A High Power Factor Rectifier Based on Buck Converter Operating in Discontinuous Inductor Current Mode

The diode clamped multilevel inverter (DCMLI) is an attractive high voltage multilevel inverter due to its robustness. The main draw back of the DCMLI is dc link capacitor voltage imbalance. A diode clamped inverter has been used in this research. The method used to balance the dc link capacitors is based on auxiliary switch-mode circuits, which are operated in a discontinuous inductor current mode. This research is focused on how to use auxiliary SMPS circuits to start up, balance, and shutdown the inverter. These functions are an issue in high voltage applications of the multilevel inverter. Simulation and experimental results are presented for the proposed auxiliary circuits operational technique.

Multi-pulse train (MPT) control technique, a novel control technique for the control of switching DC-DC converters is proposed here. Unlike traditional pulse train (PT) control technique, which realises the output voltage regulation of switching DC-DC converters by a combination of two different control pulses, MPT control technique extends these two different pulses to multi-level pulses, and thus overcomes the drawback of relatively large output voltage ripple of PT control switching DC-DC converters. Buck converter operating in discontinuous conduction mode is taken as an example to illustrate the operation principle of MPT control technique. Comprehensive analysis on the control pulse combination within a MPT repetition cycle is performed and verified by simulation and experimental results. It also shows that MPT control buck converter has much lower output voltage ripple than PT control technique, and much better transient performance than traditional pulse-width modulation buck converter.

The buck converter with LC input filter operating in discontinuous capacitor voltage mode has inherent power factor correction properties and continuous input current. The paper presents a detailed analysis of the converter operating in this mode, leading to design criteria. Finally, experimental results for a 48 V/sub dc//100 W converter are presented.

Buck converters are widely used in industry, traction, and renewables. However, most of the researches in the control of these converters are devoted to low-power applications with discontinuous current mode, or use very complex control theory without taking into account current limit and external disturbances such as rapid input voltage and load current deviations. This paper proposes a nested loop control, which idea was taken from the motor drive control theory and implemented for the buck converter of auxiliary power supply of subway train. Simulation results are presented in the paper considering variation of the disturbances as well as inaccuracies of the sensors.

In order to minimize the losses in high frequency converters such as the Quasi-Resonant (QR) Buck converter, the Zero Voltage Switching (ZVS) technique is used. Quasi-resonant Buck converters are implanted by adding reactive elements to conventional topologies, and the addition of an extra capacitor and inductor regarding the switch of a Buck converter. Such technologies nowadays are widely used as power supplies for certain battery chargers. A ZVS QR Buck converter is proposed in this paper. After having reminded the principle of operation of a classic ZVS QR Buck converter. Some simulations results are performed in SIMPLORER and ISIS soft-wares to validate the proposed ZVS QR Buck converter. Experimental results has been made on a laboratory prototype. Experimental results obtained on a laboratory prototype are presented to verify the

This manuscript deals about the configuration of a power factor correction (PFC) converter feeding a drive of brushless DC (BLDC) motor for medium and low power equipment. The front-end PFC converter working in discontinuous inductor current mode (DICM) is applied for regulating the DC link voltage and PFC is achieved inherently. The BLDC motor speed is adjusted by regulating the DC link voltage of voltage source inverter (VSI) feeding to motor. The DC link voltage of drive system is maintained by a single DC voltage actuator. A prototype is developed for evaluating the performances of anticipated drive for the speed control over a broad range. The performance of anticipated drive is also validated for its function at varying AC mains voltages (90V–265V). Test results for power quality (PQ) parameters are compared with restrictions of power quality standard IEC 61000-3-2.

This paper presents a Bridgeless Cuk converter-fed brushless DC (BLDC) motor drive using inverter technology for an air conditioning system. Inverter technology is the latest progression of technology for the optimum speed control of motors used in compressors of air conditioners. This technology helps to vary the speed of the compressor motor by varying the output voltage of the Cuk converter feeding the BLDC motor rather than merely turning on and turning off. In addition this drive utilizes a bridgeless configuration of Cuk converter operating in discontinuous inductor current mode (DICM) for the power factor correction/improvement at the AC mains for a wide range of speed control. Bridgeless configuration eliminates the need for front end diode bridge rectifiers (DBR). This helps to reduce conduction losses as well as the number of semiconductor devices used.

This paper presents a single-stage isolated power factor corrected power supply (SSIPP) fed permanent magnet brushless DC (BLDC) motor drive. An advantage of fast voltage regulation with single voltage control loop of SSIPP is utilised to develop a power factor correction (PFC) based BLDC motor drive. The speed of BLDC motor is controlled by varying the DC link voltage of the voltage source inverter (VSI) feeding BLDC motor using a single voltage sensor. A boost-flyback SSIPP operating in discontinuous inductor current mode (DICM) is used for the voltage control with improved power quality at AC mains. A fundamental frequency switching of VSI is used instead of pulse width modulation (PWM) switching to avoid high frequency switching losses in it. The performance of the proposed BLDC motor drive is evaluated for wide range of speed control with power quality indices with-in the recommended limits of international power quality standards such as IEC 61000-3-2.

A power factor corrected (PFC) Canonical Switching Cell (CSC) converter is proposed for low power consumer light-emitting diode (LED) lighting applications. The proposed CSC converter is intended to operate in discontinuous inductor current mode (DICM) to realize improved power quality performance. In low power consumer lighting applications, the CSC converter is more suitable due to its many benefits such as high energy storing capability, high input and low output impedance as compared to other buck-boost converters. This paper describes the different performance parameters of the proposed converter. Application of lighting load is also examined in view of achieving improved power quality over the wide input AC mains voltage. The measured converter efficiency of a laboratory prototype is found to be 93.8% and total harmonic distortion (THD) of the input current is observed only 6.52% at 230 V AC mains for a prototype of 50 W. Due to less switching losses, the proposed converted has shown much-improved results as compared to the conventional buck-boost converter.

This work presents a study concerning ac-to-dc drivers intended for indoor lighting OLED panels. The first topology, perhaps the most intuitive, consists on a two-stage ac-to-dc converter topology. Among the many possibilities, the paper begins comparing two different configurations: a buck-boost/buck alternative and the buck/buck option. Despite presenting slightly different behaviors, the first stage in both arrangements operates in discontinuous inductor current mode (DCM), featuring a self-power-factor correction (self PFC) ability and is also able to control the intermediate bus voltage. On the other hand, the second stage controls the current peak to protect the panel against over-current and perform a pulse width modulation strategy to provide dimming capability to the driver. A further topology is briefly described, consisting on a buck resonant ac-to-dc converter. Finally, the text presents a discussion about the practical driver implementation and the design-oriented to a low-profile feature by using planar inductors and GaN high electron mobility transistors.

The recent past saw an exponential growth in the use of drive system in the industry due to the emergence of premium, cost-effective solid state power electronic devices having high switching speeds and the developments in the low-cost digital controllers. The presence of power electronics devices in the drive system induce a reduction in the Power Factor (PF), which further results in increased energy consumption and losses. Hence, to enhance the overall performance of the motor drive system, PF improvement is inevitable. In this paper, a PF correction method for an inverter fed induction motor drive system using a Cuk converter operating in Discontinuous Inductor Current Mode (DICM) is presented. The proposed system ensured high efficiency, low Total Harmonic Distortion (THD) and better power quality, by PF improvement and closed loop speed control using the fuzzy logic controller. The effectiveness of the proposed system is manifested by simulations, and the results are experimentally validated using a prototype hardware.

It is the design criteria of driving LEDs at constant current and keeping the input current’s harmonics low, attaining a high power factor, and maximizing efficiency. For low power general purpose lighting buck converter can be chosen for simplicity and reduced cost. It is a difficult to improve power quality parameter like, the THD (total harmonic distortion) and power factor of ac mains. In the proposed topology, the operation for high power factor and low THD at the AC mains’ input is accomplished through buck converter operation in both discontinuous conduction mode (DCM) and continuous conduction mode (CCM) with a suitable control circuit. This paper assures constant current in both cases for suitable design of control circuit. Over voltage protection has been incorporated. To validate the LED driver circuit, simulation studies are carried out.

The state-space modeling and related order reduction problems of switching DC-DC converters operating in discontinuous (D) mode are treated in this paper. A unified discrete-time full-order model is proposed assuming the discontinuous current and voltage mode (DCVM) as a general operation mode from which the discontinuous current mode (DCM), the discontinuous voltage mode (DVM), and continuous made (CM) derive as special cases. Such a model permits a straightforward study of the control-to-output response, in each operation mode. The order reduction of the transfer function is carried out by means of the principal component analysis considering the joint controllability and observability properties of the circuit. It is shown that a proper order reduction can be gained not only in DC mode, as expected, but also in DV and DCV modes. A substantial difference between DC and DV modes is also evidenced in terms of controllability. The frequency analysis and state-space model order reduction for a Cuk converter are proposed to show that the method is free of the limitations affecting other methods of analysis and that its predictions fit experimental measurements.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Based on systematic decomposition of circuit graphs, a computer method for modelling a class of periodically switched networks is developed. The method is applicable to any switched network whose switching frequency is much greater than the natural frequencies of the constituent topologies. The method involves identifying the fast part of the circuit and separately modelling it as a time-invariant N-port. In modelling the fast part, the remaining slow part is treated as being composed of constant sources. The dynamics of the slow part is then restored in the final stage of the overall modelling. In this paper, the authors specifically discuss the modelling of the fast part of a periodically switched circuit such as the DC/DC converter, and demonstrate how it can be used to obtain a complete averaged model. The method is suited for any pulsewidth modulated (PWM) converter that operates in either operating modes. To illustrate the proposed method, the Cuk converter is considered and its averaged models derived for the three possible operating modes, namely continuous inductor current mode, discontinuous inductor current mode, and discontinuous capacitor voltage mode. >

This paper presents the analytical and experimental consideration of the common-mode noise generation in a single-switch (buck) converter comparison to a four-switch (full-bridge) converter by the viewpoint of circuit imbalance. The mechanism of the common-mode current (noise) generation in the buck converter and full-bridge converter can be explained by equivalent circuit of unbalanced model. Common-mode noise generation due to the effect of circuit imbalance of the buck and full-bridge converter is clarified by the experimental results.