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Boost type inverter system for compensation of voltage sag
Abstract
This paper proposes a boost type inverter system to compensate the voltage sag has appeared in voltage sources. If the voltage sag has appeared in input voltage, a boost converter would be operated to compensate it in the boost type inverter system. The boost converter would not be operated when the magnitude of input voltage is more than 90 %, and the output voltage is kept constant by a direct-quadrature frame controller in the single-phase PWM inverter. A 300 W class boost type inverter system was simulated, and the validity of the proposed system was verified by carrying out experiments.
... 이로 인하여 전기자동차가 증가하면 각 상의 전원 선에서 전류 불평형이 증가하여 변압기에서 동손과 철 손이 증가한다. 이로 인해 전원설비 이용률이 감소하고 손실이 증가하여 전기요금이 증가할 뿐만 아니라 전력 망의 공통 결합점(Point of Common Coupling : PCC)에 연결되어 있는 보호계전기의 오동작 등 전기 및 정보 통신기기에 나쁜 영향을 줄 수 있다[8]. 따라서 퇴근 이후 전기자동차의 동시 충전으로 인한 피크부하의 억제와 전원설비 각 상의 전원선에서 전류 불평형을 최소화하는 방안이 필요하다.가 ...
This study proposes an electric vehicle (EV) smart panel board and its control method on the basis of charging scheduling. The proposed system consists of batteries, a three-phase battery charger, three single-phase inverters, transfer switches for electric power distribution, and a controller. The three-phase battery charger usually charges the batteries at midnight when electric rates are cheap and in light load. When the electric power consumption of the EV standard chargers connected to one phase of the power line is relatively large or when a blackout occurs, the electric power stored in the battery is supplied by discharging through the inverters to the EV standard chargers. As a result, the value of peak load and the charging electric power quantity supplied from a utility grid are reduced, and the current unbalance is improved. The usefulness of the proposed system is confirmed through simulations, experiments, and case studies.
In this paper, a 300[W] class boost type single-phase inverter system which can compensate voltage sag on source side is designed and implemented. This system is a two-stage conversion system composed of a boost converter and a PWM inverter. If the voltage sag has appeared at the point of common coupling, the boost converter would be operated to compensate it. The boost converter and the inverter were constructed on single smart power module(SPM) to implement low cost system. The system is designed for that the THD of output voltage is below 5[%]. Finally, the validity of the design for the inverter system is verified by both simulations and experiments.
An intelligent optimization method for designing Fractional Order PID (FOPID) controllers based on Particle Swarm Optimization (PSO) is presented in this paper. Fractional calculus can provide novel and higher performance extension for FOPID controllers. However, the difficulties of designing FOPID controllers increase, because FOPID controllers append derivative order and integral order in comparison with traditional PID controllers. To design the parameters of FOPID controllers, the enhanced PSO algorithms is adopted, which guarantee the particle position inside the defined search spaces with momentum factor. The optimization performance target is the weighted combination of ITAE and control input. The numerical realization of FOPID controllers uses the methods of Tustin operator and continued fraction expansion. Experimental results show the proposed design method can design effectively the parameters of FOPID controllers.
High power density and power conversion efficiency have been required in the power converters according to the rapid growth of industry. In this context, the next generation High Speed Train(HST) requires power converter which has high-efficiency, high-performance and high-density. In this paper, the new control technique for battery charger used for the next generation HST is proposed. The phase shift ZVZCS converter is classified according to a resonant circuit which is located in the primary or secondary side. In this paper, The PWM switching technique using all-pass filter is proposed to control ZVZCS converter which has resonant circuit in the secondary side. ATmega_128 micro controller based in all-pass filter in substitute for phase shift IC is presented to have digital control. To verify the proposed topology, the simulation and experiment are performed by using PSIM software and 1[kW] experimental set-up.
The establishment of of standards and guidelines to cope with
power quality issues has become evident. Among these, voltage sags are
the most important cause of interruption of industrial processes. Sag is
heavily dependent on the supply systems configuration, process equipment
design, systems switching and protection practices, among others. In
this environment, the development and the proper use of standards to
regulate custumers, equipment manufacturers and utilities relations
regarding sags issues is a most important question. This paper presents
a discussion on the IEEE and IEC power quality related standards, and
their applicability to voltage sag evaluation in a industrial or
commercial system, utility system, and to equipment
This paper presents a Direct-Quadrature (DQ) rotating frame control method for single phase full-bridge inverters used in small hybrid power systems. A secondary orthogonal imaginary circuit is created to provide the second phase required for the transformation; thus a DQ model of the inverter is obtained and its controller designed emulating the controls of three-phase power converters. The proposed controller attains infinite loop gain in the rotating coordinate, thus providing zero steady-state error at the fundamental frequency of the converter. The proposed controller is designed and validated through simulations using a DQ-frame average model in Matlab and a detailed switching model in Saber, as well as experimental results obtained with a 2.5 kW single phase full-bridge inverter prototype using a DSP/FPGA based digital control system where the proposed DQ-frame controller is fully implemented.
AC operated electronic equipment are vulnerable to momentary losses of AC voltage, which are known as voltage sags. Voltage sags are commonly caused by lightning, accidental short circuit, loose connection, starting of large motors (or air-conditioners) or abnormal use of the AC mains. In sensitive and critical applications, such as semiconductor material processing and medical operation, voltage sags may result in serious problems. In order to tackle this problem, the Semiconductor Equipment and Materials International (SEMI) defined, in 1996, a voltage sag immunity standard, known as SEMI F47-0200, for semiconductor processing equipment manufacturers to conform to. Equipment compliant to this standard must have the specified immunity characteristics against voltage sags without the use of batteries. Based on the experience learned, the standard was redefined, in 2006, as SEMI F47-0706. It is expected that new semiconductor processing equipment will be designed to be compliant to the new standard. It is also likely that the SEMI F47-0706 requirement will be extended to other application areas. This paper describes the design of voltage sag compensators which can be operated in conjunction with a piece of equipment for SEMI F47 compliance. The voltage sag compensators described can provide sine-wave AC backup power to enable electronic equipment to meet the SEMI F47-0706 standard and to tolerate 100% momentary loss of AC mains voltage.
This paper analyses the different voltage sag phenomenon of the different voltage sag sources and summarizes the characteristics of the different voltage sag sources, including the amplitude of the voltage sag, the swell happening at the same time of the sag, the characteristics of the voltage changes during the sag and the three phases voltage balance or not. Most of the existing voltage sag source recognition methods and their disadvantages and application have been analyzed in this paper. Considering that in actual power quality monitoring network, many monitoring equipments only can provide parts of the voltage sag data, so a simple and practical method is proposed in this paper. Only the RMS voltages are calculated in this method. Based on the different voltage sag amplitudes, the voltage jump happening at the end of the sag(or the voltage changes in trends during the sag), the different deviations of the three-phase voltages and some other characters according to different sources, the characteristic value corresponding can be extracted, and then the classification of voltage sag caused by the short-faults, transformers energizing and large-capacity induction motor starting can be realized. The correctness of the method is proved by simulations.
The four-phase SRG(Switched Reluctance Generator) with 8 stator poles & 6 rotor poles is taken as an example for introducing the operating principle and actual nonlinearity of SRG. Its nonlinear mathematical model is established with Fourier series tool. As the multi-level inverter technology is not suitable for SRG generation system and the control precision of two-level SVPWM is not perfect, a SVPWM over -modulation control algorithm based on fundamental voltage amplitude linear output control is presented: the amplitude modulation index is introduced to over-modulation area; based on the index and the vertex voltage vector of space vector chart, the relationship between inverter output voltage vector and reference voltage vector is calculated; and the turn-on time of the effective vector of over-modulation area is then derived. Results of simulation with Matlab show that, the inverter based on SVPWM over-modulation control algorithm feeds the SRG output energy back to grid, achieving perfect electric energy quality in both dynamic and static conditions.
Voltage sags has been identified as the largest negative impact on industrial productivity due to a sensitivity of electrical loads, and several voltage sag immunity standards such as SEMI F47, CEBMA Curve and IEC 61000-4-11, −34 were founded to improve equipment reliability, uptime and to reduce service costs. In this paper, a novel voltage sags controller along with a new RMS averaging method, which achieves not only a fast response but also a simple implementation, is proposed for the voltage sag protector employing a single-phase ac-ac voltage converter with an autotransformer. Simple and easy implementation of the converter due to no requirement of energy storage device and synchronization of voltage phase makes hardware cost-effective. A slow detection of a conventional RMS averaging method, which have been identified as a major problem, is improved by new scheme, where all stored voltage data within a queue is tuned up by new coming voltage data, is adopted for the new RMS averaging method. Experimental results are presented to verify the fast dynamics of the proposed voltage sag controller
A control method in the direct-quadrature (DQ) rotating frame for a single-phase inverter or PFC rectifier is proposed to provide an infinite control gain (theoretically), thus zero steady state error at its fundamental frequency to achieve superior steady state and dynamic performance. This new control method transforms the physical "real circuit", in conjunction with an "imaginary orthogonal circuit", from the stationary frame to the DQ rotating frame so that the steady state voltage/current in the DQ frame become DC variables. The new control concept is validated through a single-phase grid simulator used for utility compatibility tests, as described in IEEE P1547 draft standard, IEEE Std 929, UL 1741 and NYSIR, for single-phase distributed generators (DG), such as residential fuel cell generators or photovoltaic power conditioning systems. Experimental results in steady state with programmable simulated utility line impedance are given along with the dynamic transient response for NYSIR type test. The control concept is also applicable to zero-sequence control for three-phase four-wire systems.
The recently introduced proportional-resonant (PR) controllers and filters, and their suitability for current/voltage control of grid-connected converters, are described. Using the PR controllers, the converter reference tracking performance can be enhanced and previously known shortcomings associated with conventional PI controllers can be alleviated. These shortcomings include steady-state errors in single-phase systems and the need for synchronous d-q transformation in three-phase systems. Based on similar control theory, PR filters can also be used for generating the harmonic command reference precisely in an active power filter, especially for single-phase systems, where d-q transformation theory is not directly applicable. Another advantage associated with the PR controllers and filters is the possibility of implementing selective harmonic compensation without requiring excessive computational resources. Given these advantages and the belief that PR control will find wide-ranging applications in grid-interfaced converters, PR control theory is revised in detail with a number of practical cases that have been implemented previously, described clearly to give a comprehensive reference on PR control and filtering
Testing and Measurement Techniques -Voltage Dips, Short Interruptions and Voltage Variations Immunity Tests
- Ks Iec
KS C IEC 61000-4-11, Testing and Measurement Techniques -Voltage Dips, Short Interruptions and Voltage Variations Immunity Tests.