• Journal of Power Electronics
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• v.13 no.4
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• pp.600-608
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• 2013

This paper analyzes the effect of the admittance component for the digitally controlled single-phase bridgeless power factor correction (PFC) converter. To do this, it is shown how the digital delay effects such as the digital pulse-width modulation (DPWM) and the computation delays restrict the bandwidth of the converter. After that, the admittance effect of the entire digital control system is analyzed when the bridgeless PFC converter which has the limited bandwidth is connected to the grid. From this, the waveform distortion of the input current is explained and the compensation method for the admittance component is suggested to improve the quality of the input current. Both the simulations and the experiments are performed to verify the analyses taken in this paper for the 1 kW bridgeless PFC converter prototype.

• Proceedings of the IEEK Conference
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• 2000.07b
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• pp.596-599
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• 2000

A natural admittance control system design is presented for a particular type of interaction controller that achieve high-performance and guarantees stability. The admittance control Significantly improves performance when Coulomb friction is present in the one link robot system. The technique requires a careful choice of the target impedance. Experimental performance results are presented for a two-mass system with internal Coulomb friction. Results demonstrate that the admittance control law is successful in rejecting internal Coulomb friction force disturbances. The controller was designed and implemented on our system that we set up one link robot system and hardware configuration system, and performance results are presented.

• Journal of information and communication convergence engineering
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• v.21 no.1
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• pp.1-8
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• 2023

This paper presents a design method for a wideband bandpass filter (BPF) which compensates for frequency dependency based on the image admittance and image phase. In the proposed method, new compensation methods for the admittance and phase are integrated with the conventional method. The proposed method improves the frequency shift and reduces the unwanted bandwidth when designing more than 20% of the Fractional Bandwidth (FBW), whereas the conventional method exhibits frequency degradation at only 10% FBW. The proposed design theory was verified by applying it to both lumped elements and distributed lines through circuit simulation and measurements without an optimization process. The measurement results demonstrate improvements in the frequency shift and target bandwidth. In the future, an accurate design method based on frequency dependence can be implemented for the next-generation broadband communication system applications.

• Journal of the Korean Society for Precision Engineering
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• v.31 no.12
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• pp.1141-1146
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• 2014

As life expectancy becomes longer, reduction of human muscular strength threatens quality of human life. Many robotic devices have thus been developed to support and help human daily life. This paper deals with a new type of in-wheel actuator that can be effectively used for the robotic devices. BLDC motor, drive board, brake, ARS (Attribute Reference System), and torque sensor are combined in the single actuator module. The torque sensor is used to recognize human intention and the in-wheel actuator drives walking aids in our system. Its feasibility was tested with the active walking aid device equipped with the in-wheel actuator. Based on it, we designed an admittance filter algorithm to react on uphill and downhill drive. By adjusting mass, damping, and spring parameters in accordance with the ARS output, it provided convenient drive to the old on uphill and downhill walks.