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The unbalanced and nonlinear loads could result in a significant neutral current in the three-phase four-wire distribution power system. This paper proposes a novel neutral line active power filter (APF) system based on the special connection of the transformers and single-phase inverter. The theory analysis and computer simulations show that: (a) control system would be easy to implement due to only...
A novel main circuit topology of voltage quality compensator (VQC) is proposed in this paper, composed of PWM rectifier and cascade H-bridges inverter. The three phase inverter is decoupling controlled. PWM rectifier is adopted to maintain the dc-bus voltage stably and provide or absorb real power. The inverter is controlled by carrier phase shifting with FPGA. The simulation model is set up on the...
This paper presents a unique implementation of the recursive Gauss-Newton, (GN), algorithm operated by maximum likelihood estimation for tracking and extracting the common current quality problems such as current harmonics. Moreover, this paper proves that the utilization of the ramp-comparison current controller, (the linear current controller), for the operation of the shunt power conditioner is...
In this paper, a novel grid integration system for a variable-speed wind turbine using Interior Permanent Magnet Synchronous Generator (IPMSG) is developed. The power-conditioning system consists of a series-type 12-pulse diode rectifier powered by a phase shifting transformer and then cascaded to a PWM voltage source inverter. The series-type 12-pulse diode rectifier of the generator-side converter...
Harmonic voltage amplification, due to unintentional series or parallel resonance of power factor correction capacitors, is a significant issue in the industrial power system. Conventional active filters intended to compensate the harmonic current producing by nonlinear loads would not be an effective solution in this scenario, and the harmonic voltage may still be significant. This paper proposes...
This paper presents the analysis and design of the integral cycle converter (ICC) to be used as a local point of load converter in a high frequency distributed power system. In particular, a model for the ICC is developed to investigate the degree of distortion of the input current drawn from the bus, and to study the synthesized output voltage as a function of switching sequence. An intuitive method...
This paper presents a mixed-signal power-factor-correction (PFC) control IC for the single-phase critical-conduction-mode (CRM) boost AC/DC converters. The peak current mode control is applied and analyzed by using the analog circuit. The voltage control loop is implemented in digital approach. This paper analyzes effect of the hysteresis band effect of the analog current comparator in current loop...
This paper investigates the control of a multi-level cascaded H-bridge STATCOM when used as a simultaneous active filter and VAR compensator. The control algorithms developed borrow heavily from control strategies used in variable speed drives, and use predictive current control and symmetrical PWM. A novel phase locked loop approach for the extraction of the harmonics and generation of the forward...
The repetitive control has been widely used in grid connected voltage source converters, such as uninterruptible power supplies (UPS), photovoltaic inverter (PV) and active power filter (APF). This paper introduces a new repetitive control strategy in the APF system; the proposed control strategy has a forgetting factor (FF), which could improve control system robustness. Control system stability...
This paper analyzes the characteristic of singlephase converter system and establishes the active power and reactive power model in d-q axis, which is the same with the three-phase system in d-q axis and could employ decoupling feedback control for reactive compensation and active power control. For realizing d-q transformation in single-phase system, a new orthogonal decomposition method with sliding...
A series-resonant single-phase step up/down ac chopper is presented. The main attribute of the ac chopper topology is the fact that it generates an output ac voltage larger or lower than the input ac one, depending on the instantaneous duty-cycle. This property is not found in the classical ac chopper, which produces an ac output instantaneous voltage always lower than the input ac voltage. The presented...
Invention of direct transfer of power conversion is convenient method to eliminate DC link filter. Most of the Speed control method of AC drive has DC link filter which play an important role in rectifier fed inverter system. In this paper we presented detailed review of latest control method and different control strategy of direct AC to AC conversion using matrix converter. Results are presented...
This paper deals with the input filter design of matrix converter. Regard the matrix converter as a buck type PWM rectifier in the input side, the transfer function of input current using LC input filter is deduced. The parameter selection approach for the capacitor and inductor is presented. It has been verified that when LC circuit is adopted in the input filter, the input current will oscillate...
In recent years, the increase of non-linear loads in electrical power system has sparked the research in power quality issue. The shunt active power filter (SAPF) is a power electronic device which has been developed to improve power quality. The current control of shunt power filters is critical since poor control can reinforce existing harmonic problems. Various control strategies have been proposed...
Active power filter (APF) has been widely recognized as a substitute for classical passive L-C filter for eliminating the power line harmonics/reactive current due to nonlinear loads and switching devices. The tracking capability of the current controller dominates the performance of the APF. Since the required harmonic compensating currents are of periodic, the repetitive control may be considered...
Capacity proportion frequency allocation compensation parallel control strategy based on the multiple synchronous rotating reference coordinates control is proposed to overcome difficulties in the field of high power application. The zero steady-state error compensation is implemented and the overall stability of the system may be improved by the multiple synchronous rotating reference coordinates...
In the control of PWM rectifier, it can restrain harmonic and interference effectively by constructing a virtual line-flux-linkage to serve as the oriented vector. However, there are some problems in the conventional method, such as the error of amplitude, the shift of phase angle and the nondeterminacy of initial oriented angle. In the thesis, two one-stage low-pass filters are adopted instead of...
This paper presents an implementation of hybrid active power filter for minimizing the input current distortion in a single-phase system feeding a non-linear load. In this method, the active power filter is injecting equal but opposite current to mitigate the distortion current shape the supply current to a sinusoidal form and in phase with the supply voltage. In this work, the single-switch parallel...
This paper proposes a modified one-cycle-control (OCC) scheme for regulation of three-phase pulsewidth-modulated (PWM) rectifiers under unbalanced and distorted supply conditions. Mathematical analysis is presented to show the dominant harmonic voltage across the dc-link of PWM rectifier when controlled by the existing OCC scheme. Such ripple voltage may aggravate the harmonic distortion in input...
This paper deals with analysis and reduction of dc-voltage fluctuations in a single-phase active power filter caused by a sudden load change. The analysis reveals that the delay time of the harmonic detection causes dc-voltage fluctuations in transient states. A new control method is proposed to reduce the dc-voltage fluctuations, based on the analysis. As a result, the dc capacitor can be reduced...
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