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With the steady transition towards a more dominant decentralized power generation and the further reduction of conventional fossil fuel-based power plants, future utility grids require higher demands regarding voltage quality and supply reliability. Active power filters with energy storage capability, here referred to as Power Conditioning Systems (PCS), offer grid supporting and stabilizing measures...
The paper proposes a three phase nine level T-type neutral point clamped (9L-T-NPC) inverter for medium voltage induction motor drive. The primary objective of the proposed inverter is to improve the output voltage quality with reduced number of devices and passive components. The generation of nine levels in the output pole voltage is achieved using only ten switches per phase. Although the similar...
Traditional Hysteresis current control (T-HCC) method has a good transient response performance and robustness. However, when applied in the three-phase voltage source converters (VSCs) occasions, due to the interphases dependency and coupling among the three-phase currents, current harmonics and high switching frequency will arise. Considering of this, this paper presents a new sine-like HCC (SL-HCC)...
Apart from high power density, unified power quality conditioner (UPQC) offers a cost-effective and energy-efficient way to deal with power quality issues. A single-phase transformer-less unified power quality conditioner (TL-UPQC) utilizing four switching devices only is presented. The proposed UPQC consists of two voltage source inverters, one is connected in parallel with the load and another one...
The detection of the fundamental frequency and phase angle of the positive sequence grid voltages are utmost necessary for the proper operation of controlled active power converters, which require to operate stable and robust even during the presence of diverse power quality issues. There exist various utility grid synchronization and detection methods based on Phased-Locked Loop (PLL) techniques...
This paper presents a flyback converter based partial power processing structure for battery energy storage system (BESS). It combines both of the battery balancing functionality and power stage regulation functionality into one system. The proposed BESS only have one control variable which is the common duty cycle for all the flyback converters. It is used for the voltage or current regulation. There...
Using the conventional look-up table-direct power control (LUT-DPC) strategy with its two-level hysteresis comparators and conventional switching table, poor regulation of active power (abnormal fluctuations appeared in reactive power waveform), non-sinusoidal input currents with a little high THD and depressed power factor are obtained. This study therefore set out to solve these problems; the conventional...
The electrostatic precipitator (ESP) system depends heavily on the three-phase IGBT intelligent inverter high voltage (HV) power supply. To improve the dynamic responses of ESPs during the event of flashovers and back corona, a magnificent nonlinear-controll technology called hysteretic current-mode control (HCMC) concept is proposed based on the working characteristics of ESPs. This method adapts...
This paper proposes an improved control strategy for switching frequency variation in hysteresis current controlled Voltage Source Inverter (VSI) fed induction motor drives, that provides the additional advantage of reduced peak-to-peak torque ripple, Te(p-p). The advantages of simple hysteresis controller, viz. simple implementation and fast dynamic response are added with the advantages of constant...
Power factor and harmonics are primary factors in electrical distribution network. Harmonics are generated by the non-linear and irregular loads at end users. High harmonics in devices draws the large amount of current which results in poor power factor. Hysteresis control technique is one of the techniques in power factor converter topologies. Switching losses, low power factor and high harmonic...
This paper proposes an improved control strategy for switching frequency variation in hysteresis current controlled Voltage Source Inverter (VSI) fed induction motor drives. The advantages of simple hysteresis controller, viz. simple implementation and fast dynamic response are added with the advantages of constant switching frequency and reduction in switching losses and harmonic distortion in the...
There has been a gradual increase in generation of power from renewable energy resources interfaced to existing utility grid to increase its reliability. Tapping of these resources is done in multiple ways like standalone wind generators or photovoltaic plants, microgrids etc. Interfacing DC sources like photovoltaic cells, battery, fuel cells with AC systems requires tie line inverter with robust...
Bidirectional AC/DC power conversion has become very essential for any power electronic based industry. Pulse Width Modulated (PWM) Converters can be suggested as the best solution for rectifier as well as inverter modes of operation to achieve bidirectional power flow. In rectifier mode of operation, the converters are controlled to deliver regulated and ripple free DC output with high quality of...
This paper describes a Sliding mode control (SMC) technique for a single - phase grid connected voltage source inverter (VSI) through LCL filter for distributed generation applications. SMC technique is applied as a control method with a fixed band hysteresis controller. Mathematical modeling of the VSI circuit is done through state space analysis. This control method provides robust current voltage...
This paper proposes three-level flying capacitor inverter based distribution static compensator (DSTATCOM) for shunt applications. Also, two new floating capacitors voltage balancing schemes using loss balancing technique have been proposed to balance capacitor voltages. Because of benefits like simplicity, transformation less implementation, and scope of desired power factor setting; a generalized...
Reactive current compensation is a method to improve the load power factor by locally supplying the reactive current requirement of the load using shunt compensators. Current controller of shunt compensators is usually designed using conventional PI controllers, in spite of the improved dynamic performance offered by hysteresis controllers. Conventional hysteresis current controller brings up different...
This paper presents a simple and effective control method to control the output voltage of DC-DC converters. The proposed method overcomes the problems associated with PWM hysteresis control. The method is also simpler and easier to implement than one cycle control (OCC). Boost, buck-boost, buck and cuk converters are selected for study. Two cases of study are included. The first represents disturbances...
The paper presents research concerning the use of innovative technology of AC voltage normalization in eclectic energy system, based on automatic mode voltage control in immediate proximity to the consumer of electric energy and allowing to improve the processes of Demand Side Management and also to increase statistic stability of electric energy system.
Compared to the three-level neutral point clamped (3L-NPC) inverter, its simplified version, the 3L-SNPC, uses fewer switching devices to achieve a multi-level output. However, it offers fewer voltage vector selections, limiting its usefulness for motor drive applications. This issue is overcome through a proposed direct torque control (DTC) strategy utilizing the concept of virtual voltage vectors...
This paper investigates the voltage regulation in a quadratic boost converter with high DC gain using sliding mode control. In the proposed scheme, the controller has an inner loop based on sliding-mode control whose sliding surface is defined for the input inductor current. The reference current value of the sliding surface is generated using a proportional-integral compensator in the outer loop...
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