f_{{\rm{o}}}$ . Meanwhile, for achieving good dynamic performance, a virtual parallel impedance, which exhibits infinite impedance at $2f_{{\rm{o}}}$ while low impedance at other frequencies, is introduced in parallel with the dc-bus capacitor to reduce the output impedance of the boost-derived converter at the frequencies except for $2f_{{\rm{o}}}$ . The virtual series impedance is realized by the feedback of the boost-diode current or the boost-inductor current, while the virtual parallel impedance is implemented by the feedback of the dc-bus voltage. Based on the virtual-impedance approach, a variety of SHC reduction control schemes are derived. A step-by-step closed-loop parameters design approach with considerations of reducing the SHC and improving the dynamic performance is also proposed for the derived SHC reduction control schemes. Finally, a 1-kW prototype is built and tested, and experimental results are presented to verify the effectiveness of the proposed SHC reduction control schemes.
91 citations
TL;DR: In order to make the system feedback controlled during the whole cycle of charging, the regulation loop is clamped, and hence, automatic and smooth transition from the CC to CV mode is achieved without the need of any extra switching circuit or control loop.
Abstract: This paper presents a magnetically coupled feedback-clamped optimal bidirectional battery charger. The proposed charger acts as a current source, i.e., acts in constant-current (CC) mode with a controlled output current in case of deep discharge of a battery, and as a voltage source, i.e., acts in constant-voltage (CV) mode with a controlled output voltage for near-100% battery state of charge. The proposed circuit is universal from the battery voltage point of view, i.e., can charge a battery with any given voltage rating, and adaptive from the optimum charging current requirement viewpoint, i.e., can adapt to the optimum battery charging current. The presented solution uses a magnetically coupled bidirectional converter topology. In order to make the system feedback controlled during the whole cycle of charging, the regulation loop is clamped, and hence, automatic and smooth transition from the CC to CV mode is achieved without the need of any extra switching circuit or control loop. Experimental and simulation results for a 250-W prototype are presented to verify the proposed system. The prototype shows maximum efficiencies of 90.24% under boost mode and 92.7% under buck mode of operation. The performance of the charger is verified using two different 12-V-7-Ah and 12-V-32-Ah lead-acid batteries.
64 citations
21 Mar 2009
TL;DR: In this article, the effect of the discontinuity due to the effective duty cycle derived from device switching time at the mode change is analyzed, and a technique to compensate the output voltage transient due to this discontinuity is proposed.
Abstract: With the advent of battery-powered portable devices and the mandatory adoptions of power factor correction (PFC), non-inverting buck-boost converter is attracting numerous attentions. Conventional two-switch or four-switch non-inverting buck-boost converters choose their operation modes by measuring input and output voltage magnitudes. This can cause higher output voltage transients when input and output are close to each other. For the mode selection, the comparison of input and output voltage magnitudes is not enough due to the voltage drops raised by the parasitic components. In addition, the difference in the minimum and maximum effective duty cycle between controller output and switching device yields the discontinuity at the instant of mode change. Moreover, the different properties of output voltage versus a given duty cycle of buck and boost operating modes contribute to the output voltage transients. In this paper, the effect of the discontinuity due to the effective duty cycle derived from device switching time at the mode change is analyzed. A technique to compensate the output voltage transient due to this discontinuity is proposed. In order to attain additional mitigation of output transients and linear input/output voltage characteristic in buck and boost modes, the linearization of DC-gain of large signal model in boost operation is analyzed as well. Analytical, simulation, and experimental results are presented to validate the proposed theory.
48 citations