• Title/Summary/Keyword: Circuit DQ Transformation

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Modeling of Static Var Compensator with Hybrid Cascade 5-level PWM Inverter Using Circuit DQ Transformation (회로 DQ 변환을 이용한 하이브리드 Cascade 5-레벨 PWM 인버터를 포함하는 무효전력보상기의 모델링)

  • 최남섭
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.6 no.3
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    • pp.421-426
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    • 2002
  • Hybrid cascade multilevel PWM inverter has advantages of hybrid structure which enhances the better utilization of power semiconductor switches, that is, both hi호 power-low frequency switch, GTO and low power-high frequency switch, IGBT can be used in the same circuit. In this paper, a static var compensator using hybrid cascade 5-level PWM inverter is presented for high voltage/high power applications. The proposed system is modelled by circuit DQ transformation, and thus an equivalent circuit is obtained which reveals the important characteristics of the system and lead to the related equations. Finally, circuit structure and characteristics is presented and the validity of the characteristics analysis is shown through PSIM simulation.

Characteristic Analysis of Three Phase PWM Boost AC-AC Converter Using Circuit DQ Transformation (회로 DQ 변환을 이용한 3상 PWM Boost AC-AC 컨버터의 특성해석)

  • 최남섭
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.7 no.7
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    • pp.1514-1519
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    • 2003
  • This paper presents modeling and analysis of static and dynamic characteristics in three phase PWM Boost AC-AC converter used for input voltage sag compensation of custom power. Especially, using circuit DQ transformation technique, an equivalent circuit in fundamental frequency domain is obtained which has all the system characteristics. Moreover, voltage gain and input power factor is analytically induced and linearized state equation at the specific operating point is given. Finally, PSIM simulation results show the validity of the Nosed modelling and analyses.

Modeling and Analysis of Cascade Multilevel PWM Rectifier Using Circuit DQ Transformation

  • Park, Nam-Sup
    • Journal of information and communication convergence engineering
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    • v.1 no.3
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    • pp.163-168
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    • 2003
  • This paper presents a cascade multilevel PWM rectifier without the isolation transformers for energy build-up at each inverter modules. The features and advantages of the proposed PWM rectifier can be summarized as follows; I) It realizes the high power high voltage AC/DC power conversion, 2) It uses no transformer which is bulky and heavy, 3) It has hybrid structure so that switching devices can be effectively utilized, 4) It produces high quality AC current even in high power high voltage applications, 5) The input power factor remains unity by simple modulation index control. The multilevel rectifier is analyzed by using the circuit DQ transformation whereby the characteristics and control equations are obtained. Finally, it will be shown that the system simulation reveals the validity of analyses.

Circuit DQ Modeling and Analysis of Operating Characteristics for Hybrid Cascade Five-level PWM Rectifier (하이브리드 Cascade 5-레벨 PWM 정류기의 회로 DQ모델링 및 동작특성 해석)

  • 최남섭
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.4 no.4
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    • pp.817-824
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    • 2000
  • This paper presents circuit DQ modeling and analysis of operating characteristics of hybrid cascade multilevel PWM rectifier, especially five-level, without isolation transformers. The circuit DQ transformation changes the original three-phase time varying circuit to stationary equivalent one by employing the synchronously rotating transformation matrix. As a result of circuit DQ modeling, the operating characteristics and some useful design relationships for the system are obtained with ease. That is, the analytic equations for DC voltages and active/reactive power supplied by source with respect to control variables are Presented. Moreover, the DC voltages for the multilevel output generation may be directly built up from AC utility source and the important control equation ensuring 5-level output voltage is obtained. Finally, to confirm the validity of the analysis, MATLAB simulations are carried out and the simulation results show good agreements between analytic predictions and the simulated waveforms.

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A Study on AC Machine Modeling using Complex Vector and dq Transformation (복소 벡터와 dq 변환을 이용한 교류기 모델링에 관한 연구)

  • Hong, Sun-Ki;Park, Jin-Ho
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.61 no.11
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    • pp.1601-1605
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    • 2012
  • Three-phase voltage and current is applied to the three-phase alternating current motors which are commonly used in industry. Three phase variables of a, b, c are converted into d, q, 0 axis and the AC machines are modeled and analyzed. Basically the coordinate transformation or d-q transformation is used for convenience, a few steps are needed to analyze the motor performances - separating d and q components, establishing each equivalent circuit, and solving the differential equations of the circuits. In this study, a modeling technique of induction motor using complex vector is proposed and it can explain the induction motor physically. This method does not need the separating process of d and q components. With this technique, the model becomes simple, is easy to understand in physical, and can get the same results with those from the other models. These simulation results of the proposed model are compared with them for the conformation of the proposed method.

DQ Synchronous Reference Frame Model of a Series-Parallel Tuned Inductive Power Transfer System (직렬-병렬 공진 무선전력전송 시스템의 동기 좌표계 모델)

  • Noh, Eun-Chong;Lee, Sang-Min;Lee, Seung-Hwan
    • The Transactions of the Korean Institute of Power Electronics
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    • v.25 no.6
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    • pp.477-483
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    • 2020
  • This study proposes a DQ synchronous reference frame model of a series-parallel tuned inductive power transfer (SP-IPT) system. The wireless power transmission system experiences control difficulty because the transmitter-side controller cannot directly measure the receiver-side load voltages and currents. Therefore, a control-oriented circuit model that shows the dynamics of the IPT system is required to achieve a well-behaved controller. In this study, an equivalent circuit model of the SP-IPT system in a synchronously rotating reference frame is proposed using the single-phase DQ transformation technique. The proposed circuit model is helpful in modeling the dynamics of the voltages and currents of the transmitter- and receiver-side resonant tanks and loads. The proposed circuit model is evaluated using frequency- and time-domain simulation results.

Operating Characteristics Analysis of PWM Boost AC-AC Converter for Compensation of Voltage Sag (전압 Sag 보상을 위한 PWM Boost AC-AC 컨버터의 동작 특성 해석)

  • 최남섭
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2003.10a
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    • pp.315-319
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    • 2003
  • This paper presents modeling and analysis of static and dynamic characteristics in PWM Boost AC-AC converter used for input voltage sag compensation of custom power. Especially, using circuit DQ transformation technique, an equivalent circuit in fundamental frequency domain is obtained which has all the system characteristics. Moreover, voltage gain and input power factor is analytically induced and linearized state equation at the specific operating point is given. Finally, simulation results show the validity of the proposed modelling and analyses.

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Operating Characteristics of Static Var Compensator Using Hybrid Cascade 5-level PWM Inverter (하이브리드 Cascade 5-레벨 PWM 인버터를 이용한 정지형 무효전력 보상기의 동작특성)

  • 최남섭
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2002.05a
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    • pp.318-321
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    • 2002
  • A static var compensator using hybrid cascade 5-level PWM inverter is presented for high voltage/high power applications. The proposed system is modelled by circuit DQ transformation, and thus an equivalent circuit is obtained which reveals the important characteristics of the system and lead to the related equations. The proposed system has advantages of hybrid structure which enhances the better utilization of power semiconductor switches, that is, both high power-low frequency switch, GTO and low power-high frequency switch, IGBT can be used in the same circuit. In this paper, circuit structure and characteristics is presented and the validity of the characteristics analysis is shown through PSIM simulation.

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Verification of an Autonomous Decentralized UPS System with Fast Transient Response Using a FPGA-Based Hardware Controller

  • Yokoyama, Tomoki;Doi, Nobuaki;Ishioka, Toshiya
    • Journal of Power Electronics
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    • v.9 no.3
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    • pp.507-515
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    • 2009
  • This paper proposes an autonomous decentralized control for a parallel connected uninterruptible power supply (UPS) system based on a fast power detection method using a FPGA based hardware controller for a single phase system. Each UPS unit detects only its output voltage and current without communications signal exchange and a quasi dq transformation method is applied to detect the phase and amplitude of the output voltage and the output current for the single phase system. Fast power detection can be achieved based on a quasi dq transformation, which results in a realization of very fast transient response under rapid load change. In the proposed method, the entire control system is implemented in one FPGA chip. Complicated calculations are assigned to hardware calculation logic, and the parallel processing circuit makes it possible to realize minimized calculation time. Also, an Nios II CPU core is implemented in the same FPGA chip, and the software can be applied for non-time critical calculations. Applying this control system, an autonomous decentralized UPS system with very fast transient response is realized. Feasibility and stable operation are confirmed by means of an experimental setup with three UPSs connected in parallel. Also, rapid load change is applied and excellent performance of the system is confirmed in terms of transient response and stability.

Dynamic Characteristics Analysis of PWM Cuk AC-AC Converter for Power Quality Improvement of Custom Power (Custom Power의 전력품질 향상을 위한 PWM Cuk AC-AC 컨버터의 동적 특성 해석)

  • 최남섭
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2004.05b
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    • pp.517-520
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    • 2004
  • In this paper, a PWM Cuk AC-AC converter is modelled by using complex circuit DQ transformation whereby the equivalent model is obtained which has the complete information of the Cuk converter. Using the model, the dynamicc characteristics equations such as state equations is analytically obtained. Finally, the PSIM simulation show the validity of the modelling and analysis.

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