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Showing papers on "Rectifier published in 2014"


Patent
10 Mar 2014
TL;DR: An electric power tool includes: a brushless motor having a plurality of stator windings and configured to rotate in accordance with voltages applied to the plurality of windings, an induced voltage being generated according to a rotation of the motor; a rectifier circuit configured to rectify an AC voltage; a smoothing capacitor configured to smooth the AC voltage rectified by the rectifier circuits to a pulsation voltage having a maximum value larger than the induced voltage.
Abstract: An electric power tool includes: a brushless motor having a plurality of stator windings and configured to rotate in accordance with voltages applied to the plurality of stator windings, an induced voltage being generated in accordance with a rotation of the brushless motor; a rectifier circuit configured to rectify an AC voltage; a smoothing capacitor configured to smooth the AC voltage rectified by the rectifier circuit to a pulsation voltage having a maximum value larger than the induced voltage and a minimum value smaller than the induced voltage; and an inverter circuit configured to perform switching operations to output the pulsation voltage to the plurality of stator windings by rotation.

490 citations


Journal ArticleDOI
TL;DR: In this paper, a design method for the co-design and integration of a CMOS rectifier and small loop antenna and a complementary MOS diode is proposed to improve the harvester's ability to store and hold energy over a long period of time during which there is insufficient power for rectification.
Abstract: In this paper, a design method for the co-design and integration of a CMOS rectifier and small loop antenna is described. In order to improve the sensitivity, the antenna-rectifier interface is analyzed as it plays a crucial role in the co-design optimization. Subsequently, a 5-stage cross-connected differential rectifier with a 7-bit binary-weighted capacitor bank is designed and fabricated in standard 90 nm CMOS technology. The rectifier is brought at resonance with a high-Q loop antenna by means of a control loop that compensates for any variation at the antenna-rectifier interface and passively boosts the antenna voltage to enhance the sensitivity. A complementary MOS diode is proposed to improve the harvester's ability to store and hold energy over a long period of time during which there is insufficient power for rectification. The chip is ESD protected and integrated on a compact loop antenna. Measurements in an anechoic chamber at 868 MHz demonstrate a -27 dBm sensitivity for 1 V output across a capacitive load and 27 meter range for a 1.78 W RF source in an office corridor. The end-to-end power conversion efficiency equals 40% at -17 dBm.

289 citations


Journal ArticleDOI
TL;DR: In this paper, a simple modified H-bridge zero-voltage state rectifier is proposed, to combine the benefits of the low-loss ac-decoupling method and the complete leakage current elimination of the CMV clamping method.
Abstract: Leakage current minimization is one of the most important considerations in transformerless photovoltaic (PV) inverters. In the past, various transformerless PV inverter topologies have been introduced, with leakage current minimized by the means of galvanic isolation and common-mode voltage (CMV) clamping. The galvanic isolation can be achieved via dc-decoupling or ac-decoupling, for isolation on the dc- or ac-side of the inverter, respectively. It has been shown that the latter provides lower losses due to the reduced switch count in conduction path. Nevertheless, leakage current cannot be simply eliminated by galvanic isolation and modulation techniques, due to the presence of switches’ junction capacitances and resonant circuit effects. Hence, CMV clamping is used in some topologies to completely eliminate the leakage current. In this paper, several recently proposed transformerless PV inverters with different galvanic isolation methods and CMV clamping technique are analyzed and compared. A simple modified H-bridge zero-voltage state rectifier is also proposed, to combine the benefits of the low-loss ac-decoupling method and the complete leakage current elimination of the CMV clamping method. The performances of different topologies, in terms of CMV, leakage current, total harmonic distortion, losses and efficiencies are compared. The analyses are done theoretically and via simulation studies, and further validated with experimental results. This paper is helpful for the researchers to choose the appropriate topology for transformerless PV applications and to provide the design principles in terms of common-mode behavior and efficiency.

250 citations


Journal ArticleDOI
TL;DR: In this paper, a triangular current mode (TCM) rectifier with a low height of 5 mm has been realized and measurement results are provided in order to validate the theoretical considerations.
Abstract: This paper presents the analysis and realization of a topology suitable to realize a power factor correction (PFC) rectifier with a thickness of only a few millimeters. The low height of the converter requires all components to be integrated into the printed circuit board (PCB). Still reasonable dimensions of the converter PCB are feasible (221 mm × 157 mm for a 200 W PFC rectifier), since PCB-integrated inductors and capacitors allow for high energy densities due to their large surface area which facilitates a low thermal resistance to ambient. A multicell totem-pole PFC rectifier employing a soft-switching modulation scheme over the complete mains period is identified as an adequate topology. The mode of operation is entitled triangular current mode (TCM) due to the triangular-shaped inductor currents. The modulation technique requires a reliable description of the switching transition of a half-bridge in order to provide accurate timing parameters. For this purpose, a simplified model of the nonlinear MOSFETs' output capacitances facilitates closed-form analytical expressions for duty cycle and switching frequency. Furthermore, this paper details the control of three interleaved converter cells which yields a reduction of the input current ripple. A 200 W TCM PFC rectifier with a low height of 5 mm has been realized and measurement results are provided in order to validate the theoretical considerations. The presented TCM PFC rectifier achieves an efficiency of 94.6% and a power factor of 99.3% at nominal power.

247 citations


Journal ArticleDOI
TL;DR: In this paper, the stability and control of offshore wind farms employing mediumvoltage ac collection and high-voltage dc (HVDC) transmission to the onshore power grids are investigated.
Abstract: This paper investigates the stability and control of offshore wind farms employing medium-voltage ac collection and high-voltage dc (HVDC) transmission to the onshore power grids. Type-IV (full power conversion) turbines and HVDC rectifier based on voltage-source converters are assumed. Output impedance models of the wind turbines and input impedance models of the HVDC rectifier in the positive- and negative-sequence are developed using the harmonic linearization method. An impedance-based stability criterion is then applied to determine the stability of the offshore ac collection bus. Possible instability of the ac bus voltage and resonance between the wind farm and the HVDC rectifier are examined through analysis of the system impedance model. The analytical impedance models are used to identify the root causes of such instability and resonance problems, and to develop possible solutions. Detailed circuit simulation is used to validate the analysis. Individual converter impedance models are also validated by experimental measurements of scaled-down prototypes.

189 citations


Journal ArticleDOI
TL;DR: This work shows how using specifically selected or designed waveforms in wireless power transfer systems can lead to improved RF to dc conversion efficiency in rectifier circuits in the receiving end of these systems.
Abstract: This work shows how using specifically selected or designed waveforms in wireless power transfer (WPT) systems can lead to improved RF to dc conversion efficiency in rectifier circuits in the receiving end of these systems Signals with different time domain waveforms are considered such as OFDM, white noise and chaotic waveforms, and the performance of a rectifier circuit operating at 433 MHz is evaluated when using these signals in comparison to a single carrier constant envelope signal The performed experiments show that selecting high peak to average power ratio (PAPR) signals lead to improved RF-DC conversion efficiency in rectifier circuits

183 citations


Patent
02 Apr 2014
TL;DR: In this paper, the authors describe a wireless power transfer device that includes support for wireless charging and provision of power to run the device, as well as using the techniques in connection with wireless charging or wireless provisioning of power.
Abstract: A device includes support for wireless power transfer. The device may control the timing of switching devices in a rectifier circuit and implement resonant tuning techniques that facilitate the wireless power transfer, e.g., by purposefully introducing a real or complex impedance chosen to meet a current operating goal. The device may use the techniques in connection with wireless charging or wireless provision of power to run the device, as examples.

180 citations


Journal ArticleDOI
TL;DR: In this article, a direct-current triboelectric nanogenerator (DC-TENG) based on a rotating disk design for harvesting rotational mechanical energy was proposed.
Abstract: An innovative design is reported of a direct-current triboelectric nanogenerator (DC-TENG) based on a rotating disk design for harvesting rotational mechanical energy. The DC-TENG consists of two disks and two pairs of flexible electric brushes that are made of carbon fiber and contact two electrodes, respectively. During the rotation, two disks have distinct triboelectric polarities for a cyclic in-plane charge separation between them and an alternating current is generated between the two electrodes. Because of the sliding contact and automatically switch between the electric brushes and the two electrodes, the current is reversed in the second half of the cycle and a direct current is generated. The role that the rotating speed and the segmentation number have is thoroughly investigated and shows that there is direct current enhancement not only at higher speed but also with more segments. The DC-TENG has been demonstrated as a constant current source for directly and continuously driving electronic devices and/or charging an energy storage unit without a rectifier bridge. This work presents a novel DC-TENG technology and opens up more potential applications for harvesting rotational mechanical energy and powering electronics.

175 citations


Patent
07 May 2014
TL;DR: In this article, a controlled power delivery system may operate with RF waves for supplying continuous and suitable power to a load, including one or more receiving antennas, one rectifier, a first boost converter, a charger, a storage element, and a second boost converter.
Abstract: A controlled-power delivery system may operate with RF waves for supplying continuous and suitable power to a load. The controlled-power delivery system may include one or more receiving antennas, one or more rectifiers, a first boost converter, a charger, a storage element, and a second boost converter. The first boost converter may step up the rectified DC voltage obtained from the receiving antenna and rectifier to supply a suitable voltage level that can be used for charging the storage element. The second boost converter may increase the voltage from the storage element to a suitable level that may satisfy the power requirements of the load. The charger in conjunction with the first and second boost converters may be configured to allow a plurality of modes of operation for delivering power to the load and charging the storage element.

175 citations


Journal ArticleDOI
TL;DR: In this article, a radiative thermal rectifier with a thin film of vanadium dioxide (VO2) deposited on the silicon wafer is presented, and a rectification contrast ratio as large as two is accurately obtained by utilizing a one-dimensional steady-state heat flux measurement system.
Abstract: Vanadium dioxide (VO2) exhibits a phase-change behavior from the insulating state to the metallic state around 340 K. By using this effect, we experimentally demonstrate a radiative thermal rectifier in the far-field regime with a thin film VO2 deposited on the silicon wafer. A rectification contrast ratio as large as two is accurately obtained by utilizing a one-dimensional steady-state heat flux measurement system. We develop a theoretical model of the thermal rectifier with optical responses of the materials retrieved from the measured mid-infrared reflection spectra, which is cross-checked with experimentally measured heat flux. Furthermore, we tune the operating temperatures by doping the VO2 film with tungsten (W). These results open up prospects in the fields of thermal management and thermal information processing.

158 citations


Patent
07 May 2014
TL;DR: In this paper, a novel integrated rectifier and boost converter circuit architecture is disclosed, which includes a plurality of identical half-bridge rectifiers connected to receiving antennas to convert wireless AC power into DC power.
Abstract: A novel integrated rectifier and boost converter circuit architecture is disclosed. The rectifier architecture includes a plurality of identical half-bridge rectifiers connected to receiving antennas to convert wireless AC power into DC power. The integrated rectifier may be coupled in series with a charging inductor in a boost converter. The inductor may discharge upon operation of two micro-controller-driven switching transistors using predetermined threshold and timing scheme to turn on/off. The rectifier architecture may provide high power densities, improve efficiency at larger load currents, and may be enabled in an integrated circuit with eight RF signal inputs, eight half-bridge rectifiers, and eight DC outputs ganged together as single feed into the boost converter. The rectifier circuit topology may include a comparator driven by the boost controller with a proprietary algorithm which suits control for a maximum power point tracking functionality, and an external micro-controller for additional control of the boost converter.

Journal ArticleDOI
TL;DR: A dual-band rectifier based on RCN is designed and characterized showing improved performance in comparison with a conventional dual- band envelope detector by exhibiting improved RF-dc conversion efficiency and reduced sensitivity versus output load and input power variations.
Abstract: In this work, the concept of dual-band resistance compression networks is introduced and applied to the design of rectifier circuits with improved performance. The use of resistance compression networks (RCNs) minimizes the sensitivity of rectifier circuits to variations in the surrounding environment, such as input power level and changes in the rectifier load. The proposed dual-band RCN can be used as the matching network located between the antenna and the rectifying element of a dual-band rectifier for energy harvesting applications. A dual-band ( 915 MHz /2.45 GHz) rectifier based on RCN is designed and characterized showing improved performance in comparison with a conventional dual-band envelope detector by exhibiting improved RF-dc conversion efficiency and reduced sensitivity versus output load and input power variations.

Journal ArticleDOI
TL;DR: Simulation results in MATLAB/Simulink and experiments on a 3-kW SR motor validate the effectiveness of the proposed technologies, which may have significant economic implications and improve the PHEVs' market acceptance.
Abstract: Plug-in hybrid electric vehicles (PHEVs) provide much promise in reducing greenhouse gas emissions and, thus, are a focal point of research and development. Existing on-board charging capacity is effective but requires the use of several power conversion devices and power converters, which reduce reliability and cost efficiency. This paper presents a novel three-phase switched reluctance (SR) motor drive with integrated charging functions (including internal combustion engine and grid charging). The electrical energy flow within the drivetrain is controlled by a power electronic converter with less power switching devices and magnetic devices. It allows the desired energy conversion between the engine generator, the battery, and the SR motor under different operation modes. Battery-charging techniques are developed to operate under both motor-driving mode and standstill-charging mode. During the magnetization mode, the machine's phase windings are energized by the dc-link voltage. The power converter and the machine phase windings are controlled with a three-phase relay to enable the use of the ac-dc rectifier. The power converter can work as a buck-boost-type or a buck-type dc-dc converter for charging the battery. Simulation results in MATLAB/Simulink and experiments on a 3-kW SR motor validate the effectiveness of the proposed technologies, which may have significant economic implications and improve the PHEVs' market acceptance.

Journal ArticleDOI
TL;DR: An open- switch fault detection method is proposed and can find a position of the open-switch fault and two tolerance controls based on space vector modulation are proposed and their characteristics are analyzed.
Abstract: Multilevel converter topologies are widely used in applications of wide-power range. The T-type topology, which is one of many three-level topologies, has an advantage in terms of efficiency compared to the neutral-point-clamped (NPC) type. In applications using the T-type topology, interest in reliability has been increased recently. Therefore, the open-switch fault detection method and tolerance control for T-type rectifiers, which are different from those of T-type inverters, are necessary to improve the reliability of applications. When the open-switch fault of switches connected to a neutral point occurs, an NPC-type rectifier cannot restore distorted input currents; however, a T-type rectifier is able to eliminate input current distortion completely. In this paper, an open-switch fault detection method is proposed and can find a position of the open-switch fault. Moreover, two tolerance controls based on space vector modulation are proposed and their characteristics are analyzed. The effectiveness and performance of the proposed open-switch fault detection method and two tolerance controls are verified by simulations and experiments.

Journal ArticleDOI
TL;DR: This work addresses design and implementation issues of a 24 GHz rectenna, which is developed to demonstrate the feasibility of wireless power harvesting and transmission techniques towards millimeter-wave regime.
Abstract: This work addresses design and implementation issues of a 24 GHz rectenna, which is developed to demonstrate the feasibility of wireless power harvesting and transmission (WPT) techniques towards millimeter-wave regime. The proposed structure includes a compact circularly polarized substrate integrated waveguide (SIW) cavity-backed antenna array integrated with a self-biased rectifier using commercial Schottky diodes. The antenna and the rectifier are individually designed, optimized, fabricated and measured. Then they are integrated into one circuit in order to validate the studied rectenna architecture. The maximum measured conversion efficiency and DC voltage are respectively equal to 24% and 0.6 V for an input power density of 10 mW/cm 2 .

Journal ArticleDOI
TL;DR: Even in dynamic and power converter switching environments, the neural vector controller shows strong ability to trace rapidly changing reference commands, tolerate system disturbances, and satisfy control requirements for a faulted power system.
Abstract: Three-phase grid-connected converters are widely used in renewable and electric power system applications. Traditionally, grid-connected converters are controlled with standard decoupled d-q vector control mechanisms. However, recent studies indicate that such mechanisms show limitations in their applicability to dynamic systems. This paper investigates how to mitigate such restrictions using a neural network to control a grid-connected rectifier/inverter. The neural network implements a dynamic programming algorithm and is trained by using backpropagation through time. To enhance performance and stability under disturbance, additional strategies are adopted, including the use of integrals of error signals to the network inputs and the introduction of grid disturbance voltage to the outputs of a well-trained network. The performance of the neural-network controller is studied under typical vector control conditions and compared against conventional vector control methods, which demonstrates that the neural vector control strategy proposed in this paper is effective. Even in dynamic and power converter switching environments, the neural vector controller shows strong ability to trace rapidly changing reference commands, tolerate system disturbances, and satisfy control requirements for a faulted power system.

Journal ArticleDOI
TL;DR: To the best of the knowledge, this is the first demonstration of solid-state active-thermal devices with a large rectification in the Rectifier state, which can have substantial implications ranging from autonomous thermal management of heating and cooling systems to efficient thermal energy conversion and storage.
Abstract: Active heat flow control is essential for broad applications of heating, cooling, and energy conversion. Like electronic devices developed for the control of electric power, it is very desirable to develop advanced all-thermal solid-state devices that actively control heat flow without consuming other forms of energy. Here we demonstrate temperature-gated thermal rectification using vanadium dioxide beams in which the environmental temperature actively modulates asymmetric heat flow. In this three terminal device, there are two switchable states, which can be regulated by global heating. In the "Rectifier" state, we observe up to 28% thermal rectification. In the "Resistor" state, the thermal rectification is significantly suppressed (<1%). To the best of our knowledge, this is the first demonstration of solid-state active-thermal devices with a large rectification in the Rectifier state. This temperature-gated rectifier can have substantial implications ranging from autonomous thermal management of heating and cooling systems to efficient thermal energy conversion and storage.

Journal ArticleDOI
TL;DR: In this paper, a generalized switching technique for cascaded H-bridge (CHB) converters is proposed, which employs low-frequency switching for voltage balancing of the dc-link capacitors, and the high-frequency sinusoidal pulsewidth modulation switching for shaping the input ac current.
Abstract: In this paper, a generalized switching technique for cascaded H -bridge (CHB) converters is proposed. To take advantage of both low- and high-frequency modulation techniques, a hybrid modulation method is utilized. The proposed technique employs the low-frequency switching for voltage balancing of the dc-link capacitors, and the high-frequency sinusoidal pulse-width modulation switching for shaping the input ac current. Using the proposed technique, the stable operating region of CHB converters is extended. The proposed technique is capable of maintaining the dc voltages balanced even under critical operating conditions in which the load of one H-bridge cell is removed. The validity and effectiveness of the proposed method is confirmed by several simulation and experimental tests on a seven-level CHB rectifier.

Journal ArticleDOI
Minseob Shim1, Jungmoon Kim1, Junwon Jeong1, Sejin Park1, Chulwoo Kim1 
06 Mar 2014
TL;DR: A piezoelectric (PE) energy harvesting system with one-cycle maximum power point (MPP) sensing is presented, which simplifies the design of an MPP tracking algorithm and greatly reduces the tracking time.
Abstract: A piezoelectric (PE) energy harvesting system with one-cycle maximum power point (MPP) sensing is presented. The one-cycle MPP sensing method uses a very small size sensing capacitor and it can make the transducer output voltage reach the open circuit voltage within one cycle. The proposed MPP sensing block can sense the open circuit voltage with a proposed peak detector and stores the MPP voltage using charge sharing blocks. The one-cycle MPP sensing approach simplifies the design of an MPP tracking algorithm and greatly reduces the tracking time. All control blocks are self-biased and choose the higher voltage between the input or output voltages of the switching converter as a supply voltage (V $_{DD}$ ). Therefore, a voltage multiplexer and a low-power ramp generator with V $_{DD}$ independence are also proposed to control the system without additional DC to DC converter. The entire system has been implemented in a 0.35 µm BCDMOS process. It operates at 90 kHz with a 10-mH inductor. The total power dissipation of the controller is 10 µW at a V $_{DD}$ of 2.7 V. The MPP tracking time is only 9.09 ms/V when the input voltage of the switching converter is changed from 3.4 V to 1.2 V.

Journal ArticleDOI
TL;DR: It is revealed that the equalization of the active power component of duty cycles in the cascaded multilevel rectifier stage can be a good indicator of power balance in the dc/dc stage.
Abstract: This letter proposes a current sensorless controller for balancing the power in the dc/dc stage of a cascaded multilevel converter based solid state transformer. It is revealed that the equalization of the active power component of duty cycles in the cascaded multilevel rectifier stage can be a good indicator of power balance in the dc/dc stage. Additionally, the power balance of the dc/dc stage can guarantee the voltage balance in the rectifier stage if the differences among the power devices are negligible. Based on this principle, a novel power balance controller without sensing any current in the dc/dc stage is proposed. In the end, experimental results in a seven-level three-stage solid state transformer are provided for verifying the proposed method.

Journal ArticleDOI
TL;DR: The proposed protection scheme provides advantages, such as lower dv/dt stresses and lower voltage rating of thyristor switches in addition to providing full segregation between the converter semiconductor devices and ac grid during dc-side faults.
Abstract: Two-level voltage-source converters and half-bridge modular multilevel converters are among the most popular types of HVDC converters. One of their serious drawbacks is their vulnerable nature to dc-side faults, since the freewheeling diodes act as a rectifier bridge and feed the dc faults. The severity of dc-side faults can be limited by connecting double thyristor switches across the semiconductor devices. By turning them on, the ac current contribution into the dc side is eliminated and the dc-link current will freely decay to zero. The main disadvantages of this method are: high dv/dt stresses across thyristors during normal conditions, and the absence of bypassing for the freewheeling diodes during dc faults since they are sharing the fault current with thyristors. This paper proposes combining and connecting the double thyristor switches across the ac output terminals of the HVDC converter. The proposed protection scheme provides advantages, such as lower dv/dt stresses and lower voltage rating of thyristor switches in addition to providing full segregation between the converter semiconductor devices and ac grid during dc-side faults. A simulation case study has been carried out to demonstrate the effectiveness of the proposed scheme.

Journal ArticleDOI
TL;DR: The proposed ILPS has lower ripple voltages, lower dropout voltage, and higher PCE as compared with other designs, and on-chip delay compensation control with SR-latches is proposed.
Abstract: In this paper, a 13.56 MHz CMOS near-field inductive link power supply (ILPS) that can deliver 20 mA output current for implantable medical devices (IMDs) is proposed and fabricated. In the proposed ILPS, the pair of inductive link coils is constructed in the spiral shape with a ferrite core to save space and increase efficiency. Experimental results have shown that the near-field coils can transmit power at the resonant frequency of 13.56 MHz with the transmission efficiency up to 76.3%. The CMOS power regulator is composed of active voltage doubler rectifier (VD) and low-dropout regulators (LDOs). In the active VD with the comparator, the input offset voltage is adjustable for delay compensation and a start-up control circuit is added to achieve robust start-up mechanism. On-chip delay compensation control with SR-latches is proposed to prevent from error glitch switching on offset voltage control and achieve accurate delay compensation so that the reverse current conduction can be avoided and the efficiency can be increased. Three fully-integrated LDOs with rectifier output voltage of 2 V to 1.8 V are realized for analog (ALDO), digital (DLDO), and reference-voltage (RLDO) circuits. Thus the performance of individual LDO can be optimized. The measured output ripple voltage of the active VD is 10.4 mV. The power conversion efficiency (PCE) is 85% under 20 mA output current. The measured dropout voltage is 384 mV. As compared with other designs, the proposed ILPS has lower ripple voltages, lower dropout voltage, and higher PCE.

Proceedings ArticleDOI
01 Jun 2014
TL;DR: In this article, a multi-way transmission-line resistance compression networks (TLRCNs) and their application to rf-to-dc conversion is presented. But the performance of the proposed TLRCN plus rectifier system has not yet been evaluated.
Abstract: This work presents a development of multi-way transmission-line resistance compression networks (TLRCNs) and their application to rf-to-dc conversion. We derive analytical expressions for the behavior of TLRCNs, and describe two design methodologies applicable to both single- and multi-stage implementations. A 2.45-GHz 4-way TLRCN network is implemented and applied to create a resistance-compressed rectifier system that has narrow-range resistive input characteristics over a 10-dB power range. It is demonstrated to improve the impedance match to mostly-resistive but variable input impedance class-E rectifiers over a 10-dB power range. The resulting TLRCN plus rectifier system has >50% rf-to-dc conversion efficiency over a >10-dB input power range at 2.45 GHz (peak efficiency 70%), and SWR <;1.1 over a 7.7-dB range.

Journal ArticleDOI
Geng Tang1, Zheng Xu1
TL;DR: In this article, the authors proposed a LCC and MMC hybrid HVDC topology with dc line fault clearance capability suitable for bulk power transmission, in which the rectifier adopts a line commutated converter (LCC) and the inverters adopt two modular multilevel converters (MMCs).

Journal ArticleDOI
TL;DR: In this article, a microcontroller based electronic load controller (ELC) for efficient voltage regulation of a three-phase self-excited induction generator (SEIG) feeding single-phase loads in remote locations is presented.
Abstract: This study presents analysis, design and implementation of a microcontroller based electronic load controller (ELC) for efficient voltage regulation of a three-phase self-excited induction generator (SEIG) feeding single-phase loads in remote locations. The proposed ELC has an uncontrolled rectifier, a filtering capacitor, an insulated gate bipolar transistor switch and a series dump load. The pulse-width modulation (PWM) pulses with appropriate duty cycle are generated using the dsPIC30F6010 microcontroller. The duty ratio is determined based on the closed-loop control scheme which decides the amount of power diverted to the dump load. The proposed SEIG–ELC system demonstrates an effective power switching between the main load and the dump load thereby providing an efficient voltage regulation at the machine terminals. The controller is modelled in Matlab/Simulink and the simulated results are validated by experimental results.

Journal ArticleDOI
TL;DR: In this article, a new pulse width modulation technique, named selective harmonic compensation (SHC), was proposed to actively compensate the power system background harmonics, but still operates at very low-switching frequencies.
Abstract: Compensating the grid background harmonics in a grid-interfacing converter system, such as a drive system's active-front-end rectifier or a grid-connected inverter in a distributed generation system, is an effective method of reducing line side current harmonics. However, this harmonic compensation is particularly challenging in medium-voltage high-power applications (>1 MVA). This is mainly due to the low-switching frequency operation of high-power converters (300-800 Hz) to maintain low power loss. Therefore, the traditional tasks of active power filters with relatively high-switching frequency cannot be easily realized here. This paper proposes a new pulse width modulation technique, named selective harmonic compensation (SHC), which actively compensates the power system background harmonics, but still operates at very low-switching frequencies. Details of the proposed SHC are presented. An SHC application example on a high-power current-source rectifier is provided in this paper. The simulations and experiments show that the proposed SHC scheme can effectively compensate the system background harmonics and improve the line current harmonic performance.

Journal ArticleDOI
TL;DR: In this paper, a piecewise analytical function is proposed and applied to investigate the steady-state behavior of series-parallel resonant converter operated in a discontinuous current mode.
Abstract: A piecewise analytical function is proposed and applied to investigate the steady-state behavior of series-parallel resonant converter operated in a discontinuous current mode. The converter shows two sequences of the equivalent circuits alternatively operated in the discontinuous current mode with different output voltages. To get the response time of current in one resonance, a successive solving process based on the state-space method is presented analytically in each sequence. This solving process can describe the complicated behavior resulting from the load rectifier, which makes the output capacitor appear or disappear several times in one switching period. By introducing the output voltage coefficient and the principle of energy transmission balance, the steady-state model is deduced afterward. This model is accurate and simple, making it helpful to design and optimize the converter conveniently. An excellent agreement is obtained when comparing numerical values calculated by the proposed model to the simulation and to the experimental results.

Journal ArticleDOI
TL;DR: The fast Fourier transform analysis of the output current of the converters suggests superiority of the series Z- source matrix converter over the cascaded Z-source matrix converter.
Abstract: The series Z-source network, an expansion of the popular concept of the Z-source dc link, was originally proposed for boosting the output voltage of power electronic inverters. In this paper, that idea is extended on a three-phase indirect matrix converter. The converter is based on the ultrasparse matrix topology characterized by the minimum number of semiconductor switches. The series Z-source network is placed between the three-switch input rectifier stage and the six-switch output inverter stage in either the positive or the negative rail. A brief shoot-through state produces the voltage boost. An optimal pulsewidth modulation (PWM) technique is developed for higher boosting capability of the converter and minimization of switching losses. A comparison is made between the matrix converters employing series and conventional cascade Z-source networks. The inrush current and Z-source capacitor's voltage are reduced in the series Z-source matrix converter. Furthermore, the fast Fourier transform analysis of the output current of the converters suggests superiority of the series Z-source matrix converter over the cascaded Z-source matrix converter.

Journal ArticleDOI
TL;DR: In this article, the authors proposed an indirect matrix converter (IMC) topology with dual three-phase outputs and its effective carrier-based pulse width modulation (PWM) method, which is easily implemented by using only one symmetrical triangular carrier signal to generate the PWM signals for a rectifier and five-leg inverter.
Abstract: This paper proposes an indirect matrix converter (IMC) topology with dual three-phase outputs and its effective carrier-based pulse width modulation (PWM) method. The proposed IMC topology can independently supply ac power for two three-phase loads from a single three-phase ac power source. This converter consists of a rectifier stage used in traditional three-phase IMC and a five-leg inverter. Besides a proposed IMC topology, the carrier-based PWM method suitable for this converter is also introduced. The proposed PWM method is easily implemented by using only one symmetrical triangular carrier signal to generate the PWM signals for a rectifier and five-leg inverter. Proposed IMC topology features the advantages of conventional three-phase IMC, such as sinusoidal input/output current waveforms, controllable input power factor, and simple commutation at the rectifier stage. Analysis, simulation, and experimental results are provided to demonstrate the advantages of the proposed IMC topology with dual three-phase outputs and to validate the effectiveness of the applied modulation strategy.

Patent
18 Mar 2014
TL;DR: An apparatus for supplying power includes a power input configured to receive electrical current from a fluorescent lamp fixture ballast, a rectifier connected to the power input, a constant current driver connected to an output of the rectifier, and a power output as discussed by the authors.
Abstract: An apparatus for supplying power includes a power input configured to receive electrical current from a fluorescent lamp fixture ballast, a rectifier connected to the power input, a constant current driver connected to an output of the rectifier, and a power output.