The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
This paper proposes an advanced model predictive control for the three-level active-neutral-point-clamp (ANPC) inverter in order to improve the system performance with fast dynamic response and ensure the stability of the controller. The proposed scheme is Lyapunov function based voltage mode control which utilizes the discrete behavior of the converter considering the unavoidable quantization errors...
In this paper, an improved control strategy for three-phase inverter is proposed, which ensures three-phase output voltage symmetry under unbalanced grid voltage. Firstly, the positive and negative sequence separation module is used to obtain unbalance output voltage and current during the grid faults. By calculating output power of the inverter, an improved P-ƒ, Q-U and Q-G droop control strategy...
High reliability performance of microinverters in Photovoltaic (PV) systems is a merit to match lifetime with PV panels, and to reduce the required maintenance efforts and costs. This paper applies a reliability oriented design method for a grid-connected PV microinverter to achieve specific lifetime requirement. Reliability allocation is performed from the system-level requirement to the component-level...
As the penetration level of grid-connected PV systems increases, more advanced control functionality is demanded. In order to ensure smooth and friendly grid integration as well as enable more PV installations, the power generated by PV systems needs to be flexible and capable of: 1) limiting the maximum feed-in power, 2) ensuring a smooth change rate, and 3) providing a power reserve. Besides, such...
A large amount of distributed generation is connected to the grid, reducing rotational inertia of the power system. Based on the Static Synchronous Generator Model, inertia controller is introduced on outer voltage loop in this paper to enhance grid inertia. The developed inertia controller can generate inertial current superposed in conventional current reference. The inertial current can be adjusted...
This paper proposes a novel fixed off-time control method for single-phase micro-inverter operating in discontinues conduction mode. In this method, the off-time of the active switch is fixed to a constant value over the whole power level. The on-time of the active switch is obtained for current shaping without sensing inductor current. The proposed method has two advantages. One is that the switching...
In this paper, the suppression of the circulating current flowing between inverters in parallel with non-isolated dc-link is described. If the inverters are connected in parallel through sharing inductor, circulating current would follow between inverters. In early researches, the circulating current generally is considered as zero sequence component. However, circulating current is not confined as...
This paper presents a division-summation (D-Σ) digital controlled three-phase four-leg voltage source inverter with load impedance estimation for uninterruptible power supply applications. The D-Σ digital control developed for current tracking can accommodate wide filter inductance variation, which has been successfully adopted in grid-tied applications. This paper proposes a load impedance estimation...
Photovoltaic (PV) energy has been widely interested today because it is clean and endless energy without causing pollution. To produce electricity from solar energy, it would be required an inverter to convert the direct current into alternating current. The inverter is the cause of problems that affect the stability of the power system because it is a switching device served to adjust the frequency...
To enhance the conversion efficiency and electrical reliability of a low-voltage fuel cell (FC) power generation system, this paper proposes a modular single-stage grid-connected FC inverter system equipped with a power management and remote monitoring interface. In this system, each single power module is composed of three single-stage quasi-resonant (QR) flyback current-source inverters that are...
We developed a gate driver IC that can power IGBTs of up to 500 amperes for HEVs and EVs. A newly developed Zener clamping circuit effectively suppressed the IGBT spike voltage in short circuit (SC) mode. The silicon-on-insulator (SOI) process was utilized to achieve high temperature operation and high surge protection.
In microgrids, photovoltaic (PV) and storage are integrated as a droop-controlled ideal source, which is not practical and challenges the system efficiency. Instead, PV-storage can be allocated separately. This PV-storage independent system is more flexible and easier to optimize. But, the conventional PQ-controlled PVs rely on master voltage-controlled storage sources. In this paper, a novel operation...
In this paper, the conventional three-level diode-neutral-point-clamping (3L-DNPC) inverter is deeply investigated from the view of power loss. It is concluded that the conventional 3L-DNPC inverter has high zero-vector conduction loss due to clamping Diode+ IGBT structure's high on-state voltage, high clamping diode reverse recovery loss and so on. Therefore, the clamping diodes are most deeply related...
This paper proposes a single-phase UPFC topology using an autotransformer structure. The proposed topology uses a N:1 transformer, which is connected as an autotransformer and a power converter module which consists of a single-phase half-bridge converter and an inverter. Also, the three-phase system can be comprised of three single-phase UPFCs. In three-phase system, while the conventional UPFC topology...
A square wave transmission based micro-grid, which is compatible with commercial AC sinusoidal grid components, is investigated in this paper for rural areas. The basic interface circuit unit, square wave generator (SWG) is designed to satisfy bidirectional power flow and square wave transfer. The square wave has larger power delivery compared to sine wave. The circulating current of paralleled SWGs...
The virtual synchronous generator (VSG) is a control scheme applied to the grid-tied inverter to increase system inertia by imitating the rotor inertia of synchronous generator (SG). However, due to the imitation on rotor inertia VSG control may lead to the power and frequency oscillation after a change or disturbance, which decreases the reliability of inverters. In this paper, the process of active...
This paper proposes a frequency scanning-based impedance analysis for stability assessment of grid-connected inverter system, which is able to perform stability assessment without using system mathematical models and inherit the superior feature of impedance-based stability criterion with consideration of the inverter nonlinearities. Small current disturbance is injected into grid-connected inverter...
This paper presents an FPGA-based adaptive predictive control scheme for single-phase T-type NPC inverter in applications to microgrids with high efficiency and robust performance. Predictive control is applied for current regulation to achieve fast dynamic response with low total harmonic distortion (THD). Implementation of a grid inverter with minimum inductor will result nonlinear inductance due...
In high-frequency (HF) pulsating voltage injection-based sensor-less surface-mounted permanent magnet synchronous motor (SPMSM) control, inverter nonlinearities and motor parameter asymmetries lead to harmonic errors in the estimated position. To eliminate these errors, the second-order generalized integrator (SOGI) is applied. An enhanced position observer with a selective harmonic error eliminator...
The latest trend in solar inverter application is to increase DC link voltage to 1500VDC for high power output. This paper describes a design concept of NPC1 power stack for 1500VDC megawatt level solar inverter. This stack uses three latest half-bridge IGBT modules with highest power density and operation junction temperature, which enable realization of power level beyond 1MW without paralleling...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.