Current-source PWM Rectifier Research Articles

Passivity-Based Control and Current Balance Control of a Current-Source Pulse-Width-Modulation Rectifier

To improve the static performance, dynamic performance, and current balance of a current-source PWM rectifier with multi-modules, a comprehensive control method with passivity-based control and current balance control is proposed in this paper. Current balance control, which is based on AC voltage sequencing, has the advantages of being easy to implement and not being limited by the number of modules. Mathematical modelling, controller design, and simulation verification were conducted successively, and the results show that the comprehensive control method has a low current impact and high power quality. At the same time, module currents are well balanced, even under external disturbance, when using current balance control.

The active and reactive power characteristic analysis and decoupling control of current source PWM rectifier

The current source PWM converter has the advantages of continuous and adjustable DC current and strong ability to limit short circuit current, and it is suitable for DC ice melting application of transmission line. In this paper, the mathematical model of current source PWM converter is established, the active and reactive power characteristics of constant current load and constant resistance load are analyzed thoroughly, the double closed-loop controller of active and reactive power decoupling is designed, and the simulation research is carried out in Simulink. The results show that the proposed method can realize active and reactive powers decoupling control. When the system voltage drops, it can also output stable DC current.

Multi-Loop Power Control Strategy of Current Source Pwm Rectifier

Multi-Loop Power Control Strategy of Current Source Pwm Rectifier

Application of CS-PWM rectifier for the operation and control of wind-driven generators

ABSTRACT In this study, a current source PWM rectifier (CS-PWM) system combined with vector-oriented control method has been developed for a three-phase self-excited induction generator (SEIG) supplying isolated DC load. Unlike the conventional rectifier scheme, the proposed CS-PWM rectifier uses two numbers of active switches in each leg that are connected with power diode in series to prevent the current reversal of DC link. The adopted decoupled control strategy maintains a constant DC load voltage of 220 V and CS-PWM rectifier input current harmonic content of only 4.82% at the rated 50 Hz frequency. The proposed system performance has been predetermined for various operating conditions using binary search algorithm (BSA) technique and the analysis has been carried out. An abc-dq modeling has been employed for the dynamic performance analysis of the induction generator and simulation of the proposed system has been carried out under both steady state and transient state using Matlab/Simulink toolbox to validate the successful working under various operating conditions.

전류원 PWM 정류기 / 인버터를 이용한 새로운 단조용 유도가열 전원장치의 제어회로 설계

The conventional thyristor current source rectifier/inverter-fed parallel resonant circuit widely used for induction heating of forging applications has low power factor and high THD at the input side. Because of these disadvantage the IGBT PWM current source rectifier and inverter has been recently studied as an induction heating power supply topology. Therefore, this paper proposes the design method of power factor controller, the new detecting method of current and voltage for use in system control, and also the technique to follow the resonance voltage of the tank circuit for inverter switching. The proposed techniques are implemented in a 40㎸A induction heating power supply and its performances are verified through experiments. It is expected to be used extensively in induction heating power supply systems for forging with wide power range.

Simulation for accelerator dynamic power supply based on current-source PWM rectifier

The booster power supply of high-energy photon source is dynamic power supply, and the output is 2-Hz bias sine wave. Current-source rectifier (CSR) topology can achieve the 2-Hz current directly. In order to get the output current and good power factor of the power grid, the algorithm of “indirect current control” is applied. This method needs to measure the voltage of three phases and calculates several certain parameters of the circuit. The control strategy based on the “indirect current control” of the CSR is built in the Simulink simulation environment. Parameters and algorithms are described in detail, and the control block diagram and simulation model are given. The control strategy can output the right current and make a good power factor in the side of grid. The CSR topology, as a good choice of power supply of accelerator, has a well-researched prospect.

A New Control Strategy for a Three-Phase PWM Current-Source Rectifier in the Stationary Frame

This paper presents a novel power control strategy for PWM current-source rectifiers (CSRs) in the stationary frame based on the instantaneous power theory. In the proposed control strategy, a virtual resistance based on the capacitor voltage feedback is used to realize the active damping. In addition, the proportional resonant (PR) controller under the two-phase stationary coordinate is designed to track the ac reference current and to avoid the strong coupling brought about by the coordinate transformation. The limitations on improving steady-state performance of the PR controller is investigated and mitigated using a cascaded lead-lag compensator. In the z-domain, a straightforward procedure is developed to analyze and design the control-loop with the help of MATLAB/SISO software tools. In addition, robustness against parameter variations is analyzed. Finally, simulation and experimental results verify the proposed control scheme and design method.

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

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.

Input filter pre-charge scheme for high-power PWM-current source rectifiers connected to a weak utility supply

High-power PWM current source rectifiers are normally connected to the ac grid by means of a lightly damped LC input filter. Pre-charge schemes employing pre-insertion resistors are typically used to mitigate the over-voltage across the filter capacitors during the connection to the grid. However, noticeable distortion of the grid voltage may still occur during the insertion of the input filter to the grid. This is particularly true at low ratios of the supply fault level to the converter-rated power and cannot be avoided when conventional pre-charge schemes are used. This study proposes a pre-charge scheme that yields a smooth and controllable connection of the input filter to the grid along with total absence of both over-voltage across the input filter capacitors and voltage distortion on the grid. This is novel and it is of particular interest whenever PWM-CSRs are connected to relatively weak grids. Pre-charge is carried out by the main PWM-CSR converter, which is in turn supplied on its dc-side by a small low-power low-voltage pre-charge converter. This completely eliminates the need for any pre-charge components on the ac-side [which can be bulky and expensive at medium voltage (MV) levels]. Experimental results obtained from a 150 kW PWM-CSR are included in the study.

Instantaneous Power Control of PWM Rectifier Using Hysteresis Regulator with Frequency Characteristic

This paper proposes a hysteresis regulator with a frequency characteristic, which reduces specific harmonic power in a direct power control system of a current-source PWM rectifier. The method virtually adjusts the hysteresis bandwidth in association with frequencies of the power pulsation; hence the regulator is capable to filter specific frequency components of the input current as well as the power. The paper describes a theoretical aspect of the proposed approach, and presents some experimental results of a particular case, where the 5th and the 7th harmonic input currents are mainly suppressed by eliminating the 6th harmonic component of the active power.

Complex State-Space Modeling and Nonlinear Control of Active Front-End Converters

This paper presents the modeling and control of active front-end (AFE) converters using complex state-space representation, a technique developed and thus far mostly employed for the analysis of ac machines. Particularly, three-phase PWM voltage-source and current-source rectifiers are thoroughly studied using the graphical capabilities of this approach, namely, complex signal flow graphs. These are used to directly and intuitively derive high-performance nonlinear control laws based on input-output feedback linearization. Specifically, a cascaded and a paralleled control scheme are investigated for the voltage-source rectifier, whereas a cascaded scheme is considered for the current-source rectifier. Under these strategies both converters exhibit linear and decoupled d-q axes dynamics, while also attaining a reactive power compensation capacity. Moreover, linearization of their respective dc-link voltage and current loops utterly enforces and ensures their operating stability. All this is achieved without the elaborate mathematical complexity of input-output linearization, effectively shunned out by the proposed complex state-space approach. Finally, experimental results from 5-kVA digital-signal-processor-based laboratory prototypes verify the analysis and downright performance evinced by these AFE converters.

Real-time multi-DSP control of three-phase current-source unity power factor PWM rectifier

The design of a real-time multi-DSP controller for a high-quality, six-valve, three-phase, current-source, unity power factor, PWM rectifier is discussed. With the decoupler preprocessor and the dynamic trilogic PWM trigger scheme, each of the three input currents can be controlled independently. Based on the a-b-c frame system control and the fast parallel computer control, the pole placement control method is implemented successfully to achieve fast response in the AC currents. The low frequency resonance in the AC filter LC networks has been damped effectively. The experimental results are obtained from a 1 kVA bipolar transistor current-source PWM rectifier with a real-time controller using three TMS320C25 DSPs. >

Operating limits of the current-regulated delta-modulated current-source PWM rectifier

A stand alone, three-phase, delta-modulated, current-source PWM rectifier has been built and has been shown to be capable of operating with near sinusoidal current waveforms, unity power factor. and good DC current regulation. A mathematical model that has been justified against experimental measurements and results from digital simulations is presented. The current waveform distortion limit and the asymptotic stability limit are established. It is shown that the rectifier can operate safely within these limits in the entire range of its power ratings. >