Buck Chopper Research Articles

Suppression of Initial Charging Torque for Electric Drive-Reconfigured On-Board Charger

This paper presents a new electric drive-reconfigured on-board charger and initial electromagnetic torque suppression method. This proposed reconfigured on-board charger does not need many components added to the original electric drive system: only a connector is needed, which is easy to add. Specifically, the inverter for propulsion is reconfigured as a buck chopper and a conduction path to match the reconfigured windings. Two of the machine phase windings serve as inductors, while the third phase winding is reutilized as a common-mode inductor. In addition, the initial charging torque is generated at the outset of the charging process, which may cause an instant shock or even rotational movement. In order to prevent vehicle movement, the reason for the charging torque and suppression method were analyzed. Further, predictive control of the model based on mutual inductance analysis was adopted, where the charging torque was directly used as a control object in the cost function. Finally, experimental performances were applied to verify the proposed reconfigured on-board charger under constant current and constant voltage charging.

Low Harmonics Plug-in Home Charging Electric Vehicle Battery Charger Simulation Model of Zero Crossing

Harmonic currents are high in conventional rectifiers. The previous work proposed a new battery charger circuit to reduce harmonics effect and improve total harmonic distortion (THD). The design and development of a home charging electric vehicle battery charger circuit should anticipate potential issues. For this reason, the proposed battery charger, buck chopper, and zero cross circuits must be simulated before real hardware implementation. Simulation and simulation models are needed to describe system behaviour because experimentation might be dangerous, expensive, and time-consuming. This paper describes a simulation model of a zero-crossing circuit and its control algorithm, that provide control signals to a five-level single phase Multi Level Rectifier (MLR)) to draw the MLR for a clean sinusoidal line current with low harmonics. The proposed circuit and the algorithms perform as expected when tested using MATLAB/Simulink and PROTEUS software.

Bang-Bang Funnel Control of Three-Phase Full-Bridge Inverter Under Dual-Buck Scheme

This paper proposes a bang-bang funnel control strategy for the three-phase full-bridge inverter under dual-buck scheme. By adopting the so-called dual-buck scheme, only two switches on the different phase legs are controlled at high frequency, precluding the dead-time utilization. Furthermore, the full-bridge topology can be physically decoupled into two parallel-connected buck units, which allows the inverter to be formulated and analysed by the dynamic model of buck chopper. The bang-bang funnel controller (BBFC) works with just two control values, and it is able to restrain the tracking error between the system's output and the reference within the pre-specified funnel boundaries. The nature of BBFC makes it simpler, faster and more robust, suitable for the inverter operating in dual-buck scheme. The proposed strategy not only guarantees accurate static output performance, but also promotes the inverter's dynamic response against rapid variations of the load, the reference and the input voltage, as well as its robustness to the unexpected parameter changes of the elements. Finally, the effectiveness of the proposed strategy is validated by the simulation and experimental results.

Control Strategy for Reducing Ripple Current in DC-Link Capacitor of Single-Phase UPS

This letter proposes a control strategy for reducing a ripple current in DC-link capacitor of single-phase uninterruptible power supplies (UPS). The proposed method aims to reduce the capacitor current by reducing the difference between the input and output instantaneous power. The input current waveform should satisfy harmonic current regulation and be as close as possible to the load current. Therefore, an auxiliary buck chopper was added to compensate to the ripple current in DC-link capacitor. Experimental result confirm that the proposed method reduces the RMS value of the DC-link ripple current by 27.9%.

A novel brushless de‐excitation system for synchronous generators using a buck chopper with a freewheeling discharge resistor

AbstractA new de‐excitation system for advanced brushless excitation based on a synchronous generator is presented. The proposed system uses a discharge resistor in series with a freewheeling diode of a buck chopper. It improves the reliability of the entire power plant and can be used on several excitation systems. It can be used in case of programmed shutdown of the generator and also shows good results in voltage regulation without destroying the efficiency of the excitation system under nominal operation. An analysis of the system has allowed us to suggest a methodology to obtain the appropriate value of the discharge resistance to be used. The validation of the proposed system has been done through simulations in the Matlab/Simulink environment, supported by experimental tests.

Experimental Identification and Control of a 3Kw DC Motor

In this project, it was requested to identify the parameters of a 3Kw DC machine to realize a speed control of this machine using a Dspace1103 acquisition card. The control consists to generate a PWM signal to manage a buck chopper based on an IGBT. The proposed control is based on two Proportional-Integral (PI) controllers to regulate both, the speed and the current of the identified DC motor. For this purpose, tests were carried out in order to identify the parameters of this machine. This was followed by the practical implementation of our control system. In order to validate our test bench, several diagrams and explanations have been presented in this paper. The proposed algorithm has been investigated through simulation using the MATLAB/Simulink environment and validated experimentally on a laboratory prototype using Dspace1103 real time board.

Determination of electromagnetic disturbances in a buck chopper

ABSTRACT Electrical energy performs increasingly diverse functions through the widespread use of static converters. These converters are based on the use of semiconductor switching components that generate rapid voltage (dV/dt) and/or current (dI/dt) variations. This can result in electromagnetic disturbances that must be minimised in order to respect electromagnetic compatibility standards. Compliance with standards is often achieved by adding a heavy and bulky filter to the system. In order to optimise the EMC aspects, it is interesting to take into account the EMC constraint from the design phase, in order to do so, a predictive study of these disturbances must be available. In this work, the origins of electromagnetic disturbances created by a series chopper are presented. Electromagnetic interference in this DC/DC converter is determined by using simulation and experimental measurements.

Design and Development of Buck Chopper and Applications

Design and Development of Buck Chopper and Applications

PERFORMANCE EVALUATION OF DC ELECTRIC SPRING PLACED IN MICRO GRID SYSTEMS USING SOLAR PV EMULATOR

The use of D.C micro grids(MG) in the electricity distribution level especially for domestic and commercial applications is gaining momentum. D.C power is more lucrative because of low losses due to the absence of reactive power. Hence an attempt is made to realize the effect of both critical and non- critical loads connected to DC Electric spring which forms an integral part of DC MG system. As the buck chopper function meets the requirement of energy, the chopper circuitry is christened as Electric spring. The input to the MG system is obtained from a real time output of solar PV Emulator. In order to avoid multiple AC/DC conversions, solar DC power is directly fed to the loads in addition to charging the batteries. During uncertain conditions of the input supply, the so fabricated DC Electric Spring plays vital role in maintaining constant voltage at critical loads which (this result) leads to the enhancement of the capacity of the battery which is evident from the experimental results.

Voltage balancing control based on gate signal delay in series connection of SiC‐MOSFET

AbstractRecently, research and development of SiC power devices have been done, and SiC power devices have become commercially available. The SiC power devices are suitable for realizing to medium voltage applications. Since, the voltage rating of commercial power devices is limited to less than 1.2 kV, they should be connected in series to maintain a higher voltage rating. However parasitic parameters of these devices are not the same, and therefore the voltage sharing during turn‐off operations cannot be controlled. This article proposes a digital control for the voltage balancing of series connected SiC‐MOSFETs during turn‐off operations. In order to compensate the voltage unbalance conditions, this article presents a time‐adjustment gate‐drive circuit using a digital delay line; experimental results for the feedback control using a buck chopper circuit are also presented.

A novel input power control strategy for high-power dynamic dipole power supply for proton therapy

This paper proposes a novel input power control strategy for high-power dynamic power supply for proton therapy. A buck chopper is staged in series between the input rectifier and the output chopper of the power supply to buffer the input power fluctuation, which can reduce the reactive power exchange between the power supply and power grid and reduce the power distribution requirements. The validity of this proposed control principle has been verified on a high-power dynamic dipole power supply for proton therapy.

Speed Reference Tracking for Separately Excited DC Motor Based ANFIS and Hysteresis Current Control Techniques

In this work, a closed loop control system has designed to control the speed of separately excited direct current motor (SEDCM) using Fuzzy (Mamdani and Sugeno) and an Adaptive Neuro - Fuzzy techniques (ANFIS). The action of these control techniques is to produce the reference armature current that has fed to the hysterics current controller (HCC) that produces the required gating signal to a Buck chopper .Different load conditions has been applied to the motor to obtain many mode of operation, the speed held constant at the required references values using both fuzzy (Mamdani-type and Sugeno-type) and ANFIS techniques. The results has collected and compered with a classical PID controller using MATLAB/Simulink. Step response for the speed has drawn and the control parameters for this response have evaluated. According to the results, the Mamdani fuzzy controller technique is better than as compared with the other controllers. There are many applications for this plant such as production process that need to fill or Packaging any product or used in the autopilot channels. The new goal for this proposed system is to get robust speed controllers that track the speed at any mode of operation using three artificial intelligent techniques.

A Practical Core Loss Model for Filter Inductors of Power Electronic Converters

This paper proposes a core loss model for filter inductors of power electronic converters. The model allows a computationally efficient analysis on the core loss of the inductor under the square voltage excitation and the premagnetization condition. First, the core loss of the filter inductor under buck chopper excitation is evaluated with the proposed model and compared with the conventional methods. The comparison shows that the proposed method results in a better core loss prediction under the premagnetized condition than that of conventional alternatives. Then, the core loss of the filter inductor with the pulsewidth modulated inverter excitation is evaluated, which shows that the proposed model not only accurately predicts the core loss but also identifies the hysteresis loss part. These results demonstrate that the approach can further be used for the development of magnetic materials for power electronic applications.

An Balancing Strategy Based on SOC for Lithium-Ion Battery Pack

According to the two kinds of working state of a battery pack, we designed a balancing strategy based on SOC, and expounds the working principle of balanced control strategy: the battery is charging, the battery charged state of the highest monomer battery is balanced discharge, strong single battery charging current decreases, while the other single cell in the same group is not affected; the battery is in a discharge or static state, single cell battery is the weakest balanced charge, while the other single cell in the same group are not affected. In this paper, we design a kind of lithium ion battery charging and discharging equalizer based on Buck chopper circuit and Boost-Buck chopper circuit. The equalizer is balanced charging and discharging experiments of series four lithium iron phosphate battery, the experimental results show that this equalizer has not only improved the degree not equilibrium between single cells, and improve the battery charge and discharge capacity.

A current-pulsed power supply with rapid rising and falling edges for magnetic perturbation coils on the J-TEXT tokamak

This study presents the design and principle of a current-pulsed power supply (CPPS) for the tearing mode (TM) feedback control of the J-TEXT tokamak. CPPS is a new method of stabilizing large magnetic islands and accelerating mode rotation through the use of modulated magnetic perturbation. In this application, continuous magnetic perturbation pulse trains with frequency of 1kHz to kHz, amplitude of 0.25G, and duty ratio of 20%–50% are required generating via in-vessel magnetic coils. A modified topology based on buck chopper is raised to satisfy the demands of inductive load. This modified topology is characterized by high frequency, rapid rising and falling edges, and large amplitude of current pulses. Appropriate RCD snubber circuit is applied to protect the Insulated Gate Bipolar Transistor (IGBT) switch device. Equipment with peak current that reaches 1kA, frequency that ranges from 1kHz to 3kHz, and rising and falling time within 100μs was constructed and applied to physical experiment.

Agent-based consensus on speed in the network-coupled DC motors

In this paper, a new agent-based method is proposed to address the speed synchronization problem in the network-connected motors. In this study, DC motor is used, driven by a buck chopper circuit. In the proposed method, the consensus protocol of the leader-following multi-agent system is modified, in order to make consensus on the speed among multiple motors in the network, so that they can attain synchronous speed. In order to have a stable system, a common Lyapunov function is developed such that consensus is said to be reached if the ith agent is controllable and observable. MATLAB is used for the purpose of simulation, and results obtained authorize the proposed methodology.

Fault Tolerant Operation of ISOP Multicell Dc-Dc Converter Using Active Gate Controlled SiC Protection Switch

An active gate controlled semiconductor protection switch using SiC-MOSFET is proposed to achieve the fault tolerant operation of ISOP (Input Series and Output Parallel) connected multicell dc-dc converter. The SiC-MOSFET with high temperature capability simplifies the configuration of the protection circuit, and its on-resistance control by the active gate controller realizes the smooth protection without the voltage and the current surges. The first laboratory prototype of the protection switch is fabricated by using a SiC-MOSFET with a high frequency buck chopper for the active gate controller. The effectiveness of the proposed protection switch is verified, taking the impact of the volume reduction into account.

Electromagnetic interference caused by electric load of more electric aircraft

As an increasing number of power electronic converters are used in the electrical system of more electric aircraft( MEA),electro-magnetic interference( EMI) problems are becoming more and more severe both within the electrical systems and between different systems. Based on the electrical load characteristics of MEA,electrical load was classified into rectification,chopping and inverter. The conduction EMI current of the three major electrical load during the stable operation and the load surge of electrical loads were studied by modeling and simulations. EMI characteristics caused by the inverter load obtained was verified by experiments. The research results show that the conducted EMI to the power line is concentrated in the switch frequency of the power electronic device and the multiple frequency or so; the step change of the high power electrical load after the Buck chopper circuit makes the conduction EMI characteristics change significantly,which reflected in the frequencies of local maximum of amplitude spectrum. The study results provide the guidance for the EMI identification and the filter design of an independent electrical system.

A fast-response sliding-mode controller for quadratic buck converter

The switched-mode power supplies are widely used in very low voltage and high-power applications where large conversion ratios are required. In such cases, the quadratic buck converter is the suitable one compared to buck, cascaded buck and multi-phase choppers, because of their limitations in switching frequency and losses. This paper presents mathematical analysis, design and simulation of a quadratic buck converter using fixed frequency Pulse-Width Modulation (PWM)-based Sliding-Mode (SM) controller in order to obtain fast dynamic performance. The design aspects include choice of sliding surface, deriving existing and stability conditions, control parameter selection and their analysis. The performance of the proposed converter is compared with the conventional Average Current-Mode (ACM) controller. In average current mode, the tuning of the PI controller for the inner current loop and outer voltage loop is done using bode plots. The simulation results for the two types of controllers are represented for analysing dynamic performance, as well as line and load regulations.

Laminated Bus Bar Design for Power Converter Circuit Considering Structural and Electrical Limitations

In order to improve the reliability of a power converter circuit, it is important to analyze the DC-side stray inductance between the DC capacitor and the power devices because this may affect the switching losses, lead to the occurrence of over-voltages in power devices, and increase the short-circuit current. As such, a number of studies have investigated these effects through calculations, experiments, and circuit simulations. However, thus far, no paper has discussed a design of the stray inductance. In this paper, the authors propose a design procedure for the stray inductance of the laminated bus bar for a high-speed switching circuit using SiC power devices. The relationship among the bus bar inductance, the over-voltage, and the short-circuit current is clarified using an analytical MOSFET model. In order to verify the analysis results, an experiment using SiC-MOSFET and SiC-SBD rated at 1,200V is conducted. From these results, the upper and lower limitations of the bus bar inductance for the buck chopper circuit are found, and the design procedure for the wiring structure considering the stray inductance is discussed using the inductance map.