PWM regenerative rectifiers: state of the art

New regulations impose more stringent limits on current harmonics injected by power converters that are achieved with pulsewidth-modulated (PWM) rectifiers. In addition, several applications demand the capability of power regeneration to the power supply. This paper presents the state of the art in the field of regenerative rectifiers with reduced input harmonics and improved power factor. Regenerative rectifiers are able to deliver energy back from the dc side to the ac power supply.

International Journal of Engineering Research and, 2015

Fixed DC voltage is one of the very basic requirements of the electronics' circuits in modern systems. Thus, single phase diode or thyristor rectifiers are commonly used in many industrial applications where we require a highpower DC supply or an intermediate DC link of AC/AC converters. The benefits include simple structure, high safety and most importantly, low cost. However, it is reasonable to assume that a price is to be paid for these benefits. The major drawback is the power system harmonics that these bridge rectifiers introduce within a system. The economic advantage that these systems enjoy can be nullified overnight if stricter harmonic standards are implemented. With this in mind, there is an increased interest in active filters and schemes like PWM that can counter these. The less prominent (but important from the consumers' point of view) issues include low power factor, voltage distortion, heating of transformer cores etc. A single standard scheme that can work for all applications is an ideal yet impractical solution. Thus, different schemes that have been introduced need to be compared so that it is easier to choose whichever fits best with the task at hand.

Three phase pulse width modulated voltage source rectifiers are widely used in uninterruptible power supplyand motor drive applications due to their low input current THD, adjustable input power factor,and bi-directional power transfer characteristics.In this paper utilization of this type of rectifier at the front end unit of an industrial type uninterrupted power supply is discussed. DC bus voltage is controlled through two high gain PI controllers. Sinusoidal Pulse Width Adjustable Triangle Wave Comparison for switching (SPWM) was selected as the control method. Unity power factor has been attained at the input along with very low THD values.

IEEE Transactions on Industrial Electronics, 2008

The paper presents the modeling, simulation and analysis of an AC-DC converter based PWM rectifier. It provides a suitable control algorithm for a pulse width modulation rectifier which reduces ripple from the DC output side as well as shapes the input current properly. The basic objective of a PWM rectifier is to regulate the DC output voltage and also ensure a sinusoidal input current and unity power factor operation. This is implemented by high speed IGBT switches connected in anti parallel mode across the rectifier diodes. The output voltage is controlled by switching these IGBTS and higher order ripples at the output can be easily eliminated with the help of passive filters. Lower order harmonics are eliminated using PWM technique. The control subsystem generates gating pulse to the universal bridge by passing the output voltage through a network consisting of comparator, discrete PI controller and discrete PWM generator. The output of this generator are the gating pulses to be applied to the universal bridge.

IET Power Electronics, 2016

In this study, a single-phase pulse-width modulation rectifier with regenerative capability has been presented. Here, the main purpose is to achieve unity power factor with least harmonics on AC-side source current while having regulated DC voltage at output. It is very difficult to achieve aforementioned goals with commonly used proportionalintegral (PI) regulators due to their limited control bandwidth, especially under rapidly varying input AC and dynamic load conditions. The disturbances on DC side are mainly due to double frequency ripple components, which are periodic in nature and are very much prominent in single-phase rectification. The problem may be further exaggerated due to the presence of periodic noise/disturbances in input AC supply. Hence, a repetitive controller (RC) is designed, which is well known for its capabilities in tracking periodic disturbances. The systematic design and modelling of stable RC controller based on internal model principle theory has been presented. The proposed control technique has been developed and simulated in MATLAB/SimPower System. The experimental results have been presented and analysed in detail to validate the performance of the proposed RC control technique in comparison with its PI counterpart.

Journal of The Institution of Engineers (India): Series B, 2016

This research work investigates the various applications of a PWM rectifier based on its input power factor. Most of the cases, the papers describe the operation of the rectifier used for unity power factor (UPF) operation. Beside this mode of operation, this paper compiles the application of the rectifier as STATCOM also, where the rectifier deals only with reactive power exchange. In this work, the controller is implemented by inserting a loop for reference input of phase angle which will be compared with the actual one, so that user can operate the rectifier at any power factor. Some basic formulae are derived for the input current, active power and reactive power based on which the control circuit is to be designed. Here two Proportional-Integral (PI) controllers are used. A brief description of tuning these two PI controllers is incorporated in this paper. Also some calculations are given to determine the harmonic factors of the input line current from which it is found that the rectifier when operated in each mode operation, the order of the harmonics are very low.

IJRET, 2012

Three-phase thyristor rectifiers have been used in industries for obtaining a variable dc voltage, but they have a problem of including large lower-order harmonics in the input currents. For high-power applications, a 12-pulse configuration is useful for reducing the harmonics, but it still includes the (12m ± 1) th (m: integer) harmonics. In order to further reduce the harmonics, this paper proposes to supply a ramp wave voltage at the input of a 12-pulse phase-controlled rectifier. Theoretical investigation to reduce harmonics is presented, and a strategy to control the regulated voltage and unity power factor at input side based on 12 pulse modulation technique. This paper discuss the impact of using 3-phase and 12-pulse rectifier circuit commonly found in unity power factor at input ac mains and regulate output voltage. The 12-pulse topology is known to be more expensive, but produce the least input current harmonics. However, the latter statement is completely true under balanced line conditions. In practice, the lines are inherently unbalanced. Hence, the question of whether the 12-pulse rectifier will indeed perform better in terms of the harmonics injected to the line is still under on-going discussions. This presents the modelling and simulation of both rectifier topologies to compare their input current and regulated output voltage harmonics. The rectifiers are modelled using the MATLAB/SIMULINK simulation model and several common cases conditions will be simulated to compare their harmonic levels.

IEEE Access

A novel autotransformer configuration for 24-pulse rectification is proposed that not only maintains the desired power quality but also enables a reduction in autotransformer equivalent power capacity, therefore lowering cost, volume, and weight of the overall 24-pulse rectification system. The significances of the proposed autotransformer configuration are easier implementation and have reduced windings per autotransformer core limb contrary to the established topology. The topology of the novel autotransformer is such that one of the four 3-phase rectifiers draws current directly from the input power supply instead of the autotransformer; hence, the power load on the autotransformer is significantly reduced. Higher pulse rectification systems are needed to be investigated, because they comply with the stringent power quality standards defined by IEEE-519. The performance of the novel topology is compared with the well-established 24-pulse rectification system where the proposed system exhibits superior characteristics evaluated regarding power quality and simplicity. In this paper, the performance of both 24-pulse power converters is assessed through MATLAB simulations and validated through experimental prototypes.