Single-Stage LED Driver with Dimming and Universal Input Voltage Capability

2020 ◽  
Author(s):  
Giancarlo Clerici Daros ◽  
João Pedro Scherer Cipriani ◽  
Maikel Fernando Menke ◽  
Álysson Raniere Seidel

This paper presents a boost bridgeless totem-pole converter operating as power factor correction (PFC) stage integrated with a half-bridge LLC resonant converter as power control (PC) stage. The resultant single-stage converter yields in an effective integration, reducing the number of switches from 4 to 2 (50% reduction). This integrated topology aims decreasing conduction and commutation power losses and, moreover, achieving high power factor (PF), low total harmonic distortion (THD) and good efficiency. The converter is designed to have a fixed bus voltage, which is controlled by changing the half-bridge duty cycle under universal input voltage (UIV). However, since the HB duty cycle also affects the LLC converter due to their integration, a variable inductor is employed to control the LLC impedance and achieve a controlled output current and dimming capability, consequently a constant frequency operation is achieved. Simulation results are presented to verify the theorical analysis, through a 100 W LED luminaire. The results show voltage and current levels in the topology, as well as PF and THD levels in compliance with IEC 61000-3-2. Moreover, it is shown the feasibility of output current control capability through variable inductor even with HB duty cycle variation.

2013 ◽  
Vol 392 ◽  
pp. 676-681
Author(s):  
Lin Bo Wang ◽  
Hong Kun He ◽  
Lei Shi ◽  
Jin Jin Yang ◽  
Qian Ni Feng

This paper proposes a new digital constant-current control method for high-power LED drive based on buck-boost topology. In this control system, buck-boost topology is used as the power conversion. The output voltage can be either higher or lower than the input voltage in buck-boost topology. Therefore, it solves the problem that in the buck topology the input voltage is required to be always higher than the output voltage. Furthermore, according to the input and output parameters, the duty cycle data which are used to maintain output current constant can be calculated in advance, and stored in the embedded chip. Thus, it can reduce the calculation of the embedded chip and solves the problem that the existing digital constant-current controllers need the high-speed analog-to-digital converter. In addition, in order to reduce the error generated in above calculation, the double threshold feedback circuit is used to fine-tune the duty cycle and makes the output current more steady and accurate. Meanwhile, due to adopting full-digital control, the brightness and flicker frequency of load LED can be conveniently regulated by modifying the system firmware. Therefore, this method can apply to the device of illumination, lighting decoration, visible light communication and so on.


Electronics ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 1340
Author(s):  
Yih-Her Yan ◽  
Hung-Liang Cheng ◽  
Chun-An Cheng ◽  
Yong-Nong Chang ◽  
Zong-Xun Wu

A novel single-switch single-stage high power factor LED driver is proposed by integrating a flyback converter, a buck–boost converter and a current balance circuit. Only an active switch and a corresponding control circuit are used. The LED power can be adjusted by the control scheme of pulse–width modulation (PWM). The flyback converter performs the function of power factor correction (PFC), which is operated at discontinuous-current mode (DCM) to achieve unity power factor and low total current harmonic distortion (THDi). The buck–boost converter regulates the dc-link voltage to obtain smooth dc voltage for the LED. The current–balance circuit applies the principle of ampere-second balance of capacitors to obtain equal current in each LED string. The steady-state analyses for different operation modes is provided, and the mathematical equations for designing component parameters are conducted. Finally, a 90-W prototype circuit with three LED strings was built and tested. Experimental results show that the current in each LED string is indeed consistent. High power factor and low THDi can be achieved. LED power is regulated from 100% to 25% rated power. Satisfactory performance has proved the feasibility of this circuit.


Author(s):  
Peethala Rajiv Roy ◽  
P. Parthiban ◽  
B. Chitti Babu

Abstract This paper deals with implementation of a single-phase three level converter system under low voltage condition. The frequency of the switches is made constant and involves change in ${t_{on}}$ and ${t_{off}}$ duration. For this condition the pulse width modulation control scheme for a single phase three level rectifier is developed to improve the power quality. The hysteresis current control technique is adopted to bring forth three-level PWM on the dc side of the bridge rectifier and to achieve high power factor and low harmonic distortion. Based on the proposed control scheme, the line current is driven to follow the sinusoidal current command which is in phase with the supply voltage. By using three-level voltage pattern the blocking voltage of each power device is clamped to half of the dc link voltage. The simulation and experimental results of 20W converter under low input voltage condition are shown to verify the circuit performance. Open loop simulation and hardware tests are implemented by applying a low voltage of 15 V(rms) on the input side.


Author(s):  
R. Palanisamy ◽  
K. Vijayakumar ◽  
Aishwarya Bagchi ◽  
Vachika Gupta ◽  
Swapnil Sinha

<p>This paper proposes implementation of coupled inductor based 7 level inverter with reduced number switches. The inverter which generates the sinusoidal output voltage by the use of coupled inductor with reduced total harmonic distortion. The voltage stress on each switching devices, capacitor balancing and common mode voltage can be minimized. The proposed system which gives better controlled output current and improved output voltage with diminished THD value. The switching devices of the system are controlled by using hysteresis current control algorithm by comparing the carrier signals with constant pulses with enclosed hysteresis band value. The simulation and experimental results of the proposed system outputs are verified using matlab/Simulink and TMS320F3825 dsp controller respectively.</p>


2013 ◽  
Vol 3 (1) ◽  
pp. 5-11 ◽  
Author(s):  
Yuriy Denisov ◽  
Serhii Stepenko

Abstract The problems, devoted to power quality and particularly power factor correction, are of great importance nowadays. The key requirements, which should be satisfied according to the energy efficiency paradigm, are not limited only by high quality of the output voltage (low total harmonic distortion), but also assume minimal power losses (high efficiency) in the power factor corrector (PFC). It could be satisfied by the use of quasi-resonant pulse converter (QRPC) due to its high efficiency at high switching frequency instead of the classical pulse-width modulated (PWM) boost converter. A dynamic model of QRPC with zero current switching (ZCS) is proposed. This model takes into account the main features of QRPC-ZCS as a link of a PFC closed-loop system (discreteness, sharp changes of parameters over switching period, input voltage impact on the gain). The synthesized model is also valid for conventional parallel pulse converter over an active interval of commutation. The regulator for current loop of PFC was synthesized based on digital filter using proposed model by the criterion of fast acting.


Author(s):  
R. S. Bajpai ◽  
Amarjeet Singh

This paper deals with sliding mode control of converter and its application to distributed generation. Sliding mode control is used to control the voltage source converter in voltage or current control mode. Modeling and control of H bridge converter system using sliding mode control is proposed. Easily implemented sliding surfaces provide prominent dynamic characteristics against changes in the load and in the input voltage. Distribution static compensator (DSTATCOM) is used to control the voltage of the bus to which it is connected to a balance sinusoid in respect of the harmonic distortion in supply or load side. A variable wind turbine generator is used to produces a variable DC voltage which is placed as input voltage source to converter of DSTATCOM. A control strategy for grid voltage control using DSTATCOM in voltage control mode has been implemented in respect of the wind variation. The results are validated using PSCAD/EMTDC simulation studies.


2004 ◽  
Vol 13 (03) ◽  
pp. 557-576
Author(s):  
CHUNG-WOOK ROH ◽  
GUN-WOO MOON ◽  
MYUNG-JOONG YOUN

This paper presents a new single-stage single-switched forward converter with magnetic coupled nondissipative snubber, which gives good power factor correction (PFC), low current harmonic distortion, and tight output voltage regulation. The proposed converter features low switch current and voltage stresses, essential for the design of a single-stage power factor correction converter. The prototype shows that the IEC1000-3-2 requirements are met satisfactorily with nearly unity power factor. This proposed converter with magnetic coupled nondissipative snubber is particularly suited for power supply applications with low power level.


Author(s):  
S. T. Siddharthan ◽  
O. R. Sai Ayyappa ◽  
K. Karthik Kumar

This paper provides the operation and analysis of three phase two quadrant controlled converter. In this paper, the converter is being checked with varying the duty cycle for two different loads R and RL. The Power factor, Total Harmonic Distortion (THD) and efficiency are better for very low duty cycle which is the same for RL load. This analysis estimates THD and power factor at various conditions. The FFT analysis is done to find the harmonic content present in the input current waveform. This analysis is done using MATLAB software.


Energies ◽  
2020 ◽  
Vol 13 (5) ◽  
pp. 1114
Author(s):  
Sung-Hun Kim ◽  
Bum-Jun Kim ◽  
Jung-Min Park ◽  
Chung-Yuen Won

Input-Series-Output-Parallel (ISOP) converters, a kind of modular converter, are used in high-input voltage and high-output current applications. In ISOP converters, Input Voltage Sharing (IVS) and Output Current Sharing (OCS) should be implemented for stable operation. In order to solve this problem, this paper proposes a decentralized control method. In the proposed control, output current reference is changed according to the decentralized control characteristic in individual current control loops. In this way, the proposed control method is able to implement IVS and OCS without communication. Also, this method can be easily used in current control loops and has high reliability compared to conventional control methods that require communication. In this paper, the operation principle is described to elucidate the proposed control and a small signal model of an ISOP converter is also implemented. Based on the small signal model, IVS stability analysis is performed using pole-zero maps with varying coefficients and control gains. In addition, the current control loop is designed in a stable region. In order to demonstrate the proposed control method, a prototype ISOP converter is configured using full-bridge converters. The performance of IVS and OCS in an ISOP converter is verified by experimental result.


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