• Proceedings of the KIPE Conference
• /
• 2006.06a
• /
• pp.140-142
• /
• 2006

This paper represents a digital parallel control of a synchronous buck converter using a digital signal processor (DSP). The digital PWM and load sharing controller is implemented in the DSP TMS320F2812 and the experimental results are provided to show the feasibility of the digital synchronous buck regulator.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2003.06a
• /
• pp.330-333
• /
• 2003

In this thesis. the application of the synchronizing control of the intelligent indoor lift system is showed. The separate axes of the indoor lift system are driven independently. PID controller, synchronous flexible logic compensating method and tilt sensor are applied to enhance the performance of the intelligent indoor lift system. the tilt sensor senses the horizontal error of the whole system. PID controller and synchronous flexible logic are used to compensate the synchronous errors of both the separate axes and whole system to be zero. Namely, using not the hardware coupling but the software algorithm. the indoor life system is operated without the error. Before applying the real system, the simulation using matlab testifies the possibility of the lift system. And the realization of the system is demonstrated with two DC servo motors. In the experiment test, flexible logic to compensate the synchronous error is chosen by the comparative method. the indoor lift system has to be considered the loading factor as the disturbance. Because the intelligent indoor lift system is developed to support the patients who don't change for themselves to move. finally, the system which considers the weight of the patient as the disturbance can carry the patients safely without synchronous and position error.

• Journal of Power Electronics
• /
• v.19 no.2
• /
• pp.580-590
• /
• 2019

The concept of virtual synchronous generators (VSGs) is a valuable means for improving the frequency stability of microgrids (MGs). However, a great virtual inertia in a VSG's controller may cause power oscillation, thereby deteriorating system stability. In this study, a small-signal model of an MG with two paralleled VSGs is established, and a control strategy for maintaining a constant inertial time with an increasing active-frequency droop coefficient (m) is proposed on the basis of a root locus analysis. The power oscillation is suppressed by adjusting virtual synchronous reactance, damping coefficient, and load frequency coefficient under the same inertial time constant. In addition, the dynamic load distribution is sensitive to the controller parameters, especially under the parallel operation of VSGs with different capacities. Therefore, an active power increment method is introduced to improve the precision of active power sharing in dynamic response. Simulation and experimental is used to verify the theoretical analysis findings.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.25 no.2
• /
• pp.103-112
• /
• 2011

This paper proposes a new fuzzy speed controller for the precise speed control of a permanent magnet synchronous motor(PMSM). The proposed control system needs the information of the angular acceleration instead of the load torque, so the third-order fuzzy acceleration observer estimates it. Moreover, the LMI conditions are derived for the existence of the fuzzy acceleration observer and fuzzy speed controller, and the gain matrices of the observer and controller are obtained. It is analytically proven that the proposed observer-based fuzzy speed regulator is exponentially stable. To evaluate the performance of the proposed control algorithm, experimental results as well as simulation results are provided under the conditions of motor parameter and load torque variations. Finally, it is clearly confirmed that the proposed control method can accurately control the speed of a PMSM.

• 제어로봇시스템학회:학술대회논문집
• /
• 1990.10b
• /
• pp.913-916
• /
• 1990

In this paper, attempts have been made to control AC synchronous servo motor used as actuators of joints of the FARA robot with high dynamic performance and precise positioning. The AC synchronous servo motors used in FARA robots have resolves as position sensors. Resolver to digital converters are used in order to obtain the information of rotor speed and position from resolver outputs. The proposed joint position control system consists of four speed controller and one position controller. Analog methods are used in the position controller, while digital methods are used in the position controller. For precise position control, PID control algorithm and interpolation functions are executed in two 16 bit microprocessors with sampling rate 2ms. Experimental results show that the proposed joint position control system can be effectively applied to industrial robots in order to obtain high dynamic performance and precise positioning. The proposed joint position control system is being used in the control of FARA robots of Samsung Electronics.

• Proceedings of the KIPE Conference
• /
• 2006.06a
• /
• pp.1-3
• /
• 2006

This paper deals with a novel utilization method of the predicted current in the high performance PI current controller with a control time delay. The inevitable error of the predicted current in the linear servo drive using a permanent magnet linear synchronous motor is analyzed and a modified cross-coupling decoupling synchronous frame PI current controller is proposed in order to improve the current control response under the control time delay. Simulation and experimental results show that the proposed current controller has an improved current control performance under both the electrical uncertainties of a servo drive system and the control time delay.

• Journal of Power Electronics
• /
• v.8 no.4
• /
• pp.317-324
• /
• 2008

This paper proposes a Multiband Shunt Hybrid Active Filter (SHAF) with sensorless control. A plant is modeled in the discrete- time domain and a controller is designed using the Pole shifting law in the polynomial domain. This control approach is very useful for filtering the load harmonics with reduced sensor counts where a low cost solution like SHAF is required. Multiple Synchronous Reference Frames (MSRF) and low pass filters are used to measure the $5^{th}$ and $7^{th}$ harmonic components separately from the load and filter currents. Individual current controllers are designed for the $5^{th}$ and $7^{th}$ harmonic currents. Control is realized in the stationary, three-phase (abc) reference frame. Performance of the controller is validated through simulation, using realistic plant and controller models, as well as experimentally on a full-scale distribution system.

• The Transactions of the Korean Institute of Electrical Engineers B
• /
• v.49 no.3
• /
• pp.195-203
• /
• 2000

In this paper a new controller is proposed to operate the interior permanent magnet synchronous motor(IPMSM) by the control method of the maximum torque per ampere in constant torque region. The implementation method of the conventional torque controller is explained and analyzed exactly. The proposed controller does not use the torque and q-axis current of the speed controller but the amplitude of the stator current in order to utilize not only the magnetic alignment torque but also the reluctance in the constant region, gurantees the linearity of the torque, and is easily implemented. These attractive are verified through the experiment.

• Journal of Electrical Engineering and Technology
• /
• v.13 no.1
• /
• pp.270-279
• /
• 2018

This paper elucidates a hysteresis current controller for enhancing the performance of static synchronous compensator (STATCOM) using cascaded H-bridge multilevel inverter. Due to the rising power demand and growing conventional generation costs a new alternative in renewable energy source is gaining popularity and recognition. A five level single phase cascaded multilevel inverter with two separated dc sources, which is energized by photovoltaic - wind hybrid energy source. The voltages across the each dc source is balanced and standardized by the proposed hysteresis current controller. The performance of STATCOM is analyzed by connecting with grid connected system, under the steady state & dynamic state. To reduce the Total Harmonic Distortion (THD) and to improve the output voltage, closed loop hysteresis current control is achieved using PLL and PI controller. The performance of the proposed system is scrutinized through various simulation results using matlab/simulink and hardware results are also verified with simulation results.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.25 no.8
• /
• pp.48-59
• /
• 2011

This paper presents a new gain scheduling speed controller of permanent magnet synchronous generators(PMSG) for MW-class direct-driven wind turbine systems. The proposed gain scheduling speed controller performs the speed tracking at more than one operating point, and the first-order torque observer estimates the turbine torque which is needed to precisely control the speed of PMSG. The proposed speed controller verifies that the PMSG can successfully follow the reference speed which is determined via the maximum power point tracking(MPPT) control and pitch control under turbulent wind conditions. The proposed speed control algorithm is simulated using Simulink and its performance is confirmed through comparison with the results by PI control method.