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Analysis and design of high frequency three-phase boost rectifiers
Abstract
Analysis and design of high switching frequency, high efficiency,
three-phase boost rectifiers are presented. A novel PWM scheme is
developed to reduce switch conduction loss, switching loss, and input
current ripple. An average method is proposed to calculate switch
currents and input current ripple, allowing accurate prediction of
switch loss, EMI emissions, and inductor loss. Soft switching, control
and system interaction issues are also discussed. A 9 kW, 50 kHz ZVT
boost rectifier is designed with high efficiency and light weight
... The widespread use of the active AC-DC rectifier leads to the rise in non-linearity of electronic equipment resulting in grid current degradation. Therefore, to handle such a problem efficiently, a three-phase boost power factor correction (PFC) rectifier has gained further popularity [1]- [5]. The performance of three-phase boost PFC rectifier in terms of unity power factor (PF), total harmonics distortion (THD) reduction and dynamic performance indices improvement such as overshoot (M p ), settling time (t s ), rise time (t r ) and steady-state error (E ss ) can be significantly improved by ...
... To discuss the working principle of a three-phase boost PFC rectifier. The mathematical model of the system must be established [1], [2]. Then, the static abc coordinate sys-tem corresponding to the three-phase system is applied using Clark transformation. ...
... The three-phase boost PFC rectifier state-space equation in the three-phase stationary coordinate system [1], can be written as ...
This paper performs parameter optimization of proportional-integral (PI) and repetitive controller (RC) with a new objective function by adding two degrees of freedom for a three-phase boost power factor correction (PFC) rectifier. The main objectives are to optimize the multiple control loop parameters for total harmonics distortion (THD) reduction and dynamic performance indices improvement, including overshoot, rise time, and zero steady-state error. The control parameters of the three-phase boost PFC rectifier are optimized through a standard genetic algorithm. After obtaining the optimal PI and RC parameters values, fast Fourier transform and dynamic response analysis were performed using MATLAB. Moreover, separate evaluation functions are used to validate the optimal results in terms of THD reduction and dynamic performance indices improvement. Furthermore, the results are compared with the existing objective functions to show the proposed objective function superiority. Simulation results demonstrated that our proposed objective function outperforms existing objective functions to achieve optimal PI and RC parameters value. Finally, simulation results are validated through experimental results. The experimental setup includes a 5kW three-phase PFC rectifier with DSP TMS320F28335 prototype hardware to verify controller parameter performance.
... Сучасний рівень розвитку силової електроніки дає змогу реалізувати високоефективні системи перетворення електричної енергії. Так, застосування активних випрямлячів (АВ) [2,5] дає можливість підвищити коефіцієнт потужності практично до одиниці при прямому перетворенні електричної енергії. Але при цьому залишається не до кінця вирішеною проблема роботи таких перетворювачів в режимі рекуперації. ...
... Топологія рекупераційного активного випрямляча. Існують різні топології схем АВ, що забезпечують корекцію коефіцієнта потужності [2,5]. Однак слід зазначити, що не всі топології АВ дають змогу реалізовувати двосторонню передачу енергії. ...
... Рис. 1. Схема активного трифазного підвищувального випрямляча Система керування активного випрямляча. У [2,5] розглянуто різні системи керування (СК) активним підвищувальним випрямлячем з корекцією коефіцієнта потужності. Найбільш перспективними системами керування АВ є: гістерезисна СК, векторна СК і система прямого керування потужністю. ...
У статті наведено систему керування вхідного 4Q-випрямляча, що реалізує коефіцієнт потужності тягового електропривода в режимах тяги та рекуперації близький до одиниці. Корекція коефіцієнта потужності реалізується як у режимі активного випрямляча, так і в режимі рекуперації. Виконано дослідження процесів в активному випрямлячі у програмному пакеті Matlab та виконано аналіз якості енергії. Запропоновано систему керування, яка реалізує режим рекуперації з високими енергетичними показниками.
... Another alternative for implementing the front-end converter in high-power DPS systems is achieved by using a three-phase rectifier as a PFC stage [6]. Among the three-phase rectifiers, the six-switch boost topology is able to achieve the best performance in terms of shaping the input currents and presenting bi-directional power flow capability [6]- [10]. In addition, this converter presents low input and output filter requirements, which reduces the weight and volume of the overall system. ...
... Due to their turn-off losses, the use of IGBT devices limits the switching frequency to well below 40 kHz. To improve the efficiency of the six-switch boost rectifiers, several soft-switching schemes and lossless snubbers have been presented [10]- [12]. The increase of the circuit and control complexity has made this structure expensive and difficult to accept in some industry applications. ...
... ( [3][4][5][6][7][8][9][10][11] The output voltage can be obtained by combining (3-2) with (3)(4)(5)(6)(7)(8)(9)(10)(11), as follows: ...
... There are many other approaches that can be used to enhance power quality in high-power applications. Among the three-phase rectifiers, the six-switch boost topology is able to achieve the best performance in terms of shaping the input currents and presenting reverse energy flow capability [22] [23] [24]. However, as shown in Fig. 1 MOSFETs are used in the circuit, the anti-parallel diodes will present serious reverse-recovery problems due to the high operating frequency. ...
... However, as shown in Fig. 1 MOSFETs are used in the circuit, the anti-parallel diodes will present serious reverse-recovery problems due to the high operating frequency. To improve the efficiency of the six-switch boost rectifiers, several soft-switching schemes and lossless snubbers have been presented [24] [25] [26]. Either soft-switching circuits or lossless snubbers add cost to the system, making these solutions difficult for industry to accept. ...
... A three-phase six-switch rectifier followed by an isolated dc-dc converter is typically used in three-phase applications that require high-power-factor (HPF) and galvanic isolation between the input and output [1]–[2]. While this approach offers excellent performance, its major drawback is a relatively high cost due to the high number of switches and complex control that is required to achieve a low inputcurrent harmonic rectification. ...
... In the past, several non-isolated three-phase single-switch HPF rectifiers were introduced [2]-[10]. Generally, these single-switch circuits either employ a discontinuous-currentmode (DCM) pulse-width-modulation (PWM) boost rectifier topology [4]-[8], or multi-resonant buck topology [9]-[10]. ...
A three-phase, high-power-factor (HPF), soft-switched isolated rectifier is introduced. The proposed circuit employs a discontinuous-voltage-mode (DVM) resonant input rectifier followed by a two-switch forward converter. In addition to achieving HPF rectification, the circuit also offers soft switching of the forward converter switches. The operation and performance of the proposed topology were verified on a 3-kW prototype operating from a three-phase line-to-line voltage of 220 V ± 10%. The experimental results show that the input-current-shaping using the proposed rectifier can be performed with a THD less than 6% over the entire line range and in the load range from full load down to less than 10% of full load. The measured efficiency of the experimental prototype at full load and nominal line was approximately 90%.
... The large signal model obtained, according to [2], [3], [4] and [5], is shown in figure 2, where the average of the switching functions is made by replacing them by the duty cycle that corresponds to each switch. Figure 2 also includes the average model of the full-bridge inverter with both voltage and current control loops. ...
... Consequently the power reference is converted into an AC current reference. Finally the DSP implements the Predictive Current Algorithm according to the modulation laws defined by equations (3), (4) and (5), and this guarantees that the AC input currents will be in phase with the mains voltages. ...
This paper presents the large signal model of a four-quadrant AC to DC converter, which is expected to be used in the area of particle accelerators. The system’s first stage is composed of a three-phase boost PWM (Pulse Width Modulated) rectifier with DSP (Digital Signal Processing) based power factor correction (PFC) and output voltage regulation. The second stage is a full-bridge PWM inverter that allows fast four-quadrant operation. The structure is fully reversible, and an additional resistance (brake chopper) is not needed to dissipate the energy when the beam deflection magnet acts as generator.
... Three-phase boost rectifiers, due to their high efficiency and low EMI emissions are widely used in industry as Power Factor Correction (PFC) converters [1]. Because high quality current control without the use of large reactive components, is the major objective in PFC operations, high switching frequencies are desirable to reduce the size and weight of reactive components especially inductors. ...
... In digital implementation, two current compensators in rotating frame are usually used. The advantage of the digital implementation is that all control variables are constant in steady state for a balanced system, and good steady-state current quality can be easily obtained [1]. However, problems such as the presence of the right-half plane zero in control to output transfer function severely limit the loop bandwidth for three-phase boost rectifiers [3]. ...
Three-phase boost rectifiers, due to their high efficiency and low EMI emissions are widely used in industry as power factor correction (PFC) converters. Advantages of high switching frequency in this type of converters would necessitate looking for faster and simpler PWM techniques. This paper introduces a modified SVM modulator based on classification algorithm for three-phase boost rectifiers that relatively fulfills such requirements. The proposed modulation technique make possible having, higher switching frequencies and wider control bandwidth. In addition, classification algorithm offers exact positioning of the switching instants with less computational efforts. Moreover its implementation is simpler and needs less hardware and software, when compared with conventional SVM algorithms. Simulation results on PSCAD/EMTDC, confirm the validity of the analytical work.
... Существуют различные топологии схем активных выпрямителей (далее АВ), обеспечивающие коррекцию коэффициента мощности. Одной из наиболее хорошо зарекомендовавших себя схем, имеющей высокие энергетические показатели, является схема активного полномостового повышающего выпрямителя [2]. ...
В статье приведен обзор и сравнение схем активных выпрямителей, позволяющих реализовать коррекцию коэффициента мощности и устранить высшие гармоники входного тока. Представлен ряд требований, исходя из которых была выбрана оптимальная схема трехфазного выпрямителя тяговой подстанции, обеспечивающая коррекцию коэффициента мощности
... While Using three phase six-switch converter, however, is costly and complicated given the number of active switches that must be used and the sophisticated control needed to ensure a good power factor .Cheaper and simpler methods of performing three-phase active input PFC have been developed using converters with less than six switches. [3] One such converter, first proposed, is the Two-switch boost converter. This converter is designed to operate so that its phase currents are discontinuous and bounded by a sinusoidal envelope. ...
Generally AC to DC Regulated Converter are Designed For Generator and also used telecommunication Industry and Data Servers and DC Motor and for Generators. They need Continuous DC supply for their Proper Working. There we cannot tolerate the input Variation. So we have to design such converter that gives Constant DC output under the input Variation. Here we Design and Develop commercial power supply that allows a user to have a wide range of output voltages. In this application, a user would be able to obtain stepped up and stepped down output dc voltages from the same three-phase ac supply. Many three-phase ac-dc converters that perform PFC with a reduced number of switches are variations of the converter and their output voltage is always higher than their input voltage because they are boost-type converters. This is a drawback if there is a need for a converter that needs to operate for a wide range of input ac voltages and/or produce a wide range of output dc voltages. We will design and simulate converter with above features ______________________________________
... While Using three phase six-switch converter, however, is costly and complicated given the number of active switches that must be used and the sophisticated control needed to ensure a good power factor .Cheaper and simpler methods of performing three-phase active input PFC have been developed using converters with less than six switches. [3] One such converter, first proposed, is the Two-switch boost converter. This converter is designed to operate so that its phase currents are discontinuous and bounded by a sinusoidal envelope. ...
Generally AC to DC Regulated Converter are Designed For Generator and also used telecommunication Industry and Data Servers and DC Motor and for Generators. They need Continuous DC supply for their Proper Working. There we cannot Tolerate the input Variation. So we have to design Such converter that gives Constant DC output under the input Variation. Here we Design and Develop commercial power supply that allows a user to have a wide range of output voltages. In this application, a user would be able to obtain stepped up and stepped Down output dc voltages from the same three-phase ac supply. Many three-phase ac-dc converters that perform PFC with a reduced number of switches are variations of the converter and their output voltage is always higher than their input voltage because they are boost-type converters. This is a drawback if there is a need for a converter that needs to operate for a wide range of input ac voltages and/or produce a wide range of output dc voltages. We will design and simulate converter with above features. Hardware will be designed and simulation results will be calibrated.
... These devices are currently largely used in power electronics technology like three-phase boost PWM AC-DC rectifier due to its higher efficiency and higher power density [4]. Three phase boost PWM rectifier can also be employed as a front-end power processing unit with power factor correction as it provides adjustable input displacement factor, sinusoidal input currents and dc output voltage with no low frequency harmonics [5]. ...
... A multilayer shielding enclosure is specifically machined to protect the driver by blocking stray magnetic and electromagnetic fields. Unlike the drivers used in magnetic manipulation systems, coils are driven at higher PWM frequencies, which are close to their self-resonant frequencies using the developed coil driver [Mao 1996, Patella 2003, Oliveira 2007, Shirabe 2012, Han 2017]. This method minimizes magnetic field fluctuation by reducing current ripple magnitude, which provides a more predictable field. ...
Pulse width modulation (PWM) is the most commonly used technique for coil drive in magnetic manipulation systems. Relatively low PWM frequencies generate high magnitude current ripple and magnetic field fluctuation. In this study, a high-frequency coil driver is developed to increase the efficiency of the magnetic manipulation systems by minimizing current ripple and magnetic field fluctuation. In order to protect the driver against the penetration of stray electromagnetic and magnetic waves, a multi-layer shielding enclosure is machined. The high-frequency coil driver is used to study the effect of varying PWM frequencies on current, magnetic field, and ohmic loss using Helmholtz, air and iron core coils. It is shown that current ripple magnitude is significantly minimized when the coils are driven at PWM frequencies close to their self-resonant frequencies. This results in magnetic field fluctuation reduction and provides more accurate measurement of magnetic field magnitude, which is one of the vital components for magnetic manipulation. Two orders of magnitude reduction in both current ripple and magnetic fluctuation are obtained when PWM frequency is increased from 100 Hz to 25 kHz for a Helmholtz coil. It is also observed that increasing the PWM frequency has a negligible effect on the ohmic loss. Our results show that the developed high-frequency coil driver is a good candidate for high frequency coil drive applications to increase the magnetic manipulation efficiency.
... Recently, an isolated HPF ZCS two-switch forward resonant rectifier has been introduced in [12], which employs only two active switches compared to a conventional threephase six-switch rectifier followed by an isolated dc-dc converter, which employs more than eight switches to achieve HPF and galvanic isolation between the input and output [13], [14]. Because of ZCS and the significant dependence of overall rectifier performance on switch performances, the isolated HPF ZCS two-switch forward resonant rectifier was also considered a good candidate . ...
A high-voltage silicon-carbide (SiC) power MOSFET was evaluated on two high-power factor (HPF), three-phase resonant rectifiers; a non-isolated, 2-kW buck rectifier and an isolated, 3-kW two-switch forward rectifier. By replacing an IGBT switch with a SiC power MOSFET switch that has an equivalent current rating, the efficiency of both the non-isolated and isolated resonant rectifiers were significantly improved. The non-isolated buck rectifier using SiC MOSFET switches could deliver approximately 80%-40% more power than the rectifier using equivalent IGBT switches. Moreover, the efficiency of the isolated two-switch forward rectifier, which was operating with full load and switching frequency of 67 kHz, was improved by approximately 2% when IGBT switches were replaced by SiC power MOSFET switches. The IGBT loss was approximately 4.5% of the total output power. The loss of the SiC MOSFET was only 2.5% of the total output power under the same operating condition. When the prototype circuit was modified to operate at twice the switching frequency, the rectifier using SiC MOSFET switches could deliver approximately 60% more power than the rectifier using equivalent IGBT switches.
In more electric aircrafts (MEAs), the synchronous generators are connected directly to the turbo-engine to develop a constant voltage variable frequency (CVVF) AC supply bus. In addition, the MEA has adopted high voltage DC bus in its power system to cater the various categories of load used by aircraft. Therefore, this change in power paradigm has created a requirement for AC-DC power factor correction (PFC) converters to convert CVVF AC to constant DC with high power quality in a reliable manner. In this paper, a three-phase interleaved buck-boost-derived PFC converter operated in discontinuous current conduction mode to realize the inherent unity power factor (UPF) operation for MEA wide range of supply frequency. The benefits of the proposed converter are higher power density, efficiency, and reliability. The advantages of the proposed converter are demonstrated by performing an analytical comparison with the single-cell three-phase buck-boost derived PFC converter and presented the relevant results. The experimental results from a 2.0 kW laboratory concept-proof hardware prototype have been provided to confirm the proposed converter UPF operation for wide range supply frequencies. A low input power factor of 0.9996 and a minimum current THD of 2.52 % are recorded from the developed prototype.
In more electric aircraft (MEA), three-phase power factor correction (PFC) rectifiers of several kilowatts are required. In this paper, a three-phase buck-boost derived PFC converter with three switches and with input inductors connected in delta configuration for use in MEA is presented. The proposed converter is operated in a discontinuous conduction mode to achieve PFC at ac input. This avoids the inner current control loop which further eliminates the current sensors. It requires only one output voltage sensor unlike five sensors in conventional PFC converter for its control implementation. This makes the system cost effective, more reliable, and robust. A simple voltage control loop is used to generate the gate signals. The steady state operation of the converter and detailed design calculations are presented. For each power component, the analytical expressions for calculating the average and rms current ratings are derived to facilitate the converter design. The small-signal model of the converter is presented to aid the controller design. The experimental results from a 2 kW laboratory prototype are presented to confirm the operation of the proposed converter. An input power factor of 0.999, an input current total harmonic distortion of as low as 2.76%, and a high conversion efficiency of 96% are achieved from the prototype.
To obtain low ac line current THD, the passive techniques described in the previous chapter rely on low-frequency transformers and/or reactive elements. The large size and weight of these elements are objectionable in many applications. This chapter covers active techniques that employ converters having switching frequencies much greater than the ac line frequency. The reactive elements and transformers of these converters are small, because their sizes depend on the converter switching frequency rather than the ac line frequency.
This paper presents a systematic and comprehensive approach for differential mode (DM) EMI filter design in a three-phase boost-type power factor correction rectifier. Since the DM EMI filter forms a significant portion of the overall filter as well as converter volume, reduction of DM filter component size is kept as a major objective in the filter design process in order to improve the power density. In addition to the objectives of volume optimization and conducted emission attenuation requirement to comply with the EMI standard, the filter design process also ensures a near-unity power factor operation with the optimal set of EMI filter parameters. To accomplish this, the paper analyzes the effect of EMI filter component selection on the overall lower order (1-100 kHz) frequency response, which is important for evaluating the dynamic response and stability. The results from the proposed design approach are validated through simulation, the DM Bode plot, and frequency response of the input current with and without EMI filter. As a proof-of-concept verification, the proposed EMI filter is implemented in a 4 kW three-phase boost-PFC prototype, which demonstrates minimal phase displacement (<5o) of the input current.
This manuscript proposes a new methodology to control a three-phase boost power factor correction (PFC) using a single DC output voltage sensor. Typically, a PFC control technique requires measurement from five independent sensors i.e. two input voltages, one output DC voltage and two input phase currents. Elimination of four sensors in control system of a PFC converter is theoretically feasible and implementable without compromising stability and power quality of the converter, as analyzed and presented in this manuscript. The proposed control technique uses the ripple information of measured DC link voltage, converter dynamics and switching states at a preceding sample in order to estimate the present state of four other unknown state variables and thus, establishes the control method. A 2.2-kW experimental prototype of three-phase boost PFC is developed and tested to verify the accuracy and applicability of the proposed control logic at different line and load conditions. According to the experimental measurements, conversion efficiency more than 98%, THD as low as 4.3% and an output voltage ripple of ±2% are achieved at 2.2kW output power.
To obtain low ac line current THD, the passive techniques described in the previous chapter rely on low-frequency transformers and/or reactive elements. The large size and weight of these elements are objectionable in many applications. This chapter covers active techniques that employ converters having switching frequencies much greater than the ac line frequency. The reactive elements and transformers of these converters are small, because their sizes depend on the converter switching frequency rather than the ac line frequency.
In this paper, a comparative analysis of Power Factor Improvement (PFI) of three phase boost rectifier is simulated using PSpice software. The proposed model is compared with the conventional model and the results shows that a great improvement is achieved in the power factor by reducing the total harmonic distortion (THD) using active switching and passive filters. The PFI improvement is accomplished by using pulse width modulation (PWM) technique and passive filters and also an Electro Magnetic Interference (EMI) filter is used to suppress the high frequency component generated by the boost converter. After that a series LC resonating filter is used to suppress the low frequency current components, which made the THD less than three percent and provides unity power factor. The efficiency of the circuit is also studied. The efficiency versus duty cycle, THD versus duty cycle and output voltage versus duty cycle curve for the proposed converter is given for a clear understanding of the improvement of the model.
The article proposed a structure of the frequency converter, comprising a three-level active rectifier with power factor correction. The investigations of proposed structure were performed. The proposed structure allows realizing a frequency converter with low content of higher current harmonic, unity power factor, as well as the possibility of implementing energy recovery.
This paper presents control strategies for a multimegawatt direct-drive permanent-magnet wind power generator with parallel-operating rectifiers linked by common dc bus. A model of a number of n rectifiers in parallel with a common dc link and zero-sequence current dynamics are derived and analyzed. The parallel-operating control is designed to restrain currents that flow between the power modules caused by power-device discrepancy and asynchronous operation of the parallel units. The multiple sets of pulse width modulation driving signals are generated by individual current control and produced by carrier phase-shifting synchronously. Each converter module is independent of each other identifying the rotor position by using an observer. The currents of each module are balanced and synchronized with respect to each other producing the optimal total generator torque. The experimental results that were obtained on a 1.5-MW platform proved the effectiveness of the control strategies.
This paper proposes control strategies for megawatt-level direct-drive wind generation systems based on permanent magnet synchronous generators. In the paper, a circulating current model is derived and analyzed. The parallel-operation controllers are designed to restrain reactive power circulation and beat-frequency circulation currents caused by discontinuous space-vector modulation. The control schemes do not change the configurations of the system consisting of parallel multiple converters. They are easy to implement for modular designs and large impedance required to equalize the current sharing is not needed. To increase the system reliability, a robust adaptive sliding observer is designed to sense the rotor position of the wind power generator. The experimental results proved the effectiveness of the control strategies.
Hybrid Distributed systems include many sources, storage elements, and various local loads, connected to a common distribution bus. In this work, different matching methods to adapt a 3-phase wind alternator to a variable DC-bus are reviewed, and finally a modular solution based on single-phase Boost-based PFC's is proposed. Nevertheless, Boost modules must be adapted to operate with non-isolated sources, like 3-4 wire, 3-phase generators. Magnetic coupling is introduced here to enhance the isolation among phases, reducing also converter losses and size. Sliding mode approach has been applied to the whole converter as a single unit, to verify that independent regulation of all phase modules was possible, even sharing a common output capacitor. To verify the theoretical analysis, a 1.5 kW prototype has been built confirming independent phase control and good sinusoidal input waveforms.
This paper presents a PWM converter, which enables to maintain high power-factor of arc welding power supply and to suppress input current harmonics. The main function of this system is to maintain unity power-factor by controlling input current to be sinusoidal, and to generate stable DC output voltage through half-bridge inverter and output rectifier. The proposed converter has high power factor, low harmonic distortion, and tight output regulations. A control scheme is employed to reduce the switching and rectification losses. The modeling and simulation analysis are performed to evaluate the performance characteristics. The proposed converter meets the IEC 61000-3-2 regulations with near-unity power factor and high efficiency.
Based on the inherent property of three phase AC power supply, the present scheme of the three phase rectifier utilizes auxiliary blocked phase selection and boost-buck circuits by processing only 22% amount of the power to patch the gaps of the input current waveforms of the main rectifier. That only one current loop of the three-phase inputs is regulated and one is left as low resistance state makes the system very stable, even in the situations of three-phase unbalance and load fluctuation. While the harmonics are diminished, no common mode voltage output and the energy double fed are achieved.
This paper proposes a clamping phase technique that results in power factor control at the input of a controlled rectifier by means of a current control based on One Cycle Control (OCC) technique. It minimizes phase interference, fixes operation frequency as well as improves phase coordination. Control simplicity and voltage input sensor elimination is the feature of the proposed control. Theoretical background of the clamping phase technique as well as of OCC principle has been reviewed and analyzed. Simulated results confirm the proposed technique.
One-cycle control is a unified constant-frequency control scheme, with which the three-phase rectifier achieves unity power factor and low THD. Previous research has been conducted on the OCC controlled rectifier in both balanced and unbalanced system. The analysis of the rectifier in unbalanced system indicates that although the controller is proposed for balanced system, it also works for the unbalanced system, and the phase currents will be proportional to the non-zero sequence phase voltages under unbalanced conditions. The result is satisfying since the current waveform quality is high and the source voltages have the same load stresses. However, there are still two limitations for the present OCC controller in unbalanced system: first, minimum switching losses can not be ensured, which is contradictory to the vector control goal; second, the present OCC controller will not be able to handle the extreme unbalanced system where one phase voltage is entirely zero. In light of these, this paper aims to improve the present OCC controller's performance in unbalanced system. By utilizing the non-zero sequence phase voltages for region selection, both limitations are eliminated. The proposed OCC vector controller can cope with all the system conditions, with switching losses always minimized. A 1kW experimental prototype has been built to verify the proposed controller
Power factor correction (PFC) rectifiers are essential for load side harmonic and reactive power correction. In recent years, research and applications of PFC rectifiers have attracted more attention due to the increased energy awareness in the global. The new three-phase boost PFC rectifier which is based on one cycle control and proposed by Chongming Qiao is featuring excellent performance, simple circuitry, and low cost, and under balanced or unbalanced source, the input currents being kept low harmonic and linearly proportional to the non-zero sequence of the three-phase input voltages. But C. Qiao's control strategy has shortcoming to control input currents flexibly under unbalanced source, for example, to minimize output filter, we want to control the input currents such that the input power is a constant, or we want to control the input currents keeping balanced, or we want the input currents fully in-phase with each own voltages. This paper improves the control strategy and introduces a new general current control equation which can control the input currents flexibly. By selecting different current control parameters (CCP), we can achieve four control goals: (1) the same method which has been described in literature; (2) input currents fully in-phase with its own input voltages; (3) constant input power; (4) balanced input currents. Experimental results are presented to verify the theoretical analysis
This paper presents a new current control method for three-phase pulse width modulation rectifiers with active power factor correction (PFC). Conventional three-phase PFC control requires sensing of at least two input phase currents. Since the input line must be isolated from the control circuitry, current transformers or Hall effects current sensors are required for sensing the phase currents, which are bulkier and more expensive than resistive current sensors. Such electromagnetic current sensors are also difficult to integrate with the rest of the control circuitry, representing a major barrier for low-cost integrated PFC control development. The proposed current control method solves these problems by using only the dc-rail current as the feedback signal. The dc-rail current can be easily sensed by a shunt resistor, and the sensed signal can be directly used by the control circuitry without isolation or level shifting. The control method is developed based on a nonlinear average current control principle and avoids the steady-state phase error of conventional linear PI control.
A nonlinear average current control method using only dc-rail current for three-phase power-factor-corrected (PFC) converters was introduced recently. This paper discusses the effects of dead-time, sector synchronization, input voltage harmonic distortion and sensing delay on its control performance. A dead-time compensation scheme without additional sensing requirement that is suitable to the nonlinear average current control is presented. Based on the analysis of the current control performance considering effects of different factors, design guidelines are provided for practical implementation of the control method. Measurement and simulation results are included to support the conclusions.
This paper is concerned with some experimental results and practical evaluations of a three-level phase shifted ZVS-PWM DC-DC converter with neutral point clamping diodes and flying capacitor for a variety of gas metal arc welding machines. This new DC-DC converter suitable for high power applications is implemented by modifying the high-frequency-linked half bridge soft switching PWM DC-DC converter with two active edge resonant cells (AERCs) in high side and low side DC rails, which is previously-developed put into practice by the authors. The operating principle of the three-level phase-shift ZVS-PWM DC-DC converter and its experimental and simulation results including power regulation characteristics vs. phase-shifted angle and power conversion efficiency characteristics in addition to power loss analysis are illustrated and evaluated comparatively from a practical point of view, along with the remarkable advantageous features as compared with previously-developed one.
This paper presents a new current control method for three-phase power-factor-corrected (PFC) converters. The control method is a generalization to the nonlinear average current control previously developed for single-phase PFC converters, and uses only the DC-rail current as the feedback signal, avoiding the need to sense input phase currents and greatly simplifying current sensing requirements. Principle of the control method is presented first, followed by discussions of the implementation circuit and detailed design considerations. A mixed-signal implementation using an FPGA is also presented. Performance of the proposed control method is demonstrated by measurement results from a 2 kW prototype operating with both 60 Hz and high-frequency (400-800 Hz) lines.
This thesis describes the development of a new generation of three-phase rectifier, used to power telecommunications equipment. The traditional topology for such power converters is a single-phase two-stage design, with a boost converter providing power factor correction at the input to the first stage and an isolated dc-dc converter making up the second stage. A two-stage design results in the output power being processed twice and this cascade effect results in an overall reduction in efficiency. A rectifier solution is sought that meets with all the requirements of the telecommunications industry, while not displaying the inherent weaknesses associated with a boost-derived topology, and which can be realised in a single-stage design. A number of common three-phase topologies exist that could be realised as telecommunication power supplies, however, they do not completely satisfy all the industry requirements. A new three-phase rectifier, which is a single-stage buck-derived topology, is proposed. As a consequence of incorporating a buck-derived topology, the three-phase rectifier does not exhibit any issues resulting from startup inrush currents, or high currents due to an output short circuit condition, as would result in a boost-derived topology. The new proposed rectifier is modular in nature, which has the added benefit of redundancy. As a result of the new three-phase rectifier having a single-stage topology, it is expected that the overall efficiency would able to reach close to 95%. This is due to the traditional two-stage designs having efficiencies around the 90% mark, and therefore by removing a stage, out of the power conversion process the overall losses would also be halved, resulting in the 5% gain in efficiency. The rectifier system requires only one controller as a result of being a single-stage design, thus also reducing the overall system cost. Simulations show that if this topology is combined with a three-phase phase-locked loop controller it can meet the industry compliance standards. The thesis follows the development of the three-phase power converter from the simulation stage to the realisation of the control hardware and stability modelling. It also provides a detailed report of an investigation into the power converter system’s performance. The thesis concludes with discussions concerning the viability of the new topology as a commercial product and indicates areas of possible future research and development.
In this paper, a three-phase six-switch standard boost rectifier
with unity-power-factor-correction is investigated. A general equation
is derived that relates input phase voltage and duty ratios of switches
in continuous conduction mode. Based on one of solutions and using
one-cycle control, a unified constant-frequency integration (UCI)
controller for power-factor-correction (PFC) is proposed. For the
standard bridge boost rectifier, unity-power-factor and low
total-harmonic distortion (THD) can be realized in all three phases with
a simple circuit that is composed of one integrator with reset along
with several flips-flops, comparators, and some logic and linear
components. It does not require multipliers and three-phase voltage
sensors, which are used in many other control approaches. In addition,
it employs constant switching frequency modulation that is desirable for
industrial applications. The proposed control approach is simple and
reliable. Theoretical analysis is verified by simulation and
experimental results
Buck-derived three-phase rectifiers are attractive alternatives
for low-output voltage and high-power applications. In this paper,
three-phase buck-derived rectifiers with one-cycle control are proposed.
Conventional sinusoidal pulse width modulation (SPWM) often requires
large output inductor in order to achieve low current distortion. With
one-cycle control, the input current can be controlled to follow the
sinusoidal reference in each switching cycle; therefore, low current
distortion can be achieved even if the output current has large ripple
when a small output inductor is used. All findings are supported by
experimental results
Voltage source rectifiers (VSR) among other alternatives, offer
several advantages over line-commutated rectifiers. Advantages include
displacement power factor control, reduced line current harmonic
distortion and AC four-quadrant operation can be obtained. On its DC
side, a DC-link unidirectional voltage is obtained and bidirectional
power transfer capability is possible by reversing the flow direction of
the DC-link current. This paper presents the analysis and design
procedure for a VSR with the complete control algorithm implemented with
minimum hardware. For this goal, a DSP-controller TMS320F240 has been
used. All the functions have been programmed in a DSP, digital current
and voltage controllers, decoupling of axis, space vector modulation,
phase locked loop (PLL) for the synchronization with utility, and the
acquirement of the phase currents and output voltage. It has been
programmed a complete mathematical model of the rectifier in the
synchronous reference frame. The actual currents and output voltage are
acquired through the on-chip A/D converters. A space vector modulation
has been implemented by using the PWM unit, a PLL has been implemented
by using a look-up table and two capture inputs. Experimental results
from a 1.5 kW VSR are presented
A general constant-frequency power-factor-correction (PFC)
controller is proposed for three-phase rectifiers with
parallel-connected dual-boost topologies. This paper shows that unity
fundamental power factor and low current distortion in all three phases
can be realized by one-cycle control of a linear combination of the
inductor currents using one integrator with reset along with a few logic
components. This new extension of one-cycle control provides the core
PFC function to the dual-boost topologies and the logical circuit
rotates the PFC function in three phases. It does not require
multipliers, used in many other control approaches, to scale the current
reference according to the output power level. In each 60° of AC
line cycle, only two switches are switched at high frequency; therefore
the switching losses are significantly reduced. All switches are
switched at low current, which results in reduced current ratings. This
control method is simple and general. It is applicable to three-phase
rectifiers that can be decoupled into parallel-connected dual-boost
topologies by slight modification of the logic circuit. This control
method is verified by theoretical analysis and experimental results. The
proposed controller is ready to be integrated into a three-phase PFC
control chip
For pt.I see ibid., p.2504-11 (1999). This paper presents a
general control approach to achieve power-factor-correction (PFC) for
three-phase boost rectifiers with center-tapped or split DC output
capacitors. These rectifiers can be decoupled into a series-connected
dual-boost topology during each 60° of line cycle although they have
different configurations. A new extension of constant frequency
one-cycle control strategy is proposed to provide the core PFC function
for the dual-boost topologies. The additional logic circuits rotate the
PFC functions in three-phase. No multiplier is necessary to scale the
current reference as required by many other approaches. Hence this
control approach is simple and general. Furthermore, the constant
switching frequency modulation is desirable for EMI filter design and
switching losses are minimized since only two high frequency switches
are controlled at any time. Simulation and experimental results are
present to verify the theoretical analysis
This paper presents modeling, simulation, and experimental results
of paralleled three-phase boost PFC rectifiers. The first part of the
paper describes the overall system set-up and control schemes of the
PFCs. Although individual modules work as expected, a low frequency
oscillation between the paralleled units was observed. Because the
conventional model of the three-phase rectifier cannot predict this kind
of interaction, an average model is developed for system simulation.
From this model, it is shown that the interleaved discontinuous space
vector modulation produces a periodic disturbance on the zero axis.
Because the conventional control in a balanced three-phase system with
only dq channels cannot reject this disturbance, a circulating current
will flow between the paralleled modules. Based on this observation, a
space vector modulation with control in the third axis is proposed for
the parallel operation of the rectifiers. Simulations are done to show
the feasibility of this scheme
The paper presents a new three phase PFC circuit in which the
power switches work in ZVS soft switching condition. The THD in the
input current has been reduced about 4.5% and the output DC voltage is
very close to the peak line voltage (for 204 V line, RMS three phase
system, the output DC voltage is 300 V)
The paper provides a complete design procedure of the
multi-resonant, zero-current-switched (ZCS), high-power factor (HPF)
buck rectifier for telecommunication applications and presents extensive
experimental evaluations of its performance. The evaluation was
performed on a 6 kW prototype operating from a 380 V±10%,
three-phase input voltage. The evaluation results demonstrate that the
input current shaping using the multi-resonant buck power converter can
be performed with a total harmonic distortion (THD) less than 5% and the
maximum efficiency of 95%
A reduced-order small signal model of three-phase PWM rectifiers
is proposed. By combining the PWM switch model and equivalent
multi-module model techniques in DC-DC power converters, a three-phase
rectifier can be modeled as a DC-DC power converter with equivalent
power capability and small-signal characteristics. This model reduces
the system order to two, and greatly simplifies the control design and
system analysis of three-phase power converters. In this paper, the
proposed model is also used for control design and for system
interaction analysis on the three-phase interface of a boost rectifier.
The reduced-order model is verified with the d-q model, switching-model
simulation and experimental results
This paper reviews progress in topology, control and design
aspects in three-phase power factor correction techniques. Different
switching rectifier topologies are presented for various applications.
Representative soft switching schemes, including zero-voltage and
zero-current switched PWM techniques, are investigated. Merits and
limitations of these techniques are discussed and illustrated by
experimental results obtained on prototype converters. Control and input
filter design issues are also discussed
The authors explore the dependency of the conduction losses of a bridge leg of a pulsewidth modulation (PWM) power converter system with a high pulse rate on the shape of the phase modulation functions. This is done for modulation methods that are optimized with respect to minimum harmonic current RMS values. The results are compared to the results gained for simple sinusoidal modulation. Besides conduction losses, the switching losses of the electric valves are calculated. The main topic is the determination of those power loss components of a PWM converter system that can be (besides the harmonic losses) influenced by the modulation method selected. As the calculations show, these modulation methods allow a significant increase of the effective switching frequency. The optimal modulation as calculated leads to a reduction of the harmonic power loss in the upper modulation region. Furthermore, due to the frequency modulation the spectrum is spread out to a wider frequency band as compared to operation with constant pulse frequency
The issues involved in the design of power factor correction
circuit input filters are significantly different than those involved in
the design of input filters for DC-DC power converters. So far, there
exist no guidelines for high-frequency AC power converter input filter
design. This paper addresses these issues and proposes the use of a high
order, actively damped filter to achieve the required EMI attenuation
and power factor requirements. The new filter topology typically
provides 50% filter size reduction over the standard filter designs, and
simultaneously minimizes the filter-converter interaction
A tool for determination of power factor preregulator (PFP)
conducted electromagnetic interference (EMI) emission by design is
presented. This method allows the determination of the amplitude of the
first harmonic in dB/μV in accordance with the CISPR 16 standard, for
the commonly employed PFP power converters. It can therefore can be a
useful aid for designers
Important advantages of using a DC rail diode in the three-phase
PWM boost rectifier are recognized, including reduced diode reverse
recovery and high reliability, as well as guaranteed six-step operation.
Several simple soft-switched three-phase boost rectifiers were developed
based on using the DC rail diode, further improving the converter
performance by minimizing the switching losses. All these advantages can
be achieved with three simple independent analog controllers.
Consequently, these new rectifiers can run at much higher switching
frequencies, and achieve higher efficiency and higher power density with
lower cost and higher reliability than the conventional one
This paper analyzes the zero voltage transition boost power
converter for power factor correction and presents a method for optimal
component selection. A complete circuit is shown featuring a new
specifically designed control IC. Practical design issues are discussed
and a design procedure is presented. Critical circuit waveforms are
shown, and performance with and without zero voltage transitions are
compared
The issues involved in the design of power factor correction
circuit input filters are significantly different from those involved in
the design of input filters for DC-DC power converters. In many cases,
the EMI and power factor requirements are impossible to meet using the
existing filtering technology. This paper proposes the use of high-order
elliptic filters to achieve the required EMI attenuation and power
factor. The new input filter technology provides a significant filter
size reduction over the standard filter designs, minimizes the
filter-power converter interaction, and maintains a good converter power
factor. New active and passive filter damping methods that guarantee
optimal filter pole damping, while virtually eliminating damping
resistor power dissipation, are proposed. The filter design procedure
that makes possible a simple and fast design of filters with an
arbitrary number of stages is also presented
An Improved Zero-Voltage-Transition Three-phase Rectifierhverter
- H Mao
- F C Lee
H. Mao and F. C. Lee, " An Improved Zero-Voltage-Transition Three-phase Rectifierhverter ", Proceedings of IPEC'95, pp. 853-858