• Proceedings of the KIPE Conference
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• 2000.07a
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• pp.645-650
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• 2000

this paper deals with HVDC Light(High Voltage Direct Current) system using space vector PWM(SVPWM) method. Because the system of this paper has d-q control scheme for HVDC Light system. HVDC Light system represented in this paper is capable of controlling active and reactive power independently. For this system. V-I curve and control methods are proposed. Also this paper describes the design of a digital system for applications in power converters such as those that would be used in the next generation of HVDC system. Finally HVDC system is implemented using DSP TMS320C31

• Proceedings of the KIPE Conference
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• 2000.07a
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• pp.282-285
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• 2000

A new current controller implemented in a-b-c frame for AC-DC converter is proposed. The proposed MTPWM(Modified Trapezoidal PWM) Which is quite suitable for three phase AC-DC converter. It is known that MTPWM has good harmonics characteristics for high modulation index. It is very simple and requires no transformation in it. The results of computer simulation are shown for the validity of proosal.

• Proceedings of the KIPE Conference
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• 2001.07a
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• pp.155-158
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• 2001

In this paper, the Load Current Observer Design for 3-phase Voltage Type PWM Converter with DC Meter Load. The sinusoidal input current and unity input power factor are realised based on the estimated source voltage performed by the Load Current Observer using actual currents and DC link voltage.

• Journal of Advanced Marine Engineering and Technology
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• v.36 no.6
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• pp.844-849
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• 2012

In this paper, a bidirectional Zeta-Flyback converter is proposed. The topology of the proposed converter is analyzed, which is superposition of bidirectional Flyback converter mode and bidirectional Zeta converter mode in a cycle. The proposed converter allows power flow in either a forward direction or a backward direction. Bidirectional power flow is obtained by a transformer and components. The proposed converter's output is controlled by duty of constant frequency PWM of switch. Compared to conventional bidirectional isolated DC-DC converters, the proposed isolated bidirectional DC-DC converter has high power density and high transformer utilization. To confirm the proposed converter, the simulation and experimental results are presented.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.3 no.3
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• pp.651-659
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• 1999

This Paper Proposes new speed and electromagnetic torque control of an induction motor, which is robust against time varying parameters. The control is based on adaptive vector control with serial block adaptive algorithm. Motor parameters used to estimates slip frequency and electromagnetic torque. Parameters mismatch in the control system detrimentally affects slip frequency estimation and torque response. In order to compensate lot degradation of the responses, an adaptive identifier for the magnetizing inductance and the secondary time constant is introduced. adaptive vector control system consisted of two subsystems, a vector control system realized on synchronous frame and a parameter identification system on stationary frame. the effectiveness of the proposed method was verified by some digital simulations.

• The Transactions of the Korean Institute of Power Electronics
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• v.25 no.4
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• pp.293-302
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• 2020

This study proposes a triple-loop current control method for the auxiliary power unit of fuel cell trains. The auxiliary power unit of fuel cell trains has a grid-connected function when power is supplied to the utility grid. Moreover, the auxiliary power unit of trains has a 1500 V DC link voltage; thus, PWM frequency cannot be increased to a high frequency. Owing to this low PWM frequency condition, creating a triple-loop design is difficult. In this study, a triple-loop controller is developed for a capacitor voltage controller in standalone mode that operates as an auxiliary power supply for trains and for a grid current controller in grid control mode with an inner capacitor voltage controller. The voltage controller employs an inductor current controller inner loop. To overcome low PWM frequency, a design method for the bandwidth of the capacitor voltage controller considering the bandwidth of the inner inductor current controller is described. The effectiveness of the proposed method is proven using PSIM simulation.

• Proceedings of the KIEE Conference
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• 2003.04a
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• pp.176-178
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• 2003

This paper presents a new velocity estimation strategy of a non-salient permanent magnet synchronous motor(PMSM) drive without high frequency signal injection or special PWM pattern. This approach is based on the d-axis current regulator output voltage of the drive system which has the information of rotor position error. The rotor velocity can be estimated through a rotor position tracking PI controller that controls the position error to aero. For zero and low speed operation, the PI gains of rotor position tracking controller have a variable structure. The PI tuning formulas are derived by analyzing this control system using the frequency domain specifications such as phase margin and bandwidth assignment.

• Journal of the Korean Society of Safety
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• v.14 no.4
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• pp.108-113
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• 1999

This paper presents a study on fuzzy speed and flux controller used in a vector control of a CRPWM(Current Ragulated PWM) induction motor drive. In this paper, an approach for an easier design of the fuzzy controller is presented in order to obtain the desired value for the response time with minimal overshoot and to improve the steady state performance for speed step commands. The fuzzy controller is constructed only upon the knowledge of the motor behaviour and the desired speed response, and provides fast and robust control by reducing the effects of nonlinearities, parameter changes and load disturbance. The results of applying the fuzzy logic controller to an IM drive system are compared with those obtained by application of a conventional PI controller. The fuzzy controller provided a better response than the PI controller.

• Proceedings of the KIPE Conference
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• 2007.11a
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• pp.145-147
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• 2007

This paper presents an implementation of vector control for SMPMSM using model based controller design in MATLAB/SIMULINK. The model based controller design enables fast development of control system for motor by designing controllers and performing simulation on the GUI (Graphic User Interface) platform, converting program code directly into real-time programs, and then performing tests for the responses from controllers. The controller is designed as PI controller for speed and decoupling PI controller for current. And PWM used space vector modulation method using offset voltage and system stability is also secured by close magnitude overmodulation method, maintaining dynamics of load when it overmodulation. The validity of vector control implemented is verified through simulations and experiments.

• Proceedings of the KIEE Conference
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• 1992.07b
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• pp.1221-1224
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• 1992

To obtain a robustness which is one of important characteristics needed in servo drive, the sliding mode control method is used as a control strategy. However, the undesired phenomenon of chattering is a serious problem. In this paper, an adaptive chattering alleviation algorithm for variable structure system control is proposed to solve this serious problem. Digital controller using the theory of chattering alleviation control is applied to the position control problem of an induction motor system. Comparisons of this algorithm with other variable structure system control algorithms indicate that the chattering can be alleviated. This controller is implemented using IBM-PC(8088 CPU) which controls current controlled PWM inverter consisted of IGBT as a switching device to drive motor.