Reduce Line Current Harmonics Research Articles

Solar PV Based Shunt Active Filter with p-q Theory Control for Improvement of Power Quality

In this paper, fuzzy logic controller (FLC)-based three-phase shunt active power filter with photovoltaic (PV) system is proposed. This filter comprises voltage source converter (VSC) with DC link capacitor at the input side and is supplied by PV system. The salient feature of the filter is that it provides reactive power compensation with line current harmonic reduction and also neutral compensation at point of common coupling (PCC). The PV system and a battery are connected with VSC through DC–DC converter. This paper also proposes a control algorithm using instantaneous [Formula: see text]-[Formula: see text] theory that generates a reference current to counteract the harmonics. The FLC controls the DC link voltage in reference to the above reference current. The performance of the proposed filter for compensation is confirmed by using the MATLAB/Simulink environment and results are validated.

Design of Single Phase Active Front End Converter With Reduced Line Current Harmonics for Power Factor Improvement

Low power factor and high harmonic content are the major drawbacks of conventional front end converters. This paper is based on the difference between the performance of single phase diode bridge rectifier and the active front-end converter in terms of the %THD of the line current and power factor improvement. There are some of the major disadvantage of conventional front-end rectifiers like low power factor and high harmonic content. Hence, there is a continuous need for improvement of power factor and reduction of line current harmonics. Development of new circuit topologies and control strategies for Power Factor Correction (PFC) and harmonic reduction has become still more essential with the introduction of strong technical IEC standards. This work is basically on Power Factor improvement using phase shifted Technique in which the two single phase converters are connected in parallel to meet the load demand as well as to improve the power factor. Power factor of the source side will be maintained nearly unity. Output DC link voltage will remain constant irrespective of load variation. The control strategy for single phase front end converter consists of inner current-loop and outer voltage-loop. The proposed converter operates in forward power as well as in reverse power conditions.

Line Current Harmonic Reduction in AC-DC PWM Converter Using Genetic Algorithm

In this paper, AC/DC converters are widely used to get regulated power supply for battery charging and DC motor speed control. SCR converters are preferred in the field of High voltage DC energy transmission, superconductor magnetic energy storage, etc. However these converters have low power factor and also result in higher order harmonics.This paper proposes the application of Genetic algorithms (GAs) to find the switching angles for line current harmonic reduction in AC/DC type converter. Harmonic reduction is redrafted as an optimization problem and GA is applied.The harmonic elimination methods used in AC/DC converters are similar to those employed in PWM inverters or in AC choppers. The solution is obtained using genetic algorithm tool in MATLAB. The dual objectives of harmonic elimination and output voltage regulation are reframed as an optimization task and the switching instances are identified through the steps of GA.

Simulation Analysis and Implementation of Two - Phase Interleaved Boost Converter with Ripple Steering for Power Factor Correction

By employing the power factor corrected circuits the supply current will tend to follow the supply voltage. Hence both are in phase with each other. Single-stage interleaved AC–DC converter with ripple steering technique is proposed in this paper to reduce line current harmonics and to improve the supply power factor. Interleaved Boost Converter (IBC) topology with ripple steering technique is analysed here. The proposed IBC with ripple steering is simulated in MATLAB/SIMULINK and the performance parameters such as supply Harmonics, Power Factor (PF) and Distortion Factor (DF) are computed and compared with conventional topology. Experimental results show the advantages and flexibilities of the proposed method.

Analysis and Design of Passive Filters to Reduce Line Current Harmonics for Controlled Rectifiers

Analysis and Design of Passive Filters to Reduce Line Current Harmonics for Controlled Rectifiers

A New Interleaved Three-Phase Single-Stage PFC AC–DC Converter

A new interleaved single-stage ac-dc converter is proposed in this paper to reduce line current harmonics while achieving power factor correction (PFC). The proposed rectifier can produce input currents that do not have deadband regions with high PFC, operate with a continuous output current, and minimize the input electromagnetic interference filter size. In this paper, the operation of the new converter is explained, its features and design are discussed in results, and its operation is confirmed with experimental results obtained from a prototype.

Neural Network and Bandless Hysteresis Approach to Control Switched Capacitor Active Power Filter for Reduction of Harmonics

This paper proposes a combination of neural network and a bandless hysteresis controller, for a switched capacitor active power filter (SCAPF), to improve line power factor and to reduce line current harmonics. The proposed active power filter controller forces the supply current to be sinusoidal, in phase with line voltage, and has low current harmonics. Two main controls are proposed for it: neural network detection of harmonics and bandless digital hysteresis switching algorithm. A mathematical algorithm and a suitable learning rate determine the filter's optimal operation. A digital signal controller (TMS320F2812) verifies the proposed SCAPF, implementing the neural network and bandless hysteresis algorithms. A laboratory SCAPF system is built to test its feasibility. Simulation and experimental results are provided to verify performance of the proposed SCAPF system.

A Modified Harmonics Reduction Technique for a Three-Phase Controlled Converter

Three-phase controlled converters have many applications especially in adjustable speed drives and renewable energy. A three-phase controlled converter is a good option in these applications due to its low cost, simplicity, and maintainability with respect to other solutions like a full-bridge insulated gate bipolar transistor converter or a Vienna rectifier. Line current harmonics in this converter is very high; therefore, a harmonics reduction technique is needed to remedy the problem. In this paper, an improved injection current technique is introduced to reduce line current harmonics. The optimal amplitude and phase angle of the injection current for different loads and firing angles have been mathematically determined. Simulation for this technique has been performed by using the PSIM simulation program. An experimental prototype has been built to verify the mathematical and simulation results. The simulation and experimental results show a sensitive variation in the total harmonic distortion of the line current for the amplitude and angle of injection current variations. The simulation and experimental results prove the superiority of this technique in mitigating the requirements for harmonics standards.

A 28-pulse AC–DC converter for line current harmonic reduction

A novel transformer for 28-pulse AC-DC converter configuration is designed, modelled and simulated to feed isolated DC varying loads. The proposed transformer is suitable for large current rating rectifiers such as electric-aircraft power supply, electro-winning, electro-chemical processes, induction heating, plasma torches and so on, where isolation is required mainly for stepping down the supply voltage. It consists of two paralleled 14-pulse AC-DC converters involving seven-phase shifted AC fed diode bridges. It improves power quality at AC mains and it meets power quality IEEE-519 standards requirements at varying loads.

Model Reference Adaptive Control Design for a Shunt Active-Power-Filter System

In this paper, model reference adaptive control (MRAC) is proposed for a single-phase shunt active power filter (APF) to improve line power factor and to reduce line current harmonics. The proposed APF controller forces the supply current to be sinusoidal, with low current harmonics, and to be in phase with the line voltage. The advantages of using MRAC over conventional proportional-integral control are its flexibility, adaptability, and robustness; moreover, MRAC can self-tune the controller gains to assure system stability. Since the APF is a bilinear system, it is hard to design the controller. This paper will solve the stability problem when a linearization method is used to solve the nonlinearity of the system. Moreover, by using Lyapunov's stability theory and Barbalat's lemma, an adaptive law is designed to guarantee an asymptotic output tracking of the system. To verify the proposed APF system, a digital signal controller (dsPIC30F4012) is adopted to implement the algorithm of MRAC, and a 1-kVA laboratory prototype is built to test feasibility. Experimental results are provided to verify the performance of the proposed APF system.

Evolutionary approach for line current harmonic reduction in AC/DC converters

This letter explains the application of genetic algorithms (GAs) for line current harmonic reduction in a buck-type converter. Harmonic reduction/elimination is redrafted as an optimization problem and steps of the GA are applied. Compared to conventional optimization techniques, the steps of the GA are very simple and global optimum is guaranteed in most cases. Theoretical and experimental results are provided to validate the method.

A push-pull quantum series resonant rectifier with predictive current control

A new push-pull type quantum series resonant rectifier for the power factor correction is proposed. The proposed single phase rectifier enables the zero-current switching operation of all power devices, allowing the circuit to operate at high switching frequencies and high power levels. A samples data dynamic model for this rectifier is developed and an analysis for the internal operational characteristics is explored. Based on this analysis, a predictive current control technique is investigated and its advantages over the other types of current control techniques are discussed. With the proposed control technique, the unity power factor and greatly reduced line current harmonics can be obtained.

Present Trends in Line-Current Harmonic Reduction in Single-Phase Thyristor Converters

Pulse-width modulation (PWM) technique can be applied for reduction or elimination of any M-line current harmonic components in ac/ac and ac/dc converters. PWM technique shifts the line-side harmonic spectrum to higher frequencies. Hance, filter size and cost are considerably reduced. The existing methods are compared with the proposed PWM technique. A new power circuit suitable for PWM technique is presented. The proposed schemes are experimentally verified and the results are discussed.