The Experts below are selected from a list of 1761 Experts worldwide ranked by ideXlab platform
Li Zhang - One of the best experts on this subject based on the ideXlab platform.
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one cycle control for Electrolytic Capacitor less second harmonic current compensator
IEEE Transactions on Power Electronics, 2018Co-Authors: Li Zhang, Xinbo Ruan, Xiaoyong RenAbstract:The input power of the single-phase power factor correction ac–dc converter pulsates at twice the line frequency, while the output power of the single-phase dc–ac inverter pulsates at twice the output frequency. The pulsating power will result in second harmonic current (SHC) in the ac–dc converter and dc–ac inverter. In this paper, Electrolytic Capacitor-less second harmonic current compensator (SHCC) is presented to compensate the SHC. The SHCC has two operating modes, namely, charging mode and discharging mode. To achieve an excellent SHC compensation performance, a hybrid one-cycle control (OCC) is proposed to regulate the port current of the SHCC, and the SHCC can stably operate in both the charging mode and discharging mode. To avoid the mode detection required in the hybrid OCC and ensure seamless transition between the two modes, the OCC with dc bias is further proposed. Besides, a peak voltage control is proposed to regulate the storage Capacitor voltage in the SHCC for reducing the power losses of the SHCC at light load. A 1-kW two-stage inverter with the SHCC is fabricated and tested, and the experimental results are provided to verify the effectiveness of the proposed control schemes.
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Adaptive Voltage Control for Bidirectional Converter in Flicker-Free Electrolytic Capacitor-Less AC–DC LED Driver
IEEE Transactions on Industrial Electronics, 2017Co-Authors: Jiexiu He, Xinbo Ruan, Li ZhangAbstract:In this paper, an Electrolytic Capacitor-less ac-dc light-emitting diode (LED) driver, consisting of a power factor correction (PFC) converter and a buck/boost bidirectional converter, is investigated. The buck/boost bidirectional converter is connected in parallel with the output of the PFC converter and serves to absorb the second harmonic current in the PFC output current, leaving only a dc component to drive the LEDs. This paper proposes an adaptive voltage control scheme for the storage Capacitor in the buck/boost bidirectional converter to make the storage Capacitor voltage adaptively decrease as the load becomes lighter. Hence, the power losses of the buck/boost bidirectional converter could be reduced at light load. Experimental results are provided to verify the effectiveness of the proposed control scheme.
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feed forward scheme for an Electrolytic Capacitor less ac dc led driver to reduce output current ripple
IEEE Transactions on Power Electronics, 2014Co-Authors: Yang Yang, Xinbo Ruan, Li ZhangAbstract:In order to achieve high-efficiency, high-power-factor, high-reliability, and low-cost, a flicker-free Electrolytic Capacitor-less single-phase ac/dc light emitting diode (LED) driver is investigated in this paper. This driver is composed of a power-factor-correction (PFC) converter and a bidirectional converter. The bidirectional converter is used to absorb the second harmonic component in the output current of the PFC converter, thus producing a pure dc output to drive the LEDs. The spectrum of the output Capacitor voltage of the bidirectional converter is analyzed, indicating that the output Capacitor voltage contains harmonic components at multiples of twice the line frequency apart from the dc component and second harmonic component. A feed-forward control scheme with a series of calculation operation is proposed to obtain the desired modulation signal, which contains the corresponding harmonic components, to ensure the bidirectional converter fully absorb the second harmonic current in the output of the PFC converter. Finally, a 33.6 W prototype is fabricated and tested in the lab, and the experiment results show that the proposed control scheme greatly reduces the ripple of the LED driving current.
G Q Zhang - One of the best experts on this subject based on the ideXlab platform.
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a novel lifetime prediction for integrated led lamps by electronic thermal simulation
Reliability Engineering & System Safety, 2017Co-Authors: Bo Sun, Xuejun Fan, Cheng Qian, G Q Zhang, Jiajie Fan, Willem Van DrielAbstract:Abstract In this paper, an integrated LED lamp with an Electrolytic Capacitor-free driver is considered to study the coupling effects of both LED and driver’s degradations on lamp’s lifetime. An Electrolytic Capacitor-less buck-boost driver is used. The physics of failure (PoF) based electronic thermal simulation is carried out to simulate the lamp’s lifetime in three different scenarios: Scenario 1 considers LED degradation only, Scenario 2 considers the driver degradation only, and Scenario 3 considers both degradations from LED and driver simultaneously. When these two degradations are both considered, the lamp’s lifetime is reduced by about 22% compared to the initial target of 25,000 h. The results of Scenario 1 and 3 are close to each other. Scenario 2 gives erroneous results in terms of luminous flux as the LED’s degradation over time is not taken into consideration. This implies that LED’s degradation must be taken into considerations when LED and driver’s lifetimes are comparable.
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pof simulation assisted reliability prediction for Electrolytic Capacitor in led drivers
IEEE Transactions on Industrial Electronics, 2016Co-Authors: Bo Sun, Xuejun Fan, Cheng Qian, G Q ZhangAbstract:The temperature of Electrolytic Capacitor in light-emitting diode (LED) drivers continuously increases under operation conditions, thus the Capacitors degrade faster than that with constant temperature assumption. In this paper, a physics-of-failure (PoF)-based reliability prediction methodology is developed for LED drivers to consider the temperature change of Electrolytic Capacitor. SPICE simulation, compact thermal modeling, and Monte Carlo simulation are integrated to predict the failure rate distribution of an Electrolytic Capacitor of given LED driver systems. The simulation results agree well with the accelerated test results for an RC linear AC–DC converter. Furthermore, a single inductor buck–boost DC–DC converter is simulated to understand the degradation behavior of Electrolytic Capacitor. It has been found that the temperature of an output stage Capacitor increases significantly during operation time. The Capacitor's performance without taking temperature change into account results in an overestimated driver lifetime by more than 38% for the selected case study.
Qianhong Chen - One of the best experts on this subject based on the ideXlab platform.
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a pfc single coupled inductor multiple output led driver without Electrolytic Capacitor
IEEE Transactions on Power Electronics, 2019Co-Authors: Hao Wu, Siuchung Wong, Qianhong ChenAbstract:In order to lower the system cost and reduce the form factor, single-inductor multiple-output (SIMO) converters are intensely developed for on-chip dc–dc converters and offline light emitting diode (LED) drivers. However, existing single-stage power factor correction (PFC) SIMO LED drivers are usually designed with Electrolytic Capacitors, leading to a short-life span and limited range of operation temperature. In this paper, based on a single dual-winding coupled inductor, a SIMO LED driver with PFC function is proposed without the requirement of Electrolytic Capacitors, where a small storage capacitance is used to actively decouple the ac and dc input powers. Compared with previous works, the proposed PFC SIMO LED driver has some additional benefits, including a smaller line filter, multiple output currents without double line frequency ripple, and a faster output regulation. With appropriate control strategy, an independent output regulation can be achieved for each output channel. Meanwhile, to improve the converter efficiency, the energy flow of the converter is optimized with an inductor current programming technique. Finally, the proposed Electrolytic Capacitorless PFC SIMO LED driver is developed, designed, tested, and compared with a single-stage SIMO design without active power decoupling.
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single phase led drivers with minimal power processing constant output current input power factor correction and without Electrolytic Capacitor
IEEE Transactions on Power Electronics, 2018Co-Authors: Hao Wu, Siuchung Wong, Qianhong ChenAbstract:High-power light-emitting diodes (LEDs) having properties of high luminous efficacy and long life span are becoming a major light source for general illumination. To fully utilize the advantages of LED in lighting applications, the offline power supply that drives the LED should possess the following features: high efficiency, long life span, high input power factor, and (COC). In this paper, high efficiency is achieved by using a minimal power processing (MPP) configuration. Near perfect power factor correction (PFC) is achieved by a simple dual-output disc-ontinuous-conduction-mode (DCM) pulse-width-modulated (PWM) front-end converter. One output of the front-end converter is connected to the LED load using a control switch. The other output is connected directly to a dc storage Capacitor cascaded with a downstream DCM PWM converter driving the same LED load to achieve COC driving. The power flow is controlled to achieve the required MPP that can also reduce the storage capacitance by balancing only the ac input ripple power and the dc output power without power recycling. Thus, the design requires no Electrolytic Capacitor, hence extending the system life span. The achievement of input PFC, MPP, and COC requires design tradeoff among design freedom, ease of control and component count. LED drivers having all these properties are developed, designed, and tested.
Hitoshi Haga - One of the best experts on this subject based on the ideXlab platform.
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direct dc link current control considering voltage saturation for realization of sinusoidal source current waveform without passive components for ipmsm drives
IEEE Transactions on Industrial Electronics, 2018Co-Authors: Hitoshi Haga, Yuki YokokuraAbstract:In order to reduce the cost and the size of a single-phase to three-phase power converter, an Electrolytic Capacitor-less single-phase to three-phase inverter is proposed. As the system does not have energy storage, such as an Electrolytic Capacitor, it results in source current harmonics due to the spatial harmonics of the motor. Adding an inductor for filtering the source current harmonics increases the cost and size of the system. In order to improve the source current waveform without adding passive components, it is necessary to reduce the source current harmonics via inverter control. However, when the inverter control reduces the source current harmonics, voltage saturation of the inverter causes source current distortion. At the rated speed and load, the voltage saturation region amounts to 40–50% of the source period, and the source current harmonics do not meet the guideline of IEC 61000-3-2. This paper proposes a direct dc-link current control (DDCCC) considering voltage saturation and the dq -axis current reference calculation for applying the DDCCC, which reduces the source current harmonics below the guideline. The effectiveness of the proposed method is verified through experiments.
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fine current harmonics reduction method for Electrolytic Capacitor less and inductor less inverter based on motor torque control and fast voltage feedforward control for ipmsm
IEEE Transactions on Industrial Electronics, 2017Co-Authors: Hitoshi Haga, Yuki YokokuraAbstract:In an Electrolytic Capacitor-less and inductor-less single-phase-to-three-phase inverter, the inverter controls not only the motor but also the input power factor. If the motor has large spatial harmonics, the harmonics flow into the input current at the source side. This paper proposes two new power factor correction methods to improve the input current response of a fundamental frequency and to reduce the input current harmonics. The first method realizes high-power-factor operation by adopting a motor torque control strategy that focuses on the relationship between the input power and the motor torque. The motor torque control allows for designing the gain of the controller to realize a high power factor and enhances the robustness against motor parameter variations. The second method improves the inverter output power response by using a fast voltage feedforward control (FVFFC) that controls the inverter output power directly by focusing on the average dc-link current. The FVFFC reduces the input current harmonics owing to the spatial harmonics of an interior permanent-magnet synchronous motor, and the input current harmonics satisfy the recommendations of guideline JIS 61000-3-2. The effectiveness of the proposed methods is verified through experiments.
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Instantaneous voltage vector control and d-axis current reference calculation to improve source current waveform for an Electrolytic Capacitor-less single-phase to three-phase inverter
2016 19th International Conference on Electrical Machines and Systems (ICEMS), 2016Co-Authors: Hitoshi Haga, Yuki YokokuraAbstract:In an Electrolytic Capacitor-less single-phase to three-phase inverter, a control bandwidth limitation adversely affects the source current response. Since the inverter does not energy buffer such as an Electrolytic Capacitor, the spatial harmonics of motor cause the source current harmonics. Moreover, d-axis current reference of the system is obtained by trial and error in off-line. This paper proposes an instantaneous voltage vector control that focuses the relationship of the voltage vector and the average DC-link current to improve the source current waveform. Moreover, d-axis current reference for the system is calculated on the basis of the analysis of the instantaneous voltage vector control. The effectiveness of the proposed method is verified by numerical simulation.
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Harmonic current reduction control of IPMSM drive inverter without inductor or Electrolytic Capacitor
IECON 2016 - 42nd Annual Conference of the IEEE Industrial Electronics Society, 2016Co-Authors: Kodai Abe, Hitoshi Haga, Kiyoshi Ohishi, Yuki YokokuraAbstract:In a single-phase to three-phase inverter that does not have an inductor or Electrolytic Capacitor, the inverter must control not only the motor but also the input power factor because there is no power factor correction circuit or energy buffer. To improve the input power factor, several control methods are proposed. However, if the motor has large spatial harmonics caused by the rotor structure, the bandwidth limitations of the control system adversely affect the source current response and thereby cause source current harmonics. This paper proposes a harmonic current reduction controller that makes it possible to obtain a sinusoidal source current. The proposed controller focuses on the relationship between the source current and the average DC-link current and controls the source current using a feedforward control method. The effectiveness of the proposed method is experimentally verified.
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Input current harmonics reduction control for Electrolytic Capacitor less inverter based IPMSM drive system
2014 International Power Electronics Conference (IPEC-Hiroshima 2014 - ECCE ASIA), 2014Co-Authors: Hitoshi HagaAbstract:This paper proposes a current harmonics reduction method to improve the input current waveform of Electrolytic Capacitor less single-phase to three-phase power converters. Typically, the back electromotive force (EMF) on interior permanent magnet (IPM) motor is not sinusoidal and contains harmonics caused by the rotor structure; therefore, it causes harmonic distortion in the motor control system and generates harmonics in the input current. This paper analyzes the cause of the input current harmonics aims to the back EMF and the d-q axis current controller. This paper proposes two control methods to reduce the current harmonics distortion. The first method filters out the harmonics of feedback d-q axis current by using harmonics filter. The second method compensates the d-q axis voltage references to reduce the input current harmonics. The d-q axis compensation voltages are obtained by feed forward controller. The maximum power factor of the proposed method obtains 98.47 %. The experimental results confirm that the proposed control method clears the guideline EN61000-3-2.
Xinbo Ruan - One of the best experts on this subject based on the ideXlab platform.
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a virtual impedance based control scheme for modular Electrolytic Capacitor less second harmonic current compensator
IEEE Transactions on Industrial Electronics, 2021Co-Authors: Xinze Huang, Xinbo Ruan, Jie Fang, Shiqi KanAbstract:The second harmonic current compensator (SHCC) can be added into the single-phase converters for compensating the second harmonic current (SHC) and thus removing the undesired Electrolytic Capacitor. In this paper, a virtual impedance, which is in the form of a Capacitor and a resistor connected in parallel, is introduced to be in parallel at the bus-side port of the SHCC for effectively compensating the SHC while guaranteeing the system stability. This virtual parallel impedance is realized by feeding forward the bus-side port voltage of the SHCC, and thus the SHCC can be modular designed. The closed-loop parameter design of the SHCC is also presented. A 3.3-kW prototype of a two-stage single-phase power factor correction converter is built and tested in the laboratory, and the experimental results verify the effectiveness and feasibility of the proposed control method.
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one cycle control for Electrolytic Capacitor less second harmonic current compensator
IEEE Transactions on Power Electronics, 2018Co-Authors: Li Zhang, Xinbo Ruan, Xiaoyong RenAbstract:The input power of the single-phase power factor correction ac–dc converter pulsates at twice the line frequency, while the output power of the single-phase dc–ac inverter pulsates at twice the output frequency. The pulsating power will result in second harmonic current (SHC) in the ac–dc converter and dc–ac inverter. In this paper, Electrolytic Capacitor-less second harmonic current compensator (SHCC) is presented to compensate the SHC. The SHCC has two operating modes, namely, charging mode and discharging mode. To achieve an excellent SHC compensation performance, a hybrid one-cycle control (OCC) is proposed to regulate the port current of the SHCC, and the SHCC can stably operate in both the charging mode and discharging mode. To avoid the mode detection required in the hybrid OCC and ensure seamless transition between the two modes, the OCC with dc bias is further proposed. Besides, a peak voltage control is proposed to regulate the storage Capacitor voltage in the SHCC for reducing the power losses of the SHCC at light load. A 1-kW two-stage inverter with the SHCC is fabricated and tested, and the experimental results are provided to verify the effectiveness of the proposed control schemes.
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Adaptive Voltage Control for Bidirectional Converter in Flicker-Free Electrolytic Capacitor-Less AC–DC LED Driver
IEEE Transactions on Industrial Electronics, 2017Co-Authors: Jiexiu He, Xinbo Ruan, Li ZhangAbstract:In this paper, an Electrolytic Capacitor-less ac-dc light-emitting diode (LED) driver, consisting of a power factor correction (PFC) converter and a buck/boost bidirectional converter, is investigated. The buck/boost bidirectional converter is connected in parallel with the output of the PFC converter and serves to absorb the second harmonic current in the PFC output current, leaving only a dc component to drive the LEDs. This paper proposes an adaptive voltage control scheme for the storage Capacitor in the buck/boost bidirectional converter to make the storage Capacitor voltage adaptively decrease as the load becomes lighter. Hence, the power losses of the buck/boost bidirectional converter could be reduced at light load. Experimental results are provided to verify the effectiveness of the proposed control scheme.
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feed forward scheme for an Electrolytic Capacitor less ac dc led driver to reduce output current ripple
IEEE Transactions on Power Electronics, 2014Co-Authors: Yang Yang, Xinbo Ruan, Li ZhangAbstract:In order to achieve high-efficiency, high-power-factor, high-reliability, and low-cost, a flicker-free Electrolytic Capacitor-less single-phase ac/dc light emitting diode (LED) driver is investigated in this paper. This driver is composed of a power-factor-correction (PFC) converter and a bidirectional converter. The bidirectional converter is used to absorb the second harmonic component in the output current of the PFC converter, thus producing a pure dc output to drive the LEDs. The spectrum of the output Capacitor voltage of the bidirectional converter is analyzed, indicating that the output Capacitor voltage contains harmonic components at multiples of twice the line frequency apart from the dc component and second harmonic component. A feed-forward control scheme with a series of calculation operation is proposed to obtain the desired modulation signal, which contains the corresponding harmonic components, to ensure the bidirectional converter fully absorb the second harmonic current in the output of the PFC converter. Finally, a 33.6 W prototype is fabricated and tested in the lab, and the experiment results show that the proposed control scheme greatly reduces the ripple of the LED driving current.
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boost flyback single stage pfc converter with large dc bus voltage ripple
Applied Power Electronics Conference, 2009Co-Authors: Kai Yao, Xinbo RuanAbstract:The life time of lighting emitting diode (LED) can reach 100,000 hours. Compared to other power supplies, the power supply for LED requires long life time in addition to high efficiency and high power factor. Electrolytic Capacitor has the shortest life in switching power supplies. In order to prolong the life time of power supply, it is necessary to reduce the storage capacitance and use other kind of Capacitor instead of Electrolytic Capacitor. In this paper the relationship between storage Capacitor voltage ripple and capacitance is analyzed. The PF and DC bus voltage of the Boost-Flyback single-stage PFC converter is analyzed. When Flyback works in DCM, the DC bus voltage is independent of the load. Then the capacitance is reduced and the voltage ripple is increased, in this way, the high voltage ceramic Capacitor can be used instead of Electrolytic Capacitor. The analysis is verified by the experiment.