• Journal of Power Electronics
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• 제15권4호
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• pp.951-963
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• 2015

In this paper, a new symmetric multilevel inverter is proposed. A simple structure for the cascaded multilevel inverter topology is also proposed, which produces a high number of levels with the application of few power electronic devices. The symmetric multilevel inverter can generate 2n+1 levels with a reduced number of power switches. The basic unit is composed of a single and double source unit (SDS-unit). The application of this SDS-unit is for reducing the number of power electronic components like insulated gate bipolar transistors, freewheeling diodes, gate driver circuits, dc voltage sources, and blocked voltages by switches. Various new algorithms are recommended to determine the magnitude of dc sources in a cascaded structure. Furthermore, the proposed topology is optimized for different goals. The proposed cascaded structure is compared with other similar topologies. For verifying the performance of the proposed basic symmetric and cascaded structure, results from a computer-based MATLAB/Simulink simulation and from experimental hardware are also discussed.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2012년도 전력전자학술대회 논문집
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• pp.486-487
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• 2012

In this paper, novel three-port active power decoupling (APD) method for applying 250[W] micro-inverter. This type using third port for active power decoupling stores the surplus energy and supplies sufficient energy to grid. Conventional decoupling circuit is applied in single phase grid connected micro-inverter especially single-stage configuration like flyback-type DC-AC inverter. In this passive power decoupling method, electrolytic capacitor with large capacitance is needed for decoupling from constant DC power and instantaneous AC power. However the decoupling capacitor is replaced with film capacitor by using APD, thus the overall system can achieve smaller size and long lifespan. Proposed three-port flyback inverter is verified by design and simulation.

• KEPCO Journal on Electric Power and Energy
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• 제7권1호
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• pp.107-114
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• 2021

High penetration of renewable energy generators causes unnecessary investment for power system facilities. Especially with Korean government policies such as Renewable Energy 3020 and Inter-connection support Responsibility of KEPCO for 1 MW DERs, the applications of DER interconnection in distribution system have been increasing. To save the investment, smart control functions for DERs are required and the test bed for the inverters which have not been prepared are necessary to insure DER inter-connection stability. For this, test bed for advanced functions of a smart inverter has been constructed and the tests for necessary functions have been implemented. In this paper, the test bed and environment as well as specifications are introduced and the test results for the validation of the functions are analyzed.

• 전력전자학회:학술대회논문집
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• 전력전자학회 1998년도 전력전자학술대회 논문집
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• pp.113-115
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• 1998

This paper present a buck-boost PWM inverter and its application for residential system. The PWM power inverter is realized by driving a inverter constructed with a high frequency buck-boost chopper in the discontinuous conduction mode (DCM)

• IEIE Transactions on Smart Processing and Computing
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• 제5권1호
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• pp.35-42
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• 2016

Developments in power electronics have enabled the widespread application of Pulse Width Modulation (PWM) inverters, notably for connecting renewable systems to the grid. This study demonstrates that a high-quality power can be achieved using a stand-alone inverter, whereby the comparison between the power quality of the stand-alone inverter with battery storage (off-grid) and the power quality of the utility network is presented. Multi-loop control techniques for a single phase stand-alone inverter are used. A capacitor current control is used to give active damping and enhance the transient and steady state inverter performance. A capacitor current control is cheaper than the inductor current control, where a small current sensing resistor is used. The output voltage control is used to improve the system performance and also control the output voltage. The inner control loop uses a proportional gain current controller and the outer loop is implemented using internal model control proportional-integral-derivative to ensure stability. The optimal controls are achieved by using the Sisotool tool in MATLAB/Simulink. The outcome of the control scheme of the numerical model of the stand-alone inverter has a smooth and good dynamic performance, but also a strong robustness to load variations. The numerical model of the stand-alone inverter and its power quality are presented, and the power quality is shown to meet the IEEE 519-2014. Furthermore, the power quality of the off-grid system is measured experimentally and compared with the grid power, showing power quality of off-grid system to be better than that of the utility network.

• International Journal of Automotive Technology
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• 제4권1호
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• pp.41-45
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• 2003

The 42V Mild Hybrid System has been released into market by Toyota for the first time in the world in 2001. The set-up employs an inverter unit to control the motor/generator (MG) electronically. The driving system called such as Toyota Mild Hybrid System (TMHS) has additional new functions to conventional internal combustion engines. When stopping vehicle, the engine stops promptly. When starting vehicle, by releasing the brake pedal MG starts the vehicle at the same time (EV-driving mode). When stepping on the accelerator pedal, or after a given period of time the engine firing occurs and the engine-driving mode starts. When running by motor, the power is supplied to the motor from 36V battery through the inverter. High outputs and instant responses are required for Inverter. At the same time, the compact volume is required to fit into the limited space of the engine room. The compact size and high output are also required to Power Capacitor used for this inverter. The power capacitors has been newly developed, shaped in "flat" type, suitably for the inverter. The points of developments on inverter and power capacitor are described in this paper.his paper.

• Journal of Power Electronics
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• 제16권4호
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• pp.1245-1255
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• 2016

The single resonant inverter is widely employed in typical inductive power transfer (IPT) systems to generate a high-frequency current in the primary side. However, the power capacity of a single resonant inverter is limited by the constraints of power electronic devices and the relevant cost. Consequently, IPT systems fail to meet high-power application requirements, such as those in rail applications. Total harmonic distortion (THD) may also violate the standard electromagnetic interference requirements with phase shift control under light load conditions. A power regulation approach with selective harmonic elimination is proposed on the basis of a parallel multi-inverter to upgrade the power levels of IPT systems and suppress THD under light load conditions by changing the output voltage pulse width and phase shift angle among parallel multi-inverters. The validity of the proposed control approach is verified by using a 1,412.3 W prototype system, which achieves a maximum transfer efficiency of 90.602%. Output power levels can be dramatically improved with the same semiconductor capacity, and distortion can be effectively suppressed under various load conditions.

• Journal of Power Electronics
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• 제6권2호
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• pp.95-103
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• 2006

In this paper, a novel prototype of auxiliary switched capacitor assisted voltage source soft switching PWM Single-Ended Push Pull (SEPP) series capacitor compensated load resonant inverter with two auxiliary edge resonant lossless inductor snubbers is proposed and discussed for small scale consumer high-frequency induction heating (IH) appliances. The operation principle of this inverter is described by using switching mode equivalent circuits. The newly developed multi resonant high-frequency inverter using trench gate IGBTs can regulate its output AC power via constant frequency edge-resonant associated soft switching commutation by using an asymmetrical PWM control or duty cycle control scheme. The brand-new consumer IH products which use the newly proposed edge-resonant soft switching PWM-SEPP type series load resonant high-frequency inverters are evaluated using power regulation characteristics, actual efficiency vs. duty cycle and input power vs. actual efficiency characteristics. Their operating performance compared with some conventional soft switching high-frequency inverters for IH appliances is discussed on the basis of simulation and experimental results. The practical effectiveness of the newly proposed soft switching PWM SEPP series load resonant inverter is verified from an application point of view as being suitable for consumer high-frequency IH appliances.

• Journal of Power Electronics
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• 제4권2호
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• pp.77-86
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• 2004

This paper presents a novel three-phase power module bridge type auxiliary resonant AC link snubber for the three-phase voltage-fed sinwave soft switching PWM inverter operating under specific instantaneous space voltage vector modulation. The operating principle of this resonant snubber is described for current source load model during one switching period, along with its design approach based on the simulation data. The performance evaluations of space vector modulation three-phase sinewave soft switching inverter with a new three-phase active auxiliary resonant AC link snubber are discussed as compared with those of three-phase voltage source-fed sinewave hard switching PWM inverter with a standard space voltage vector modulation strategy. The power loss analysis and conventional efficiency estimation of three-phase soft switching PWM inverter using ICBT modules are carried out including all the conduction power losses based upon the measured v-i characteristics of IGBT and its antiparallel diode as well as their switching losses.

• 디지털산업정보학회논문지
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• 제15권4호
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• pp.9-17
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• 2019

Sun power generation systems which use large capacity centralized inverters have loss of power generation due to cloud and building shadows, pollution, cell deterioration, etc. To minimize loss of power generation, decentralized solar power systems using multiple micro-inverters are being proposed as an alternative. A distributed solar power system consisting of a system-connected system uses power line communication to collect data from the micro-inverters. Power line communication has the advantage of using power lines without separate lines for data transmission, but in distributed solar power generation systems that use a large number of micro-inverters, the bit error rate is less reliable due to the phenomenon caused by limited transmission power, high load interference and noise, variable signal attenuation, and impedance characteristics. So we proposed wireless intelligent controller for micro-inverter that is used to build distributed solar power systems. and we design and implement that. Further, the proposed wireless intelligent controller for micro-inverter was used to establish a small-volume solar power plant to check its function and operation.