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This article proposes a single-stage inductive-power-transfer (IPT) converter operating as a wireless constant-power (CP) and maximum-efficiency battery charger. By maintaining a constant output power rather than providing a constant output current throughout the dominant stage of battery charging, the IPT converter can make the utmost of its power capability, thus having a faster charging rate. The proposed single-stage IPT converter adopts series–series compensation and includes a switch-controlled capacitor (SCC) and a semiactive rectifier (SAR) in the secondary side. Manipulating the SCC and the SAR to emulate the optimum impedance of the resonator and the load, we propose a novel operation approach combining the merits of load-independent transfer characteristic and load impedance matching, to achieve a simple solution to CP charging and maximum efficiency throughout the charging process. Since the control scheme is based on fixed operating frequency and secondary-side real-time regulation, wireless feedback communication is not required. Moreover, soft switching and low voltage stress can be easily achieved in this IPT converter. [ABSTRACT FROM AUTHOR]

The proliferation of massive non‐linear loads, large motor loadings, renewable energy generation systems etc. creates many problems to the electrical power systems, such as harmonics, oscillations, which lead to the unnecessary economic cost. It is critical to implement satisfying continuous monitoring of the power quality (PQ) over the power systems. Previous works have proposed many PQ detection methodologies with promising accuracy and performance, but as more and more renewable energy is integrated into the power systems, a new challenge of frequency deviation has been raised. The accuracy of the conventional methodologies will be degraded under the frequency deviated environment, then the authors proposed in this study an instantaneous PQ indices (PQIs) detection methodology based on adaptive data resampling technique to improve the accuracy of PQIs detection within a frequency deviated environment. Finally, they validated the effectiveness of the proposal, which obtains better accuracy and performance under a frequency deviated environment with less readjustment, through simulation and measurement. Furthermore, the proposed methodology satisfies the definitions and recommendations of the IEEE Std 1459 and IEEE Std 519. [ABSTRACT FROM AUTHOR]

In this paper, the structure, coordinate control method, and parameter design of a hybrid system are proposed for active power injection and nonactive power (reactive, harmonic, and unbalance power) compensation. The proposed hybrid system consists of a static var compensator (SVC) in parallel with a capacitive-coupling grid-connected inverter (CGCI) (SVC//CGCI). In SVC//CGCI, the SVC part is used to dynamic compensate the reactive power and unbalance power, while the low rating CGCI part is used to inject active power, provide harmonic power and a fixed amount of capacitive reactive power. Compared with conventional inductive-coupling grid-connected inverter (IGCI), the CGCI can provide active, reactive and harmonic power with low rating of active inverter part. The cost of the SVC part is much lower than that of active inverter part, thus the reduction of inverter rating can lead to a decrease in the total cost of the SVC//CGCI. Therefore, the SVC//CGCI can be a cost effective solution for active power injection and nonactive power compensation. Finally, simulation and experimental results are provided to show the advantages and validity of the proposed SVC//CGCI in compared with the conventional IGCI and SVC//IGCI. [ABSTRACT FROM AUTHOR]

In this study, a minimizing inverter capacity design is proposed, and the characteristics and performance of static VAR compensator (SVC) coupling hybrid active power filters (SVC-HAPFs) are analyzed. The cost of the SVC part is much lower than that of the active inverter part, and thus, the reduction of inverter part capacity can lead to a decrease in the total cost of SVC-HAPF. To demonstrate the advantages of the proposed minimizing inverter capacity design of SVC-HAPF, comparisons are given between the conventional and the proposed SVC-HAPF designs. Comparisons are also provided among active power filters (APFs), HAPFs, and the proposed SVC-HAPF in terms of dc-link voltage, compensation range, and performance. Finally, simulation and laboratory-scale experimental results are given to validate the minimizing inverter capacity design, and to verify the characteristics and compensation performances of APF, HAPF, and the proposed SVC-HAPF. [ABSTRACT FROM AUTHOR]

Among various modeling methods for DC-DC converters introduced in the past two decades, the state-space averaging (SSA) and the circuit averaging (CA) are the most general and popular exhibiting high accuracy. However, their deduction approaches are not entirely equivalent since they incorporate different averaging processes, thus yielding different small signal transfer functions even under identical operating conditions. Some research studies claimed that the improved SSA can obtain the highest accuracy among all the modeling methods, but this paper discovers and clearly verifies that this is not the case. In this paper, we first review and study these two modeling methods for various DC-DC converters operating in the discontinuous conduction mode (DCM). We also streamline the general model-deriving processes for DC-DC converters, and test and compare the accuracy of these two methods under various conditions. Finally, we provide a selection strategy for a high-accuracy modeling method for different DC-DC converters operating in DCM and verified by simulations, which revealed necessary and beneficial for designing a more accurate DCM closed-loop controller for DC-DC converters, thus achieving better stability and transient response. [ABSTRACT FROM AUTHOR]

This paper proposes a new type dc/ac inverter named: hybrid-coupling grid-connected inverter (HGCI) for photovoltaic active power generation with power quality conditioning, which consists of a full-bridge three-phase dc/ac inverter coupling to the power grid in series with a thyristor-controlled LC filter. Compared with the conventional inductive-coupling grid-connected inverter (IGCI) and capacitive-coupling grid-connected inverter (CGCI), the proposed HGCI has distinct characteristics of wide operational range and low dc-link operating voltage. Based on these prominent characteristics, the system cost and operational cost can be reduced. Moreover, it can transfer the active power and compensate reactive power, unbalanced power, and harmonic power simultaneously. In this paper, the analysis of the structure, parameter design, and control method of the HGCI is proposed and presented. Finally, simulation and experimental results are provided to verify the effectiveness and performance of the proposed HGCI in comparison with the IGCI and CGCI. [ABSTRACT FROM AUTHOR]

When the load generated harmonic, unbalanced, and reactive power is beyond the limited capacity of a thyristor-controlled LC-coupling hybrid active power filter (TCLC-HAPF), the TCLC-HAPF with the conventional control methods cannot provide satisfactory compensation performance. In this paper, a selective compensation control method of harmonic distortion, unbalanced and reactive power of the TCLC-HAPF is proposed, which can function even at different voltage conditions (e.g., voltage dip, voltage fault, etc.). First, the proposed control method decomposes the load power into fundamental positive-sequence reactive power, fundamental negative-sequence power (unbalanced power), and harmonic power. Then, the decomposed reactive, unbalanced, and harmonic power can be selectively or fully compensated based on the capacity of the TCLC-HAPF. Finally, simulation and experimental results are provided to verify the effectiveness of the proposed selective compensation control method for the TCLC-HAPF. [ABSTRACT FROM PUBLISHER]

In this paper, a new modeling and parameter design method for the thyristor-controlled LC-coupled hybrid active power filter (TCLC-HAPF) is proposed, which includes the analysis of the inner flowed three-phase unbalanced power during unbalanced condition. Different from the conventional method which ignores the inner flowed three-phase unbalanced power, the proposed design method can achieve better performance during unbalanced compensation. To verify the validity and advantages of the proposed modeling and parameter design method of TCLC-HAPF, the mathematical analysis, representative simulation and experimental results for compensating different unbalanced loading situation are presented in comparison with the conventional design method. [ABSTRACT FROM PUBLISHER]

This paper proposes a control strategy for a three-phase three-wire thyristor-controlled LC -coupling hybrid active power filter (TCLC-HAPF), which can balance active power and compensate reactive power and harmonic currents under unbalanced loading. Compared with TCLC-HAPF with conventional control strategy, active power filters and hybrid active power filters which either fail to perform satisfactory compensation or require high-rating active inverter part for unbalanced compensation, a control strategy was proposed for TCLC-HAPF to operate with a small rating active inverter part for a variety of loads with satisfactory performance. The control idea is to provide different firing angles for each phase of the thyristor-controlled LC-coupling part (TCLC) to balance active power and compensate reactive power, while the active inverter part aims to compensate harmonic currents. First, the required different TCLC impedances are deduced. Then, independent firing angles referenced to the phase angle of voltage across TCLC are calculated. After angle transformations, final firing angles referenced to phase angle of load voltages are obtained. In this paper, a novel controller for TCLC-HAPF under unbalanced loading is proposed. Simulation and experimental results are provided to verify the effectiveness of the proposed controller in comparison with a state-of-the-art controller. [ABSTRACT FROM PUBLISHER]

This paper proposes a hybrid static synchronous compensator (hybrid-STATCOM) in a three-phase power transmission system that has a wide compensation range and low dc-link voltage. Because of these prominent characteristics, the system costs can be greatly reduced. In this paper, the circuit configuration of hybrid-STATCOM is introduced first. Its V–I characteristic is then analyzed, discussed, and compared with traditional STATCOM and capacitive-coupled STATCOM (C-STATCOM). The system parameter design is then proposed on the basis of consideration of the reactive power compensation range and avoidance of the potential resonance problem. After that, a control strategy for hybrid-STATCOM is proposed to allow operation under different voltage and current conditions, such as unbalanced current, voltage dip, and voltage fault. Finally, simulation and experimental results are provided to verify the wide compensation range and low dc-link voltage characteristics and the good dynamic performance of the proposed hybrid-STATCOM. [ABSTRACT FROM PUBLISHER]

The 3‐level boost (3LB) converters have the characteristics of higher‐voltage conversion ratio and efficiency, lower inductor current ripples, output voltage ripples and voltage stresses on switches when compared with the conventional boost converters in continuous conduction mode (CCM). When implemented into an integrated circuit, the 3LB converter discontinuous conduction mode (DCM) operation cannot be avoided due to a smaller inductance. Its DCM operation analysis is deduced including CCM/DCM boundary, DCM voltage gain and DCM small signal transfer function. The deduced DCM operation theory is verified using MATLAB and Cadence, to obtain a feasible DCM closed‐loop controller design in future. [ABSTRACT FROM AUTHOR]

This paper proposes an adaptive low-dc-link-voltage-controlled LC coupling hybrid active power filter (LC-HAPF) with a neutral inductor, which can compensate both dynamic reactive power and current harmonics in three-phase four-wire distribution power systems. Due to its adaptive low-dc-link-voltage characteristic, it can obtain the least switching loss and switching noise and the best compensating performances, compared with the conventional fixed and newly adaptive dc-voltage-controlled LC-HAPFs. The design procedures of the dc-link voltage controller are discussed, so that the proportional and integral gains can be designed accordingly. Moreover, the general design procedures for the adaptive dc-voltage-controlled LC-HAPF with a neutral inductor are also given. The validity and effectiveness of the adaptive dc-link voltage-controlled LC -HAPF with a neutral inductor are confirmed by experimental results obtained from a 220-V 10-kVA laboratory prototype compared with the conventional fixed and adaptive dc-link voltage-controlled LC-HAPFs without a neutral inductor. [ABSTRACT FROM AUTHOR]

A KY converter has the characteristics of non‐pulsating output current, low‐output voltage ripple and no right‐half plane zero in continuous conduction mode which can overcome the drawbacks of the conventional boost and buck–boost converters. However, when the KY converter is implemented into an integrated circuit, its discontinuous conduction mode (DCM) operation cannot be avoided due to a small‐inductor value. The boundary for the DCM operation region, DCM dc voltage and small‐signal transfer functions are proposed, which fill the gap of the DCM operation theory for the KY converter. Simulation results, using MATLAB and Cadence, are provided to verify the deduced DCM operation theory of the KY converter. The DCM closed‐loop controller design can be achievable in future. [ABSTRACT FROM AUTHOR]

In this article, a vector proportional–integral (VPI) current controller for the LC-coupling hybrid active power (LC-HAPF) with ideally zero steady-state error, optimal transient response, and good robustness is proposed. First, the transfer function of the proposed VPI current controller is introduced, and its parameter design for obtaining optimal transient response is discussed. Second, a detailed robustness analysis of the VPI current controller, including the system parameter variation, distorted grid voltage, and grid frequency variation conditions, is proposed. Third, the digital implementation method of the VPI controller and an overall control block diagram for the LC-HAPF with the proposed VPI current controller are presented. Moreover, a comparative study and analysis between the VPI current controller and the other representative current controllers under the minimum dc-link voltage is discussed in which the VPI current controller obtains the best performances under the minimum dc-link voltage operation. The simulation and experimental results are provided to verify the advantages and effectiveness of the proposed VPI current controller for a three-phase four-wire LC-HAPF in comparison with the other representative current controllers under different dc-link voltage conditions. Finally, the robustness under different grid conditions and unbalanced compensation capability of the proposed VPI-controlled LC-HAPF are also verified by the experimental results. [ABSTRACT FROM AUTHOR]

In this article, a second-order sliding-mode control (SOSMC) based on supertwisting controller for LC-coupling hybrid active power filter (LC-HAPF) is proposed. Among the literatures review studies, hysteresis-based current controller, which is a special implementation of sliding-mode control, is usually used due to its simplicity, robustness, and good dynamic performance for reference tracking. However, it generates a nonfixed switching frequency for the power filter, which leads to undesirable harmonics problem. The proposed SOSMC ensures the good robustness and dynamic performance of using the conventional sliding mode control with an improved steady-state performance and disturbance rejection capability. In addition, with the help of supertwisting controller, the proposed SOSMC can achieve fixed switching frequency characteristic. First, the control objective and the design methodology of sliding surface are discussed and given in this article. Second, a detailed parameter design procedure under stability, system parameter variation, distorted grid voltage, and grid frequency variation consideration is provided. Then, experimental results on a three-phase four-wire LC-HAPF are carried out to verify the steady-state and dynamic performances of the proposed SOSMC compared with other representative current controllers. Finally, the disturbance rejection capability under different grid conditions of the proposed SOSMC is also verified by experimental results. [ABSTRACT FROM AUTHOR]

Load-independent output with zero-phase-angle (ZPA) input is desirable in wireless inductive power transfer (IPT) converters for effective power delivery, but it usually greatly relies on the parameters of the loosely coupled transformer, normally fixed or constrained by space. Thus, customizable outputs cannot be readily achieved unless a new transformer is redesigned. In this article, we elaborate the rather complex relationships among compensation parameters, customizable load-independent-voltage (LIV) outputs with ZPA input, power efficiency, and overall compensation capacitance cost of the series/series-parallel (S/SP) IPT converter. We present a cost-effective compensation design to free the customization of LIV outputs from a parameter-constrained loosely coupled transformer, with optimization between efficiency enhancement and overall compensation capacitance cost. We conducted the proposed design supported by experimental results in S/SP IPT converters with an identical loosely coupled transformer and various sets of compensation capacitors. Compared with a conventional design, the proposed design provides custom ranges of LIV outputs in both a weak and a relatively strong coupling condition, with over 5.9% and 5% efficiency improvement, respectively. The overall compensation capacitance can also be reduced by up to 37% and 21.5%, respectively. [ABSTRACT FROM AUTHOR]

Magnetically coupled impedance-source networks can achieve a higher voltage gain with smaller shoot-through duty ratio in comparison with the conventional impedance-source networks without coupled inductors. However, the practical voltage gain is seriously affected by the parasitic resistances in passive components and power devices, which is necessary to be investigated. This article derives and analyzes the effects of parasitic resistances on the voltage gain of magnetically coupled impedance-source networks under three different scenarios: first, different resistance ratio between parasitic resistances and output equivalent resistance, second, different shoot-through duty ratio, and third, different winding ratio. First of all, a generalized equivalent circuit model considering parasitic resistances for the three typical magnetically coupled impedance-source networks—Trans-Z-source, Г-source, and Y-source networks are proposed. Based on it, the effects of parasitic resistances on the voltage gain is mathematically derived and discussed under the aforementioned three different scenarios. And the maximum voltage gain under the consideration of the three resistance ratios simultaneously is also derived. Finally, representative simulation and experimental results are provided to verify the proposed generalized equivalent circuit models, the corresponding mathematical derivations, and the effects of the parasitic resistances on the magnetically coupled impedance-source networks. [ABSTRACT FROM AUTHOR]

• A two-layer framework is proposed for building HVAC and associated multi-energy consumption optimization. • 100% renewable complementarities are proposed for building multi-energy supplies. • A R-C thermodynamic network is formulated to model the building HVAC. • AC slow charging and DC fast charging types of EVs are considered and managed via a novel real-time supply–demand pricing. Building heating, ventilation, and air conditioning (HVAC) and associated energy consumption make up the more and more important part of the world, whose reduction provides a cost-effective path to the "dual carbon" goal. This paper proposes a two-layer management of HVAC-based multi-energy buildings under proactive demand response of fast/slow-charging electric vehicles (EVs). In this paper, the building HVAC is mathematically formulated via a R-C thermodynamic model, which coordinates with multi-energy converters and storages to form a 100% renewable building. The building management is a challenging optimization problem due to its severe constraints and strong spatio-temporal couplings. In the first layer, a day-ahead multi-energy dispatch is formulated to economically optimize the electrical, heat, gas energy carriers. In the second layer, alternating current (AC) slow charging and direct current (DC) fast charging types of EVs are considered and managed via a novel real-time supply–demand pricing mechanism. After acquiring the economical dispatch references in the first layer, the second layer implements a model predictive control (MPC)-based real-time scheduling to handle the multi-energy supply–demand fluctuations. The original two-layer optimization is further handled via mixed-integer linear program (MILP) reformulation for high-efficient solving. Comparisons have shown the advantageous performances of the proposed two-layer optimization over economics and practicability. Simulations results show that the overall system operating cost can be reduced by at most 3.01% with a higher operational flexibility in building management. [ABSTRACT FROM AUTHOR]

In this paper, the structure, modeling, parameter design, and control method are proposed for a new hybrid structure of a static var compensator in parallel with a hybrid active power filter (SVC//HAPF). The SVC part of the SVC//HAPF is used to dynamically compensate the reactive power. And, the HAPF part is used to provide harmonic power and small amount of reactive power compensation. Due to the large fundamental voltage drop on coupling the LC part, the active inverter part of the SVC//HAPF has low voltage rating. Meanwhile, the parallel-connected SVC acts as a current divider to reduce the active inverter current. Therefore, the proposed SVC//HAPF shows the great promise in compensating harmonic current and wide-range reactive power with a low (both) voltage and current rating active inverter part. To show the advantages of the proposed SVC//HAPF, simulation comparisons among the active power filter (APF), HAPF, SVC in series with HAPF (SVC−HAPF), and the proposed SVC//HAPF are provided. Finally, experimental results based on the laboratory-scaled hardware prototype are given to show the validity of the SVC//HAPF. [ABSTRACT FROM PUBLISHER]

In this article, a half-tangent phase-locked loop (HTan-PLL) is proposed for variable-frequency grids of more electric aircrafts. First, the pros and cons of the synchronous reference frame PLL (SRF-PLL) are discussed in a nonlinear framework. To address the disadvantages, a half-tangent phase detector (PD) is developed and a novel PLL is then proposed. Subsequently, a phase portrait-based analysis and a Lyapunov function-based argument are provided. It is proven that the HTan-PLL has a good performance in terms of steady-state accuracy and fast dynamics, even under large frequency changes. Compared with the conventional SRF-PLL, the proposed HTan-PLL outperforms with the following features: faster dynamics than the SRF-PLL when the frequency varies largely; no unstable equilibrium points, while the SRF-PLL has infinite unstable equilibrium points; and when the grid frequency jumps widely, the HTan-PLL converges to the unique equilibrium point (0,0). By contrast, the SRF-PLL goes to different equilibrium points. Experimental tests are provided, which verify the superior performance of the HTan-PLL. [ABSTRACT FROM AUTHOR]

The intelligent substations should be developed to perform multifunction operations, including power flow control, voltage regulation, and cost-effective power quality (PQ) improvement. In this article, an intelligent substation by a distribution transformer integrated with a capacitive-coupling winding tap injection static synchronous compensator (CWTI-DSTATCOM) is proposed for balance and unbalance operations. Compared with the state-of-the-art approaches, CWTI-DSTATCOM can operate at a low dc voltage with a small active inverter rating, which also can provide distributed voltage, reactive, and unbalanced current compensation. The power rating reduction mechanism is mathematically revealed via balance and unbalance compensation analysis, which is further used to determine the optimal inverter power rating of unbalance operation via an optimal LC filter design method. Furthermore, a comprehensive compensation control strategy is developed to coordinate the transformer taps and the active inverter under balanced and unbalanced operations. Simulation and real-time digital simulator hardware-in-the-loop experiments are performed to prove the validity and effectiveness of the proposed topology over inverter rating reduction and PQ enhancement. [ABSTRACT FROM AUTHOR]

The capacitive-coupling grid-connected inverter (CGCI) is coupled to the point of common coupling via a second-order LC branch. Its operational voltage is much lower than that of a conventional inductive-coupling grid-connected inverter (IGCI) when it serves as a multifunctional inverter to compensate reactive power and transfer active power simultaneously. It is a promising solution for microgrid and building-integrated distributed generator systems. A quasi-proportional-resonant (quasi-PR) controller is applied to reduce the steady-state current tracking errors of the CGCI in this paper. The quasi-PR controller generates the voltage reference for use of carrier-based pulse-width modulation, which can effectively reduce output current ripples. The second-order coupling impedance of the CGCI causes its modeling and controller design to differ from that of the conventional IGCI. A comprehensive design method for the quasi-PR controller in a CGCI is developed. The quasi-PR controller is also compared with a proportional-integration current controller. Simulation results are provided to verify the effectiveness of the quasi-PR controller and its design method in a CGCI. The current tracking errors are greatly reduced when the quasi-PR controller rather than the proportional-integration controller is applied. Experimental results are also provided to validate the CGCI as a multifunctional grid-connected inverter. [ABSTRACT FROM PUBLISHER]

A finite-set model predictive control (FS-MPC) with coupling capacitor voltage observer scheme is proposed for thyristor-controlled LC-coupling hybrid active power filter (TCLC-HAPF) in this article. It ensures the fast transient response, low steady-state error, and good robustness under both inductive and capacitive load situations. Generally, the implementation of FS-MPC for TCLC-HAPF requires sensing of coupling capacitor voltage and thyristor-controlled reactor current in addition to sensing load voltage, load current, and compensation current, which increases the system complexity and cost. To relax this problem, the simplified predictive model is first proposed, thus reducing the required sensing signals and system order. Then, a coupling capacitor voltage observer is utilized to reduce the hardware costs, which can obtain a comparable performance with directly sensed capacitor voltage. The delay compensation is also considered for the control delay in practical realization. Finally, the effectiveness and performance of the FS-MPC with coupling capacitor voltage observer for TCLC-HAPF are verified by simulated and experimental results. [ABSTRACT FROM AUTHOR]

This paper proposes a FPAA-FPGA/DSP-based mixed signal controller that achieves superior performance when compared with conventional digital controllers in power quality compensation. This includes adaptive signal conditioning and programmability on-the-fly, higher flexibility, parallel computation capability, and easy implementation. In practical applications, the power quality compensator may suffer from poor compensation performance, particularly during light loading. The adaptive signal gain and programmable on-the-fly functions of the mixed signal controller are intended to improve the system compensation performance, which cannot be achieved by using conventional digital controllers alone. In this study, an approximate total harmonic distortion (ATHD) is proposed to determine the total harmonic distortion value more quickly, reducing the evaluation time of the power quality compensation system performance. With hysteresis pulse width modulations, when the hysteresis error margin is designed, the ATHD can be determined instantaneously. Finally, representative simulation and experimental results of a three-phase four-wire center-split hybrid active power filter are presented. These verify the validity and effectiveness of the proposed mixed signal controller in improving current quality compensation performance during light load conditions, compared with a conventional digital controller. [ABSTRACT FROM AUTHOR]

Single-phase traction transformers are widely used in traction power supply systems due to their characteristics such as a low cost and a simple structure. Railway power conditioners (RPCs) could increase the loading capacity of substations and improve the supply quality. In this paper, a hybrid RPC (HRPC) is applied to reduce reactive power, relieve system unbalance, and suppress harmonics. The operational voltage of the HRPC is much lower than that of a conventional RPC. A method named partial compensation was used to reduce the current rating of the RPC, in which the compensating currents are expressed as a function of the power factor target at the grid side. When this method is used in the HPRC, the operational voltage varies with the compensating currents over a wide range. A comprehensive design procedure is proposed so that both the current and voltage ratings of the HRPC are reduced with partial compensation. A reduction of more than 50% is achieved by compensating the power factor at the grid side to 0.95 instead of to unity. The control block diagram for the HRPC with partial compensation is presented. The design and control of the HRPC are validated by simulation and experimental results. [ABSTRACT FROM PUBLISHER]

In high-power applications, different multilevel voltage source converter (VSC) topologies are usually applied. The hybrid parallel multiconverters, which is a combination of multiactive and hybrid VSCs connecting in parallel, can be a promising solution in a high-power grid. In this article, the fusion VSC topology concept is proposed in which fusion VSC takes the advantages of both active (inductive coupling) VSC and hybrid (capacitive coupling) VSC. It corresponds to overcoming the insufficient-capacity problems when active VSCs are employed alone and vice versa. This article proposes fusion active power filter topology by combing active and hybrid power VSC through their equivalent model for power quality compensation. With the proposed VSC's equivalent model, it can reduce the converter rating by 17%–80% compared with the conventional approaches. Additionally, the corresponding control algorithm is proposed for the FAPF for power quality compensation. Finally, the simulation and real-time digital simulator hardware-in-the-loop experimental results of the proposed FAPF topology are given to demonstrate the validity and effectiveness for reducing its capacity and power loss compared with the conventional multi-VSC in power quality compensation. [ABSTRACT FROM AUTHOR]

Compared with the conventional active power filter, the thyristor-controlled LC-coupling hybrid active power filter (TCLC-HAPF) has a distinct characteristics of low dc-link operating voltage, which can lower the system and operational costs in the medium-voltage-level system. It also has a wider operational range than the conventional hybrid active power filter. Besides that, the TCLC-HAPF can provide reactive, harmonic, and unbalanced powers compensation simultaneously. In this article, the modeling of the TCLC-HAPF is investigated based on the linear control aspect. Then, the analysis, design, and implementation of a multi-quasi-proportional-resonant (MQPR) controller with gain scheduling for the TCLC-HAPF will be proposed, which can automatically change the resonant gain between the inductive and capacitive loads operation to improve its compensation performances. The proposed controller can significantly reduce the TCLC-HAPF steady-state current tracking errors and output current ripple. Finally, the simulation and experimental results are also provided to verify the effectiveness and performance of the MQPR controller for the TCLC-HAPF in comparison with the hysteresis current controller and quasi-proportional-resonant (QPR) controller, which shows superior compensating performances. [ABSTRACT FROM AUTHOR]

Previous researches on space vector modulation (SVM) in active power filters (APFs) topologies find that compared with sinusoidal pulse width modulation, the SVM offers a better harmonic spectrum and has 15.47% more voltage utilization. The article not only proposes SVM for hybrid active power filters (HAPFs) but also answers the following questions. 1) Under what conditions both filters are equivalent to one another? 2) Which filter can enhance better tracking ability and better performance? 3) How the coupling component parameters and dc voltage affect the performance of both filters? The representative simulation and experimental results are given to verify the discussions. The conclusions can be application guidelines for the design of inductive and capacitive coupling inverters (e.g., APFs and HAPFs) in smart grids and development of energy internet due to their generalities to applications. [ABSTRACT FROM AUTHOR]

A three-level buck (TLB) converter has the characteristics of higher voltage conversion efficiency, lower inductor current ripples, output voltage ripples and voltage stresses on switches when compared with the buck converters in continuous conduction mode (CCM). With a TLB converter integrated on a chip, we cannot avoid its discontinuous conduction mode (DCM) operation due to a smaller inductance and load variation. In this paper, we'll present and discuss the analysis, design and control of a TLB converter under DCM operation, implemented in a 65 nm CMOS process. Transistor level simulation results show that when the TLB converter operates at 100 MHz with a 5 nH on-chip inductor, a 10 nF output capacitor and a 10 nF flying capacitor, it can achieve an output conversion range of 0.7–1.2 V from a 2.4 V input supply, with a peak efficiency of 81.5%@120 mW. The output load transient response is 100 mV with 101 ns for undershoot, and 86 mV with 110 ns for overshoot when I OUT = 1 0 –100 mA. The maximum output voltage ripple is less than 19 mV. [ABSTRACT FROM AUTHOR]

Building‐integrated photovoltaics (PVs) is one of the most promising and elegant ways of producing on‐site electricity. The compact and cost‐effective PV integration system needs to be developed to convert dc voltage into ac compatible with the grid. A single‐stage PV inverter is proposed, and its design and control system implementation are focused on. The proposed system is able to transfer active power to the grid with maximum power point tracking. At the same time, the PV inverter can control reactive power and suppress harmonics due to non‐linear loads. By coupling to grid via a series LC branch, the proposed system operates on a dc bus voltage much lower than that of the conventional PV inverter, so that less PV panels need to be connected in series. Therefore, the proposed system is a low‐cost and multi‐functional alternative to PV inverters in building‐integrated applications. Simulation and experimental results are provided to validate its effectiveness. [ABSTRACT FROM AUTHOR]

Railway hybrid power quality conditioner (HPQC) is advantageous over conventional railway power quality conditioner (RPC) for its reduction in operation voltage and device ratings in co-phase traction power compensation. In order to further reduce the power loss during operation, flexible dc control has been proposed. However, the operation voltage range for railway HPQC has not yet been discussed. This is important since in contrast to traditional power quality compensation devices, active power compensation is involved in co-phase traction power. Compensation capability in co-phase traction power thus does refer not only to reactive power compensation but also to active power compensation ability. Satisfactory compensation performance can be provided only when railway HPQC can provide enough active and reactive compensation power output at the same time. In this paper, the effects of operation range in flexible dc voltage control on railway HPQC compensation capability is briefly discussed and analyzed. The analysis is verified via PSCAD simulations. A laboratory-scaled hardware prototype is also constructed to obtain experimental results for further verifications. [ABSTRACT FROM AUTHOR]

Railway hybrid power quality conditioner (HPQC) is one of the newly proposed devices for power quality compensation in co-phase high-speed traction power supply for its benefit in reduction of operation voltage over conventional railway power quality conditioner (RPC). However, initial railway HPQC design is developed based on minimum operation voltage at predefined fixed rated load. This may not be applicable in practical condition when load varies. In order to solve this problem, a railway HPQC design with increased operation voltage has been investigated to enhance the compensation capability. Nevertheless, the compensation capability is even larger than that required during load variations such that the operation voltage is higher than it actually requires. A lower operation voltage can actually be used to provide required compensation capability when the coupled impedance is different from the designed rated one. In this paper, the effect of coupled impedance on the compensation capability in co-phase railway HPQC is being analyzed. An impedance-mapping design technique based on required compensation capability is then proposed based on the analysis. The proposed method is advantageous for lower operation voltage and smaller capacitance value. The effectiveness of impedance-mapping technique is verified via simulation and experimental results. [ABSTRACT FROM AUTHOR]

Hybrid Railway Power Quality Conditioner (HPQC) is newly proposed for its effective reduction in dc-link operation voltage while providing similar power quality compensation in cophase traction power supply compared to conventional railway power quality conditioner. However, reduction in HPQC operation voltage limits its power quality compensation capability. For instance, the previously proposed HPQC design based on minimum operation voltage under fixed rated load has minimum power quality compensation capability. Under practical conditions when load varies, the required HPQC active and reactive compensation power also changes. The dc-link operation voltage of HPQC may therefore need to be enhanced to increase its power quality compensation capability. Therefore in this paper, the relationship between dc-link voltage of HPQC and its power quality compensation capability, as well as its limitations, are being analyzed. Simulation and experimental results are also presented to verify the mentioned relationship via investigations of system performance under different loading conditions. The research can provide a guideline for determination of HPQC operation voltage when load varies. [ABSTRACT FROM PUBLISHER]

Cophase traction power system has high potential to be power supply for high-speed railway. However, the dc operation voltage of conventional power quality compensation device within, such as railway power quality conditioner, is high and may limit its application and development. The hybrid power quality conditioner (HPQC), in which a capacitive coupled $LC$ structure is added, is thus proposed for lower operation voltage. However, there is less investigation and study on the HPQC parameter design for minimum operation voltage when harmonic compensation is concerned. In this paper, the HPQC design for minimum dc operation voltage under comprehensive fundamental and harmonic compensation is being proposed and introduced. Analysis and case study are also performed to show the advantage of the proposed HPQC design. Simulation and laboratory-scaled experimental results are presented to show effective reduction in dc operation voltage using the proposed HPQC design. Through the simulation and experimental case study and verification, there is a reduction of 15% in operation voltage using the proposed hybrid $LC$ structure design compared with the conventional design. The proposed design does not add much additional cost and can also reduce the coupling inductance value. Similar analysis procedure may be also applied to other $LC$ hybrid-structured active power compensators. [ABSTRACT FROM PUBLISHER]

This paper proposes a precision bandgap voltage reference (BGR) with a segmented curvature compensation technique, demonstrating both small temperature coefficient (TC) and low power consumption. By segmenting the output voltage of a conventional first-order BGR over a wide temperature range and implementing compensation for each segment, the output reference voltage can be systematically aligned to an identical voltage level, effectively reducing the achievable TC. An additional circuit consists of comparators, logic gates, switches and current mirrors is proposed to achieve this compensation scheme, which also optimizes the overall BGR power consumption. Implemented and simulated in a standard 65 ​nm CMOS process, the proposed BGR achieves an average output of 496.17 ​mV and a TC of 1.08 ​ppm/°C from −40 ​°C to 125 ​°C. It consumes a current of 765 ​nA under a 1.2 ​V supply while exhibiting a line regulation of 0.725%/V with V DD from 1.0 to 1.8 ​V ​at 27 ​°C. [ABSTRACT FROM AUTHOR]