• Proceedings of the KIEE Conference
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• 1991.11a
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• pp.164-166
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• 1991

This paper achieved by Pulse-Withed Modulation of the inverter switchs. But Conventional PWM inverter is employed hard switching by means a switching device. Moreover, this paper presents resonant DC link Voltage type inverter thet it was not necessary snubber circuit and dead time and modeling of motor drive control system and simulating analysis are discussed.

• Proceedings of the KIEE Conference
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• 1991.07a
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• pp.627-630
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• 1991

This study is about vector controlled inverter for high quality elevator drive that is to improve the settling accuracy of elevator car and passenger's comfort in commercial buildings. In this study, an instantaneous space vector control type inverter was used to reduce the torque ripple ant to improve the velocity follow-up. This method calculates Instantaneous actual output torque and flux of induction motor by voltage and current, then compares them with a reference values by a speed regulator. The outputs of comparators select a switching mode, for an optimal voltage vector. Also, this study used IGBT (Insulated Gate Bipolar-Transistor), a high speed switching element, to reduce sound noise level, and DSP (Digital Signal Processor) was used to improve the reliability of the control circuit by fully digitalization.

• Journal of international Conference on Electrical Machines and Systems
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• v.1 no.2
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• pp.105-110
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• 2012

This paper designs the high-efficiency and the low-cost drive system of the smallsize electric vehicles (EVs). The power circuit for driving the dc motor is designed by considering both the cost and efficiency. In order to reduce the conduction loss of MOTFET and diode for controlling an armature voltage, some MOSFETs and diodes at the armature are in parallel connection. An operating sequence for both the field current and the armature voltage according to the accelerator pedal angle is suggested for changing smoothly the rotating direction of dc motor. Through the simulation studies, the performances of the proposed methods are verified.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.980-981
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• 2008

Mechanical spring and hydraulic pressure operated mechanisms are applied in most of today's High Voltage Gas Insulated Switchgear(GIS)s. This paper proposes a new type of operation mechanism for GIS circuit breakers rated at 245kV and 40kA. The Motor-Direct-Drive-Mechanism (MDDM) has many advantages compared to conventional operating mechanisms. It has a very simple structure with only one moving part, low mechanical stress and audible noise. It also allows monitoring, operation speed control and self-diagnosis functions.

• Journal of the Korean Society of Industry Convergence
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• v.2 no.2
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• pp.103-108
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• 1999

The paper describes a implementation of space vector pulse-width modulation voltage source inverter and interfacing of DSP using field programmable gate array(FPGA) for a induction motor vector control system. The implemented chip is included logic circuits for SVPWM, dead time compensation and speed detection using Quick Logic, QLl6X24B. The maximum operating frequency and delay time can be set to 110MHz and 6 nsec. The designed Application Specific Integrated Circuit(ASIC) for SVPWM can be incorporated with a digital signal processing to provide a simple and effective solution for high performance induction motor drives with a voltage source inverter. Simulation and implementation results are shown to verify the usefulness of ASIC in a motor drive system and power electronics applications.

• Proceedings of the KIPE Conference
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• 2007.07a
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• pp.114-116
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• 2007

Mechanical spring and hydraulic pressure operated mechanisms are applied in most of today's High Voltage Gas Insulated Switchgear(GIS)s. This paper proposes a new type of operation mechanism for GIS circuit breakers rated at 245kV and 40kA. The Motor-Direct-Drive-Mechanism (MDDM) has many advantages compared to conventional operating mechanisms. It has a very simple structure with only one moving part, low mechanical stress and audible noise. It also allows monitoring, operation speed control and self-diagnosis functions.

• The Transactions of the Korean Institute of Power Electronics
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• v.21 no.2
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• pp.175-181
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• 2016

In the conventional E-bike, a 42 V/10 A Li-ion battery drives a 24 V/10 A BLDC motor via a 6-switch PWM DC/AC inverter. The major problems of the conventional battery-fed motor drive systems are listed as follows. To charge the battery, an external battery charger (adapter) is required, which degrades the portability of E-bike users. In addition, given the high-frequency operation of the motor drive inverter, the switching losses are significant, which degrades the whole power efficiency. High-voltage batteries (42 V) require a complex battery management system (BMS), which degrades the reliability of the battery pack. In this paper, an embedded boost-converter battery charger for E-bikes is proposed. The variable output boost converter, which converts 16.8 V battery voltage to the required variable voltage of the inverter input, can use a low-voltage battery and thus improve the reliability of batteries. By varying the inverter input voltage via boost converter, a DC link voltage control method can be applied to reduce the switching frequency of the inverter, which improves the whole power efficiency. Given that the function of a flyback charger is integrated in the proposed boost converter, the portability of the E-bike user can be maximized by excluding an external adapter. The validity of the proposed circuit will be confirmed by operation mode analysis and simulation. Moreover, experimental results of integrative charger using Li-ion battery and 200 W motor test will be showed with a prototype sample as well.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2018.10a
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• pp.39-42
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• 2018

In this paper, a low-power MPPT interface circuit for vibration energy harvesting sources is presented. The designed circuit rectifies the harvested ac type energy to the dc type energy required to drive the system, and periodically samples and holds the open circuit voltage (Voc) through the MPPT controller, and transfers the harvested power to the load while maintaining the input voltage at 1/2 of the maximum available power point. All circuits have been designed using a 0.35-um CMOS technology, and the operation has been verified through simulation. Simulation results show that the designed circuit consumes 98nA of current at 3V input voltage and the maximum power efficiency is 99.21%. The designed chip occupies $1.281mm{\times}1.236mm$.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.11 no.6
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• pp.732-741
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• 2018

In order to maximize the usable capacity of a BMS (battery management system) that uses several battery cells connected in series, a cell balancing technique that equips each cell with the same voltage is needed. In the active cell balancing circuit using a multi-winding transformer, a balancing circuit that transfers energy directly to the cell (cell-to-cell) is composed of a PMOS switch and a gate driving chip for driving the NMOS switch. The TLP2748 photocoupler and the TLP2745 photocoupler are required, resulting in increased cost and reduced integration. In this paper, instead of driving PMOS and NMOS switching devices by using photocoupler, we proposed 70V BCD process based PMOS gate driving circuit, NMOS gate driving circuit, PMOS gate driving circuit and NMOS gate driving circuit with improved switching time. ${\Delta}t$ of the PMOS gate drive switch with improved switching time was 8.9 ns and ${\Delta}t$ of the NMOS gate drive switch was 9.9 ns.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.40 no.2
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• pp.162-172
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• 1991

In proportion to the capacity enlargement of the induction motor system controlled by current source inverter, the capacitance of the commutating capacitor is enlarged and then the spike value of output voltage is increased at the moment of charge and discharge. Moreover, the output currnet includes a number of harmonic components. Such voltage spike and harmonics generate the torque ripple and lead to bad effects on the performance of the induction motor. In this study, all the harmonics excluding 17th and 19th harmonics were mostly elimunated by adopting 18-phase Triple High Frequency Current Source Inverter(HFCSI), and the spike component of output voltage was reduced by adding the Voltage Clamping Circuit(VCC). As a result, the torque ripple and the commutation loss were reduced and the performance of the system was improved. Experiments for speed control were carried out in the tripple current source inverter system for induction motor drive. Overall system was controlled by ONE CHIP MICROCOMPUTER(INTEL 8751). Control circuits were simplified and good experimental results in the constant V/F control were obtained due to the flexibility of the microcomputer.