Ripple Mitigation With Improved Line-Load Transients Response in a Two-Stage DC–DC–AC Converter: Adaptive SMC Approach
TL;DR: A new adaptive sliding mode control for a two-stage dc–dc–ac converter to reduce proliferation of ripple without compromising dynamic performance and a fast voltage recovery with small undershoot/overshoot can be achieved at transients using the proposed controller.
Abstract: A substantial pulsation of the second-order harmonic current ripple with angular frequency $2\omega$ is reflected at the input of a single-phase inverter when loads are supplied at its output with angular frequency $\omega$ . Moreover, this ripple back-propagates and injects into the source in the absence of a bulky dc-link passive filter, an active compensator or a suitable digital controller with a front-end converter in the two-stage converter. This paper proposes a new adaptive sliding mode control for a two-stage dc–dc–ac converter to reduce proliferation of ripple without compromising dynamic performance. The front-end boost converter in the considered two-stage converter interfaces a battery bank and single-phase inverter fed loads. The control shapes the output impedance of the boost converter to reduce the ripple component at battery input. Second, the proposed controller achieves good dynamic performance at line and load transients. A fast voltage recovery with small undershoot/overshoot can be achieved at transients using the proposed controller. The proposed technique is validated using a hardware of the 1-kW two-stage converter.
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TL;DR: This paper provides a comprehensive review of the control approaches and the power-decoupling topologies to mitigate the ripple problem in the single-phase inverters, its solutions, and discusses open challenges yet to be addressed.
Abstract: This paper provides a comprehensive review of the control approaches and the power-decoupling topologies to mitigate 2ω-ripple problem in the single-phase inverters, its solutions, and discusses open challenges yet to be addressed. The cause and effects of 2ω-ripple problem and its solution based on the passive and active power-decoupling techniques are discussed. A subcategory of the active power-decoupling technique nominated as the control-oriented compensation technique is reviewed in detail, this technique can achieve the ripple-mitigation at the source through the control but not necessarily adds extra circuit or active filter to the system. The control-oriented compensation techniques can be applied in the two-stage DC-DC-AC converters and the single-stage inverters having a front-end control capability with the H-bridge such as in the quasi-switched-boost inverters. The merits and associated challenges of these techniques are listed and summarized in a tabular form. Finally, a conclusive discussion with open challenges is presented.
39 citations
Cites background or methods from "Ripple Mitigation With Improved Lin..."
...(a) Non-linear compensator technique proposed in [59] (b) Adaptive-SMC based ripple-mitigation technique proposed in [130]....
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...In [130], [131], authors have proposed an adaptive switching function to minimize the 2ω−ripple at the input of the boost-derived two-stage converter using the fixed-frequency based-SMC....
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03 Jun 2020
TL;DR: This article presents a thorough review of different EV power electronic converters on which the authors have worked for more than one decade and will find this review interesting to design current products and to devise/invent new converters for emerging applications in EV.
Abstract: Power electronic converters for electric vehicles (EVs) have been the subject of great interest over the last several decades. This article presents a thorough review of different EV power electronic converters on which the authors have worked for more than one decade. The readers will find this review interesting to design current products and to devise/invent new converters for emerging applications in EV.
37 citations
TL;DR: In this paper, a front-end dc-dc converter with dc transformer (DCX)- LLC resonant converter is proposed to suppress the second harmonic current (SHC) in the front end.
Abstract: In a two-stage inverter, the instantaneous output power pulsates at twice the output frequency (2 f o), generating the second harmonic current (SHC), which will propagate into the front-end dc–dc converter. This article aims for suppressing the SHC in the front-end dc–dc converter with dc transformer (DCX)- LLC resonant converter. The small-signal model of the DCX- LLC resonant converter is proposed, and based on which, the unified small-signal model of the preregulator+ LLC converter is built. Then, the basic ideas for reducing the SHC are proposed, including the determination of the filter capacitors in the preregulator+ LLC converter and the control approach. After that, from a perspective of output impedance, the control schemes for reducing the SHC in the front-end preregulator+ LLC converter are proposed. By inserting a notch filter in the voltage loop and/or introducing a virtual impedance in series with the output rectifier of the LLC resonant converter, the output impedance of the preregulator+ LLC converter at 2 f o is increased and, thus, the SHC can be reduced. Finally, a 6-kVA two-stage three-phase inverter with boost+ LLC converter as the front-end dc–dc converter was fabricated and tested. The experimental results are provided to verify the proposed control schemes.
32 citations
Cites background from "Ripple Mitigation With Improved Lin..."
...In the two-stage single-phase inverter, the instantaneous output power pulsates at twice the output frequency (2fo), generating a second harmonic current (SHC) at the input of the downstream dc–ac inverter, which will propagate back to the front-end dc–dc converter [4]....
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TL;DR: An adaptive sliding mode control based output impedance shaping (ASMC-OIS) methodology is proposed for voltage regulation, proportional load sharing, and second-order ripple management in a dc microgrid.
Abstract: Inverter connected single-phase AC loads cause second-order oscillations in source currents and DC bus voltage. These oscillations degrade the efficiency and reliability of the dc microgrid. In this paper, an adaptive sliding mode control based output impedance shaping (ASMC-OIS) methodology is proposed for voltage regulation, proportional load sharing, and second-order ripple management in a dc microgrid. By using the proposed control method, the magnitude of the output impedance of the source interfacing converter is increased at 2 $f_{ac}$ programmably, which results in the reduction of second-order ripple currents propagating through the converter. Instead, it is propagated to the dc-link capacitor or towards the nodes which consists of some ripple absorption active or passive filter. This leads to an increase in the energy density of the ripple filters. The dynamic consensus-based secondary control is incorporated to ensure proportional load current sharing. A graph theoretical analysis is presented to analyze per unit load sharing among all the nodes. Stability of the proposed controller is analyzed considering multiple source nodes using Lyapunov's approach. A dc microgrid consisting of parallel-connected dc-dc boost converters, dc load, and inverter load is simulated to verify the proposed control strategy. The proposed ASMC-OIS methodology is validated through experimentation.
23 citations
Cites background from "Ripple Mitigation With Improved Lin..."
...The switching function is adaptive in nature as in [19]....
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...This makes the second term negative denite [19]....
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TL;DR: In this paper, the authors focused on the economic power generation model mainly based on solar resources to minimize the electricity cost and provide income for the excess energy produced, and the study resulted in a low-cost (four times cheaper), reliable, and affordable grid-connected PV and battery microgrid model for a residential home with a minimum daily load of 5.467
Abstract: Photovoltaic microgrids provide free renewable energy solutions for Rwandans. Although solar technology keeps on its advancement, hydropower remains the principal power source in Rwanda. Other renewable power sources include wind and geothermal energies that are not yet fully exploited. Nonrenewable sources in Rwanda including methane, peat, thermal, and fuels are also used for providing energy solutions for the citizens. Rwanda Energy Group (REG) sets the energy strategic plan since 2015 for achieving the minimum of 512 MW of energy production in 2024/2025 to meet the total energy demand. The plan predicted 52% for grid-connected and 48% for off-grid (standalone) connections. The literature survey and data analysis collected on site were used to evaluate and determine the best cheaper microgrid model from the three comparison case studies for the household in Rwanda. The study focused on the economic power generation model mainly based on solar resources to minimize the electricity cost and provide income for the excess energy produced. Moreover, the study resulted in a low-cost (four times cheaper), reliable, and affordable grid-connected PV and battery microgrid model for a residential home with a minimum daily load of 5.467 kWh. The simulation results based on economic comparison analysis found the levelized cost of energy (LCOE) and net present cost (NPC) for each power-generated model by using Hybrid Optimization Model for Electric Renewable (Homer) pro software. The results show that the LCOE for electricity production by each of the Grid connected-PV-Battery system, Diesel GenSet-PV-Batteries, and PV-Batteries systems was 0.0645 US$/1 kWh, 1.38 US$/1 kWh and 1.82 US$/1 kWh, respectively, compared with 0.2621 US$/1 kWh, the current residential electricity price (2020) for Rwanda.
18 citations
Cites methods from "Ripple Mitigation With Improved Lin..."
...Studies [8, 9] used HOMER to simulate, analyze, and optimize renewable power sources which can substitute conventional energy sources, and the authors confirmed a feasibility solution of a reliable standalone electric power system for people living far from the national grid....
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References
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Book•
27 Aug 1998
TL;DR: This text provides the reader with a grounding in sliding mode control and is appropriate for the graduate with a basic knowledge of classical control theory and some knowledge of state-space methods.
Abstract: In the formation of any control problem there will be discrepancies between the actual plant and the mathematical model for controller design. Sliding mode control theory seeks to produce controllers to over some such mismatches. This text provides the reader with a grounding in sliding mode control and is appropriate for the graduate with a basic knowledge of classical control theory and some knowledge of state-space methods. From this basis, more advanced theoretical results are developed. Two industrial case studies, which present the results of sliding mode controller implementations, are used to illustrate the successful practical application theory.
3,355 citations
"Ripple Mitigation With Improved Lin..." refers background in this paper
...The existence of sliding mode for the switching function given by (4a) can be guaranteed if the η− reachability condition [21]...
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TL;DR: A tutorial account of variable structure control with sliding mode is presented, introducing in a concise manner the fundamental theory, main results, and practical applications of this powerful control system design approach.
Abstract: A tutorial account of variable structure control with sliding mode is presented. The purpose is to introduce in a concise manner the fundamental theory, main results, and practical applications of this powerful control system design approach. This approach is particularly attractive for the control of nonlinear systems. Prominent characteristics such as invariance, robustness, order reduction, and control chattering are discussed in detail. Methods for coping with chattering are presented. Both linear and nonlinear systems are considered. Future research areas are suggested and an extensive list of references is included. >
2,884 citations
"Ripple Mitigation With Improved Lin..." refers methods in this paper
...We have chosen the reaching dynamics given as follows [19]:...
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...A sliding mode controller is one of the established techniques [19]....
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TL;DR: In this paper, an improved and easy-to-use battery dynamic model is presented, and the charge and the discharge dynamics of the battery model are validated experimentally with four batteries types.
Abstract: This paper presents an improved and easy-to-use battery dynamic model. The charge and the discharge dynamics of the battery model are validated experimentally with four batteries types. An interesting feature of this model is the simplicity to extract the dynamic model parameters from batteries datasheets. Only three points on the manufacturer’s discharge curve in steady state are required to obtain the parameters. Finally, the battery model is included in the SimPowerSystems simulation software and used in a detailed simulation of an electric vehicle based on a hybrid fuel cell-battery power source. The results show that the model can accurately represent the dynamic behaviour of the battery.
1,020 citations
TL;DR: In this article, a ripple power port is proposed to manage energy storage and decouple capacitor ripple from power ripple, allowing the designer to make a choice of capacitor voltage independent of other system voltages.
Abstract: Converters with a dc port and a single-phase ac port must store energy to buffer the inherent double-frequency power flow at the ac port. The minimum energy storage required to isolate the power ripple from the dc port is presented, and leads to the minimum capacitance required for converters that use capacitive energy storage. This paper presents a ripple power port to manage energy storage and decouple capacitor ripple from power ripple. A ripple power port allows the designer to make a choice of capacitor voltage independent of other system voltages. A combination of an ac link converter and a ripple power port leads to a dramatic increase in reliability: it is shown that converters with nominal ratings up to 200 W can be designed with expected mean-time-between-failure ratings on the order of 1.4 × 106 h-sufficient for hundred-year operation in long-life applications such as photovoltaic converters and LED lamps. This large increase in life is achieved with minimal extra cost.
464 citations
"Ripple Mitigation With Improved Lin..." refers background in this paper
...Incorporation of active compensation circuits like a dc-link ripple port [9], [10] or a bidirectional converter [11] reduce SHC ripple at the source....
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TL;DR: In this paper, an advanced active control technique is proposed to incorporate a current control loop in the dc-dc converter for ripple reduction, and the proposed active ripple reduction method has been verified with computer simulation and hardware experiment with a proton exchange membrane type fuel cell using a multiphase dc-DC converter along with a full-bridge dc-ac inverter.
Abstract: A fuel cell power system that contains a single-phase dc-ac inverter tends to draw an ac ripple current at twice the output frequency. Such a ripple current may shorten fuel cell life span and worsen the fuel efficiency due to the hystersis effect. The most obvious impact is it tends to reduce the fuel cell output capacity because the fuel cell controller trips under instantaneous over-current condition. In this paper, the ripple current propagation path is analyzed, and its linearized ac model is derived. The equivalent circuit model and ripple current reduction with passive energy storage component are simulated and verified with experiments. An advanced active control technique is then proposed to incorporate a current control loop in the dc-dc converter for ripple reduction. The proposed active ripple reduction method has been verified with computer simulation and hardware experiment with a proton exchange membrane type fuel cell using a multiphase dc-dc converter along with a full-bridge dc-ac inverter. Test results with open loop, single voltage loop, and the proposed active current-loop control are provided for comparison.
302 citations