• Title/Summary/Keyword: current sampling

Search Result 822, Processing Time 0.035 seconds

The Effect of Transformer Leakage Inductance on the Steady State Performance of Push-pull based Converter with Continuous Current

  • Chen, Qian;Zheng, Trillion Q.;Li, Yan;Shao, Tiancong
    • Journal of Power Electronics
    • /
    • v.13 no.3
    • /
    • pp.349-361
    • /
    • 2013
  • As a result of the advantages such as high efficiency, continuous current and high stability margin, push-pull converter with continuous current (PPCWCC) is competitive for battery discharge regulator (BDR) which plays an important role in power conditioning unit (PCU). Leakage inductance yields current spike in low-ripple current of PPCWCCs. The operating modes are added due to leakage inductance. Therefore the steady state performance is affected, which is embodied in the spike of low-ripple current. PPCWCCs which are suitable for BDR can be separated into three types by current spike characteristics. Three representative topologies IIs1, IIcb2 and Is3 are analyzed in order to investigate the factors on the magnitude and duration of spike. Equivalent current sampling method (ECSM) which eliminates the sampling time delay and achieves excellent dynamic performance is adopted to prevent the spike disturbance on current sampling. However, ECSM reduces the sampling accuracy and telemetry accuracy due to neglecting the spike. In this paper, ECSM used in PPCWCCs is summarized. The current sampling error is analyzed in quality and quantity, which provides the foundation for offsetting and enhancing the telemetry accuracy. Finally, current sampling error rate of three topologies is compared by experiment results, which verify the theoretical analysis.

Analysis and Compensation of Current Sampling Error in Discontinuous PWM Inverter for AC Drive (교류 전동기 구동용 불연속 PWM 인버터의 전류 샘플링 오차 해석 및 보상)

  • Song, Seung-Ho;Son, Yo-Chan;Seol, Seung-Gi
    • The Transactions of the Korean Institute of Electrical Engineers B
    • /
    • v.48 no.9
    • /
    • pp.517-522
    • /
    • 1999
  • This paper addresses the issue of current sampling in a high performance AC drive system fed by a discontinuous PWM inverter. The effect of the sampling error due to the measurement delay produced by an input stage low pass filter and an A/D converter is described in the case of discontinuous PWM. To compensate for the sampling error, a method to estimate the delay time of the whole measurement system based on the measured current is proposed and its effectiveness is verified by experimental results. The proposed algorithm can automatically estimate the system delay introduced by the low pass filter and the A/D converter at the commissioning stage. By delaying the current sampling by the estimated value, experimental results indicate that more than 50% reduction of current ripple can be achieved.

  • PDF

Small Signal Modeling of Current Mode Control (전류모드 제어의 소신호 모델링)

  • 정영석;강정일;최현칠;윤명중
    • The Transactions of the Korean Institute of Power Electronics
    • /
    • v.3 no.4
    • /
    • pp.338-345
    • /
    • 1998
  • The mathematical interpretation of a practical sampler which is useful to obtain the small signal models for the peak and average current mode controls is proposed. Due to the difficulties in applying the Shannons sampling theorem to the analysis of sampling effects embedded in the current mode control, several different approaches have been reported. However, these approaches require the information of the inductor current in a discrete expression, which restricts the application of the reported method only to the peak current mode control. In this paper, the mathematical expressions of sampling effects on a current loop which can directly apply the Shannons sampling theorem are newly proposed, and applied to the modeling of the peak current mode control. By the newly derived models of a practial smapler, the models in a discrete time domain and a continuous time domain are obtained. It is expected that the derived models are useful for the control loop design of power supplies. The effectiveness of the derived models are verified through the simulation and experimental results.

  • PDF

Modeling of the Sampling Effect in the P-Type Average Current Mode Control

  • Jung, Young-Seok;Kim, Marn-Go
    • Journal of Power Electronics
    • /
    • v.11 no.1
    • /
    • pp.59-63
    • /
    • 2011
  • This paper presents the modeling of the sampling effect in the p-type average current mode control. The prediction of the high frequency components near half of the switching frequency in the current loop gain is given for the p-type average current mode control. By the proposed model, the prediction accuracy is improved when compared to that of conventional models. The proposed method is applied to a buck converter, and then the measurement results are analyzed.

Modeling of a Converter Utilizing Current Mode Control (전류모드제어 방식을 이용하는 컨버터의 모델링)

  • 정영석;이준영;강정일;윤명중
    • Proceedings of the KIPE Conference
    • /
    • 1998.07a
    • /
    • pp.275-278
    • /
    • 1998
  • The mathematical interpretation of a practical sampler which is useful to obtain the small signal models for the peak and average current mode controls is proposed. Due to the difficulties in applying the Shannon's sampling theorem to the analysis of sampling effects embedded in the current mode control, several different approaches have been reported. However, these approaches require the information of the inductor current in a discrete expression, which restricts the application of the reported method only to the peak current mode control. In this paper, the mathematical expressions of sampling effects on a current loop which can directly apply the Shannon's sampling theorem are newly proposed, and applied to the modeling of the peak current mode control. By the newly derived models of a practical sampler, the models in a discrete time domain and a continuous time domain are obtained. It is expected that the derived models are useful for the control loop design of power supplies. The effectiveness of the derived models are verified through the simulation and experimental results.

  • PDF

High precision Gating Algorithm for Predictive Current Control of Phase Controlled Rectifier (위상제어 정류기의 예측전류제어를 위한 새로운 고정밀 게이팅 알고리즘)

  • 정세종;송승호
    • The Transactions of the Korean Institute of Electrical Engineers B
    • /
    • v.53 no.3
    • /
    • pp.206-211
    • /
    • 2004
  • In phase controlled rectifier, it's been known that a fast response is achieved by predictive current control without any overshoot. The frequent sampling period is essential to improve the firing accuracy in conventional predict current control. However, improving the firing accuracy if difficult to reduce the period of sampling efficiently because current sampling and predictive current control is carried out in every period and the ON-OFF current control is performed by comparing two different one. To improve the firing accuracy at the predictive current control, the calculated firing angle is loaded into the high-accuracy hardware timer. So the calculation of exact crossing point between the predictive and actual current is the most important. In this paper, the flow chart for proposed firing angle calculation algorithm is obtained for the fastest current control performance in transient state. The performance of proposed algorithm is verified through simulations and experiments.

Analysis and Compensation of Current Measurement Error in Digitally Controlled AC Drives (디지털 제어 교류 전동기 구동시스템의 전류 측정 오차 해석 및 보상)

  • 송승호;최종우;설승기
    • The Transactions of the Korean Institute of Power Electronics
    • /
    • v.4 no.5
    • /
    • pp.462-473
    • /
    • 1999
  • This paper addresses the current measurement issue of all digital field oriented control of ac motors. The p paper focuses on the effect of low-pass filter and also on the sampling of the fundamental component of the m motor current. The low-pass filter, which suppresses the switching noise of the motor current, introduces v variable phase delay according to the current ripple frequency. It is shown that the current sampling error c consists of the fundamental component and high frL'quency ripple components. In this paper, the dependency of t this current sampling e$\pi$or on the reference voltage vector is investigated analytically and a sampling technique i is proposed to minimize the error. The work is based on the three phase symmetry pulse width modulation l inverter driving an induction machine. With this technique, the bandwidth of current regulator can be extended t to the limit given by the switching frequency of the inverter and more precise torque regulation is possible.

  • PDF

Low Power-loss Current Measurement Technique Using Resistive Sensor and Bypass Switch (바이패스 스위치와 저항센서를 이용한 저손실 전류 측정방법)

  • Lee, Hwa-Seok;Thayalan, I. Daniel Thena;Park, Joung-Hu
    • The Transactions of the Korean Institute of Power Electronics
    • /
    • v.17 no.5
    • /
    • pp.416-422
    • /
    • 2012
  • This paper proposes a low power-loss current measurement using a resistor and bypass switch. Conventional current sensing method using a resistor has a disadvantage of power loss which degrades the efficiency of the entire systems. On the other hand, proposed measurement technique operating with bypass-switch connected in parallel with sensing resistor can reduce power loss significantly the current sensor. The propose measurement works for discrete-time sampling of current sensing. Even while the analog-digital conversion does not occur at the controller, the sensing voltage across the sensor still causes ohmic conduction loss without information delivery. Hence, the bypass switch bypasses the sensing current with a small amount of power loss. In this paper, a 90[W] prototype hardware has been implemented for photovoltaic MPPT experimental verification of the proposed low power-loss current measurement technique. From the results, it can be seen that PV power observation is successfully done with the proposed method.

A Study on the Design of a Current Type ROIC for Uncooled Bolometer Thermal Image Sensor Using Correlated Double Sampling

  • Kwak, Sang-Hyeon;Lee, Po;Jung, Eun-Sik;Sung, Man-Young
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
    • /
    • 2009.06a
    • /
    • pp.7-8
    • /
    • 2009
  • In the presence of infrared light, a CMOS Readout IC (ROIC) for a microbolometer typed infrared sensor detects the voltage or current that is caused by the changing in resistance in the bolometer sensor. A serious problem in designing the ROIC is how the value of the bolometer and reference resistors vary because of variations in manufacturing process. Since different pixel have different, resistance values, sensor operations must contend with fixed pattern noise (FPN) problems. In this paper, we propose a novel technique to compensate for the fluctuation in reference resistance by tiling into account the process variation. By using constant current source basing and correlated double sampling, we solved FPN.

  • PDF

A Fully Optimized Electrowinning Cell for Achieving a Uniform Current Distribution at Electrodes Utilizing Sampling-Based Sensitivity Approach

  • Choi, Nak-Sun;Kim, Dong-Wook;Cho, Jeonghun;Kim, Dong-Hun
    • Journal of Electrical Engineering and Technology
    • /
    • v.10 no.2
    • /
    • pp.641-646
    • /
    • 2015
  • In this paper, a zinc electrowinning cell is fully optimized to achieve a uniform current distribution at electrode surfaces. To effectively deal with an electromagnetically coupled problem with multi-dimensional design variables, a sampling-based sensitivity approach is combined with a highly tuned multiphysics simulation model. The model involves the interrelation between electrochemical reactions and electromagnetic phenomena so as to predict accurate current distributions in the electrowinning cell. In the sampling-based sensitivity approach, Kriging-based surrogate models are generated in a local window, and accordingly their sensitivity values are extracted. Such unique design strategy facilitates optimizing very complicated multiphysics and multi-dimensional design problems. Finally, ten design variables deciding the electrolytic cell structure are optimized, and then the uniformity of current distribution in the optimized cell is examined through the comparison with existing cell designs.