IET Power Electronics
Volume 9, Issue 9, 27 July 2016
Volumes & issues:
Volume 9, Issue 9
27 July 2016
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- Author(s): Lei Zhao ; Haoyu Li ; Yue Hou ; Yanxue Yu
- Source: IET Power Electronics, Volume 9, Issue 9, p. 1777 –1783
- DOI: 10.1049/iet-pel.2015.0174
- Type: Article
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During the dead-time interval for a phase-shifted full-bridge (PSFB) converter, switches can achieve zero-voltage switching (ZVS) operation by using the energy stored in the transformer leakage inductance to discharge or charge the output capacitance of the switches. The value of dead-time has a great effect on ZVS range so it is a key parameter that needs to be optimised during designing the converter. This study develops theoretical analysis to estimate the dead-time as a function of load current for PSFB converter. The equivalent circuits of PSFB converter during the dead-time interval with considering magnetising inductance are mainly analysed in this study. Compared with previous analyses, the influences of dead-time on ZVS range and efficiency are discussed in detail. The analysis results show that the magnetising inductance of transformer can ensure ZVS over a wide range of load conditions, especially under discontinued current mode operation, without a penalty on the heavy-load efficiency. By adjusting the dead-time dynamically, both conduction and switching losses can be reduced. A 1 kW prototype is implemented and experimental results are consistent with the theoretical analysis.
- Author(s): Guo Xu ; Deshang Sha ; Xiaozhong Liao
- Source: IET Power Electronics, Volume 9, Issue 9, p. 1784 –1791
- DOI: 10.1049/iet-pel.2015.0383
- Type: Article
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1784
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A control strategy for input-series-output-parallel (ISOP) connected modular high frequency isolated AC–AC converter is proposed in this study. The circulating currents among all the constituent modules are avoided by the proposed pulse width modulation sequence generation method. Based on the revealed relationship between input voltage sharing (IVS) and output current sharing (OCS), a stable control strategy is proposed by using an output voltage loop and positive inner-current compensation loops. The individual input voltage sharing loops are eliminated. With the proposed control strategy, OCS or IVS can be achieved well for ISOP modular AC–AC converters under both steady and dynamic state, even in the case when the parameters of individual modules are mismatched. Simulation and experimental results are presented to verify the effectiveness of the control strategy.
- Author(s): Hsuang-Chang Chiang ; Faa-Jeng Lin ; Jin-Kuan Chang ; Kun-Feng Chen ; Yi-Lun Chen ; Ke-Chih Liu
- Source: IET Power Electronics, Volume 9, Issue 9, p. 1792 –1800
- DOI: 10.1049/iet-pel.2015.0914
- Type: Article
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1792
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Continuous conduction mode power factor correction AC–DC converters are widely employed as the front stage in power supplies with medium or high output power. The second-order reactive input power in single-phase systems causes second-order ripple in the DC-link voltage. The speed of voltage regulation is thus limited by the second-order frequency in seeking to achieve low distorted input current. This study presents a fast second-order voltage estimation method, wherein an integrator is used for the estimation of second-order voltage ripple to obtain rapid voltage feedback without ripple and thereby cope with the limitations imposed by the second-order frequency. This approach greatly expands the bandwidth of the voltage control loop beyond the second-order frequency while reducing the total harmonic distortion associated with the input current. This also makes it possible to reduce the DC capacitance to reduce costs. The authors opted for full digital control using a TI F28335 DSP IC, in conjunction with feedback plus feedforward control to facilitate the design of the current loop. A feedback current corrector is used to reduce distortion associated with the input current over a wide load range. The effectiveness of the proposed control method was confirmed with some simulation and experimental results.
- Author(s): Qin-Qin Li ; Xin-Quan Lai ; Qiang Ye ; Bing Yuan
- Source: IET Power Electronics, Volume 9, Issue 9, p. 1801 –1807
- DOI: 10.1049/iet-pel.2015.0960
- Type: Article
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1801
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This study presents a fixed-frequency adaptive on-time buck converter with adaptive ramp compensation internally, which uses valley current-mode control. The on-time is obtained by feed forwarding input voltage and output voltage, which is easy to implement. The control method provides fast transient response, wide duty ratio and high efficiency for both heavy and light load. In a traditional adaptive on-time buck converter, the output voltage ripple determines the moment when the main power metal oxide semiconductor field effect transistor is being turned on. Different from that way, this study proposes a new way by which the valley current flowing through the inductor determines the moment. This avoids the problem induced by insufficient output ripple when a low equivalent series resistance capacitor like ceramic output capacitor is used. An adequate and simple ramp compensation circuit is proposed to optimise its jitter performance for wide duty ratio applications.
- Author(s): Guo-Rong Zhu ; Cheng-Yuan Xiao ; Hao-Ran Wang ; Siew-Chong Tan
- Source: IET Power Electronics, Volume 9, Issue 9, p. 1808 –1818
- DOI: 10.1049/iet-pel.2015.0603
- Type: Article
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1808
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The input current of single-phase inverter typically has an AC ripple component at twice the output frequency, which causes a reduction in both the operating lifetime of its DC source and the efficiency of the system. In this paper, the closed-loop performance of a proposed waveform control method to eliminate such a ripple current in boost inverter is investigated. The small-signal stability and the dynamic characteristic of the inverter system for input voltage or wide range load variations under the closed-loop waveform control method are studied. It is validated that with the closed-loop waveform control, not only was stability achieved, the reference voltage of the boost inverter capacitors can be instantaneously adjusted to match the new load, thereby achieving improved ripple mitigation for a wide load range. Furthermore, with the control and feedback mechanism, there is minimal level of ripple component at the DC bus during steady state, and the transient response is rapid with negligible effect on the output voltage. Analysis, simulation and experimental results are presented to support the investigation.
- Author(s): Olive Ray and Santanu Mishra
- Source: IET Power Electronics, Volume 9, Issue 9, p. 1819 –1827
- DOI: 10.1049/iet-pel.2015.0731
- Type: Article
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1819
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Single-input–hybrid-output converters provide dc and ac outputs simultaneously from a single dc source in an integrated architecture. These topologies are well suited for applications comprising both dc and ac distribution buses. In this work, the three-phase boost-derived hybrid converter (3-φ BDHC) has been studied which provides a 3-φ ac output in addition to the step-up output obtained from a boost converter. The changes in design and the characteristic behaviour of the proposed BDHC topology have been studied in comparison to single-phase BDHC. The pulse-width-modulation (PWM) control associated with these topologies involves shoot-through states incorporated within the conventional sine-PWM strategies. The work proposes a PWM switching strategy with controllable shoot-through occurring at constant frequency to achieve lower inductor current ripple. The operating principle of the 3-φ BDHC under balanced-load conditions using the proposed constant-frequency shoot-through sine PWM has been validated using experimental results.
- Author(s): Ebrahim Babaei ; Elias Shokati Asl ; Mohsen Hasan Babayi ; Sara Laali
- Source: IET Power Electronics, Volume 9, Issue 9, p. 1828 –1841
- DOI: 10.1049/iet-pel.2015.0921
- Type: Article
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In this study, a new topology for switched Z-source inverter is proposed. This inverter in comparison with the conventional Z-source inverter needs higher number of active elements, lower number of capacitors and inductors. Reduction of weight, size and cost are the main advantages of the proposed topology. In addition, this inverter is able to solve the problem of short circuit across the inverter leg and consists of higher value of voltage gain when compared with the conventional switched boost inverter. Moreover, the developed topology of the proposed inverter based on switched-inductor cells is introduced. The performance of the proposed inverter in different operating modes is investigated. The proposed topologies are also compared with the conventional Z-source inverters from different points of view such as number of elements, the voltage gain and capability of tolerate the inverter short circuit. Finally, the accuracy performance of the proposed inverter is reconfirmed by using the simulation results in EMTDC/PSCAD software and also experimental results.
- Author(s): Guilherme H.F. Fuzato ; Cassius R. Aguiar ; Klebber de A. Ottoboni ; Renan F. Bastos ; Ricardo Q. Machado
- Source: IET Power Electronics, Volume 9, Issue 9, p. 1842 –1851
- DOI: 10.1049/iet-pel.2015.0598
- Type: Article
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The connection of low power renewable energy sources, such as fuel cells, to the distribution generation system requires power electronics structures with high voltage gain, high capability to power processing and consequently, high levels of current flowing through the dc/dc converter. In this context, this study analyses how the parasitic resistances of the passive components and the load power demand affect the dc/dc converter voltage gain. Taking into account the mathematical model, the boundaries of operation of the Interleaved Boost with Voltage Multiplier converter is determined through a set of equations and by means of a graphical analysis. The theoretical analysis, simulations and experimental results are used to validate the proposed approach presented in this study.
- Author(s): Hyuntae Choi ; Minsoo Jang ; Mihai Ciobotaru ; Vassilios G. Agelidis
- Source: IET Power Electronics, Volume 9, Issue 9, p. 1852 –1861
- DOI: 10.1049/iet-pel.2015.0644
- Type: Article
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This study presents the experimental verification of an interleaved high-gain (IHG) DC–DC converter using series and parallel configurations. The interleaved configurations allow the converter to achieve high voltage gain and high current rating, thus increasing the power rating of the converter. Analytical expressions for the design of these interleaved converter configurations are included in the study. The efficiency of the IHG DC–DC converter is increased due to the zero-voltage switching of all active switches and the zero-current switching of all diodes. Experimental results taken from three 1 kW prototypes with different configuration (non-interleaved, and series and parallel interleaved) are presented to verify the interleaving performance and efficiency. Moreover, the effect of soft-switching in terms of efficiency is demonstrated.
- Author(s): Kangle Ren ; Xing Zhang ; Fusheng Wang ; Renxian Cao
- Source: IET Power Electronics, Volume 9, Issue 9, p. 1862 –1872
- DOI: 10.1049/iet-pel.2015.0727
- Type: Article
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1862
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Owing to their capability to reduce switching losses, discontinuous pulse-width modulations (DPWMs) have been widely discussed in the last decades. However, when using the classical DPWMs in three-level (3L) converters, neutral-point (NP) voltage balancing may not be efficiently achieved, because the reference signals are clamped and saturated at regular intervals, and consequently it is difficult to inject the desired zero-sequence component (ZSC). In this study, as the foundation, the general implementation method of 3L carrier-based DPWM (CBDPWM) by injecting discontinuous ZSC (DZSC) is introduced. Following this, a corresponding NP voltage control method is presented and discussed. Finally, on the basis of output prediction and roll optimising method, a novel 3L generalised CBDPWM strategy is proposed which selects and injects the optimal DZSC. With this adjustment, the NP potential can be quickly and flexibly controlled within the given range, while the switching losses can be minimised. The proposed strategy is general and simple. It is applicable to any operating condition without complex calculation and extra efforts. The performance of the proposed strategy is comprehensively evaluated and compared with the traditional DPWMs, and the feasibility and effectiveness of the proposed strategy are validated by the experimental results.
- Author(s): Hadi Moradisizkoohi ; Jafar Milimonfared ; Meghdad Taheri ; Sina Salehi
- Source: IET Power Electronics, Volume 9, Issue 9, p. 1873 –1884
- DOI: 10.1049/iet-pel.2015.0543
- Type: Article
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This study describes a duty-cycle-controlled resonant dual-half-bridge converter with multifunctional capacitors for enhancing the voltage level of fuel cell and photovoltaic sources to 380 V. Owing to the incorporation of dc-link capacitors and leakage inductance into two various resonant circuits, both switches turn-on under the zero-voltage-switching circumstance and turn-off with low current because of quasi-resonant operation. Since the currents of diodes are controlled by the leakage inductances of transformers, it is not obligatory for a designer to employ the diodes with reverse-recovery current specification; consequently, less expensive diodes can be adopted. The complementary effects of series-connected secondary windings of transformers and switched-capacitor circuits result in forming the balanced voltage multiplier stage, augmenting the voltage conversion ratio substantially without the need for utilising a transformer having higher turns ratio; so, one of the magnificent factors of growth of the conduction losses has been avoided. Ultimately, the results of the laboratory prototype operating with 58 kHz switching frequency, 18 V input voltage, 380 V output voltage, and 500 W output power prove that the proposed topology would be proficient to fulfil its function in systems using distributed generation resources.
- Author(s): Xiaoyan Huang ; Yuqing Gao ; Jing Zhou ; Jien Ma ; Jian Zhang ; Youtong Fang
- Source: IET Power Electronics, Volume 9, Issue 9, p. 1885 –1893
- DOI: 10.1049/iet-pel.2015.0915
- Type: Article
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1885
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This study proposes a model of multiple receivers in resonant wireless power transmission. Based on the dual-load series-resonant wireless power transfer system, the expression of system efficiency and its calculation model is achieved using the coupled mode theory. Considering the mutual coupling between loads, the system transmission efficiency is analysed against the intrinsic decay rate and coupling coefficient by Matlab simulation. The diversity effects of introducing aluminium material are analysed by electromagnetic field analysis through JMAG. Base on the principles of the eddy current loss, the laminated aluminium structure is adopted to restore the transmission characteristics effectively. Finally, 96 kHz magnetic resonant wireless power transfer test platform is established to verify the correctness of theoretical analysis.
- Author(s): Rasoul Shalchi Alishah ; Seyed Hossein Hosseini ; Ebrahim Babaei ; Mehran Sabahi ; Asghar Zare
- Source: IET Power Electronics, Volume 9, Issue 9, p. 1894 –1902
- DOI: 10.1049/iet-pel.2015.0893
- Type: Article
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1894
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This study presents a new high step-up multilevel converter topology. The proposed multilevel converter comprises of two dc voltage sources, several capacitors, unidirectional switches, and power diodes. The proposed topology can increase the values of input dc voltage sources substantially. The voltage gain of the proposed topology depends on the number of used capacitors. The proposed topology is simple and can be extended to produce higher-output voltage levels. The values of two used dc voltage sources can be selected as symmetric and asymmetric. In symmetric type, the values of two dc sources are similar. However, the dc sources magnitudes in asymmetric type are unequal and their values are obtained based on mathematical method. Inherent voltage balancing of used capacitors is an important feature of the proposed topology. The proposed topology is compared with other recently proposed high step-up multilevel converters and conventional topologies in terms of the number of used switches, capacitors, dc sources, and voltage on switches. It is indicated that the proposed structure requires the least number of devices and the voltage rating on power switches is low. The performance of the proposed topology and theoretical analysis are confirmed using experimental works.
- Author(s): Suvendu Samanta and Akshay Kumar Rathore
- Source: IET Power Electronics, Volume 9, Issue 9, p. 1903 –1913
- DOI: 10.1049/iet-pel.2015.0775
- Type: Article
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1903
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This paper studies, explores and analyses a wireless power transfer (WPT) system using current-fed power electronics topology for electric vehicles and battery charging applications. The main contribution is analysis, design, and implementation of a current-fed technology for WPT application. The required resonance in both the transmitter and receiver coils is parallel (L)(C) and series (LC) type, respectively. A detailed mathematical analysis and design have been reported. Stiff DC current at the input of the inverter limits the inverter switch current stress. Also, the inductor in DClink provides natural short-circuit protection during inverter fault. It is quite important in such application. Resonant converter facilitates soft-switching at turn-off of the transmitter side switches. Also, soft-commutation of rectifier diodes reduces reverse recovery loss. Mathematical analysis is verified by simulation results using PSIM 9.3. A 420 W proof-of-concept lab hardware prototype is developed and the experimental results are demonstrated to validate the mathematical analysis and simulation results. The maximum efficiency of DC–DC WPT stage obtained from the proof-of-concept lab-prototype is close to 90% with a coefficient of coupling 18%. It is suitable for solar-to-vehicle and single-phase residential slow charging.
- Author(s): Hui Fang ; Zhenbin Zhang ; Xiaoyun Feng ; Ralph Kennel
- Source: IET Power Electronics, Volume 9, Issue 9, p. 1914 –1923
- DOI: 10.1049/iet-pel.2015.0857
- Type: Article
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1914
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Model predictive control (MPC) is an attractive technique for power electronics and drives. It requires no extra modulators and considers the non-linear nature of the power converter, so remarkable control performance can be achieved. However, since the conventional MPC scheme uses only one switching state during the whole control interval, ripples of the control variables are more evident than that of the classical modulator based techniques. This study proposed a ripple-reduced model predictive direct power control (RR-MPDPC) scheme for the grid-tied active front end using a fully field programmable gate array-based platform. The novelty of the proposed RR-MPDPC is that through extended switching vectors and time-optimised control, more freedoms and precise tracking possibility are realised in the predictive controller. The proposed control scheme is compared with the conventional MPDPC and the recently reported duty optimal MPDPC scheme (DutyOpt-MPDPC) through experimental data. Experimental results confirm that better performance is achieved using the proposed RR-MPDPC scheme.
- Author(s): Chih-Chiang Hua ; Yi-Hsiung Fang ; Yen-Liang Chen
- Source: IET Power Electronics, Volume 9, Issue 9, p. 1924 –1932
- DOI: 10.1049/iet-pel.2015.0847
- Type: Article
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1924
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Two modified rectifications for improving the charge equalisation performance of series-connected battery stack are proposed in this study. Not only high reliability can be achieved because only one power switch is required, but also the control circuit is simple due to no voltage sensors. In addition, high efficiency can be achieved because of zero-voltage-switching. In this study, two modified rectifications are presented to eliminate the voltage differences between the odd and even batteries, which are not removed by the conventional methods, and reduce the number of transformer windings and diodes. Hence, the cost, size and complexity of the system can be reduced. The circuit topology and operation analysis of the proposed equaliser are described in detail. Finally, the simulations and experimental results are provided to demonstrate the performance of the proposed charge equaliser.
- Author(s): Rachid Errouissi ; Ahmed Al-Durra ; S.M. Muyeen
- Source: IET Power Electronics, Volume 9, Issue 9, p. 1933 –1942
- DOI: 10.1049/iet-pel.2015.0961
- Type: Article
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1933
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In this study, a state feedback control law is combined with a disturbance observer to enhance disturbance rejection capability of a grid-connected photovoltaic (PV) inverter. The control law is based on input–output feedback linearisation technique, while the existing disturbance observer is simplified and adopted for the system under investigation. The resulting control law has a proportional–integral (PI)/almost PI–derivative-like structure, which is convenient for real-time implementation. The objective of the proposed approach is to improve the DC-bus voltage regulation, while at the same time control the power exchange between the PV system and the grid. The stability of the closed-loop system under the composite controller is guaranteed by simple design parameters. Both simulation and experimental results show that the proposed method has significant abilities to initiate fast current control and accurate adjustment of the DC-bus voltage under model uncertainty and external disturbance.
- Author(s): Mukul Garg ; Rajeev Kumar Singh ; Ranjit Mahanty
- Source: IET Power Electronics, Volume 9, Issue 9, p. 1943 –1951
- DOI: 10.1049/iet-pel.2015.0641
- Type: Article
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1943
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A magnetically coupled boost (MCB) converter with the enhanced equivalent series resistance (ESR) of the filter capacitor for DC microgrid applications has been presented in this study. The proposed MCB converter with enhanced ESR filter capacitor uses only four state variables and exhibits a fourth-order minimum phase behaviour because of the complete elimination of right half plane zero. The characteristic of displaying fourth-order minimum phase behaviour of the proposed MCB converter with the enhanced ESR filter capacitor makes the design and analysis simple. Closed-loop operation of the proposed MCB converter with the enhanced ESR filter capacitor with photovoltaic input using maximum power point tracking has been carried out to verify its applicability in DC microgrid. Steady state and dynamic modelling of the MCB converter has been carried out to demonstrate its advantages. The proposed algorithm is validated on a 145 W prototype through simulation and experimentation.
- Author(s): Siyang Li ; Ka Wai E. Cheng ; Yuanmao Ye ; Zhanghai Shi
- Source: IET Power Electronics, Volume 9, Issue 9, p. 1952 –1961
- DOI: 10.1049/iet-pel.2015.0591
- Type: Article
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1952
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In this study, a new circuit topology of tapped-inductor DC–DC converter has been introduced, considering the impacts of parasitic elements. The converter is able to provide wide input and wide output voltage range with high efficiency, including buck, boost and buck–boost modes. First, the principle and algorithm of the new converter has been investigated in detail. Then, the power conversion efficiency has been examined under different duty ratios. The voltage gain and efficiency have simultaneously been analysed with various loads. Finally, the experimental results show that the efficiencies of the new topology are high in most ranges, thus verified the correctness of theory and the effectiveness of the proposed topology.
- Author(s): Mauro André Pagliosa ; Rafael Gomes Faust ; Telles Brunelli Lazzarin ; Ivo Barbi
- Source: IET Power Electronics, Volume 9, Issue 9, p. 1962 –1970
- DOI: 10.1049/iet-pel.2015.0935
- Type: Article
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1962
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This study proposes a modular isolated dc–dc converter, based on the input-series and output-series connection of flyback converters operating in discontinuous conduction mode, as an alternative to provide higher voltage capability for medium-voltage applications (1–10 kV), from low-voltage semiconductors and passive components. The proposed architecture allows the modular system to operate with a simplified control scheme thanks to an intrinsic voltage-balancing mechanism. The voltage-balancing mechanism is investigated by theoretical analysis, both for steady-state and dynamic operations. A small-signal ac modelling of the architecture is developed to design the total output-voltage controller. To experimentally verify the proposed technique, a laboratory prototype system with three single-switch flyback converters, with 3 kW output power, 600 V dc input and output voltages, and 40 kHz of switching frequency was built.
- Author(s): Majid Sanatkar-Chayjani and Mohammad Monfared
- Source: IET Power Electronics, Volume 9, Issue 9, p. 1971 –1978
- DOI: 10.1049/iet-pel.2015.0922
- Type: Article
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1971
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Compared with the traditional L filters, the high order LCL and LLCL filters for grid integration of voltage source converters offer better switching harmonic attenuation even with smaller passive elements. However, the inherent resonance of the high order filters complicates the control of the converter and also the design of filter parameters, especially at presence of digital delays and grid impedance variations. This study proposes a simple design procedure for the LCL and the LLCL filters of a delay-based stabilised converter that satisfies the predefined constraints on the converter current ripple, grid current harmonics and the reactive power of the capacitor and at the same time, ensures adequate stability of the simple single loop current control against the resonance. Moreover, the effect of grid impedance on the filter performance and controller stability is taken into account, thus the proposed method is robust against a wide range of grid impedance variations. Experimental results for a 3 kW test rig under steady state and transient conditions confirm the effectiveness of the proposed filter design algorithm.
- Author(s): Xin Yang ; Zhiqiang Long ; Yanhui Wen ; Haokai Huang ; Patrick R. Palmer
- Source: IET Power Electronics, Volume 9, Issue 9, p. 1979 –1984
- DOI: 10.1049/iet-pel.2015.1035
- Type: Article
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1979
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Over three decades of development effort has brought insulated gate bipolar transistor (IGBT) technology to a high-level of maturity. IGBT converters have been widely used in industry. However, the high-speed switching transient of the IGBT-freewheel diode chopper cell causes high-level electromagnetic interference (EMI). Electromagnetic compatibility requirements are normally taken into account by utilising costly EMI filters or shielding on the load and supply side. The risk of this traditional method is to incur a delay in commercialising the converters since identification of the failure causes, modifications, and successfully re-testing are required. A promising alternative is to constrain the EMI at source by introducing active voltage control technique and shaping the IGBT switching transient into a sophisticated ‘S’-shape. Previously, IGBT switching waveforms have been successfully shaped into an advanced Gaussian ‘S’-shape with the EMI greatly reduced. In this study, the authors further investigated the trade-off between EMI generation and switching losses in such an S-shaping method. The investigation was carried out in an accurate physical IGBT/diode model that is able to accurately simulate the device switching transient. From the results, it can be seen that by using the Gaussian S-shaping method the trade-off between EMI and switching losses could be much improved.
- Author(s): Luis Fernando Correa Monteiro ; Mauricio Aredes ; Jose Gabriel Pinto ; Bruno Fernandes Exposto ; Joao Luiz Afonso
- Source: IET Power Electronics, Volume 9, Issue 9, p. 1985 –1994
- DOI: 10.1049/iet-pel.2015.0642
- Type: Article
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1985
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This study presents control algorithms for a new unified power quality conditioner (UPQC) without the series transformers that are frequently used to make the insertion of the series converter of the UPQC between the power supply and the load. The behaviour of the proposed UPQC is evaluated in presence of voltage imbalances, as well as under non-sinusoidal voltage-and current conditions. The presented algorithms derive from the concepts involving the active and non-active currents, together with a phase-locked-loop circuit. Based on these real-time algorithms, and considering the proposed hardware topology, the UPQC is able to compensate the harmonic components of the voltages and currents, correct the power factor, and keep the load voltages regulated, all of this in a dynamic way, responding instantaneously to changes in the loads or in the electrical power system. The control algorithms were distributed in a two-DSP digital control architecture, without any communication between them. Consequently, can be increased the sampling frequency of the acquired voltages and currents and improve the UPQC performance. Furthermore, some constraints of the proposed UPQC are evidenced, particularly when the main voltages are imbalanced. Simulation and experimental results are presented to verify the UPQC performance under transient and steady state conditions.
- Author(s): Junxiao Wang ; Shihua Li ; Jun Yang ; Bin Wu ; Qi Li
- Source: IET Power Electronics, Volume 9, Issue 9, p. 1995 –2002
- DOI: 10.1049/iet-pel.2015.0178
- Type: Article
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1995
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This study investigates a finite-time disturbance observer (FTDO) based non-singular terminal sliding-mode control (NTSMC) approach for pulse width modulation based DC–DC buck converters subject to matched/mismatched resistance load disturbances. Considering the mismatched resistance load disturbance which does not act in the same channel as the control input, a novel non-singular terminal sliding-mode manifold incorporating with a disturbance estimation technique is designed. A FTDO-based NTSMC method is introduced for DC–DC buck converter systems. A rigorous finite-time stability analysis is also presented. As compared with the nominal NTSMC and existed SMC+ extended stated observer (ESO) method, the proposed method obtains a better disturbance rejection ability no matter the disturbances satisfy the so-called matching condition or not. Simulation and experimental comparison results are implemented to verify the effectiveness of the proposed control method.
- Author(s): Yie-Tone Chen ; Zong-Xing Lu ; Ruey-Hsun Liang ; Chung-Wen Hung
- Source: IET Power Electronics, Volume 9, Issue 9, p. 2003 –2012
- DOI: 10.1049/iet-pel.2015.0784
- Type: Article
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2003
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A new high step-up dc–dc converter is proposed in this study. This new high step-up converter utilises the input voltage, clamped-capacitor, and the secondary side of the coupled-inductor to charge the switched-capacitor and the secondary side of the coupled inductor also charges two multiplier capacitors in parallel during the turn-on interval of the switch. The input voltage, coupled-inductor, and multiplier capacitors are in series connection to the output to accomplish the purpose of high voltage gain during the turn-off interval of the switch. By adjusting the turns ratio of the coupled inductors, the proposed circuit does not need to be operated at high duty cycle to achieve the high voltage gain. The voltage stress of the switch and diodes can be decreased to cut down the cost. Moreover, the energy of the leakage inductance can be recovered to reduce the voltage spike of the switch. Therefore, the switch with lower conduction resistance can be applied to reduce the conduction loss and increase the efficiency. Finally, simulation and experiments are conducted. A prototype circuit with input voltage of 24 V, output voltage of 400 V, and output power of 200 W is implemented to validate the property of the proposed converter.
Operation analysis of a phase-shifted full-bridge converter during the dead-time interval
Input-series-output-parallel connected modular high frequency isolated AC–AC converters with positive compensation of inner-current loop
Control method for improving the response of single-phase continuous conduction mode boost power factor correction converter
Fixed-frequency adaptive on-time buck converter with ramp compensation
Closed-loop waveform control of boost inverter
Constant-frequency shoot-through sine pulse-width-modulation scheme for three-phase single-input–hybrid-output converter
Developed embedded switched-Z-source inverter
Voltage gain analysis of the interleaved boost with voltage multiplier converter used as electronic interface for fuel cells systems
Performance evaluation of interleaved high-gain converter configurations
Carrier-based generalised discontinuous pulse-width modulation strategy with flexible neutral-point voltage control and optimal losses for a three-level converter
Duty-cycle-controlled resonant dual-half-bridge converter with multifunctional capacitors for distributed generation applications
Magnetic field design for optimal wireless power transfer to multiple receivers
Extended high step-up structure for multilevel converter
Wireless power transfer technology using full-bridge current-fed topology for medium power applications
Ripple-reduced model predictive direct power control for active front-end power converters with extended switching vectors and time-optimised control
Modified rectifications for improving the charge equalisation performance of series-connected battery stack
Offset-free feedback linearisation control of a three-phase grid-connected photovoltaic system
Magnetically coupled boost converter with enhanced equivalent series resistance filter capacitor for DC microgrid
Wide input and wide output topology analysis for tapped-inductor converters with consideration of parasitic elements
Input-series and output-series connected modular single-switch flyback converter operating in the discontinuous conduction mode
Design of LCL and LLCL filters for single-phase grid connected converters
Investigation of the trade-off between switching losses and EMI generation in Gaussian S-shaping for high-power IGBT switching transients by active voltage control
Control algorithms based on the active and non-active currents for a UPQC without series transformers
Finite-time disturbance observer based non-singular terminal sliding-mode control for pulse width modulation based DC–DC buck converters with mismatched load disturbances
Analysis and implementation of a novel high step-up DC–DC converter with low switch voltage stress and reduced diode voltage stress
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