Second-order Harmonic Ripple Mitigation: A Solution for the Micro-Inverter Applications
01 Sep 2018-pp 1-6
TL;DR: The proposed controller shapes the output-impedance of the boost circuit of quasi-switched boost inverter such that the propagation of the ripple to DC source is resisted and the control technique is verified using Matlab-Simulink.
Abstract: Single-phase inverter suffers an unwanted second-order ripple at DC input of it. A substantial amount of this ripple may propagate through the system components and inject into the DC source. This causes several problems; related to system efficiency, life, cost, size, reliability and stability. This paper proposes an adaptive non-linear sliding mode controller for quasi-switched boost inverter used mainly in microinverter applications. The proposed controller shapes the output-impedance of the boost circuit of quasi-switched boost inverter such that the propagation of the ripple to DC source is resisted. The proposed control technique is verified using Matlab-Simulink.
Citations
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TL;DR: This paper proposes an adaptive sliding-mode controller to shape the output impedance of the boost-circuit of quasi-switched boost inverter such that the propagation of the ripple from dc link to the dc-input source is resisted.
Abstract: There have been several advanced topologies proposed by the community for micro-inverter applications. However, many such applications suffer from unwanted second-order harmonic current ripple at dc input. Moreover, in the absence of suitable passive filter or ripple compensator, the second-order harmonics ripple may propagate into the dc source. This results in several problems to the system, related to system efficiency, life, cost, size, reliability, and stability. This paper proposes an adaptive sliding-mode controller to shape the output impedance of the boost-circuit of quasi-switched boost inverter such that the propagation of the ripple from dc link to the dc-input source is resisted. The quasi-switched boost inverter is one of the advanced and suitable topologies for the micro-inverter applications. The adaptive nature of the proposed controller improves the transient performance of the system at the line–load transients unlike some existing solutions, which affects dynamics adversely to achieve ripple mitigation objective. The controller ensures voltage regulation within ${5\%}$ at dc link. The proposed control technique is verified using a lab-prototype of 500 W quasi-switched boost inverter.
12 citations
Additional excerpts
...The proposed switching function is a modified one from our earlier work [26], [27]....
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TL;DR: A PWM control method is applied to the CHB-qSBI topology to improve the modulation index and the voltage stress across power semiconductor devices and the capacitor are significantly lower using improved pulse-width modulation (PWM) control.
Abstract: This paper presents a three-phase cascaded five-level H-bridge quasi-switched boost inverter (CHB-qSBI). The merits of the CHB-qSBI are as follows: single-stage conversion, shoot-through immunity, buck-boost voltage, and reduced passive components. Furthermore, a PWM control method is applied to the CHB-qSBI topology to improve the modulation index. The voltage stress across power semiconductor devices and the capacitor are significantly lower using improved pulse-width modulation (PWM) control. Additionally, by controlling individual shoot-through duty cycle, the DC-link voltage of each module can achieve the same values. As a result, the imbalance problem of the DC-link voltage can be solved. A detailed analysis and operating principle with the modulation scheme and comprehensive comparison for the CHB-qSBI are illustrated. The experimental and simulation results are presented to validate the operating principle of the three-phase CHB-qSBI.
7 citations
References
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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
Additional excerpts
...The reaching dynamics chosen in this paper is given below [22], σ̇ =−Γσ −Qsgn(σ) Γ,Q ∈ R+−{0} (14) A finite-time reaching of the system states on the sliding surface (σ = 0) is ensured by (14)....
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TL;DR: The Z-source converter employs a unique impedance network to couple the converter main circuit to the power source, thus providing unique features that cannot be obtained in the traditional voltage-source (or voltage-fed) and current-source converters where a capacitor and inductor are used, respectively.
Abstract: This paper presents an impedance-source (or impedance-fed) power converter (abbreviated as Z-source converter) and its control method for implementing DC-to-AC, AC-to-DC, AC-to-AC, and DC-to-DC power conversion. The Z-source converter employs a unique impedance network (or circuit) to couple the converter main circuit to the power source, thus providing unique features that cannot be obtained in the traditional voltage-source (or voltage-fed) and current-source (or current-fed) converters where a capacitor and inductor are used, respectively. The Z-source converter overcomes the conceptual and theoretical barriers and limitations of the traditional voltage-source converter (abbreviated as V-source converter) and current-source converter (abbreviated as I-source converter) and provides a novel power conversion concept. The Z-source concept can be applied to all DC-to-AC, AC-to-DC, AC-to-AC, and DC-to-DC power conversion. To describe the operating principle and control, this paper focuses on an example: a Z-source inverter for DC-AC power conversion needed in fuel cell applications. Simulation and experimental results are presented to demonstrate the new features.
2,851 citations
"Second-order Harmonic Ripple Mitiga..." refers methods in this paper
...Quasi-Switched Boost Inverter (q-SBI) [1], [3]–[5] is one of the Impedance-Source (IS) converter, derived from the quasi-Z source inverter (qZSI) [6]–[9]....
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TL;DR: This review paper is the first of its kind with the aim of providing a “one-stop” information source and a selection guide on impedance-source networks for power conversion for researchers, designers, and application engineers.
Abstract: Impedance networks cover the entire of electric power conversion from dc (converter, rectifier), ac (inverter), to phase and frequency conversion (ac-ac) in a wide range of applications. Various converter topologies have been reported in the literature to overcome the limitations and problems of the traditional voltage source, current source as well as various classical buck-boost, unidirectional, and bidirectional converter topologies. Proper implementation of the impedance-source network with appropriate switching configurations and topologies reduces the number of power conversion stages in the system power chain, which may improve the reliability and performance of the power system. The first part of this paper provides a comprehensive review of the various impedance-source-networks-based power converters and discusses the main topologies from an application point of view. This review paper is the first of its kind with the aim of providing a “one-stop” information source and a selection guide on impedance-source networks for power conversion for researchers, designers, and application engineers. A comprehensive review of various modeling, control, and modulation techniques for the impedance-source converters/inverters will be presented in Part II.
601 citations
"Second-order Harmonic Ripple Mitiga..." refers methods in this paper
...Quasi-Switched Boost Inverter (q-SBI) [1], [3]–[5] is one of the Impedance-Source (IS) converter, derived from the quasi-Z source inverter (qZSI) [6]–[9]....
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TL;DR: Detailed modeling and control issues of the qZSI used for distributed generation (DG), such as PV or fuel cell power conditioning, are addressed and constant capacitor voltage control method is proposed in a two-stage control manner.
Abstract: The voltage-fed Z-source inverter/quasi-Z-source inverter (qZSI) has been presented suitable for photovoltaic (PV) applications mainly because of its single-stage buck and boost capability and improved reliability. This paper further addresses detailed modeling and control issues of the qZSI used for distributed generation (DG), such as PV or fuel cell power conditioning. The dynamical characteristics of the qZSI network are first investigated by small-signal analysis. Based on the dynamic model, stand-alone operation and grid-connected operation with closed-loop control methods are carried out, which are the two necessary operation modes of DG in distributed power grids. Due to the mutual limitation between the modulation index and shoot-through duty ratio of qZSI, constant capacitor voltage control method is proposed in a two-stage control manner. Minimum switching stress on devices can be achieved by choosing a proper capacitor voltage reference. Experimental results are presented for validation of the theoretical analysis and controller design.
362 citations
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