Showing papers on "PWM rectifier published in 2015"

A bidirectional series resonant matrix converter topology for electric vehicle DC fast charging

Abstract: A series resonant matrix converter (MC) based topology for high power electric vehicle (EV) battery charging is presented. The system performs DC fast charging and is capable of bidirectional power flow, for V2G (vehicle-to-grid) applications. The proposed topology can be divided into three sections: (i) a front-end 3×1 matrix converter, (ii) L r C r series resonant tank and high frequency (HF) transformer, and (iii) a single phase PWM rectifier. The matrix converter takes a three phase line frequency voltage and produces a high frequency (14.94 kHz) AC output. The resonant tank frequency is set to 13.7 kHz and helps to achieve zero voltage switching (ZVS) turn ON and low turn OFF switching losses. The secondary of the transformer is then interfaced to the EV battery bank through a PWM rectifier. The advantages of such a system include high efficiency due to soft switching operation, low VA transformer ratings due to resonant operation, and high power density due to the absence of electrolytic capacitors. A design example rated 30 kW, which charges a 500 V battery system, is presented. Analysis and simulation results demonstrate the performance of the proposed bidirectional topology. Preliminary experimental results are provided for a scaled down prototype operating at 500 W using a 15 kHz ferrite transformer.

A High-Frequency-Link Single-Phase PWM Rectifier

Abstract: This paper proposes a high-performance “cycloconverter-type” high-frequency-link (HFL) single-phase rectifier with an active voltage clamper, which provides bidirectional two-stage galvanic isolation ac-dc power conversion Modulation strategy, modeling method, and control scheme are comprehensively developed for the HFL rectifier to guarantee its superior performances: 1) two-stage power conversion and soft-switching switch devices lead to high conversion efficiency; 2) complete elimination of voltage spikes during commutation ensures safe operation of high-frequency switching devices; and 3) it can equally function as a high-performance conventional Pulsewidth Modulation (PWM) rectifier: sinusoidal input current, constant dc output voltage, bidirectional power flows between dc side and ac side, and adjustable power factor A prototype of the proposed HFL rectifier is built for evaluation The experiment results demonstrate the efficacy of the soft-switching HFL rectifier and its highly promising control performance The proposed rectifier offers a high-efficiency, high-power-density, and high-performance galvanic isolation power conversion solution to extensive applications

A Novel Load Adaptive ZVS Auxiliary Circuit for PWM Three-Level DC–DC Converters

Abstract: Three-level PWM dc–dc converters convert high dc voltage (>500 V) generally at the output of a three-phase ac–dc PWM rectifier in ac–dc converters to an isolated dc output voltage which can be used to power data center loads Strict efficiency requirements at loads from 20% to 50% of full load of ac–dc converters for telecom applications have been introduced by energy star enforcing industries to improve efficiency of the dc–dc converter in an ac–dc converter powering data-center loads at those loads High-efficiency requirements at low and mid loads in high switching frequency PWM dc–dc three-level converters implemented with MOSFETs can be achieved by reducing switching losses through optimized load adaptive ZVS for the entire load range In this paper, a simple yet novel load adaptive ZVS auxiliary circuit for three-level converter is proposed for so that the resulting three-phase ac–dc converter can meet energy star platinum efficiency standard The operation of the proposed dc–dc converter is described, analyzed, and validated by experimental results from an industrial prototype of a three-phase ac–dc converter comprising of a front-end three-phase boost PWM rectifier followed by the proposed converter

Multi-system converter device

Abstract: The invention discloses a multi-system converter device. The multi-system converter device comprises an alternating current precharge unit and a direct current precharge unit. The input end of the alternating current precharge unit and the input end of the direct current precharge unit are both connected with an overhead line system. The output end of the alternating current precharge unit is connected with a PWM rectifier module. The PWM rectifier module and the direct current precharge unit are both connected with a middle direct current loop. The middle direct current loop is connected with a power supply device through a VVVF inversion module. The alternating current precharge unit and the direct current precharge unit are both connected with a change-over switch. The alternating current precharge unit, the direct current precharge unit, the change-over switch, the PWM rectifier module and the VVVF inversion module are all connected with a drive control unit. Under the traction condition, the multi-system converter device conducts dispatching operation like traction through a traction power supply system; under the braking condition, the multi-system converter device enables regenerative braking energy of a traction motor to be stored and reused through power grid feedback.

Modelling and optimal power control for permanent magnet synchronous generator wind turbine system connected to utility grid with fault conditions

Abstract: This paper develops the model and the optimal power control strategy of maximizing wind energy tracking for Variable Speed Wind Energy Conversion System (VS-WECS) based Permanent Magnet Syn- chronous Generator (PMSG) and interconnected to the electric network. The VS-WECS model includes a Wind Turbine (WT), a PMSG, PWM rectifier in generator-side, intermediate DC circuit and PWM inverter in grid-side. Model of the proposed system in d-q axes reference frame is elaborated. The proposed strategy is based on a Vector Control (VC) approach for control of both PMSG and grid- side inverter of VS-WECS. The PMSG side rectifier control is used to keep the generator rotor velocity at an optimal value obtained from the Maximum Power Point Tracking (MPPT) algorithm to maximize the generated power from Wind Turbine Generator (WTG) under low, medium or high wind velocity mode. The grid-side inverter injects the generated power into the AC network, regulates DC-link voltage and it is used to achieve unity power factor. So, the proposed VC strategy is capable to fully decouple the quadrature (q) and direct (d) components of the currents. Moreover, a pitch control scheme is proposed to prevent wind turbine damage from excessive wind speed and to achieve power limitation. The performance of the proposed VC is evaluated with MATLAB/ Simulink environment in terms of MPPT, control of dc voltage, power limitation and power factor control. Simulation results reveal the achievability of the proposed control approach over the whole VS-WECS oper- ating regions. The simulation results show that the proposed strategy has excellent performance for normal working conditions as well as for low voltage drop conditions.

Pwm rectifier including capacitance calculation unit

Abstract: A PWM rectifier includes a main circuit unit carrying out AC-DC power conversion by PWM-control, a PWM control unit PWM-controlling the main circuit unit, a DC voltage detection unit detecting a DC voltage across a smoothing capacitor connected to the DC-side of the main circuit unit, a DC voltage storage unit storing respective DC voltages at the start and end times of an initial boost period during which the smoothing capacitor having been charged to an AC voltage peak value is further charged to a higher voltage, an input power calculation unit calculating input power flowing in from the AC-side based on an AC voltage and current, an integral power calculation unit calculating integral power from the input power over the initial boost period, and a capacitance calculation unit calculating the capacitance of the smoothing capacitor based on the respective DC voltages and the integral power.

Soft-switching three-phase matrix based isolated AC-DC converter for DC distribution system

Abstract: In this paper, a novel three-phase matrix based isolated AC-DC converter is proposed for DC distribution system. The circuit is derived from boost converter based matrix PWM rectifier by only adding a small commutation capacitor and inductor. Compare to traditional power factor correction rectifier plus DC/DC two-stage configuration, the proposed converter has higher efficiency and power density. Soft-switching can be realized for all switches and the intermediate DC capacitor is eliminated in the proposed topology. Also, compared to the buck-derived single stage solution, it requires smaller size EMI filter in the AC input stage. Furthermore, a novel space vector modulation (SVM) scheme is developed for the converter to control the input current and enable the soft-switching operation. In this paper, the topology derivation and circuit operational analysis for soft commutation are given. The proposed SVM scheme is introduced and a simulation is carried out to verify the circuit.

Fault tolerant control method for open circuit faults of three-phase bridge PWM rectifier switching tube

Abstract: The invention discloses a fault tolerant control method for open circuit faults of a three-phase bridge PWM rectifier switching tube and belongs to the field of three-phase AC-DC (Alternating Current-Direct Current) conversion The invention solves problems that multi-tube fault tolerant control is imperfect, the hardware cost is high and the like of the conventional fault tolerant scheme According to the method, the characteristic that a local space voltage vector changes when a fault occurs to any switching tube of a three-phase bridge PWM rectifier is utilized; a PWM switching mode is corrected, ie, a fundamental voltage vector is selected again and the action sequence and time is adjusted; and composition is conducted again to recover or approach an original rotary reference voltage vector, so that the normal operation of a system is maintained, and the fault tolerant control operation is achieved According to the method disclosed by the invention, the effective fault tolerant control operation can be achieved when an open circuit fault occurs to a single switching tube and multiple switching tubes in the three-phase bridge PWM rectifier, and only a software algorithm is required The method is simple and easy to achieve while no additional hardware cost is required

Space vector demonstration and analysis of zero-voltage switching transitions in three-phase isolated PWM rectifier

Abstract: The zero-voltage switched (ZVS) PWM converter exhibits low primary-side switching loss and generated EMI. Furthermore, the ZVS technique can be used to increase the converter efficiency and higher power density. In this paper the ZVS operation of the MOSFET switches leveraged for a three-phase, isolated AC/DC converter is analyzed and operating states during the switch transitions discussed. The presented PWM method permits the switching devices to operate under zero-voltage switching by using circuit parasitic such as a transformer leakage inductance and devices junction capacitance and switch's body diodes. The operation principles and steady state analysis of converter are addressed and verified by the simulation result.

Three-phase bridge PWM rectifier switching tube open-circuit fault diagnosis method

Abstract: The invention discloses a three-phase bridge PWM rectifier switching tube open-circuit fault diagnosis method, and belongs to the field of a three-phase AC/DC converter. The invention aims to solve the problems of inaccurate, poor robustness and the like in multi-tube fault diagnosis in an existing diagnostic scheme. The method uses the characteristic that a fault phase grid-side current occurs to be a zero region when an open-circuit fault happens to any one of switching tubes in a three-phase bridge PWM rectifier, a current phase angle is extracted from a three-phase grid-side current, and fault detection and positioning are achieved according to the variation amount of the current phase angle and a power grid phase angle. The method disclosed by the invention can achieve effective diagnosis of open-circuit faults of both a single switching tube and a plurality of switching tubes in the three-phase bridge PWM rectifier, the software algorithm is simple, no additional hardware circuit is required, and the transient state of a system is highly robust.

PWM rectifier control method based on model prediction and voltage square control

Abstract: The invention discloses a PWM rectifier control method based on model prediction and voltage square control. The square of the output direct-current side voltage is controlled to serve as the given inner ring active current, the quick response of a controller is ensured through the linear relation between the square of the voltage and the active current, and the anti-disturbance capacity of a rectifier is further enhanced through the model prediction control of the inner ring current. The cost function of model prediction is quickly obtained through the finite set on-off state so that the control method can be easily achieved on a digital controller. The dynamic response and the anti-disturbance capacity of the whole controller can be enhanced through the selection of the weighting coefficient in the cost function and the coordination with the pre-charging soft start strategy. By means of the double-closed-loop control method, the quick response and the high anti-disturbance capacity for load disturbance are achieved while it is ensured that the alternating-current side of the rectifier reaches the unit power factor and the current total harmonic distortion rate reaches the national standard requirement. By means of the double-closed-loop control method combined with the voltage square model prediction control, the control over the unit power factor and the disturbance resistance of the three-phase voltage type PWM rectifier is achieved, and great reference value is provided for engineering.

Improved Control Strategy Based on Space Vectors for Suppressing Grid-Side Current Harmonics in Three-Phase Current Source Rectifiers with a Hybrid Switch

Abstract: This paper analyses the harmonic pollution to power grids caused by several high-power rectifiers, summarizes the requirements for rectifiers in suppressing grid-side current harmonics and optimizes a new-type of current source PWM rectifier with a hybrid switch. The rectifier with a hybrid switch boasts significant current characteristics and cost advantages in the high-power area. To further enhance the working frequency of the current source rectifier with a hybrid switch for suppressing grid-side harmonics and reducing the inductance size, this paper proposes an optimal control strategy based on space vector. It also verifies that the optimal control strategy based on space vector can reduce the total harmonic distortion of the grid-side current of the rectifier with a hybrid switch via circuit simulation and experimental results.

Arc suppression coil device and method for compensating for active component in single-phase grounding fault current

Abstract: The invention discloses an arc suppression coil device and method for compensating for an active component in single-phase grounding fault current. The device comprises a Z-type grounding transformer module with a secondary winding, a single-phase arc suppression coil module, a low-voltage reactor module controlled by a thyristor, a single-phase full-bridge inverter module, a three-phase PWM rectifier module and a controller module. The method includes the steps that the active component in the grounding current is compensated for by the arc suppression coil in the mode that a three-phase PWM rectifier is combined with a single-phase full-bridge inverter, when a single-phase grounding fault happens in a power distribution network, the single-phase full-bridge inverter module is controlled to compensate for the active component in the grounding current with the formula (please see the formula in the specification) as instruction current, an appropriate PWM control strategy is adopted for generating driving signals to adjust and control corresponding electric and electronic devices so that the electric and electronic devices can be controlled to output compensation current same to the active component current in magnitude and opposite to the active component current in phase, the active component in the grounding current is optimally compensated for, reliable and stable operation of the arc suppression coil is guaranteed, and the operation safety of the power distribution network is improved.

Magnetic coupling resonant wireless electric energy transmission device based on low frequency PWM rectifier

Abstract: The invention discloses a magnetic coupling resonant wireless electric energy transmission device based on a low frequency PWM rectifier. The device comprises a rectifier, a voltage stabilizing capacitor, an inverter power switch, an emission circuit resonant capacitor, an emission circuit resonant coil, an emission circuit current sampling resistor, a receiving circuit resonant coil, a receiving circuit current sampling resistor, a rectifier power switch, a resonant filter capacitor, a resonant filter inductor, a load resistor, a transmitting end signal conditioning circuit, a transmitting end analog to digital converter, a transmitting end microprocessor, a transmitting end high frequency inverter driving circuit, an induction voltage detection coil, a receiving end signal conditioning circuit, a receiving end analog to digital converter, a receiving end microprocessor and a PWM rectifier driving circuit. According to the device, the resonance of an emission loop is ensured, the tracking of transmitting end working frequency, the resonance of a receiving circuit and the constant output of load voltage are realized, the requirement of working frequency by a power switch device is greatly reduced, and a space is provided for the device to raise power supply working frequency.

Modeling and simulation of a brushless DC permanent-magnet generator-based wind energy conversion system

Abstract: This paper deals with a brushless DC (BLDC) generator-based wind energy conversion system (WECS) for distributed electric power generation. Three-phase PWM rectifier and maximum-power-point-tracking algorithm are used for controlling the BLDC generator speed to achieve optimum energy output from the wind turbine. A PWM voltage-source inverter is connected to the DC bus for voltage and frequency regulation of AC supply to consumer loads. The BLDC generator-based WECS is modeled by sub-systems, and its dynamic behavior is simulated in MATLAB/SIMULINK environment for different wind-speed conditions and consumer loads.

A Novel SVM Control Strategy for a Single-Phase High Frequency Link Matrix Rectifier

Abstract: The single-phase isolated high power factor PWM rectifier is studied as the research object. A novel space vector pulse width modulation (SVPWM) strategy is proposed pointing to the topology character of the single-phase high frequency link matrix rectifier (HFLMR). The SVPWM working principle is described, the specific working states are analyzed and the experiments based on DSP2812 are done. All of them results uniformly show that the novel SVPWM strategy for the single-phase HFLMR is feasible and effective.

Direct power active disturbance rejection control method for three-phase voltage source PWM rectifier

Abstract: The invention discloses a direct power active disturbance rejection control method for a three-phase voltage source PWM rectifier The method includes the following steps that the input instantaneous active power and the input instantaneous reactive power of the three-phase voltage source PWM rectifier are obtained; the instantaneous active power and the instantaneous reactive power serve as input of an expanded state observer, and based on the real-time observation value, the active power instruction value and the reactive power instruction value of system disturbance quantity, active power control quantity and reactive power control quantity can be respectively obtained according to the active power control rate and the reactive power control rate; according to the active power control quantity, the reactive power control quantity and a network voltage sampling value, the alpha-beta axis component instruction value of the input voltage on the alternating-current side of the rectifier is calculated; according to the alpha-beta axis component instruction value of the input voltage on the alternating-current side of the rectifier, a rectifier switching signal is obtained through a PWM module Through the method, direct power control over the rectifier is achieved in a static coordinate system, no phase-locked rings are needed, and phase information of network voltage does not need to be detected in real time

Single-phase PWM rectifier based on ADRC and PR control

Abstract: For single-phase pulse width modulation (PWM) rectifier, there exist second-order ripple voltage on DC bus, and it results that the grid-connected current exist odd order harmonic. Generally, a bulk capacitor or filter installed in the DC link and low-pass filter in the controller is needed, which is not conductive to improving the power density and control performance. This paper proposed an novel control strategy based on active disturbance rejection control (ADRC) and proportional-resonant (PR) control to reduce the grid-connected harmonic current and enhance the ability of disturbance rejection. Simulation is provided for verification purposes.

The design and analysis of the pi regulator of three-phase voltage source PWM rectifier

Abstract: In order to quicken the dynamic response and strengthen the ability against the disturbance of nonlinear load, three-phase voltage source PWM rectifier widely employs dual loop PI control scheme which consists of inner current controller and external voltage controller. The parameters of dual loop PI regulators have significant influence on the dc-link voltage, AC harmonic components and power factor of three-phase voltage source PWM rectifier. The design of dual loop PI regulator parameters is a very important, complicated and empirical work. With the simulation tool of Matlab/Simulink, this paper analyzes the influence of different dual loop PI regulator parameters on the operating characteristics of three-phase voltage source PWM rectifier. Based on that, a adjustment approach of dual loop PI regulator parameters which is simple and convenient is proposed. The simulation results show the effectiveness and feasibility of the proposed approach.

Simple and fast synchronous reference frame current control for single-phase grid-connnected votage souce converters

Abstract: Zero steady state error in the line current of a single-phase grid-connected voltage source converter is usually obtained in the synchronous reference frame with different orthogonal signal generation schemes, which may lead to slow dynamic response and stability problems. This paper analyzes a simple rotating reference frame current control of the single-phase converters using the desired steady state fictitious current as the orthogonal signal. Double line frequency components are present in the current error signals, which will be completely eliminated at the steady state condition. The control loops were tuned at the bandwidth greater than such oscillating frequency, which gave the dynamic performance even better than the ideal balance two-phase system. The generated orthogonal current was mathematically proved that no potential stability problem was found. Only two multiplications and one addition were required without stored memory for the calculation of the quadrature current. Simulation and experimental results of a 1.5-kVA PWM rectifier validated the proposed control scheme.

Harmonic reduction for 12-pulse four star thyristor rectifier with active auxiliary circuit

Abstract: 12-pulse four star thyristor rectifiers are widely used in electro-chemical industries, but large lower-order harmonics are included in the input currents. In order to reduce the harmonics to an acceptable level, a dc-side compensation strategy to reduce the harmonic of input line current in 12-pulse four star thyristor rectifier is proposed. According to the proposed strategy, a new active auxiliary circuit is added to the dc side of the 12-pulse thyristor rectifier and injects a specific triangular current. The specific triangular current shapes the distorted input line current as sine wave approximately. The active auxiliary circuit consists of a single transformer, a single PWM rectifier and a buck converter. Analysis of the proposed scheme is examined and simulation results are shown.

Unipolar and bipolar hybrid modulation method for single-phase voltage type PWM rectifier

Abstract: The invention discloses a unipolar and bipolar hybrid modulation method for a single-phase voltage type PWM rectifier. By the adoption of the hybrid modulation manner with unipolar modulation and bipolar modulation combined, the problem that zero crossing point current distorts in the unipolar modulation process is solved, the sine degree of current is improved, and the problem of large switching losses in the bipolar modulation process is also solved. The purpose that harmonic pollution on a power grid from net-side unit power factors is low is achieved, and meanwhile the efficiency of the PWM rectifier can be improved.

Single-phase SEPIC rectifier with double voltage gain provided by a switched capacitor cell

Abstract: This paper proposes a novel single-phase PWM rectifier topology based on a DCM SEPIC integrated to a switched capacitor cell. A comparison with the classic SEPIC shows that the proposed converter might either provide reduced voltage stress on the semiconductors to the same output voltage level, or it might supply double the gain in the output voltage with the same voltage stress. As results, the proposed structure can be applied in order to improve the static gain of the DCM SEPIC rectifier and thus make it suitable for high voltage applications. The paper also proposes a modified switched capacitor cell, which does not change the operation of the storage capacitor structure. The paper presents the complete theoretical analysis and experimental verification, according to the following specification: 500W output power; 220V input voltage; 400V output voltage and 50 kHz switching frequency.

Systematic design method for alternating current permanent magnet generator under control of PWM rectifier

Abstract: The invention discloses a systematic design method for an alternating current permanent magnet generator under the control of a PWM rectifier. The method mainly comprises two parts: a fundamental wave characteristic design and harmonic analysis and verification, wherein the fundamental wave characteristic design is mainly used to complete a motor parameter design and fundamental wave performance verification, and is combined with the control of the PWM rectifier based on a conventional permanent magnet generator design method; the harmonic analysis and verification is used to analyze the current harmonic wave content of a generator stator, the space harmonic wave of an electromagnetic field and the loss generated of the stator in a rotor under the condition of system control based on the existing motor design parameter and judges whether the design requirement is satisfied or not. The method disclosed by the invention inherits the advantages of magnetic circuit computation and parameter calculation analytical algorithms in the existing design method, creates a design method combining the fundamental wave characteristic design and harmonic analysis and verification and solves the critical problems of system, harmonic waves, rotor loss and the like in the permanent magnet generator design and the like which cannot be solved in the existing method.

Machine design and control strategy for wide-speed-range PMSG systems

Abstract: Purpose – The purpose of this paper is to focus on the machine design and control strategy of the permanent magnet synchronous generator (PMSG) system, especially utilized in variable speed applications, in order to stabilize the output voltage on the dc link over a wide speed range. Design/methodology/approach – Different ac/dc power converter topologies are comparatively studied, each with an accordingly designed PMSG, so as to investigate the influence of the armature winding inductance as well as the relationship between the PMSG and power converter topologies. Findings – Pulse width modulation (PWM) rectifier is preferable for the said application due to its good performance and controllability. Moreover, by employing the PWM rectifier, relatively large inductance of the PMSG is considered for both short-circuit current reduction and field regulation. Originality/value – Field-regulating control is realized with a space vector PWM (SVPWM) rectifier, which can weaken the PMSG magnetic field during hig...

Performance analysis and design of robust controller for PWM rectifier

Abstract: In this paper, a new controller has been proposed for pulse width modulation (PWM) based rectifiers. Control scheme of proposed PWM rectifier is used two Neuro-Fuzzy Controllers (NFC) which has robust and nonlinear structure in order to control the reactive power and DC voltage of PWM rectifier. Thus, reactive power and DC voltage are controlled effectively. Moreover, simulation studies are carried out to test the performance of the proposed control scheme at Matlab/Simulink environment. The simulation results obtained from the proposed control scheme are not only superior in the rise time, settling time and overshoot but have high power factor, lower total harmonic distortion (THD) and good power quality.

Performance evaluation of custom-made 1.2-kV 100-A silicon carbide half-bridge module in three-phase grid connected PWM rectifier

Abstract: This paper studies experimentally the benefits of silicon carbide based power semiconductor technology in a low-voltage grid connected three-phase three-wire pulse width modulated rectifier. The power semiconductor module used in the study is a custom-made 1.2-kV 100-A fully silicon carbide based half-bridge type module designed for fast switching speeds and high temperature operation. The experimental tests are carried out with a 40-kVA prototype system built in the frame of a commercial low-voltage motor drive unit. In addition, the impact of the high switching speeds enabled by the silicon carbide based semiconductor devices on conductive electromagnetic emissions are also investigated. The results show that the conversion efficiency can be significantly improved with silicon carbide compared to the state-of-the-art silicon based semiconductor technology. As a drawback, the faster switching speeds increase the conductive electromagnetic emissions to some extent.

Feedback hysteresis control method for PWM (pulse-width modulation) rectifier for servo drive

Abstract: The invention provides a feedback hysteresis control method for a PWM (pulse-width modulation) rectifier for servo drive The PWM rectifier adopts double closed loop control, an outer loop is a voltage loop, and an inner loop is a current loop; the control objective of the voltage loop is set to be in an interval, and the work state of the PWM rectifier is divided into a rectification work state, a feedback work state and an intermediate work state according to the interval; in the intermediate work state, the PWM rectifier does not perform rectification nor energy feedback The invention provides the novel voltage loop feedback hysteresis control method to solve the application problem of the PWM rectifier in the field of servo motor drive, the times of energy feedback and the magnitude of feed-back energy can be reduced, the loss in the energy feedback process is reduced, and the efficiency of the PWM rectifier in a servo drive device is improved