• Journal of Power Electronics
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• v.15 no.5
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• pp.1235-1243
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• 2015

This paper presents a modified Space Vector Pulse Width Modulation Technique (SVPWM), which solves the well-known problem of voltage imbalance in the capacitors of a single-phase multilevel inverter. The proposed solution is based on the measurement of DC voltage levels at each capacitor of the inverter DC bus. The measurements are then used to adjust the size of the active vectors within the SVPWM algorithm to keep the voltage waveform sinusoidal regardless of any voltage imbalance on the DC link capacitors. When a voltage deviation exceeds a predetermined hysteresis band, the correspondent voltage vector is restricted to restore the voltage level to an acceptable threshold. Hence, the need for external voltage regulators for the voltage capacitors is eliminated. The functionality of the proposed algorithm is successfully demonstrated through simulations and experiments on a grid tied application.

• Proceedings of the KIEE Conference
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• 1991.07a
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• pp.568-572
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• 1991

This paper describes the three-phase inverter system for 1/2[HP] induction servo motor, using TMS370C050 single-chip microprocessor. The Power MOSFETs are used for PWM inverter circuit because of the advantages such as less harmonic losses and smaller peak current, less torque ripples and noises. Single-chip microprocessor enables the whole controller to be simple and reduced size as well as to more stable and flexible. The basic structures are shown for the power circuit, including the protection and driving circuitry, and the control loops for inverter control functions. The experimental results are given for the prototype PWM inverter system.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.17 no.5
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• pp.521-528
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• 1992

this paper a new PAM-PWM Inverter using IGBT Is described. The output waveforms in the proposed PAM-PWM inverter are investigated both theoretiically and experimentally. The line-voltage waveform is composed of fundamental component and the sidebands of carrier frequency. The lower order harmonics are not included In the output waveform. As each inverter arm does not operate during two-thirds period, the heats, generated in the devices are reduced. That is the size of the inverter system can be minimized because of the reduction In the heat dissipating equipemnt.

• Proceedings of the KIPE Conference
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• 2012.11a
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• pp.137-138
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• 2012

In this paper, three-port flyback inverter with Active Power Decoupling(APD) circuit is analyzed. Conventional flyback inverter with passive power decoupling circuit needs the electrolytic capacitor with large capacitance for decoupling between constant DC power and instantaneous AC power. However the electrolytic capacitor has low lifespan about 50000 to 100000 hours. So the active power decoupling techniques are applied to reduce input capacitance of flyback inverter. Thus the overall system can achieve smaller size and longer lifespan. Proposed three-port flyback inverter is verified by design optimization, simulation and experimental result.

• Proceedings of the KIPE Conference
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• 2012.07a
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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.

• Journal of the Korean Society for Precision Engineering
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• v.27 no.4
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• pp.14-19
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• 2010

In this paper, using interleaved power factor correction how to improve the inverter efficiency studied. Interleaved method can reduce the conduction losses and the inductor energy. Generally, critical conduction mode (CRM) boost PFC converter used low power level because of the high peak currents. if you use the interleaved mode, CRM PFC can be used medium or high power application. interleaved CRM PFC can reduce current ripple for higher system reliability and size of buck capacitor and EMI filter size. Interleaved CRM PFC that is installed in front of inverter can maintain the constant voltage regardless of the input voltage.

• The Transactions of the Korean Institute of Power Electronics
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• v.9 no.4
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• pp.334-340
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• 2004

In this paper, an efficient switching pattern to equalize the size of transformer is proposed for a multi-level inverter employing cascaded transformers. It is based on the prior selected harmonic elimination PWM(SHEPWM) method. Because the maximum magnetic flux imposed on each transformer becomes exactly equal each to each, all transformers can be designed with the same size regardless of their position. Therefore, identical full-bridge inverter units can be utilized, thus improving modularity and manufacturability. The fundamental idea of the proposed switching pattern is illustrated and then analyzed theoretically. The validity of the proposed switching strategy is verified by experimental results.

• Proceedings of the KIPE Conference
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• 2001.10a
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• pp.668-672
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• 2001

The utility interactive sinewave modulated inverter for the solar photovoltaic (PV) power conversion and conditioning with a new high frequency pulse modulated link is presented for domestic residential applications. As compared with the conventional full-bridge hard switching PWM inverter with a high frequency AC link, the simplest single-ended quasi-resonant soft switching sinewave modulated inverter with a duty cycle pulse control is implemented, resulting in size and weight reduction and low-cost. This paper presents a prototype circuit of the single-ended zero voltage soft switching sinewave inverter for solar power conditioner and its operating principle. In addition, this paper proposes a control system to deliver high quality output current. Major design of each component and the power loss analysis under actual power processing is also discussed from an experimental point of view. A newly developed interactive sinewave power processor which has $92.5\%$ efficiencty at 4kW output is demonstrated. It is designed 540mm-300mm-125mm in size, and 20kg in weight.

• Proceedings of the KIEE Conference
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• 1991.07a
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• pp.611-614
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• 1991

In variable speed driving system of three phase induction motor controlled by an inverter, because of the switching of semiconductor devices in inverter, an appreciable amount of harmonic components of voltage waveform can cause the motor to generate losses, torque ripple, acoustic noise and oscillation of semiconductor devices. In this paper a new PAM type PWM inverter using IGBT is described. The output waveforms in the proposed PAM type PWM inverter are investigated both theoretiically and experimentally. The line-voltage waveform is composed of fundamental component and the sidebands of carrier frequency. The lower order harmonics are not included in the output wave form. As each inverter arm does not operate during two-thirds period, the heats, generated in the devices are reduced. That is, the size of the inverter system can he minimized because of the reduction in the heat dissipating equipment.

• The Transactions of the Korean Institute of Power Electronics
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• v.19 no.5
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• pp.391-398
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• 2014

This paper presents a resonant step-down DC/DC converter to reduce the voltage stresses of a 3-phase inverter module under the three-phase AC utility line condition. Under this condition, a conventional 3-phase inverter module suffers from high voltage stresses as a result of the high rectified DC link voltage; hence, a high-cost high-voltage-rating inverter module must be used. However, using the proposed converter, a low-cost low-voltage-rating inverter module may be adopted to drive the motor even under the 3-phase AC line condition. The proposed converter, which can be realized with small size inductor and low-voltage-rating semiconductor devices, operates at a high-efficiency mode because of the zero-current switching operations of all the semiconductor devices. The operational principles are explained and a design example is provided in the study. Experimental results demonstrate the validity of the proposed converter.