Input Current THD Research Articles

Novel Voltage Balance Strategy for a Cascade H-Bridge with a Wide Stable Operating Region and a Low Input Current THD

Novel Voltage Balance Strategy for a Cascade H-Bridge with a Wide Stable Operating Region and a Low Input Current THD

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.

A Novel Diode Rectifier with a Series Connected Chopper for Reduced Input Current THD

A Novel Diode Rectifier with a Series Connected Chopper for Reduced Input Current THD

AC-DC DAB Converter with Power Factor Correction

AC-DC conversion is required in many applications, and in some of them isolation is strictly required, certainly while maintaining characteristics such as a high power factor and low input current THD. In this paper, an AC-DC converter, comprising a full-bridge diode rectifier and a dual-active-bridge (DAB) converter, is utilized to fulfill these characteristics. The used modulation makes the converter behave as a resistive load, maintaining the output voltage constant while achieving a high power factor and low input current THD. The operation of the converter is simple, as only two voltage sensors are required, and no inner current loop is utilized. A low-power prototype was experimentally tested to corroborate the proposal.

Control Method of Electrolytic Capacitor-Less Dual Inverter-Fed IPMSM under Periodic Load Torque Fluctuations

This paper proposes a control method for an electrolytic capacitor-less dual inverter for compressors. Single-phase motor drive systems are required to minimize vibrations, maintain a high power factor, and meet the limit for harmonic current emissions. The proposed control method achieves the harmonic reduction of the dq-axis currents, a high power factor, and a low grid current THD under periodic load torque fluctuations. The effectiveness of the proposed method is demonstrated via experimental results, using an open-end winding IPMSM and an electrolytic capacitor-less dual inverter. The proposed method reduced the 100Hz harmonic components of dq-axis currents up to 98% under periodic load torque fluctuations compared with an electrolytic capacitor-less single inverter. The results of FFT analysis of the input current show that the power factor and input current THD of the proposed method are equivalent to or superior to those of conventional methods. Therefore, the proposed control method can effectively achieve vibration reduction, a high power factor, and a reduction in the input current THD under periodic load torque fluctuations.

An Improved Swiss Rectifier and Its Nonlinear Control for Lower THD

Three-phase power factor correction (PFC) converters capable of step-down voltage are attractive in lower components voltage stress, and optimal design of following dcdc stage, which is an alternative for next-generation datacenter power conversion. An improved three-phase step-down PFC converter (swiss rectifier) based on harmonic-current-injection (HCI) concept is proposed. It improves input current quality by eliminating switching dead zone of HCI network and avoids short circuit fault from hardware level. According to one-cycle control (OCC), a novel nonlinear control strategy (termed as closed-loop OCC) is presented, which reduces the impact of dc inductor current ripple on input current. The principles of the improved swiss rectifier and closed-loop OCC are analyzed in detail, verified by simulation and on an 80 kHz, 300 V/2 kW prototype with digital controller. At rated condition, input current THD < 2%.

Simplified model predictive current control based on fast vector selection method in a VIENNA rectifier

This paper presents a simplified finite-control-set model predictive control (S-FCS-MPC) based on fast vector selection method in a three-level VIENNA rectifier. This method features a high-power factor, a low input current THD as a well-controlled DC-link voltage with fewer redundant vectors and lower computational load. Moreover, the converter with the proposed control technique exhibits a faster dynamic response in terms of input current and DC-link voltage compared with conventional finite-control-set model predictive control (C-FCS-MPC). In addition, the average switching frequency can be effectively reduced due to fewer switching times in a subset sector using the proposed method, which means fewer switching losses. Finally, the operation principle of the proposed algorithm has been analysed and an execution time comparison between S-FCS-MPC and C-FCS-M has been undertaken. The effectiveness of the proposed control technique has been validated using both simulation and experimental results.

A Novel LED Driving Power Supply with High Power Factor and Low Total Harmonic Distortion

proposing a new type of LED driving power supply which is based on buck-boost cascade quad and analysing it in this paper. The main circuit topology structure is based on a quadratic buck and a buck-boost converter. They share the same switch through cascading which not only simplify the topology but also control strategy, reducing the cost of the control circuit. Eliminate the input current dead-time problem of the original quadratic buck topology by adopting two-stage cascade structure. The main circuit topology improves the power factor and ameliorates the input current THD as well. Meanwhile, making the duty cycle of the switch operates in a more plausible area. Finally, relevant experiments demonstrate that the theoretical analysis is correct.

Dynamic Voltage Stability Enhancement in Electric Vehicle Battery Charger Using Particle Swarm Optimization

Electric vehicles (EVs) are poised to lead the transportation sector as the primary choice of automobile due to their efficiency and environmental benefits. EVs with enhanced autonomy and reduced pricing have become feasible in the market, enabling a gradual transition for higher EV penetration. However, electric vehicles require highly efficient and stabilized charging stations in urban areas to ensure the vehicle’s charging time is not compromised. In this regard, the Vienna rectifier with a voltage-oriented controller (VOC) plays a significant role in improving the power quality of the utility grid for EV battery charger applications. The low stability of the battery charger’s output voltage and current is due to the trial-and-error method used to select the PI controller gains. In order to improve the voltage and current stability, the particle swarm optimization (PSO) technique is used to optimize VOC’s PI controller gains. The code composer studio (CCS) platform integrates the PSO technique for EV battery chargers in the experimental setup. The Vienna rectifier with VOC for EV battery charger is implemented using TMS 320F28337 digital signal controller in the test board. Findings indicate that the PSO optimized VOC improves the output voltage and current stability by 12% compared to the existing trial-and-error technique. Furthermore, the proposed system is tested in an experimental setup that provides input current THD to less than 5% for different load variations (up to 1.5kW) to meet the IEEE-519 standards. Results from simulations and experimental setup verify that the proposed PSO-PI controller-based Vienna rectifier significantly improves EV battery chargers’ output voltage and current stability.

Modelling and analysis of vienna rectifier for more electric aircraft applications using wide band-gap materials

This paper presents a comprehensive study on the switching effects of wide bandgap devices and the importance of power electronics in an aircraft application. Silicon (Si), silicon carbide (SiC), and gallium nitride (GaN) are wide bandgap devices that act as a power electronic switch in the AC-DC converter for More Electric Aircraft (MEA) applications. Therefore, it is important to observe their converting efficiency to identify the most suitable wide bandgap device among three devices for AC-DC converters in aircraft applications to provide high efficiency and high-power density. In this study, the characteristics of Si, SIC, and GaN devices are simulated using PSIM software. Also, this paper presents the performance of the Vienna rectifier for aircraft application. The Vienna rectifier using Si, SiC, and GaN devices are simulated using PSIM software for aircraft application. GaN with Vienna rectifier provides better performance than Si and SiC devices for aircraft applications among the three devices. It gives high efficiency, high power density, low input current THD to meet IEEE-519 standard, and high-power factor at mains.

An Optimized Single-Stage Isolated Swiss-Type AC/DC Converter Based on Single Full-Bridge With Midpoint-Clamper

The Swiss-type rectifier (SR) uses harmonic injection circuit and two dc–dc converters to help three-phase uncontrolled rectifier bridge to achieve better power factor correction (PFC). By applying the full-bridge topology to the dc structure, both the soft switching and the high-frequency galvanic isolation can be achieved. However, two full-bridge structures are required to realize the PFC principle of SR. That means the current flows through at least four switches and two transformers during the power conduction or freewheeling period. There are improvements in both conduction loss and core utilization. Thus, an optimized single-stage isolated Swiss-type ac/dc converter based on a single full-bridge with midpoint-clamper is proposed. Only one full-bridge structure is used to improve the conduction loss and core utilization. Two bidirectional voltage clampers are used to implement the PFC principle of the SR. The performance of the proposed converter has been verified by experiments. A total of 95.4% efficiency under half rated power and 5% input current THD under rated power have been achieved under a 10-kW 380 Vac input/400 Vdc output prototype with 90 kHz switching frequency.

Port-Controlled Hamiltonian Based Controller for Three-Level Ćuk PFC Converter for Battery Charging Application

This paper reveals energy shaping passivity-based control methodology for a three-level (TL) Ćuk PFC converter. The proposed control methodology is based on the dynamic model of the system along with the idea of energy shaping and damping injection. First, a dynamic model of the TL Ćuk PFC converter is developed using the port-controlled Hamiltonian formulation and the state-space averaging technique. Then, the PCH control technique is implemented in the system and the stability analysis is carried out. In order to eliminate the steady state error, a PI controller is integrated with the PCH-PBC control scheme. Further, the performances of aforesaid system are investigated for battery charging application with the help of MATLAB/Simulink. To validate the simulation study, a prototype model of TL Ćuk PFC converter with proposed controller is built using OP-5142 real-time simulator and test results are recorded. Furthermore, the power quality features of TL Ćuk PFC converter are assessed through monitoring of input current THD under different operating conditions. To assess the system performance in terms of efficiency, input p.f., input current THD, and controller parameters, the proposed controller is compared with benchmark PI controller under dynamic variations at the input voltage and the load.

A bridgeless CUK PFC converter with positive output voltage

The output voltage of the traditional CUK PFC converter is negative, and an additional inverting amplifier circuit is needed, which increases the volume and cost of the converter. A new type of bridgeless CUK PFC converter topology is proposed in this paper, which makes the converter have a positive output voltage without the need of an additional inverting amplifier circuit, and has the advantages of simple control, high efficiency, and low cost. Through topology optimization, one input capacitor is reduced, and the two diodes are converted from the high-current working state of high frequency to low-current working state of power frequency, ordinary rectifier diodes can be selected instead of fast recovery diodes, thereby reducing the volume and cost of the converter. The converter works in DCM, so no current control loop is required, which simplifies the control circuit. In addition, the main switch is turned on under ZVS condition, and the output diode is turned off under ZCS condition, which reduces the switching loss and improves the efficiency of the converter. A simulation model was built in PSIM, and a prototype with a rated power of 150 W was fabricated to verify the effectiveness and superiority of the proposed converter. Experimental results show that the PF of the proposed converter is 0.995 7, and the input current THD is 3.78% under rated input conditions.

Harmonics mitigation approach by using pulse‐doubling circuit in the AC–DC rectifier

SummaryIn this research, a novel pulse‐doubling circuit (PDC) is employed to upgrade the 28‐pulse rectifier to the efficient 56‐pulse rectifier. The main objective of this research is to reduce the power kVA rating. In the autotransformer with a 14‐phase polygon structure, the kVA rating is approximately 39.5% of the load power. Since the pulse‐doubling method is utilized, the rectifier with 56 pulses has benefited from a simpler structure. With a comparison to the other rectifiers, the harmonic mitigation is the clearest feature of the proposed rectifier. According to the experimental and theoretical results, in the proposed rectifier with 56 pulses, the input current THD is less than 3%. Finally, the volume and cost of the proposed rectifier with 56 pulses show a notable reduction. In other words, the proposed rectifier is an economical choice for most sectors of the industry.

A Computationally Simple Predictive CCM Average Current Controller With Nearly Zero Tracking Error for Boost PFC Converter

Predictive current controllers offer superior control action in power factor correction (PFC) converters, however, cause tracking error in the average inductor current due to the unmodeled circuit parameters and variations which could lead to higher harmonic currents, higher input current THD and impact on the output voltage. Attempts to make the predictive current control equations accurate leads to increased computational complexity, thus limiting the switching frequency of operation or increasing the processing requirements. This article proposes a computationally simple predictive continuous conduction mode average current controller based on the concept of moving averages for the boost PFC converter and achieves nearly zero tracking error in the average inductor current. Additionally, a predictive current controller is derived for performance comparison by considering the effect of major converter nonidealities and digital implementation aspects. The performance of the proposed predictive current controller is compared with that of a PI current controller, an ideal predictive current controller and the derived predictive current controller with nonidealities included. Experimental studies on a boost PFC converter hardware prototype validate the effectiveness of the proposed predictive current controller.

Power quality enhancement of a T-connected autotransformer based on 72-pulse AC–DC converter with rated power reduction

In this paper, a thorough analysis is carried out in order to achieve an optimal design of a T-connected autotransformer based on 72-pulse AC–DC converter. Accordingly, the main purpose of the paper is focused on the power KVA rating reduction for power quality applications. The first merit is that the T-connected autotransformer configuration requires two single-phase transformers, which is more economical (in weight and volume) as compared with other topologies using three single-phase transformers. The second one is that the application of the pulse doubling technique with a low power rating (0.6% of the load power rating) results in a simpler and more economical configuration of the whole system and increased number of pulses. It provides a more economical solution to achieve harmonic mitigation in electric power systems as compared with other 72-pulse AC–DC converters. The simulation and experimental results show that the input current THD is less than 3% using the proposed topology. The results indicate a significant reduction in the total cost and volume of the proposed 72-pulse configuration in comparison with similar configurations. Also, it is shown that the proposed converter rating is about 43.61% of the DC load power.

Multi-Phase Shifting Autotransformer Based Rectifier

In this paper, a thorough analysis is carried out in order to achieve an optimal design of a forty-four pulse rectifier. In this study, a novel Multi-phase Shifting Autotransformer (MPSA) is introduced, discussed, simulated and implemented to forty-four pulse rectifier with acceptable power rates. Accordingly, the main purpose of the paper is focused on the power kVA rating reduction for power quality applications. It provides a more economical solution to achieve harmonic mitigation in electric power systems as compared with other rectifiers. The simulation and experimental results show that the input current THD is less than 3% using the proposed topology. The results indicate a significant reduction in the total cost and volume of the proposed forty-four pulse configuration in comparison with similar configurations. Also, it is shown that the proposed converter rating is about 42% of the DC load power.

Integrated on board Battery Charger Using Fuzzy Logic Controller for Plug-in Electrical Vehicles

Expanding usage of PHEV has certain considerations like high charging time, low range of driving and less number of stations for charging. PHEV chargers are known for two types as off board and on-board chargers. In this, 1-phase integrated on-board charger utilizing Fuzzy Logic based PEV 3-phase ac machine (PMSM) with its converter for traction, is proposed. The process for charging enables Power Factor Correction (PFC) in the source end. The 3-phase windings of the machine are used in the place of inductors to act as interleaved boost converter. A circuit utilizing 3-phase PMSM is built in MATLAB SIMULINK as well as verified the execution by using Fuzzy Logic Controller (FLC). An approximately unified power factor (PF) with less amount of THD of input current is obtained.

Adaptive LUT-Based Variable On-Time Control for CRM Boost PFC Converters

This paper proposes an adaptive look-up-table (LUT)-based variable on-time (VOT) control for CRM boost PFC converters, which combines advantages of conventional LUT method and real-time calculation method. By the numerical fitting method, the approximate functional form of the on-time is derived, which is related to both the input voltage and load. The mapping relationships of VOT tables under different load and input RMS voltage are investigated. Based on the mapping relationships, only one VOT table is required to be preloaded in LUT. The adaptability of the proposed control is conveniently realized within the universal ac input and entire load range through the inherent voltage loop and a simple linear calculation. With the proposed control, the required memory space for VOT tables is effectively reduced and the computation time is significantly shortened, leading to a low system cost. Moreover, compared with the constant on-time control and other VOT controls, the proposed control can further suppress the input current distortion. The experimental results of an 160-W universal ac input prototype are built to verify the effectiveness and advantage of the proposed control. With the proposed control, the input current THD is only 0.97% at 110 Vac input with full load and is limited within 2.9% at 220 Vac input with full load.

A Front-End Bridgeless Power Factor Corrector For Electric Vehicle Battery Chargers

In this paper, a bridgeless power factor corrector converter is suggested for electric vehicle battery chargers. The converter is applicable as a front-end stage for residential charging, i.e. automotive level 1. It is presented a steady state operation analysis for the proposed converter. It operates in current continuous conduction mode controlled by a voltage outer loop and a current inner loop control strategy. Experimental results were performed for a 1 kW prototype, considering 220 V grid voltage, 400 V dc output voltage, 70 kHz switching frequency, and the control system implemented by the UCC28070. The experimental results are satisfactory, which demonstrate a peak efficiency of 98.4% at half load, and features high efficiency from light load to full load. Additionally, the input current THD is less than 5% from half to full load and the power factor is higher than 0.99 from half to full load.