• Journal of Power Electronics
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• v.17 no.6
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• pp.1535-1544
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• 2017

Advances in FPGA technology have enabled fast real-time simulation of power converters, filters and loads. FPGA based HIL (Hardware-In-the-Loop) simulators have revolutionized control hardware and software development for power electronics. Common time step sizes in the order of 100ns are sufficient for simulating switching frequency current and voltage ripples. In order to keep the time step as small as possible, ideal switching function models are often used to simulate the phase legs. This often produces inferior results when simulating the discontinuous conduction mode (DCM) and disabled operational states. Therefore, the corresponding measurement and protection units cannot be tested properly. This paper describes a new solution for this problem utilizing a discrete-time PI controller. The PI controller simulates the proper DC and low frequency AC components of the phase leg voltage during disabled operation. It also retains the advantage of fast real-time execution of switch-based models when an accurate simulation of high frequency junction capacitor oscillations is not necessary.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2016.10a
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• pp.219-220
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• 2016

A power management system (PMS) has been an important part in a ship integrated control system. To evaluate a PMS for a liquefied natural gas carrier (LNGC), this research proposes a real-time hardware-in-the-loop simulation (HILS), which is composed of major component models such as turbine generator, diesel generator, governor, circuit breaker, and 3-phase loads on MATLAB/Simulink. In addition, FPGA based control console and main switchboard (MSBD) are constructed in order to develop an efficient control and a similar real environment in an LNGC PMS. A comparative study on the performance evaluation of PMS functions is conducted using two test cases for sharing electric power to consumers in an LNGC. The result shows that the proposed system has a high verification capability for the operating function and failure insertion evaluation as a PMS simulator.

• Journal of KIISE:Computer Systems and Theory
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• v.31 no.7
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• pp.402-413
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• 2004

This paper presents an Implementation of Korean standard 128-bit block cipher SEED for the small (8 or 16-bits) embedded system using a low-cost FPGA(Field Programmable Gate Array) chip. Due to their limited computing and storage capacities most of the 8-bits/16-bits small embedded systems require a separate and dedicated cryptography processor for data encryption and decryption process which require relatively heavy computation job. So, in order to integrate the SEED with other logic circuit block in a single chip we need to invent a design which minimizes the area demand while maintaining the proper performance. But, the straight-forward mapping of the SEED specification into hardware design results in exceedingly large circuit area for a low-cost FPGA capacity. Therefore, in this paper we present a design which maximize the resource sharing and utilizing the modern FPGA features to reduce the area demand resulting in the successful implementation of the SEED plus interface logic with single low-cost FPGA. We achieved 66% area accupation by our SEED design for the XC2S100 (a Spartan-II series FPGA from Xilinx) and data throughput more than 66Mbps. This Performance is sufficient for the small scale embedded system while achieving tight area requirement.

• Journal of IKEEE
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• v.23 no.4
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• pp.1321-1327
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• 2019

This paper describes an efficient hardware implementation of modular square root (MSQR) computation over GF(p), which is the operation needed to map plaintext messages to points on elliptic curves for elliptic curve (EC)-ElGamal public-key encryption. Our method supports five sizes of elliptic curves over GF(p) defined by the National Institute of Standards and Technology (NIST) standard. For the Koblitz curves and the pseudorandom curves with 192-bit, 256-bit, 384-bit and 521-bit, the Euler's Criterion based on the characteristic of the modulo values was applied. For the elliptic curves with 224-bit, the Tonelli-Shanks algorithm was simplified and applied to compute MSQR. The proposed method was implemented using the finite field arithmetic circuit with 32-bit datapath and memory block of elliptic curve cryptography (ECC) processor, and its hardware operation was verified by implementing it on the Virtex-5 field programmable gate array (FPGA) device. When the implemented circuit operates with a 50 MHz clock, the computation of MSQR takes about 18 ms for 224-bit pseudorandom curves and about 4 ms for 256-bit Koblitz curves.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.4B
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• pp.298-305
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• 2003

In this paper, we proposed a high performance lookup controller for IP packet forwarding engine of ATM based label edge routers. The lookup controller is designed to provide services such as MPLS, VPN, ELL, and RT services as well as the best effort. For high speed searching for IP addresses, we employed a TCAM based hardware search device not using traditional algorithmic approaches. We also implement lookup control functions into FPGA for fast processing of packet header and lookup control. The proposed lookup controller is designed to support differenciated services for users and to process in pipelined mechanism for performance improvement. A two-step search scheme is also applied to perform lookup for the key combined with multi-field of packet header. We found that the proposed lookup controller provides the performance of about 16M packets per second through simulations.

• ETRI Journal
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• v.27 no.5
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• pp.525-532
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• 2005

In this paper, we propose and present implementation results of a high-speed turbo decoding algorithm. The latency caused by (de)interleaving and iterative decoding in a conventional maximum a posteriori turbo decoder can be dramatically reduced with the proposed design. The source of the latency reduction is from the combination of the radix-4, center to top, parallel decoding, and early-stop algorithms. This reduced latency enables the use of the turbo decoder as a forward error correction scheme in real-time wireless communication services. The proposed scheme results in a slight degradation in bit error rate performance for large block sizes because the effective interleaver size in a radix-4 implementation is reduced to half, relative to the conventional method. To prove the latency reduction, we implemented the proposed scheme on a field-programmable gate array and compared its decoding speed with that of a conventional decoder. The results show an improvement of at least five fold for a single iteration of turbo decoding.

• Proceedings of the KSR Conference
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• 2011.05a
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• pp.1195-1201
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• 2011

Since the release of safety standard IEC 61508 which defines functional safety of electronic safety-related systems, SIL(Safety Integrity Level) certification for railway systems has gained lots of attention lately. In this paper, we propose a new design technique of the computer board for train control systems with high reliability and safety. The board is designed with TMR(Triple Modular Redundancy) using a certified SIL3 Texas Instrument(TI)'s TMS570 MCU(Micro-Controller Unit) to guarantee safety and reliability. TMR for the control device is implemented on FPGA(Field Programmable Gate Array) which integrates a comparator, a CAN(Controller Area Network) communication module, built-in self-error checking, error discriminant function to improve the reliability of the board. Even if a malfunction of a processing module occurs, the safety control function based on the proposed technique lets the system operate properly by detecting and masking the malfunction. An RTOS (Real Time Operation System) called FreeRTOS is ported on the board so that reliable and stable operation and convenient software development can be provided.

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.14 no.2
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• pp.136-144
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• 2014

The existing conventional motion controller does not perform well in the presence of nonlinear properties, uncertain factors, and servo lag phenomena of industrial actuators. Hence, a feasible and effective fuzzy self-tuning proportional integral derivative (PID) and feed-forward control scheme is introduced to overcome these problems. In this design, a fuzzy tuner is used to tune the PID parameters resulting in the rejection of the disturbance, which achieves better performance. Then, both velocity and acceleration feed-forward units are added to considerably reduce the tracking error due to servo lag. To verify the capability and effectiveness of the proposed control scheme, the hardware configuration includes digital signal processing (DSP) which plays the main role, dual-port RAM (DPRAM) to guarantee rapid and reliable communication with the host, field-programmable gate array (FPGA) to handle the task of the address decoder and receive the feed-back encoder signal, and several peripheral logic circuits. The results from the experiments show that the proposed motion controller has a smooth profile, with high tracking precision and real-time performance, which are applicable in various manufacturing fields.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2014.06a
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• pp.243-245
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• 2014

본 논문에서는 OFDM(Orthogonal Frequency Division Multiplexing)시스템에서 OFDM 심벌 타이밍 옵셋에 따른 4096QAM 의 uncoded-BER(Bit Error Rate) 및 성상도를 측정하였다. uncoded-BER 은 수신기의 FEC(Forward Error Correction) 복호기 이전에서 측정된 BER 을 의미한다. 측정을 위해, OFDM 을 사용하는 DVB-C2(Digital Video Broadcasting for Cable Systems 2) 송수신기를 FPGA(Field Programmable Gate Array)를 이용하여 구현하였으며, OFDM 심벌의 CP(Cyclic Prefix)를 이용하여 OFDM 심벌 동기를 수행하였다. 일반적으로, OFDM 심벌 동기는 OFDM 심벌에서 CP 가 반복된다는 특성을 이용한 상관기를 사용한다. 또한, ISI(Inter Symbol Interference) 및 ICI(Inter Channel Interference)를 최소화하기 위해, 채널의 최대 지연시간을 고려하여 CP 내에서 OFDM 심벌 동기가 획득된다. 이럴 경우 수신기에서는 각 부반송파에 할당된 QAM 심벌들의 위상 회전이 발생하지만, 등화기에서 이러한 위상 회전이 보상된다. 부반송파에 할당된 파일롯 심벌들을 이용하여 채널 추정 및 보상을 하는 등화기에서, 파일롯 심볼들도 OFDM 심벌 타이밍 옵셋에 의해 위상회전이 발생하기 때문에 채널 추정 값에 영향을 미친다. 따라서, 본 논문에서는 4096QAM 과 ZF-LE(Zero Forcing Linear Equalizer)를 사용한 경우, OFDM 심벌 타이밍 옵셋에 따른 uncoded-BER 및 성상도의 측정 결과를 제시하였다.

• Proceedings of the Korean Information Science Society Conference
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• 2006.10c
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• pp.575-580
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• 2006

인터넷 네트워크에 존재하는 방화벽(Firewall) 또는 라우터(Router) 장비에서의 패킷 필터 기능은 모든 방화벽 장비의 기본적인 기능이 될 수 있다. 하지만 최근에 등장한 세션기반의 악의적 침입과 바이러스의 출현으로 패킷 필터기는 단순한 정적 패킷 필터 기능이 아닌 상태기반 패킷 필터의 동적 패킷 필터 기능을 요구하게 되었다. 또한 최근에 인터넷 속도가 급증하는 환경변화에 맞추어 방화벽 장비의 TCP 패킷 처리기능은 매우 빠른 처리속도를 요구하고 있다. 이에 우리는 매우 빠른 고속의 TCP 상태기반 패킷 필터 처리를 요구하는 에지(Edge)급 라우터의 방화벽 옵션카드를 만들기 위해 하드웨어 기반의 TCAM(Ternary CAM) 관리를 이용한 TCP 세션 상태기반 (Stateful) 패킷 필터기를 구현하였으며, TCAM 제어와 패킷의 상태기반 검사 등 모든 기능처리는 FPGA(Field Programmable Gate Array)를 이용한 하드웨어 로직(Logic) 및 상태기(State Machine)로 구현하였다. 그리고 본 논문의 구현방식을 적용한 방화벽 옵션카드는 인-라인(In-line) 모드로 구성될 경우 1GHz 이상의 Wire Speed를 만족하는 처리성능을 보여주었다.