Three-phase Diode Bridge Rectifier Research Articles

Quasi-Z-Source Three-Phase Voltage Source Inverter with Virtual Space Vector Modulation to Increase the Voltage Gain and for the Reduction of Common Mode Voltage

Abstract A quasi-Z-source network is used to boost the DC bus voltage of a voltage source two-level H-bridge inverter to increase the voltage gain. With the increase in the DC bus voltage, the common mode voltage (CMV) also increases. The CMV is reduced using virtual space vector pulse width modulation (SVPWM). Due to the presence of a quasi-Z-source network, the expression of the CMV changes significantly with respect to the conventional voltage source two-level H-bridge inverter fed from a pure DC supply. In this paper, a detailed analysis of the origin of the CMV for the quasi-Z-source two-level H-bridge inverter is presented. Additionally, it is shown how the CMV is affected for a DC input supply taken from a three-phase diode bridge rectifier. The work also details the scheme for suitable placement of shoot-through time intervals required for boosting within the non-active time intervals in virtual SVPWM. The simulation and experimental results show the scheme is effective in increasing the voltage gain and reducing the CMV arising at the third harmonic of the desired output frequency by at least 33.33%.

A Study on Various Causes of Low Frequency Components in Common Mode Voltage of a Space Vector Pulse Width Modulated Three– Phase Quasi–Z–Source H–Bridge Inverter Fed from a Three–Phase Diode Bridge Rectifier

Abstract The presence of low frequency components in the common mode voltage can cause harmful electromagnetic interference. A critical study on various causes of low frequency components in the common mode voltage of a space vector pulse width modulated Quasi–Z– source three–phase H–bridge voltage source inverter fed from a three–phase diode bridge rectifier is presented in this paper. The Quasi–Z–source network is utilized in boosting the rectified dc voltage which increases the overall voltage gain. The study considers the effect of boosting on the low frequency components. The input three-phase diode bridge rectifier has its influence in modulating the instantaneous common mode voltage and contributes low frequency components. The unbalanced three-phase supply can contribute additionally ac supply frequency component in the common mode voltage. The major contribution of this paper is the analytical, simulated and experiment-based study on various causes of the low frequency common mode voltages due to the combined action of the input non-ideal three phase grid, the front-end diode bridge rectifier as well as the load-end Z-source H-bridge three-phase inverter feeding a three-phase inductive load, while operated through a space vector pulse width modulation strategy.

New Smart Sensor for Voltage Unbalance Measurements in Electrical Power Systems.

This paper deals with voltage unbalances and how they can be quantified according to the standards. Firstly, a comparison between the different unbalance voltage factors is conducted in order to remark on their divergences. Secondly, according to the standard that better represents the phenomenon, i.e., EN 50160, a new methodology is proposed to quantify the voltage unbalance factor (VUF). In order to do so, it is recommended to measure the voltage unbalance in three-phase installations by means of a new smart sensor based on a single voltage sensor, which measures the direct-current (DC) voltage at the output of a three-phase diode bridge rectifier, while current methods make use of three voltage sensors (which can measure either phase-to-neutral voltages or phase-to-phase voltages). Furthermore, both simulation and experimental results have been carried out to validate the proposed methodology. Finally, a new voltage unbalance factor (and the corresponding methodology to obtain it from the measured DC voltage) is proposed.

Modelling and Analysis of Wind Turbine using Permanent Magnet synchronous generator for Maximum Power Tracking Control

This research uses Matlab/Simulink simulation tools to analyse and simulate the performance of a wind power system powered by a low-speed Permanent Magnet Synchronous Generator (PMSG). A wind turbine (WT), PMSG, maximum power point tracking (MPPT), a three-phase diode bridge rectifier, a dc bus connected to a capacitor, and a PWM voltage source inverter regulated by a current source are all part of the system. With an MPPT control, the optimum coefficient of performance parameter was attained in the WT model as a function of wind velocity. The use of low-speed PMSG, which results in improved efficiency, eliminates the need for a gearbox. The ac output power obtained from PMSG is supplied to a three-phase rectifier bridge, which allows for maximum power extraction by using the boost converter's optimal voltage and current settings. The total system is connected to the electrical utility using a current source PWM inverter for dc/ac conversion.

An Improved Mechanical Sensorless Maximum Power Point Tracking Method for Permanent-Magnet Synchronous Generator-Based Small Wind Turbines Systems

This article proposes an improved maximum power point tracking (MPPT) method without mechanical and voltage sensors for small wind turbines (SWT) systems. The technique is suitable for SWT systems that employ a permanent-magnet synchronous generator (PMSG), a three-phase diode bridge rectifier, and a dc–dc converter, which is one of the most popular configuration for this kind of system. The proposed MPPT extracts the maximum available power from the PMSG operating with variable speed, and it is based on the output power characteristic in relation to the output current of the rectifier. The article proves that a constant output current in the rectifier ensures extracting the maximum electrical power available in the SWT system, independent of the rotational speed. Additionally, this constant current value depends solely on the PMSG characteristics. Therefore, the proposed MPPT control strategy is a simple current mesh with a constant reference that is implemented in a dc–dc converter connected in series to the rectifier, which is responsible to guarantee a constant current in the rectifier output. The proposed MPPT method was corroborated through simulation and experimental results in a 1.5-kW SWT. The tracking efficiency of the proposed MPPT was close to 97.64%.

Energy Management of a Renewable Hybrid Isolated DC Microgrid

Abstract: Hybrid microgrid is the key solution to energize remote rural areas. The microgrid system incorporates more than one Distributed Renewable Energy (DRE) source to complement one another. This paper proposes a hybrid DC microgrid system to be operated in isolated mode. The proposed microgrid consists of a PMSG based Wind Turbine, PV array, and Lead-acid battery as an energy storage device. The Wind Turbine generator is connected to the DC bus through a Three-phase Diode Bridge Rectifier. The PV array is tied to the DC bus by a Boost converter and incremental conductance algorithm is used to extract the maximum power from the PV array. The battery uses a bidirectional converter for charging and discharging. A simple PI-based closed-loop control system is incorporated for proper energy management. The bus voltage is maintained either by the boost converter or the bidirectional converter depending upon the operating condition. The proposed microgrid system is modeled in MATLAB/SIMULINK software. Simulation of this model is done for varying irradiance, temperature, wind condition, and different load condition. The simulation results show that the system is stable under various load and supply conditions. Keywords: Hybrid microgrid, Distributed Renewable Energy (DRE), PMSG, PV array, DC bus, Boost converter, incremental conductance, bidirectional converter

A Novel Inductor for Stabilizing the DC Link of Adjustable Speed Drive

The DC-link filter which includes a magnetic inductor and a storage capacitor is one of the key parts of adjustable speed drives in the market. It significantly affects the stability, reliability, and power density of the motor-drive system. This paper proposes a novel, variable active inductor to improve the performance of DC links in terms of stability, reliability, size, and cost. In contrast to conventional DC-link magnetic inductors, the variable active inductor is made of power electronic circuits, including active switches, passive filters, and smart controllers, which no longer rely on magnetic material. The demonstration shows that the inductor can emulate the electrical characteristics of the magnetic inductor for filtering harmonics and stabilizing the DC link, meanwhile representing a smaller size, lighter weight, and lower cost compared with a conventional one. Furthermore, this paper proposes a variable inductance control method which is able to adaptively tune the inductance value with the operating conditions of the drive system. The DC link can be stabilized, and high performance can be maintained in both balanced and unbalanced grid voltage conditions. A case study of the proposed variable inductor in a motor drive with a three-phase diode-bridge rectifier as the front end is discussed. Experimental results are given to verify the functionality and effectiveness of the proposed variable inductor.

Power loss and efficiency analysis of an onboard three-level brushless synchronous generator

ABSTRACT This paper develops a mathematic model to calculate the power losses and efficiency for an onboard three-level brushless synchronous generator (TLBLSG) which consists of pilot exciter (PE), main exciter (ME), and main generator (MG). A back-iteration algorithm which combines an analytical model of the MG stator loading with a three-phase diode bridge rectifier (TPDBR) and a capacitor, an equivalent circuit model of the MG, and a model of steady-state excitation current based on the open circuit characteristic (OCC) is employed to determine the electrical parameters in the MG. Besides, both ME rotor and PE stator currents are calculated by the model of induced electromotive force loading with a TPDBR and an inductance. All the obtained electrical parameters can reflect the influence of rotating speed and load change as well as the saturation effect. Finally, changing laws of the electrical parameters and power losses as a function of speed and load are simulated and discussed in detail. Moreover, efficiencies under different speeds and loads are analysed. The TLBLSG is suggested to be operated in a relatively high-speed range (from 15,000 to 25,000 r/min) and a relatively large load (from 25 to 65 kW) for a high efficiency.

Comparative analysis of two different interphase reactors applied in 36‐pulse diode rectifier

This study presents a comparative analysis of two different interphase reactors (IPRs) applied in a 36-pulse diode rectifier. One is traditional triple-tapped IPR; the other is unconventional IPR (UIPR) composed of the primary winding and secondary winding. The primary winding is double-tapped conventionally and the secondary winding is connected with a single-phase full-wave rectifier. The operation modes and optimal parameters of both IPRs are analysed. The effect of different operation modes on output currents of the two three-phase diode-bridge rectifiers, input currents and load voltages is also analysed. Under the optimal parameters, both rectifiers operate as 36-pulse diode rectifiers and reduce the total harmonic distortion of input line currents to be 5%. Especially, the proposed rectifier using UIPR is easy and simple to implement. Some experiments are provided to validate the theoretical analysis.

Coupled Inductor Based Regenerative Cascaded Multicell Converter for Drives With Multilevel Voltage Operation at Both Input and Output Sides

Cascaded multicell converter (CMC) is proved to be an effective solution for medium voltage drives. Three-phase diode bridge rectifiers are normally used in this converter, which do not have regeneration capability. Pulsewidth-modulated (PWM) rectifier-based power cells enable the drives with regeneration capability. However, due to their two-level voltage operation at the input side, an inductor is required for each cell to filter out the switching frequency components from the input current. In this paper, a new configuration with single-phase PWM rectifier-based power cell is proposed to achieve multilevel voltage operation at both the input and output sides of the converter. Therefore, the devices at the rectifier side are also operated at reduced switching frequency without using any filter inductor for each cell. In the proposed converter, simple modular transformers are used instead of a single large and complex transformer that is used in the conventional CMC. Further, input phase currents of the converter are controlled in the synchronously rotating d–q frame, which requires only two current sensors at the input side instead of individual current sensors for each cell. Experimental validation of the proposed converter configuration is carried out on a 4.5-kVA prototype, and the results are presented.

Power Quality Research On Three-Phase Pfc Rectifier (Minnesota Rectifier)

The Minnesota rectifier is a well established topology, however, no serious attempts have been made to explicitly investigate the improvement in power quality by the use of this rectifier. This paper discusses the harmonic reduction in the line currents of a three-phase diode bridge rectifier by third harmonic current injection technique. The improved performance of the current injection technique is validated by comparing the simulation results of a rectifier unit with and without current injection technique.

Harmonic Analysis of Three-Phase Diode Bridge Rectifiers Under Unbalanced and Distorted Supply

Developing an effective harmonic power flow tool requires fast and accurate calculations of the harmonics generated by the nonlinear elements. This paper presents a time-domain-based method for obtaining all steady-state characteristic and noncharacteristic harmonics generated by three-phase diode bridge rectifiers, under unbalanced and distorted supply. The developed model is generic and able to address both continuous- and discontinuous-conduction modes with a single formulation. By introducing a virtual resistance on the rectifier's DC side, the model is extended to accommodate any DC-side filter. Further, a unique analytical Jacobian matrix is developed to guarantee a quadratic convergence for the iterative part of the proposed method. The effectiveness of the proposed method for harmonic analysis is confirmed through a comparative evaluation with time-domain simulations using PSCAD/EMTDC.

Improved TOGI-Based Voltage and Frequency Control for PMSG Feeding Single-Phase Loads in Isolated Pico-Hydro Generation

ABSTRACT This paper deals with the performance of a three-phase permanent magnet synchronous generator (PMSG) for stand-alone pico-hydro generation feeding single-phase load using improved third-order generalized integrator (ITOGI). The proposed control algorithm is used for load balancing, harmonics mitigation and reactive power compensation when a three-phase PMSG feeds a single-phase nonlinear load. A PMSG, voltage source converter (VSC), three-phase diode bridge rectifier (DBR) circuit connected in series with an IGBT switch-based DC–DC converter and a single-phase consumer load are parallelly interfaced at the point of common interface (PCI). The voltage and frequency of the proposed system are controlled in a decoupled manner. The VSC is used for voltage control by providing reactive power compensation along with the power quality improvement. The duty ratio from the frequency controller to IGBT switch connected in series with DBR circuit regulates the system frequency by feeding excess power into an auxiliary load. An ITOGI-based control algorithm is used to extract the fundamental component of load current for power quality improvement by providing proper switching pulses to VSC. The comparative analysis of already existing major state of art techniques is given with proposed ITOGI-based control technique using a Bode diagram and a step response. An appropriate tuning procedure is provided for deciding the control parameters for this algorithm. Simulated behaviour of proposed system and experimental test results are demonstrated using the prototype developed in the laboratory. The feasibility of this control strategy is illustrated using dynamic and steady-state performances of the proposed system feeding the single-phase consumer loads.

A Two-Terminal Active Inductor With Minimum Apparent Power for the Auxiliary Circuit

This letter proposes a two-terminal active inductor concept with minimum apparent power processed by the auxiliary circuits, which are implemented by power semiconductor switches and passive elements. It has the same level of convenience as a passive inductor with two power terminals only. Compared with a conventional inductor with the same equivalent inductance and current rating, the energy storage requirement of the inductor can be reduced significantly, as well as the weight and volume. The auxiliary circuit in the active inductor processes both partial voltage and partial current, with the lowest apparent power rating compared to existing solutions. A case study for the dc-link filter inductor in a three-phase diode-bridge rectifier is discussed. Proof-of-concept experimental results are given to verify the functionality and effectiveness of the proposed active inductor.

Modular Transformer-Based Regenerative-Cascaded Multicell Converter for Drives With Multilevel Voltage Operation at Both Input and Output Sides

Cascaded multicell converter (CMC) is proved to be an effective solution for medium voltage drives. Three-phase diode bridge rectifiers are normally used in this converter, which do not have regeneration capability. Pulsewidth-modulated (PWM) rectifier-based power cells enable the drives with regeneration capability. However, due to their two-level voltage operation at the input side, an inductor is required for each cell to filter out the switching frequency components from the input current. In this paper, a new configuration with single-phase PWM rectifier-based power cell is proposed to achieve multilevel voltage operation at both the input and output sides of the converter. Therefore, the devices at the rectifier side are also operated at reduced switching frequency without using any filter inductor for each cell. In the proposed converter, simple modular transformers are used instead of a single large and complex transformer that is used in the conventional CMC. Further, input phase currents of the converter are controlled in the synchronously rotating d-q frame, which requires only two current sensors at the input side instead of individual current sensors for each cell. Experimental validation of the proposed converter configuration is carried out on a 4.5-kVA prototype, and the results are presented.

A Fuzzy Logic Based Mppt Controller For Wind-Driven Three-Phase Self-Excited Induction Generators Supplying Dc Microgrid

<p class="Default"><span lang="EN-US">In this paper, a straightforward strategy for tracking the maximum power (MP) accessible in the wind energy conversion system for dc microgrid is proposed. A three-phase diode bridge rectifier alongside a dc-dc converter has been utilized between the terminals of wind-driven induction generator and dc microgrid. Induction generator is being worked in self-energized mode with excitation capacitor at stator. The output current i.e., dc grid current act as a control variable to track the MP in the proposed WECS. In this manner, the proposed calculation for maximum power point tracking (MPPT) is autonomous of the machine and wind-turbine parameters. Further, a technique has been created for deciding the obligation proportion of the dc-dc converter for working the proposed system in MPPT condition utilizing wind turbine qualities, relentless state proportionate circuit of prompting generator and power balance in power converters. Circuit straightforwardness and basic control calculation are the significant points of interest of the proposed setup for supplying energy to the dc microgrid from WECS. The fruitful working of the proposed calculation for Fuzzy logic based MPPT has been shown with broad exploratory results alongside the simulated values.</span></p>

Analysis and MPPT control of a wind‐driven three‐phase induction generator feeding single‐phase utility grid

In this study, a three-phase diode bridge rectifier and a single-phase voltage source inverter topology has been proposed for feeding single-phase utility grid employing a three-phase induction generator fed from wind energy. A self-excited induction generator configuration has been chosen for wide speed operation of wind turbine system, which gives the scope for extracting maximum power available in the wind. In addition to maximum power point tracking (MPPT), the generator can be loaded to its rated capacity for feeding single-phase utility grid using a three-phase induction machine, whereas it is not possible with existing configurations because of the absence of power converters. For the proposed system, MPPT algorithm has been devised by continuously monitoring the grid current and a proportional resonant controller has been employed for grid synchronisation of voltage source inverter with single-phase grid. A MATLAB/Simulink model of the proposed system has been developed to ascertain its successful working by predetermining the overall performance characteristics. The present proposal has also been tested with sag, swell and distortion in the grid voltage. The control strategy has been implemented using field programmable gate array (FPGA) controller with modularised programming approach. The efficacy of the system has been demonstrated with the results obtained from an experimental set-up in the laboratory.

Frequency‐domain harmonic matrix model for three‐phase diode‐bridge rectifier

Three-phase diode-bridge rectifier is a common front end for variable frequency drives/dc-to-dc converters, and is a well-known harmonic source. The rectifier may operate in a dc current continuous or discontinuous mode, which creates a challenge in modelling the harmonic-generation characteristics of such device. This study proposes a method to determine the operational modes of the rectifier under balanced operating conditions and then develops appropriate frequency-domain harmonic models for each mode. The result is an integrated analytical harmonic matrix model for the three-phase diode-bridge rectifier. The matrix model can explicitly show the harmonic coupling effects between the rectifier ac supply voltages and its generated harmonic currents. Simulation and experiments have been done to verify the proposed model. The harmonic model has been applied to analyse the rectifier harmonic generating characteristics and the harmonic interactions between the rectifier and the grid.

Pulse Pattern-Modulated Strategy for Harmonic Current Components Reduction in Three-Phase AC–DC Converters

Generated harmonic current as a consequence of employing power electronics converter is known as an important power quality issue in distribution networks. From industry point of view, complying with international standards is mandatory; however, cost and efficiency are two other important features, which need to be considered in order to be competitive in the market. Therefore, having a flexibility to meet various requirements imposed by the standard recommendations or costumer needs is at most desirable. This makes the generated harmonic current mitigation a challenging task especially with three-phase diode-bridge rectifier, which is still preferred in many power electronic systems. This paper addresses a novel current modulation strategy using a single-switch boost three-phase diode-bridge rectifier. The proposed method can selectively mitigate current harmonics, which makes it suitable for different applications. The obtained results at experimental and simulation levels verify and confirm the robustness of the proposed approach.

A Single-Sensor-Based MPPT Controller for Wind-Driven Induction Generators Supplying DC Microgrid

In this paper, a simple method of tracking the maximum power (MP) available in the wind energy conversion system (WECS) for dc microgrid application is proposed. A three-phase diode bridge rectifier along with a dc–dc converter has been employed between the terminals of a wind-driven induction generator and dc microgrid. Induction generator is being operated in self-excited mode with excitation capacitor at stator. The output current of the dc–dc converter, i.e., dc-grid current is considered as a control variable to track the MP in the proposed WECS. Thus, the proposed algorithm for maximum power point tracking (MPPT) is independent of the machine and wind-turbine parameters. This algorithm has been implemented using dsPIC30F4011 controller. Furthermore, a method has been developed for determining the duty ratio of the dc–dc converter for operating the proposed system in MPPT condition using wind-turbine characteristics, steady-state equivalent circuit of a induction generator, and power balance in power converters. Circuit simplicity and simple control algorithm are the major advantages of the proposed configuration for supplying power to the dc microgrid from the proposed small-scale WECS. The successful working of the proposed algorithm for MPPT has been demonstrated with extensive experimental results along with the simulated values.