• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.9
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• pp.1706-1713
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• 2009

In this paper, a parallel operation algorithm for high power PEMFC generation systems is proposed. According to increasing the capacity of fuel cell systems with several fuel cell stacks, the different dynamic characteristics of each fuel cell stack effect on imbalance of load sharing and current distribution, so that a robust parallel operation algorithm is desired. Therefore, a power-sharing technique is developed and explained in order to design an optimal distributed PEMFC generation system. In addition, an optimal controller design procedure for the proposed parallel operation algorithm is introduced, along with informative simulations and experimental results.

• JSTS:Journal of Semiconductor Technology and Science
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• v.15 no.4
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• pp.477-483
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• 2015

The k-Winners-Take-All (kWTA) is an operation to find the largest k (>1) inputs among N inputs. Parallel search algorithm of kWTA for digital inputs is not invented yet, so most of digital kWTA architectures have O(N) time complexity. A parallel search algorithm for digital kWTA operation and the circuits for its VLSI implementation are presented in this paper. The proposed kWTA architecture can compare all inputs simultaneously in parallel. The time complexity of the new architecture is O(logN), so that it is scalable to a large number of digital data. The high-speed kWTA operation and its O(logN) dependency of the new architecture are verified by simulations. It takes 290 ns in searching for 5 winners among 1024 of 32 bit data, which is more than thousands of times faster than existing digital kWTA circuits, as well as existing analog kWTA circuits.

• Journal of KIISE:Computer Systems and Theory
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• v.30 no.3_4
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• pp.117-129
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• 2003

In this paper, we propose advanced parallel join algorithm to efficiently process join operation on hypercube systems. This algorithm uses a broadcasting method in processing relation R which is compatible with hypercube structure. Hence, we can present optimized parallel join algorithm for that hypercube structure. The proposed algorithm has a complete solution of two essential problems - load balancing problem and data skew problem - in parallelization of join operation. In order to solve these problems, we made good use of the characteristics of clustering effect in the algorithm. As a result of this, performance is improved on the whole system than existing algorithms. Moreover. new algorithm has an advantage that can implement non-equijoin operation easily which is difficult to be implemented in hash based algorithm. Finally, according to the cost model analysis. this algorithm showed better performance than existing parallel join algorithms.

• 한국신재생에너지학회:학술대회논문집
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• 2008.05a
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• pp.65-68
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• 2008

This paper proposes the parallel operation control algorithm of a power conditioning system (PCS) for a distributed Fuel Cell power generation system. A proposed control algorithm is made good a drawback of the conventional control algorithm. The controller must also supervise the total PCS operation while communicating with the fuel cell system controller. Simulation results are presented to performance of a proposed control algorithm for the PCS.

• Proceedings of the KIPE Conference
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• 2016.07a
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• pp.479-480
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• 2016

This paper introduces a master and slave control algorithm for parallel operation of UPS system. If each module of UPS system control the output voltage and filter inductor current in parallel operation, it occur unbalanced output power each module. To operate UPS system parallel, it need a algorithm that control output power of modules. A master and slave control algorithm is helpful to balance output power of modules by controlling output current. The effect of a master and slave control algorithm is proved by simulations.

• The Transactions of the Korean Institute of Power Electronics
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• v.7 no.5
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• pp.499-508
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• 2002

In this paper, a novel wireless parallel operation algorithm of N+l redundant UPS system with no control interconnections for load-sharing is presented. The proposed control system eliminates the sensing noise and interconnections interference of conventional parallel operation system. To reduce a reactive power deviation in wireless control method, this technique automatically compensates for inverter parameter variation and line impedance imbalances with wireless auto-tuning method. In addition, to increase reliability on transient characteristics of parallel operation, a virtual injected impedance is adopted to eliminate a circulation current among inverter modules. Simulation results are provided in this paper to prove the proposed novel wireless algorithm.

• Proceedings of the KIPE Conference
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• 1996.06a
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• pp.56-59
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• 1996

In this paper, we developed a micro-stepping drive circuit of step motor and proposed software algorithm for parallel operation of step motors drived by micro-stepping circuit. Also, we implemented a parallel operation controller with a 16-bit micro-controller.

• Proceedings of the KIPE Conference
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• 2002.07a
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• pp.734-738
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• 2002

In this paper, a novel wireless parallel operation algorithm of N+1 redundant UPS system with no control interconnections is presented. The load sharing of multiple UPS modules are controlled by Q-V droop and $P-\delta$ droop algorithm. This algorithm compensates for inverter parameter variation and line impedance imbalances with wireless auto-tuning method. And to increase the reliability of transient characteristic under parallel operation, a virtual injected Impedance is proposed to decrease a circulation current between inverter modules. Simulation results are provided to prove the novel wireless algorithm.

• Proceedings of the KIPE Conference
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• 2008.06a
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• pp.24-27
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• 2008

For high voltage DC-DC converters, the parallel operation of several high voltage source modules is necessary to reduce the material cost. In the conventional parallel operation with HDC module control unit, it is difficult to repair the HDC system for the failure of control unit. To overcome these problems, new parallel operating algorithm for high voltage DC-DC converter is presented. The proposed algorithm has no main control unit and each module can be selected as the master according to the operating conditions. Therefore, one of modules can be replaced as the master immediately when the previous master module is failed. In addition, the extension of extra modules can be simple.

• Transactions of the Korean Society of Automotive Engineers
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• v.9 no.5
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• pp.122-130
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• 2001

In this paper, an operational algorithm for a 2-shaft parallel hybrid electric vehicle is suggested for the minimization of operation cost. The operation cost is obtained as a summation of the engine fuel cost and the motor electricity cost. The electrical cost function is estimated in case of motoring, and generating when the recuperation is carried out during the braking. In addition, weight function is introduced in order to maintain the battery state of charge. Based on the operation algorithm, the optimal engine operation point that minimizes the operation cost is obtained with respect to the required vehicle power for every state of charge of battery. The optimal operation point provides the optimal power distribution of the engine and the motor for a required vehicle power Simulation was performed and the fuel economy of the hybrid vehicle was compared to that of the conventional vehicle. Simulation results showed that hybrid vehicle's fuel economy can be improved as much as 45∼48% compared to the conventional vehicle's.