Discontinuous Inductor Current Mode Research Articles

Enriched PQ-based bridgeless isolated one-stage sepic PFC converter for power solutions

ABSTRACT This article deals with an enriched power quality (PQ) based bridgeless isolated one-stage (BIOS) Sepic PFC converter as a cost-effective power solution. The presented revamped bridgeless structure on the front-end avoids unnecessary capacitive coupling and assures less current harmonic distortions, better power factor (PF) at the AC mains to confirm the permissible power quality (PQ) metrics as per IEC 61,000-3–2 standards. This PFC circuit is modelled to be operated on discontinuous inductor current mode (DICM) to reveal the innate zero current switching (ZCS) and power factor correction (PFC) capability. The added merits of DICM and high-frequency isolation involve lesser number of sensors, part count, control complications, size and cost associated with the entire power conversion. Further, the hardware setup of 250W/48 V power solution is assembled to testify the performance of the developed circuit. From the experimental outcomes it is notable that this power solution retains the bettered PQ profile within the perceivable limits even under broad range of source voltage and load discrepancies. Finally, the extensive loss modelling of the power circuit is formulated to evaluate the actual efficiency of the entire power conversion.

Enhanced Power Factor Correction and Torque Ripple Mitigation for DC–DC Converter Based BLDC Drive

A novel approach to the design of power factor correction (PFC) and torque ripple minimization in a brushless direct current (BLDC) motor drive with a new pulse width modulation (PWM) technique is demonstrated. The drive was designed to have a better power factor (PF) and less torque ripple. On the other hand, the modified Zeta converter is used to enhance the power factor of the proposed system. The modified Zeta converter is operated in discontinuous inductor current mode (DICM) by using a voltage follower technique, which only needs a voltage sensor for power factor correction (PFC) operation and DC-link voltage control. The output voltage of the VSI is determined by switching patterns generated by the PWM-ON-PWM switching strategy, and it reduces the torque ripples. The proposed drive is developed and simulated in a MATLAB/Simulink environment. The power factor of 0.9999 is produced by the PFC modified zeta converter topology and the PWM-ON-PWM scheme reduce the torque ripple in the commutation region by 34.2% as compared with the PWM-ON scheme. This demonstrates the effectiveness of the suggested control method.

A Single-Stage Charger for LEV Based on Quadratic Buck-Boost AC-DC Converter Topology

A single-stage AC-DC converter, which uses a quadratic buck-boost voltage gain, for LEVs' (Light Electric Vehicles) battery charging is presented in this work. Unlike conventional BCs (Battery Chargers), which employ transformer (low or high frequency) based approaches to charge low voltages LEVs' batteries, the presented charger utilizes transformerless single-stage power architecture. In order to realize desired charging of LEVs and to maintain proper transformerless voltage gain, the presented quadratic buck-boost AC-DC converter ensures high step-down gain characteristics between AC mains and low voltage battery packs. Besides realizing desired battery charging profile, the presented single-stage BC ensures high PQ (Power Quality) indices (low input current distortions and unity power factor operation) at the supply side. Notably, the presented quadratic buck-boost AC-DC converter exhibits an intrinsic power factor correction (PFC) feature at the AC input mains under discontinuous inductor current mode (DICM) operation, thereby, incurring minimum complexities during the control implementation, which further reduces the cost of the charger. The DICM operation facilitates negligible switch turn-on and diode reverse recovery losses, and therefore, ensures an improved conversion efficiency of the BC. Even if, the presented AC-DC converter employs two switching devices, the simultaneous switching of both switches shrinks the cost and complexity of driving circuitry even further. Finally, a comprehensive operational analysis, component selection criteria, and modelling of the presented quadratic buck-boost AC-DC converter-based LEVs BC are carried out and its performance is validated through a test bench set-up in a laboratory environment. Relevant results are presented to validate the efficacy of the presented quadratic buck-boost AC-DC converter for LEVs charging applications.

A Bridgeless Cuk-BB-Converter-Based BLDCM Drive for MEV Applications

This article presents a brushless DC motor (BLDCM) drive for a maritime electric vehicle (MEV) application. The presented BLDCM drive uses a bridgeless Cuk-buckboost (BL-Cuk-BB) converter for input-side power factor (PF) improvement. The BL-Cuk-BB converter uses the buckboost converter for the negative half-cycles of the input AC voltages and the Cuk converter for the positive half-cycles. In the case of MEVs, the drive systems are generally fed by diesel engine generators (DEGs). The asymmetric BL-Cuk-BB converter is operated in a discontinuous inductor current mode (DICM) in the present work to attain better power quality. The usage of a second-order buckboost converter with a fourth-order Cuk converter results in a decrement in the net order of the system. Additionally, the input inductor of the Cuk converter also participates as the filter component along with capacitor C2 during buckboost converter operation to enhance the power quality. The total component count reduction in the BL-Cuk-BB converter is also achieved by eliminating the usage of extra/external back-feeding diodes, which are generally used in bridgeless schemes. The present scheme uses the inbuilt anti-parallel diodes for the same purpose. The lesser components requirement in the BL-Cuk-BB-converter-based BLDCM drive implies lesser cost and volume, along with greater reliability, lower conduction losses, and lower weight of the BLDCM drive, which adds to the merits of the model. The paper includes a detailed mathematical model and stability analysis using pole-zero maps and bode plots of the BL-Cuk-BB converter for each half-supply AC voltage cycle. The BL-Cuk-BB-converter-based BLDCM drive for an EV application has been developed on the MATLAB/Simulink platform for a DICM operation, and the MATLAB simulation results have been presented for validation of the BL-Cuk-BB-converter-based BLDCM drive.

A novel approach to design of a power factor correction and total harmonic distortion reduction-based BLDC motor drive

This study describes a novel approach to design of a power factor correction (PFC) and total harmonic distortion (THD) reduction-based brushless DC (BLDC) motor drive. The drive was designed to obtain a reduced THD for PFC. The basic design of the BLDC motor drive contains an AC voltage source as input for a diode bridge rectifier. The output DC voltage is filtered out to reduce ripples. The smooth DC output voltage is supplied to the modified Zeta converter. The output voltage of the modified Zeta converter is controlled by using pulse width modulation (PWM). The modified Zeta converter is utilized in discontinuous inductor current mode (DICM) for better power factor. This controlled DC voltage is supplied to the voltage source inverter (VSI) as input. The VSI is designed to convert input DC into a suitable AC voltage source. The output voltage of the VSI depends upon switching patterns applied to power transistors generated by space vector PWM. Additionally, the output of the VSI is supplied to the BLDC motor for speed control. The main purpose of this paper is to simulate and assess BLDC motor function via the MATLAB/Simulink environment, using SimPowerSystems and the Simscape toolbox, with the goals of improved power factor, lower THD, and better speed control. The PFC modified Zeta converter topology produced the best power factor, currently 0.981, which is better than other topologies, with a THD of only 9.81%, the lowest of all three topologies, which demonstrates the significance of the proposed model.

Three-phase AC-DC Converter for Direct-drive PMSG-based Wind Energy Conversion System

In this paper, a wind energy conversion system (WECS) is presented for the electrification of rural areas with wind energy availability. A three-phase AC-DC converter based on a bridgeless Cuk converter is used for power extraction from the permanent magnet synchronous generator (PMSG). The bridgeless topology enables the elimination of the front-end diode bridge rectifier (DBR). Moreover, the converter has fewer components, simple control, and high efficiency, making it suitable for a small-scale WECS. A squirrel cage induction motor (SCIM) is used to emulate a MOD-2 wind turbine to implement the PMSG-based WECS. A direct-drive eight-pole PMSG is used in this study; thus, a low-input-voltage system is designed. The converter is designed to operate in the discontinuous inductor current mode (DICM) for inherent power factor correction (PFC) and the maximum power point tracking (MPPT) is achieved through the tip-speed ratio (TSR) following. The performance of the developed system is analyzed through simulation, and a 500 W hardware prototype is developed and tested in different wind speed conditions.

A BL-CC Converter-Based BLDC Motor Drive for Marine Electric Vehicle Applications

This article presents a BLDC (permanent magnet brushless DC) motor drive for marine electric vehicle (MEV) application. The presented scheme uses bridgeless canonical cell (BL-CC) converter with center-tapped inductor (shown as two separate inductors for analysis purpose) for source-side power factor correction (PFC); however, the BL-CC converter requires two inductors. In the presented scheme use of one center-tapped inductor eliminates the requirement of one extra inductor. Thus, center-tapped inductor usage in BLDC motor drive results in decrement in components count. The BL-CC converter-based BLDC motor drive scheme do not require extra back-feeding diodes like other bridgeless (BL) schemes, but it uses inbuilt antiparallel diodes of insulated gate bipolar transistor (IGBT) switches for the same purpose this again leads to decrement in required component count. In this work, PFC BL-CC converter is operated in discontinuous inductor current (DIC) mode to attain better power quality. The DIC mode operation requires only one voltage sensor to sense DC-link voltage, whereas in continuous conduction mode (CCM), the sensor requirement increases to three (two voltage sensors and one current sensor). The PFC BL-CC converter also eliminates the diode bridge rectifier stage. The elimination of one extra inductor, two extra back-feeding diodes, DBR stage and also requirement of only one voltage sensor in DIC mode operation instead of three sensors for CCM implies reduction in components count which implies the reduction in cost and also the volume and weight of the BLDC motor drive. The weight reduction for marine (on-board) electric vehicle is very important as this enhances the vehicle performance. This paper also presents the detailed mathematical modeling and stability analysis of presented BL-CC converter using pole zero map and Bode plot. The BL-CC converter-based BLDC motor driving system for MEV application for DIC mode operation has been developed in the laboratory as well as on MATLAB/Simulink platform and simulated MATLAB and real-time experimental results have been presented to validate the presented BLDC motor drive under steady-state and dynamic operating conditions.

Bridgeless Isolated Positive Output Luo Converter Based High Power Factor Single Stage Charging Solution for Light Electric Vehicles

In this article, a high-power factor ac–dc conversion system based on bridgeless isolated positive output Luo converter is demonstrated for light electric vehicles charging. Unlike conventional bridgeless Luo converters, the presented topology ensures positive voltage polarity at its output and incorporates a minimum component count over the universal supply voltage range of 85 <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">V</i> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">RMS</sub> to 265 <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">V</i> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">RMS</sub> . Meanwhile, the volume of magnetic components and the charger's cost are reduced by considering a discontinuous inductor current mode (DICM) design. To accomplish desired charging profile of the battery, a simple control incorporating few sensing devices and single gate drive circuitry, is utilized. It is noteworthy that, the single stage bridgeless structure of the presented topology with DICM design considerably reduces conduction and switching losses of the charger. Finally, the presented topology is designed and modeled through MATLAB environment, and its efficacy is tested through a prototype in the laboratory environment. The critical test results at various operating conditions are demonstrated to verify design and control objectives of the charger. A brief comparative analysis with existing solutions, is presented to justify the effectiveness of the presented solution.

Implementation of BL-PFC Converter Fed BLDC Motor Drive for Application less than 800 W

This article analyses the performance of a PFC SEPIC-fed BLDC motor drive for low-power applications. The BLDC motor’s speed is regulated by changing the DC connection voltage of the VSI that supplies the BLDC motor. The VSI feeding BLDC motor is used to electronically commutate the BLDC motor, which works at a low frequency to minimise switching losses. A bridgeless design of a single-ended primary-inductor converter is proposed that eliminates the need for a diode bridge rectifier. A PFC-based SEPIC is intended to operate in a discontinuous inductor current mode, with a single voltage sensor, to achieve inherent power factor correction at the AC mains. The converter proposed here has a low conduction loss, a low harmonic content, and a power factor that approaches unity. Simulate the circuit by connecting the output voltage to a resistive load. The recommended drive’s output is tested experimentally on a built prototype. At the AC mains, improved power quality is achieved under all conditions, and thus the obtained power quality indices are obtained. MATLAB-Simulink is used for all simulation work.

Design and development of a new three‐phase AC‐DC single‐stage wind energy conversion system

The prevalent use of the diode bridge rectifier in three phase wind energy conversion systems decreases the efficiency of the power generation. In standalone wind energy generation, bridgeless converters can address this problem by eliminating the front-end diode bridge rectifier. This work presents a novel single-stage three-phase bridgeless AC to DC c̀uk converter for wind energy conversion systems. The proposed converter is designed to work in discontinuous inductor current mode because of its inherent power factor correction and less harmonic distortion. Using body-diodes of the MOSFETs per phase component reduction is also done in this converter. A unique maximum power point tracking technique is developed for this converter using three-phase voltages and currents, instead of the DC link states. A wind energy emulation system using a DC motor and self excited induction generator is used to test the laboratory prototype of the proposed converter.

Series-Capacitor-Based Buck PFC Converter With High Power Factor and Ultrahigh Step-Down Conversion Ratio

In this paper, a series-capacitor-based interleaving buck power factor correction (PFC) converter is proposed, the intermediate energy storage capacitance of which is operated at discontinuous capacitor voltage mode (DCVM), and automatic power factor (PF) correction for this converter is obtained. Moreover, the voltage across the series capacitor of the proposed PFC converter is clamped at the input voltage, and thus peak voltage stress existed in the traditional DCVM buck PFC could be relieved. By effectively regulating the charge/discharge time for the series capacitor, ultrahigh step-down conversion ratio of the proposed converter is achieved, the conversion ratio of which is independent of the duty cycle and only related to the switching frequency and circuit parameters. Therefore, high PF can be obtained due to very narrow deadtime of the input current. Meanwhile, the proposed PFC converter can realize the soft turn- on of part power switch and soft turn- off of part power diodes. In addition, comparing with the traditional discontinuous inductor current mode PFC, the input current of the proposed PFC converter is continuous so that the peak value and root-mean-square value of input current can be reduced. The operational principle, performance analysis, and parameter design principle are given in this paper. The analysis results show that the PF and total harmonic distortion are also independent of the duty cycle. Finally, a 220-Vac input, 60 W/15 V output experimental prototype is built to verify the validity of the theoretical analysis.

A Universal Input PFC CSC Converter in Low Power Consumer Lighting Applications

ABSTRACT 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.

Bridgeless SEPIC PFC Converter for Multistring LED Driver

This paper deals with Power Factor Correction (PFC) in Low Voltage High Current (LVHC) multi-string light emitting diode (LED) using a bridgeless (BL) single ended primary inductance converter (SEPIC). This application is designed for large area LED lighting with illumination control. A multi-mode LED dimming technique is used for the lighting control. The BL-SEPIC PFC converter is used as a load emulator for high power factor. The regulated low voltage from flyback converter is a source power to the synchronous buck converters for multi-string LED driver and forced cooling system for LED junction. The BL-SEPIC PFC converter inductor design is based on Discontinuous Inductor Current Modes (DICM) which provides good PFC at low cost. Test results are found quite satisfactory for universal input AC (90–265 V). There is significant improvement in the power factor and input current Total Harmonic Distortion (THD) with good margin of harmonic limits for lighting IEC 61000-3-2 Class C.

Nonzero Discontinuous Inductor Current Mode in Certain Z-Source Converters

The continuous current mode (CCM) and discontinuous current mode (DCM) are common inductor current phenomenon seen in various Z-source converters. The CCM is characterized by nonzero rising or falling inductor current while inductor current acquires zero value during DCM. Primarily, DCM occurs in case of low inductor or light load condition. This results in difficult control of the converter due to aberrant voltage at dc terminal. However, in certain dc–ac Z-source converters, the inductor current acquires the profile of an ac load current or become constant in nature. This constant nature of inductor current occurs in case of low duty cycle condition. Constant nature in the current creates similar difficulty in control as DCM. Furthermore, it deteriorates the performance of the converter in terms of total harmonic distortion, high dc voltage ripple, increased dc voltage, and reduced peak ac voltage. This letter explains the nonzero discontinuous inductor current mode, in which constant current phenomenon appears, existence condition and case study along with performance parameters analysis.

BLDC Motor Drive Based on Bridgeless Landsman PFC Converter With Single Sensor and Reduced Stress on Power Devices

The Landsman converter based on a power factor correction (PFC) in bridgeless (BL) configuration feeding a brushless dc motor (BLDCM) drive is proposed for low-power household appliances. The conduction losses associated with diodes are reduced by BL configuration and switching losses of solid-state switches of voltage source inverter are reduced by the use of low frequency switching signals in electronic commutation for the BLDCM. The front-end BL PFC based Landsman converter operating in the discontinuous inductor current mode is used for controlling the dc link voltage, and PFC is attained naturally with reduced conduction losses and switch stress. A single voltage sensor is used for controlling the dc bus voltage. A prototype is developed to study performance of the system for wide range speed control and power quality improvement. The experimental performance of BLDCM is presented for its functions at varying voltages of ac mains (90–265 V) to adhere to the limits defined by IEC61000-3-2 standard.

Variable speed drive with PFC front‐end for three‐phase induction motor

A variable frequency drive for an induction motor is proposed. The drive uses a power factor (PF) correction bridgeless single-ended primary inductor converter-controlled rectifier operating in discontinuous inductor current mode as a front-end in order to improve the input power quality and a variation of the constant volts per hertz controller, with feedback to regulate the velocity of the motor shaft. The frequency slip is measured and compensated, since the input stage. Experiments with and without load are carried out and presented. Input power quality measurements are also presented. The proposed system is effective to regulate the velocity and achieving a close to unity PF.

A maximum power point tracking scheme for a 1kw stand-alone solar energy based power supply

This paper elucidates one of the tracking schemes for a photovoltaic (PV) systems using Cuk converter operating in discontinuous inductor current mode (DICM) as an interface. A method for efficiently maximizing the output power of a solar panel supplying a load or battery bus under varying meteorological conditions is investigated and results presented therein. The incremental conductance (InCond) method of maximum power point tracking (MPPT) using the Cuks dc to dc converter operating in a discontinuous inductor current mode (DICM) was modeled and studied in relation to PV system interface. Also, laboratory setup was implemented based on the model. This was the main objective of the research. Similarly, the PV simulator was also modeled alongside with Cuk converter operating in DICM. MATLAB/SIMULINK software was used to carry out simulation test. With the incremental conductance method, the problem of sustained oscillation around the maximum power point of the solar panel which is the usual characteristic of the perturbation and observation method is essentially absent. The result disclosed that the power available for the load when MPPT was applied was 1.1 kW which gives a tolerance of 0.1% to the load it powers. But without MPPT, the available power is 0.9 kW using the same number of PV panels and batteries as back up. Hence, MPPT has 17.65% edge in power delivery over non-MPPT PV powered energy supply. An experimental prototype of a 1kW, 230V, 50Hz stand-alone solar based power supply with the incremental conductance scheme was successfully implemented using PIC 16F877 microcontroller, tested and results presented therein. The experimental results agreed with the simulated results. Keywords : Maximum Power point tracking, Cuk converter, Photovoltaic system, PIC 16F877A micro-controller, inverter, batteries.

Bridgeless canonical switching cell based PFC converter for high power LED driver

This paper deals with power factor correction (PFC) in high-brightness (HB) light emitting diode (LED) module using a bridgeless canonical switching cell (BL-CSC) converter. This application is designed for large area LED projection application with full brightness control of HB red-green-blue LED module. A PWM technique is used for brightness control of LED driver. This BL-CSC PFC converter is used to feed dual flyback DC-DC converter which supplies power to the cooling unit and the LED module with galvanic isolation. Synchronous buck converters are used for brightness control using PWM dimming technique of the multiple LED strings. The BL-CSC PFC converter is designed for discontinuous inductor current mode operation to provide natural PFC at AC mains. A working prototype of the proposed LED driver is developed for experimental verifications. The performance parameters of the proposed HB LED driver is evaluated for a full brightness control capability with high power factor at universal input AC (90–265 V). The improved power quality parameters observed at AC mains are found within the acceptable limits of international power quality standard IEC 61000-3-2.

Dynamic Performance Analysis of Novel Modified Bridge Less Canonical Switching Cell Converter

This article studies on the design of a Novel Modified Bridge Less Canonical Switching Cell converter (MBL-CSC) in discontinuous inductor current mode (DICM) using voltage follower approach. The main benefits of existing canonical switching cell (CSC) converter are energy saving, rapid response, complete removal of diode bridge rectifier (DBR) at the front end. Though the existing CSC converter has benefits, it needs to have lesser number of components, least conducting devices, unity power factor improvement, and efficiency improvement. With the intention of decreasing number of components, conduction losses, attainment of least conducting devices and improvement of unity power factor, recent CSC converter is modified as a novel bridge less canonical switching cell(MBL-CSC)converter and it improves considerable increase in efficiency on the magnitude of 2–3%. Here the proposed novel modified bridgeless canonical switching cell converter uses discontinuous inductor current mode by using voltage follower approach to regulate the load voltage and unity power factor improvement. In addition making use of this converter for injecting LED lamp driver is studied for developing economic cost solution for low power application. A voltage follower approach is useful for having control over the brightness of LED lamp and power factor correction. The operation, design and control of novel modified bridgeless canonical switching cell converter on LED lamp driver is described. Steady state as well as dynamic state performance is done through MATLAB/SIMULINK model. Simulation results are obtained with enhanced power quality at the ac mains for extensive range of LED lamp load voltages and input supply voltages.

Power Factor Corrected Welding Power Supply Using Modified Zeta Converter

A power factor (PF) corrected single stage, two-switch isolated zeta converter is proposed for arc welding. This modified zeta converter is having two switches and two clamping diodes on the primary side of a high-frequency transformer. This, in turn, results in reduced switch stress. The proposed converter is designed to operate in a discontinuous inductor current mode (DICM) to achieve inherent PF correction at the utility. The DICM operation substantially reduces the complexity of the control and effectively regulates the output dc voltage. The proposed converter offers several features, such as inherent overload current limit and fast parametrical response, to the load and source voltage conditions. This, in turn, results in an improved performance in terms of power quality indices and an enhanced weld bead quality. The proposed modified zeta converter is designed and its performance is simulated in the MATLAB/Simulink environment. Simulated results are also verified experimentally on a developed prototype of the converter. The performance of the system is investigated in terms of its input PF, displacement PF, total harmonic distortion of ac mains current, voltage regulation, and robustness to prove its efficacy in overall performance.