• The Journal of the Korea institute of electronic communication sciences
• /
• v.17 no.5
• /
• pp.859-866
• /
• 2022

Active disturbance rejection control is a method in which the disturbance is removed from the controller by estimating the state variable using the Luenberger observer. The Luenberger observer is estimated by defining a nonlinear term including disturbance with constant characteristics in a steady state as a state variable. It can be shown that the speed tracking performance is improved by compensating the estimated state variable to the PI controller and the IP controller. The disturbance removal performance of the tracking control can be confirmed by observing that the estimated state error is within 1.9 [%] in the case of load fluctuation and the steady-state state tracking error converges to zero.

• Proceedings of the KIEE Conference
• /
• 2002.07b
• /
• pp.1313-1315
• /
• 2002

This paper proposes an inverter for the grid-connected photovoltaic system based on the transformer-less inverter. This system consists of a high frequency inverter bridge, high frequency transformer, diode bridge rectifiers, a DC filter, a low frequency inverter bridge, and an AD filter. The high frequency inverter bridge switching at 20kHz is used to generate bipolar PWM pulse, which is subsequently rectified by diode bridge rectifiers to result in a full-wave rectified sine wave. Finally, it is unfolded by a low frequency inverter bridge to result in a 60Hz sine wave power output. In this paper, the control algorithm for synchronous current feedback control method and a maximum power point tracking (MPPT) method using DSP are described. And, the simulation and experimental results are shown to verify the validity of the proposed system.

• Journal of Power Electronics
• /
• v.12 no.1
• /
• pp.136-144
• /
• 2012

In this paper, the different techniques for the field weakening, also known as constant power speed range (CPSR) operation, for permanent magnet synchronous motor (PMSM) will be introduced and analysed. Field weakening of PMSM, can be done using either vector control (VC) or conventional phase in advance (CPA). Implementation of these techniques depending on some features and constrains. Most of these features and constrains came from the motor parameters. One of these constrains is the motor inductance which determining whether the motor can be driven in the CPSR or not. A new approach for the field weakening will be discussed and to be verified to overcome this constrain. The new approach will be verified through both techniques VC and CPA.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.63 no.4
• /
• pp.484-489
• /
• 2014

Three phase PWM(Pulse Width Modulation) converter of the small-scale wind power system is able to charge battery under the rated wind speed regions. However, it is impossible to control output power of converter at the over win speed region because back-EMF(Electro Motive Force) of PMSG(Permanent Magnet Synchronous Generator) is higher than the battery terminal voltage of PMSG is reduced. However, the cut-off wind speed exists although battery charging algorithm is implemented by flux weakening control method. Therefore, this paper performs analysis of other factors which affects limitation wind speed. The validity of the analysis are verified through simulation.

• International Journal of Control, Automation, and Systems
• /
• v.4 no.2
• /
• pp.165-171
• /
• 2006

This paper proposes a data fusion algorithm of nonlinear multi sensor dynamic systems of synchronous sampling based on filtering step by step. Firstly, the object state variable at the next time index can be predicted by the previous global information with the systems, then the predicted estimation can be updated in turn by use of the extended Kalman filter when all of the observations aiming at the target state variable arrive. Finally a fusion estimation of the object state variable is obtained based on the system global information. Synchronously, we formulate the new algorithm and compare its performances with those of the traditional nonlinear centralized and distributed data fusion algorithms by the indexes that include the computational complexity, data communicational burden, time delay and estimation accuracy, etc.. These compared results indicate that the performance from the new algorithm is superior to the performances from the two traditional nonlinear data fusion algorithms.

• Proceedings of the IEEK Conference
• /
• 2000.06b
• /
• pp.221-225
• /
• 2000

We designed asynchronous event logic library with 0.25$\mu\textrm{m}$ CMOS technology and interface chip for heterogeneous system with high-speed asynchronous FIFO operating at 1.6㎓. Optimized asynchronous standard cell layouts and Verilog models are designed for top-down design methodology. A method for mitigating a design bottleneck when it comes to tolerate clock skew is described. This communication scheme using clock control circuits, which is used for the free of synchronization failures, is analyzed and implemented. With clock control circuit and FIFO, high-speed communication between synchronous modules operating at different clock frequencies or with asynchronous modules is performed. The core size of implemented high-speed 32bit-interface chip for heterogeneous system is about 1.1mm ${\times}$ 1.1mm.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
• /
• 2007.11a
• /
• pp.319-322
• /
• 2007

In the development of paralleling techniques, Multi-Phase Interleaved(MPI) converter constitutes one of the most promising alternatives reported in the last years. This technique consists of a phase shifting of the control signals of several cells in parallel operating at the same switching frequency. As a result, the aggregated input and output current waveform exhibit lower ripple amplitude and smaller harmonics content than in synchronous or stochastic operation modes. Based on the inherent advantages of the MPI converter, in this paper, a control scheme, which can reduce current and voltage rifle, is proposed for PEMFC generation systems. The MPI boost converter is composed of several identical boost converters connected in parallel.

• Proceedings of the KIEE Conference
• /
• 2006.04b
• /
• pp.229-231
• /
• 2006

The paper presents a sensorless speed control of interior permanent magnet synchronous motors using an adaptive integral binary observer in view of composition with a main loop regulator and an auxiliary loop regulator. The binary observer has a property of the chattering alleviation in the constant boundary layer; however, the steady state estimation accuracy and robustness are dependent upon with width of the constant boundary. In order to improve the steady state performance of the binary observer, the binary observer is formed by adding extra integral dynamic to the switching hyperplane equation.

• Proceedings of the KIEE Conference
• /
• 2008.04c
• /
• pp.122-124
• /
• 2008

Interior permanent magnet synchronous motor(IPMSM) has become a popular choice in electric vehicle applications, due to their excellent power to weight ratio. In order to maximize the efficiency in such applications, this paper proposes the Adaptive-FNIS(Fuzzy Neural Network Inference System). The controllable electrical loss which consists of the copper loss and the iron loss can be minimized by the optimal d-axis current $i_d$. This paper considers the parameter variation about the motor operation. The operating characteristics controlled by efficiency optimization control are examined in detail.

• Proceedings of the KIEE Conference
• /
• 1997.07f
• /
• pp.2088-2090
• /
• 1997

This paper consists of the speed sensorless vector control of induction motors with the estimation of rotor resistance. In the application of variable-speed induction motor drives, if an inaccurate rotor resistance is used because the rotor resistance can change due to skin effects and temperature variables, it is difficult to achieve a collect field orientation. In this paper, to overcome these difficulties adaptive algorithm is designed for rotor resistance identification. The proposed adaptive algorithm for rotor resistance estimation in the synchronous reference frame is applied by sliding mode current controller satisfing persistent excitation(PE) condition. Adaptive flux observer is here used for the purpose of estimating rotor flux and speed in the speed sensorless scheme. Computer simulations are carried out to verify the validity of the proposed algorithm.