MOSFETs In Inverter Research Articles

Early detection of photovoltaic system inverter faults

Photovoltaic (PV) systems are increasingly adopted as a source of green energy. The reliability of PV systems mainly depends on the reliability of the power MOSFETs of their inverter(s). It has been shown that short and open faults are the most frequent power MOSFET faults. They may compromise the inverter reliability, with consequent significant impact on the PV system energy efficiency. It has been proven that the likelihood of such faults is related to the value of the MOSFET ON-state resistance, which may increase over time due to aging mechanisms. When the value of such a resistance reaches a critical value, the likelihood of the MOSFETs subsequently failing as open or short becomes very high. In this paper, we first evaluate the effects of the MOSFETs' ON-state resistance increase on the harmonic components of the inverter input and output currents. Then, based on the obtained results, we propose an innovative strategy for the early detection (also referred to as condition monitoring [1]) of inverter faults, which enables to generate an alarm message when the ON-state resistance of any inverter MOSFET reaches the critical value. Upon the generation of such an alarm message, proper recovery strategies can be activated, to enable the online replacement of the affected transistors before they actually become faulty. Our detection strategy does not require to interrupt the inverter normal operation in the field and can be implemented using the microcontroller typically embedded within the control circuitry of PV systems.

Research on Dual-LCC MCRWPT system based on controlled rectifier

Among many types of Wireless Power Transfer (WPT) technology, Magnetically Coupled Resonance Wireless Power Transfer (MCRWPT) technology has been studied more and more due to its stable transmission Power and strong anti-interference ability. In this paper, the operating characteristics of the Dual-LCC MCRWPT system based on the secondary side controlled rectifier are analyzed, and the variation of the system current with D, the phase relationship between the input voltage and current of the resonant network, the phase relationship between the output voltage and current of the resonant network, and the variation of the input and output load of the system are studied in depth. Through the simulation analysis of inverter MOSFET switching state, verify the effectiveness of the controlled rectifier control mode and the rationality of theoretical analysis, provide a solid theoretical basis for the optimization of the controlled rectifier control mode.

Performance Evaluation & Operation of DSP Control UPS System

An uninterruptible power supply (UPS) is a power conditioner that provides emergency power to a load when the supply power fails. In on-line UPS, the load is always connected to the inverter through the UPS static switch. Specialized expertise was required for collection, analysis, and dissemination of technical information relating to high quality uninterruptible power systems. Inherent in these responsibilities is the coordination of technical and contractual matters relating to the procurement and installation of uninterruptible power supply (UPS) systems which were required to support these facilities. The proposed circuit incorporates an AC/DC & DC & AC converter, which provided power factor correction and to assure feedback control. In our project when the AC main is available, the rectifier circuit will supply the power to the inverter as well as to the battery and battery will be charged. If the supply power fails suddenly, the battery will supply power to the inverter without any interruption and delay. In the constant current charging technique, a digital charger was designed and controlled through PIC12F675 microcontroller. In the realized system, The PIC16C73B was used as microcontroller. It was used to generate sinusoidal PWM (Pulse Width Modulation) signals that are connected to drive n-channel MOSFETs in inverter to assure feedback control and display units. The power circuit of the proposed UPS system was presented and analyzed. Circuit models were derived and a UPS digital control system using a digital signal processing (DSP) with microcontroller has been developed. The uninterruptible Power Supplies (UPS) are widely used by power supply during interruption of regular power supply due to load shedding, power failure, power fluctuations including telecommunication systems, medical systems, industrial control systems etc.

MOSFET Power Loss Estimation in LLC Resonant Converters: Time Interval Analysis

In the past ten years, LLC resonant converters have become a mainstream topology for dc/dc power conversion, and multiple design tools have been developed for this topology, including controllers, regulators, soft-switching techniques, etc. While many tools are available for designing this converter, techniques for accurately determining power losses in the inverter mosfet s of the topology based on time-domain analysis have not been fully explored yet. Precise power loss estimation is fundamental to determine the thermal behavior of the switches before the converter is built, which accelerates and optimizes the thermal management design process. In addition, accurate methods of estimating conduction losses, which are dominant in this topology, switching losses, and body diode losses are lacking in the literature. This paper proposes a method for enhancing power loss estimation in LLC inverter mosfet s based on time-domain analysis of the converter. Moreover, a detailed characterization of mosfet 's conduction losses ( $P_{\text{cond}}$ ), switching losses ( $P_{\text{sw}}$ ), and body diode losses ( $P_{\text{diode}}$ ), including the effects of different parameters such as gate-source voltage ( $V_{\text{GS}}$ ), junction temperature ( $T_{j}$ ), drain current ( $\displaystyle I_{D}$ ), and drain-source voltage ( $V_{\text{DS}}$ ), is presented, which can further improve power loss assessment in this topology. The developed method based on time interval analysis replaces the simplistic first-harmonic approximation (FHA), which allows for improved power loss calculations. Further improvement is obtained with the detailed characterization of the switching device. As verified by simulation and experimental results, the proposed estimation tool provides a significant boost in accuracy for power loss determination when compared to the existing method for power loss estimation using FHA.

Performance Evaluation and Operation of DSP Control UPS System

An uninterruptible power supply (UPS) is a power controller that gives emergency electricity to a load when the mains energy fails. In on-line UPS, the load is always connected to the inverter though the UPS static switch. Specialized expertise is required for collection, analysis, and dissemination of technical information relating to high quality uninterruptible power systems. Inherent in these responsibilities is the coordination of technical and contractual matters relating to the procurement and installation of uninterruptible power supply (UPS) systems which are required to support these facilities. The proposed circuit incorporates an AC/DC & DC/AC converter, which provides power factor correction and to assure feedback control. In our project when the AC main is available, the rectifier circuit will supply the power to the inverter as well as to the battery and battery will be charged. If the supply power fails suddenly, the battery will supply power to the inverter without any interruption and delay. In the constant current charging technique, a digital charger is designed and is controlled through PIC12F675 microcontroller. In the realized system, The PIC16C73B was used as microcontroller. It was used to generate sinusoidal PWM (Pulse Width Modulation) signals that are used to drive n-channel MOSFETs in inverter to assure feedback control and display units. The power circuit of the proposed UPS system is presented and analyzed. Circuit models are derived and a UPS digital control system using a digital signal processing (DSP) with microcontroller is developed. The uninterruptible power supplies (UPS) are widely used as standby power supply during interruption of regular power supply due to load shedding, power failure, power fluctuations including telecommunication systems, medical systems, industrial control systems etc. Keywords: Uninterruptible power supply, PIC12F675 microcontroller, Pulse Width Modulation, MOSFET, power fluctuations

Implementation of floating gate MOSFET in inverter for threshold voltage tunability

This paper presents the ability of floating gate MOSFET (FGMOS) threshold voltage to be programmed or tuned which is exploited to improve the performance of electronic circuit design. This special characteristic owns by FGMOS is definitely contributes towards low voltage and low power circuit design. The comparison of threshold voltage between FGMOS and conventional NMOS is done in order to prove that FGMOS is able to produce a lower threshold voltage compared to conventional NMOS. In addition, in this paper, an implementation of FGMOS into inverter circuit is also done to show the programmability of FGMOS threshold voltage. The operations of the inverter circuits are verified using Sypnopsys simulation in 0.1μm CMOS technology with supply voltage of 1.8V.

ISG 구동용 인버터의 열유동 해석에 관한 연구

Recently, many vehicles have applied electric parts for saving fuel consumption and reducing levels of environmental pollution. ISG (integrated starter & generator) is one of main electric parts and can improve fuel efficiency by using idle stop & go function and regenerative braking system. However, if ISG driving inverter works under the continuously high load condition, it will make the performance and durability of the inverter decreased with rising temperature. In this study, we carried out the analysis on the fluid flow and thermal characteristics of the inverter. As a result, we found the MOSFET of the air cooled inverter was increased up to <TEX>$116^{\circ}C$</TEX> over the limit temperature. On the other hand, the liquid cooled type inverter's MOSFET was decreased by about <TEX>$17^{\circ}C$</TEX> compared to that of the air cooled inverter. Therefore, we verified the feasibility of the liquid cooled type using the present cooling structure.

Delay analysis of series-connected MOSFET circuits

In order to derive analytical delay expressions for CMOS gates in the submicrometer region, a realistic MOS model which incorporates an nth power law MOS model is developed. Closed-form delay formulas are obtained for CMOS inverters and series-connected MOSFET structures (SCMSs) that include short-channel effects. It is shown that the ratio of the delay of NAND/NOR to the delay of the inverter becomes smaller in the submicrometer region, because the V/sub DS/ and V/sub GS/ of each MOSFET in the SCMS are smaller than those of an inverter MOSFET. The smaller voltages in turn mitigate and relax the severe carrier velocity saturation in miniaturized MOSFETs. The results of the analysis for submicrometer VLSI designs show that if the maximum number of series-connected MOSFETs is considered to be five in 2- mu m designs, then the number can be increased to six or seven in the submicrometer circuit design. In typical cases in VLSI designs, the delay ratio for N-SCMS is much less than N/sup 2/. The delay dependence on input terminal position for SCMS structures is also described. >