Output Current Ripple Research Articles

Research on Cascaded On‐Board DC/DC Converter Based on Three‐Phase Interleaved LLC

ABSTRACTThe on‐board DC/DC converter proposed in this research consists of a Buck converter and a three‐phase interleaved LLC resonant converter. This paper analyzes the average current and output current ripple characteristics of the rear‐stage converter in addition to explaining the topology and working principles of the front‐stage Buck converter and the rear‐stage three‐phase interleaved LLC resonant converter. To establish a single‐phase fundamental equivalent circuit for the rear‐stage converter, apply the fundamental wave analysis method, and it is essential for comprehending the impact of relevant system parameters on voltage gain characteristics and resonant operating regions. Conducting research on the two‐stage on‐board DC/DC converter's control strategy involves establishing small‐signal circuit models for both front and rear stage converters, derivation of parameters for double closed‐loop control, and determination of the control strategy employing phase‐shifted current sharing for the rear‐stage converter in cases where significant tolerance exists in resonant components. The simulation for a two‐stage on‐board DC/DC converter results indicates that under various conditions of resonant component tolerance, the converter is capable of achieving balanced phase currents and demonstrates minimal output current ripple prior to capacitor filtering. A 1.5‐kW experimental prototype has been fabricated, and the experimental findings indicate that the output voltage remains stable at 13.8 V despite fluctuations in input voltage. The highest efficiency of the prototype is about 96.27%, and the utilization of phase‐shifting current balancing control results in a notable reduction in output current ripple. This provides more evidence that the design of a two‐stage on‐board DC/DC converter is correct.

Performance Improvement of Wireless Power Transfer System for Sustainable EV Charging Using Dead-Time Integrated Pulse Density Modulation Approach

The recent developments in electric vehicle (EV) necessities the requirement of a human intervention free charging system for safe and reliable operation. Wireless power transfer (WPT) technology shows promising options to automate the charging process with user convenience. However, the operation of the WPT system is designed to operate at a high-frequency (HF) range, which requires proper control and modulation technique to improve the performance of power electronic modules. This paper proposes a dead-time (DT) integrated Pulse Density Modulation (PDM) technique to provide better control with minimal voltage and current ripples at the switches. The proposed technique is investigated using a LCC-LCL compensated WPT system, which predominantly affects the high-frequency voltage and current ripples. The performance analysis is studied at different density conditions to explore the impact of the integrated PDM approach. Moreover, the PDM technique gives better control over the power transfer at different levels of load requirement. The simulation and experimental analysis was performed for a 3.7 kW WPT prototype test system under different modes of operation of the high-frequency power converters. Both the simulated and experimental results demonstrate that the proposed PDM technique effectively enhances the efficiency of the HF inverter while significantly reducing output current ripples, power dissipation and improving the overall WPT system efficiency to 92%, and leading to a reduction in the power loss in the range of 10% to 20%. This leads to improved overall system control and performance.

A Novel Non-Isolated Bidirectional DC-DC Converter with Improved Current Ripples for Low-Voltage On-Board Charging

This paper presents a novel single-phase non-isolated bidirectional buck converter topology. The proposed converter uses a basic switching cell structure with a coupled inductor and an interleaving switching scheme. This article addresses a crucial challenge in bidirectional DC-DC conversion by prioritizing reducing output current ripples and minimizing filter inductor size. The employed method includes using MOSFETs with fast recovery diodes to mitigate reverse recovery and body diode losses. Furthermore, the optimization of the switching frequency of the output inductor to be twice the actual switching frequency contributes to reducing the component size of the converter. The coupled inductor also helps to reduce stress on components by distributing currents among its legs. The experimental result demonstrates the proposed converter has a very low ripple current as compared to the conventional converter. The low current ripples and smaller filter inductor size enabled by high-frequency operation have improved the efficiency and size of the converter. A common ground between input and output terminals ensures robust performance without common mode current concerns. Overall, the proposed converter represents a significant improvement in DC-DC converters, promising enhanced efficiency, reliability, and compactness in bidirectional DC-DC conversion systems. In order to verify the performance of the proposed converter, a 460 W buck converter prototype was built and tested.

Design, analysis, and implementation of a phase‐shift controlled cascaded H‐bridge and anti‐interleaved zeta converter‐based E‐bike battery charging circuitry

AbstractThe rapid extinction of the fossil fuels across the globe has led to the technological advancements in the field of renewable energy sector and the electric vehicular technology. In order to match the paradigm shift in the energy sector and the technology, the battery charging circuitry of electric vehicle (EV) led to the revolutionary changes in the field of power electronics. Accordingly, various conventional topologies of DC‐DC converters were evolved. But there are a few drawbacks such as bulkiness, nonmultiple ports, and less control over the output current ripple. This work proposes a DC‐DC converter which is a hybrid combination of the full‐bridge converter and the zeta converter. The current and the voltage reversals at the high‐frequency transformer (HFT) terminals are made steady by anti‐interleaving the zeta converters on the secondary side. The control pulses of the full‐bridge converter are phase‐shifted to have the tight grip over the output. The modes of operation of the proposed DC‐DC converter has have presented. The calculation of the energy, current, and the voltage for the active and the passive components of the proposed converter has been provided. The proposed system is simulated, and the plots of the voltages and currents of different components of the converter are presented. The converter prototype has been developed to charge a 36 V lithium‐ion battery, and the effect of the phase shift on input current can be seen from the exhaustive results. The comparison of the calculated and simulated currents and voltages has been graphically illustrated. The proposed converter provides a novel converter topology which includes better output control with phase shift and reduced size of memory elements due to high‐frequency switching.

Power converter for battery charger of electric vehicle with controllable charging current

Research on electric vehicle chargers primarily focuses on improving charging technology to enhance the convenience, quality, efficiency, and affordability of charging electric vehicles. This paper discusses a different AC-DC power converter topology proposed as a potential candidate for electric vehicle battery charger. Using the proposed converter circuit, the charging process of electric vehicle battery can be simply adjusted to meet the battery requirement, and even for increasing the charging speed while avoiding overcharging of battery. During the charging process, if the voltage of battery approaches to the targeted battery voltage level, the charging current can be reduced gradually to zero. Hence it will prevent the battery from overcharging condition. Moreover, the ability of working at high power factor operation, low distortion of alternating current (AC) input current, and low direct current (DC) output current ripple are other features of the proposed charger circuits. Some test results of the proposed power converter were presented. The test results revealed potential features of the converter for battery charger of electric vehicle with power factor 0.9996, total harmonic distortion (THD) of AC current 2.73%, and low charging current ripple, i.e. 3.91%. Therefore, it minimizes the negative effects caused by ripples of charging current especially for lithium-ion batteries widely used in electric vehicles.

Analysis of the effect of mutual inductance on reducing output current ripple of the modified DC-DC Cuk converter

DC-DC converters exhibiting minimal input and output ripple are extensively employed across a diverse range of applications. This paper presents a proposed modification to the DC-DC Cuk converter. The converter is developed by modifying a conventional Cuk DC-DC converter to exhibit boost characteristics. The DC-DC converters possess the capability to function as versatile units that can be employed in a multitude of applications, ranging from DC-DC conversion to DC-AC conversion (inversion). This paper presents a novel DC-DC converter design that aims to achieve reduced ripple in both input and output currents. By employing the principle of mutual inductance, it is possible to further mitigate the presence of ripple current. The analysis of the impact of mutual inductance on the output voltage and ripple current of the proposed converter has been conducted. The validity of the derived analytical method has been confirmed through both simulated and experimental investigations. The utilization of mutual inductance in the proposed modified Cuk converter has been demonstrated to result in reduced current ripple.

A Spread-Spectrum Modulation Scheme for a 3 × 6 Indirect Matrix Converter Based on a Current Ripple Model

Focused on addressing harmonic suppression in multiphase indirect matrix converters (IMCs), this study explores spread-spectrum modulation technology through ripple analysis calculations. We introduce a current ripple spread-spectrum modulation (CR-SSM) method tailored for multiphase IMC systems. In this approach, a 3 × 6-phase IMC is modeled as a two-port network, and a small-signal model of the output side is established. The transfer function is utilized to analyze the two-port network in the complex frequency domain (s-plane). The time-domain expression of the output current ripple is derived in vector form. Subsequently, the distribution of the output ripple and locus are determined based on specified constraints. The carrier frequency is dynamically adjusted online according to the specified ripple locus. Compared to classical periodic PWM methods, this approach offers a broader range of frequency variations and achieves a more uniform output spectrum. Furthermore, CR-SSM optimizes system efficiency and enhances spread-spectrum modulation. Experimental results demonstrate that this method effectively enhances the quality of input and output waveforms in multiphase IMC systems.

Paralleled Variable Inductor Phase-Shifted Full-Bridge Converter With Full-Load Range ZVS and Low Duty Cycle Loss

This paper presents a new phase-shifted full-bridge topology using a new variable inductor. In this topology, a variable inductor is connected in parallel with a near-ideal transformer. The ZVS of the switches is achieved over the full load range using the parallel current provided by the variable inductor. And the adjustable parallel current reduces conduction losses. Under the orthogonal DC magnetic potential, the variable inductor has similar characteristics to the saturated inductor, which is beneficial to reduce the conduction loss caused by the parallel current. Since the topology has no series inductor and the leakage inductor is extremely small, the proposed converter has the advantages of extremely small duty cycle loss, larger transformer turns ratio, smaller primary current stress, smaller secondary voltage stress, and smaller output current ripple, which are beneficial to improve the efficiency and frequency of the converter. An experimental platform was established. Theoretical analysis and experimental verification were carried out.

Inductor integration for internal parallel inverters

SummaryIn addition to inheriting the merits of interleaved parallel inverters, the internal parallel structure (IPS) inverter has the advantages of reduced circulating current and lower switching loss. Currently, however, the suppression of circulating current and output current ripple individually results in an evident increase in the number and volume of inductors. In this work, an inductor integration scheme is developed to improve the IPS inverter. Two integrated inductors are developed for different application configurations. As a result, the circulating current and output current ripple are simultaneously suppressed by an integrated inductor, making each phase of the IPS inverter to be equipped with only one integrated inductor implemented by wounding two coils on one magnetic core. The feasibility of the inductor integration scheme for the IPS inverter is experimentally verified by a downscale prototype.

High-Efficiency Multiphase Stacked Interleaved DC-DC Buck Converter with Very Low Output Current Ripple and Low Current–Voltage Stress

High-Efficiency Multiphase Stacked Interleaved DC-DC Buck Converter with Very Low Output Current Ripple and Low Current–Voltage Stress

Develop an automated data acquisition system for TPS correction magnet power supply

Taiwan Photon Source is a third-generation 3 GeV synchrotron light source. Since the successful operation of the first beamline in 2013, comprehensive long-term testing and acceptance work has been carried out to ensure the stable operation of various types of correction magnet power supplies, totalling 1038 units. To standardise and save workforce and time for the measurement of correction magnet power supplies, an automated data acquisition system platform for correction magnet power supplies was developed using LabVIEW. This platform integrates control interface cards, high-resolution digital voltmeters, and analysis instruments. It also includes linearization and calibration compensation for the multi-channel direct constant current transformer to ensure simultaneous measurement of 24 magnet power supplies. Furthermore, it can automatically generate test reports in Word format, saving significant human resources and time. This platform has verified TPS correction magnet power supplies before installation, reducing the failure rate. Regarding measurement results, the output current ripple for the DCCT version is within five ppm, while the shunt resistor version is within ten ppm. The long-term current stability is consistently within ten ppm. The development of the fully automated data acquisition system platform and the measurement of 1038 power supplies were completed in four months.

Design of dual loop controller for boost converter based on PI controller

Boost converters are widely used in industry for many applications, such as electrical vehicles, wind energy systems, and photovoltaic energy systems, to step up the low voltages. Using the topology structure of the DC–DC boost circuit, this paper studied and designed a dual loop control method based on proportional integral controllers for improving the converter efficiency. The inner loop and outer loop controls of the traditional boost circuit are adopted in MATLAB/Simulink software to make the output of the system more stable. The input voltage is set to 24 V DC, and the desired output voltage varies from 36 to 48 V. Through simulation verification, the influence of a 1 kW sudden load connection by using a switch at a nominal output voltage of 48 V DC is studied, and the results show that it reduces the transient output voltage dips during the sudden load connection. Simulation analysis verifies the design scheme of the system, reduces the fluctuation in output voltage and power, reduces the output current ripple, minimizes the dip in voltage to a minimum possible value, and improves the dynamic characteristics and overall efficiency of the converter.

Performance analysis of a bridgeless power factor correction (PFC) buck–boost LED driver with ripple diversion scheme for extended lifespan

SummaryIn the state of the art of AC‐fed light‐emitting diode (LED) drivers, power factor correction (PFC), second harmonic LED current ripple elimination, low current total harmonic distortion (iTHD), removal of electrolytic capacitors (EC) and flicker‐free operation are the major challenging issues. This paper proposes a bridgeless universal voltagerange AC‐fed LED driver that overcome the major issues of LED driver. The bridgeless buck–boost PFC configuration minimizes the losses relative to the front‐end bridge rectifier‐based configurations. Operating in discontinuous conduction mode (DCM), the source current tracks the input voltage shape for a wide operating range, achieves inherent PFC and maintains low input current THD. Also, this provides significant reduction in the output current ripple with the ripple diversion circuit (RDC) connected in shunt across the LED load, which relatively reduces and utilizes low value of output capacitance. Hence, a flicker‐free operation is achieved without the use of electrolytic capacitors. In addition, the elimination of ECs improves the operating lifespan of the proposed LED driver. A detailed theoretical analysis and results of the proposed LED driver are validated on DSP and analog controller platforms with a 62 W/62 V experimental laboratory prototype. The experimental results confirm that the proposed LED driver achieves a power factor of 0.94–0.997, input current THD of maximum 6.8%, output current ripple of 5%, and a peak efficiency of 91.25% for the wide range of input voltage variation. These indices also satisfy IEC‐61000‐3‐2 and IEEE 1789‐2015 standard limits.

Transformerless Inverter with Charge Pump Circuit Concept for PV Application

This paper introduces a new single phase transformerless photovoltaic (PV) inverter for grid connected PV systems using the concept of a charge pump. It consists of four power switches, two diodes, two capacitors and an LC filter at the output stage. The neutral of the grid is directly connected to the negative terminal of PV panel. This common ground creates a constant Common Mode (CM) voltage and zero leakage current. Meanwhile, the charge pump circuit generates the negative bus voltage for the inverter during the negative power cycle. A unipolar Sinusoidal Pulse Width Modulation (SPWM) technique is applied to the proposed inverter with three level output voltage to reduce the output current ripple and the filter requirements. The main advantages of the proposed inverter are (1) the negative polarity of the PV is directly connected to the grid, so the leakage current eliminated, (2) it has a compact size, (3) peak of output voltage is equal to input dc voltage (unlike Neutral Point Clamped (NPC) inverter, Active NPC (ANPC) and some topologies, which requires two times of the peak ac-voltage magnitude), flexible grounding configuration and high efficiency. The operating principle and analysis of the proposed topology are presented in details. Experimental results of a 500 W prototype are demonstrated to validate the proposed topology and the overall concept. The obtained results clearly verify the performance of the proposed inverter and its practical application for grid connected PV systems.

Analysis of Inverter Output Current Ripple and Design of Inverter-Side Output Filter Inductor for Grid-Connected Applications

Analysis of Inverter Output Current Ripple and Design of Inverter-Side Output Filter Inductor for Grid-Connected Applications

Carrier-Based PWM Strategy for Output Current Ripple Minimization in Multiphase Motor Drives

Carrier-Based PWM Strategy for Output Current Ripple Minimization in Multiphase Motor Drives

Low Output Current Ripple Ultra High Step-Down Two-Phase Buck Converter With Low Switching Losses

Low Output Current Ripple Ultra High Step-Down Two-Phase Buck Converter With Low Switching Losses

A Soft-Switched Three-Phase Inductor Coupling Quasi-Z-Source Integrated Charger with Reduced Output Current Ripple for Electric Vehicles

A Soft-Switched Three-Phase Inductor Coupling Quasi-Z-Source Integrated Charger with Reduced Output Current Ripple for Electric Vehicles

Development of linear power operational amplifier power supply with pre-regulated voltage controller for TPS correction magnets

The Taiwan Photon Source (TPS) is a renowned 3 GeV synchrotron accelerator light source. Over the past decade of successful operation, it has demonstrated outstanding performance, notably in average beam trip downtime, meeting international standards. A continuous regimen of scheduled equipment upgrades has been maintained across all subsystems to ensure ongoing improvement and the preservation of an optimal research facility environment. The central focus of this study revolves around the design and realization of a TPS correction magnet power supply employing Linear Power Operational Amplifiers (LPOA) in conjunction with a pre-regulated voltage controller. The power source predominantly features APEX Corporation's PA05 LPOA, characterized by bipolar output, high internal power dissipation, and wide bandwidth. Additionally, a DC Current Transducer (DCCT) was employed as the current feedback element, integrated with the pre-regulator voltage controller to form a closed-loop current modulation circuit, providing the variable voltage required by the LPOA. Through these measures, we have successfully developed an LPOA power supply unit equipped with a pre-regulated voltage controller for TPS correction magnets. The prototype device boasts a maximum output current of ±10 A, operating at 24 V. Validation through control loop design has led to rapid and stable output current performance. The output current ripple is maintained within 100 μA, with a rise time of 75 μs during step response. During frequency response testing utilizing a 0.1 V disturbance signal, the gain margin resides within -3 dB at an 11.2 kHz bandwidth and the phase margin within -45∘ at a 5.1 kHz range. Long-term output current stability is sustained within ten ppm. Finally, a hardware prototype circuit has been constructed in the power supply laboratory, featuring a ±24 V input voltage and ±10 A output current, achieving a maximum rated power of 240 W.

Design Considerations of Multi-Phase Buck DC-DC Converter

The main objective of this article is to propose a rational methodology for designing multi-phase step-down DC-DC converters, which can find applications both in engineering practice and in power electronics education. This study discusses the main types of losses in the multi-phase synchronous buck converter circuit (transistors’ conduction losses, high-side MOSFET’s switching losses, reverse recovery losses in the body diode, dead time losses, output capacitance losses in the MOSFETs, gate charge losses in MOSFETs, conduction losses in the inductor, and losses in the input and output capacitors) and provides analytical dependencies for their calculation. Based on the control examples for applications characterized by low voltage and high output current, the multi-phase buck converter’s output and input current ripples are analyzed and compared analytically and graphically (3D plots). Furthermore, graphical results of the converter efficiency at different numbers of phases (N = 2, 4, 6, 8, and 12) are presented. An analysis of the impact of various parameters on power losses is conducted. Thus, a discussion on assessing the factors influencing the selection of the number of phases in the multi-phase synchronous buck converter is presented. The proposed systematized approach, which offers a fast and accurate method for calculating power losses and overall converter efficiency, reduces the need for extensive preliminary computational procedures and achieves optimized solutions. Simulation results for investigating power losses in 8-phase multi-phase synchronous buck converters are also presented. The relative error between analytical and simulation results does not exceed 4%.