• The Transactions of the Korean Institute of Electrical Engineers B
• /
• v.49 no.9
• /
• pp.598-606
• /
• 2000

This paper proposes a new snubber circuit for 4-level inverter and converter. The snubber circuit makes use of Undeland snubber and McMurray efficient snubber as basic snubber unit and can be regarded as a generalized combined Undeland and McMurray efficient snubber. The proposed snubber keeps such good features as fewer number of components improved efficiency due to low snubber loss capability of clamping overvoltage across main switching devices and no unbalance problem of blocking voltage. Furthermore the proposed concept of constructing a snubber circuit for 4-level inverter and converter can apply to any level of converterand inverter.

• The Transactions of the Korean Institute of Power Electronics
• /
• v.11 no.6
• /
• pp.489-493
• /
• 2006

The aim of the paper is to design the PLS(Plasma Lighting System) driving inverter circuit with optimal efficiency. In general, it is known that the PLS driven by a pulse has a higher light-conversion efficiency. There are the Class-E type resonant inverter and the semi-bridge inverter as a circuit which can make a pulse with low duty ratio. In this paper, we analyze the losses of the above two circuits. To verify the loss analysis, the inverter circuit with 220V 380W input consumption is manufactured and tested. Throughout the experimental results, the high efficiency PLS system has confirmed.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.67 no.12
• /
• pp.1611-1618
• /
• 2018

This paper proposes a new auxiliary resonant commutated pole (ARCP) inverter which has a modified auxiliary circuit. The proposed auxiliary circuit includes two auxiliary IGBT switches, an LC resonant circuit, and two clamping diodes. In order to analyze the performance of proposed ARCP inverter, computer simulations with PSCAD, and hardware experiments were carried out. Through analyzing the experimental results, it is known that the proposed ARCP inverter offers efficiency improvement of 1.5% compared with the hard-switching inverter.

• 제어로봇시스템학회:학술대회논문집
• /
• 1996.10a
• /
• pp.255-258
• /
• 1996

This paper describes a DC voltage controller for the DC power supply which is constructed using the full-bridged MOS-FET DC-to-RF power inverter and rectifier. The full-bridged MOS-FET DC-to-RF inverter consisting of four MOSFET arrays and an output power transformer has a control function which is able to control the RF output power when the widths of the pulse voltages which are fed to four MOS-FET arrays of the fall-bridged inverter are changed using the pulse width control circuit. The power conversion efficiency of the full-bridged MOS-FET DC-to-RF power inverter was approximately 85 % when the duty cycles of the pulse voltages were changed from 30 % to 50 %. The RF output voltage from the full-bridged MOS-FET DC-to-RF inverter is fed to the rectifier circuit through the output transformer. The rectifier circuit consists of GaAs schottky diodes and filters, each of which is made of a coil and capacitors. The power conversion efficiency of the rectifier circuit was over 80 % when the duty cycles of the pulse voltages were changed from 30 % to 50 %. The output voltage of the rectifier circuit was changed from 34.7V to 37.6 V when the duty cycles of the pulse voltages were changed from 30 % to 50 %.

• Journal of Power Electronics
• /
• v.16 no.4
• /
• pp.1504-1512
• /
• 2016

This paper presents a new single-phase asymmetrical cascaded multilevel DC-link inverter. The proposed inverter comprises two stages. The main stage of the inverter consists of multiple similar cells, each of which is a half-bridge inverter consisting of two switches and a single DC source. All cells are connected in a cascaded manner with a fixed neutral point. The DC source values are not made equal to increase the performance of the inverter. The second circuit is a folded cascaded H-bridge circuit operating at a line frequency. One of the main advantages of this proposed topology is that it is a modular type and can thus be extended to high stages without changing the configuration of the main stage circuit. Two control schemes, namely, low switching with selective harmonic elimination and sinusoidal pulse width modulation, are employed to validate the proposed topology. The detailed approach of each control scheme and switching pulses are discussed in detail. A 150W prototype of the proposed system is implemented in the laboratory to verify the validity of the proposed topology.

• The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.9 no.5
• /
• pp.51-56
• /
• 1995

The transistors of single phase 3 level PWM Inverter compose output power transistors and neutral point clamping transistors, which are NPN transistors. Waveforms of driving signals for this are PWM waves for power transistors and period operating waves for neutral point clamping transistors, which signals made W-type modulation from rectangular and sine wave. The output power transistors operate at ON-time complementary and neutral point clamping transistors operate at OFF-time complementary respectively. Therefore, each transistors operate in half period at parallel. Characteristics of this inverter circuit is parallel switching method about series switching method of general inverter. As modulation of 3 level drive signals made from full-wave rectifier of sine wave and rectangular wave, which are level wave about 3 level of complementary transistor inverter. So, this circuit composed complementary operation inverter of NPN transistors only compare with PNP-NPN complementary inverter, which have high power 3 level inverter of complementary operation.

• Proceedings of the KIEE Conference
• /
• 1993.07b
• /
• pp.731-735
• /
• 1993

When induction motor is driven with a load commutated inverter, the output part of the inverter must be capacitive. But, in order to be a good load commutation at the low speed range, very large capacitor or force commutated circuit must be used regarding the capacity of motor. This paper proposed the force commutated circuit for driving the motor in case of the installation of capacitor which can be capable of load commutation at the rating speed. The force commutated circuit is operated by the LC resonant circuit, auxiliary source and SCR, and also composed of the commutation circuit which control the interval of the inverse voltage across the inverter.

• Journal of Power Electronics
• /
• v.2 no.2
• /
• pp.112-123
• /
• 2002

This paper presents a novel prototype of the utility AC power interfaced soft-switching sinewave pulse modulated inverter using the high-frequency flyback for the small scale distributed renewable energy power conditioner. The proposed cricuit with a high-frequency isolation link has a funtion of electrical isolation, which is more cost-effective and reliable for the small-scale distributed renwal energy utilization system from a safety point of riew. The discontinuous conduction mode(DCM) operation of the high-frequency flyback transformer is adopted to establish a simple and low-cost circuit configuration and control scheme. For the simplicity, the circuit operating principle is described on the basis of the modified conventional full bridge inverter, whitch is the typical conventional high-frequency full-bridge inverter employing the high requency flyback transformer to eanble the effictive function of the electrical isolation. Than, the new circuit topology of the unility-interfaced soft-switching sinewave pulse modulated inverter using IGBTs is proposed. The proposed cricuit topology is additionally composed of the auxiliary power regenerating snubber cricuits, which are also mathematically analyzed for the parameter desigen settings. Finally, the performance of the propose inverter is evaluated on the basis of computer-aid simulation. It is noted that the sinewave pulse modulated output current of the inverter is synchronous to the AC main voltage.

• Proceedings of the KIPE Conference
• /
• 1998.11a
• /
• pp.9-12
• /
• 1998

In this paper, the power factor correction circuit using a parallel drive method is proposed so that the high power inverter air-conditioner with 3[ph] compressor motor may obtain the cost down and the improved performance. The adequate design procedures are presented to reduce the material costs by eliminating the power factor improving LC filter and derating output capacitor and inverter switches. Using the determined components, the prototype circuit with 6[kW] power consumption is built and tested to verify the operation of the proposed circuit.

• Proceedings of the KIPE Conference
• /
• 1997.07a
• /
• pp.261-265
• /
• 1997

Driving the electrodeless fluorescent lamp, the high ac voltage with high frequency is required. The linear power amplifier has been widely used as a driving circuit of electrodeless fluorescent lamp. However, the low efficiency of the power amplifier causes th driving circuit to be replaced by a PWM switching inverter. In order to use a PWM switching inverter as the driving circuit of an electrodeless fluorescent lamp, the high switching frequency is required. But due to the switching loss at switches of the inverter, the limitation of high switching frequency appears in the inverter. One solution to this limitation is to reduce the switching loss by using the zero voltage switching technique. In this paper, zero voltage switching resonant inverter for driving an electrodeless fluorescent lamp is discussed. The results of analysis about the inverter are presented and the equations for design are established. And the validity of the analyzed results are verified through the experiment.