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Ji Jianfei,Wang Lihui,Yuan Yubo,Yang Yifei 보안공학연구지원센터 2016 International Journal of Signal Processing, Image Vol.9 No.1
With the increase of voltage level and more and more secondary devices are located in field, the secondary circuit of substation is in a strong electromagnetic environment. Because the secondary circuit is affected by the interference of switch operations, there are many trip accidents happened in substations without any fault in recently years, which constitutes a serious threat to the power network and harms the safe operation of the electric power system. It is of great theoretical significance and practical value to study the Electromagnetic Compatibility problem of the transformer substations substation secondary circuit. In this paper, the abnormal phenomenon of one 110kV intelligent substation merging unit is described. And the reason of the abnormal phenomenon is analyzed. Firstly, the Electromagnetic Compatibility experiments specified by the IEC61000-4 standard are carried out. Furthermore, to verify the anti–interference performance of the merging unit, the Electromagnetic Compatibility experiments above the standard are carried out. The structure of merging unit is improved until the merging unit operates normally. Secondly, to quantitatively analyze the disturbance strength, the electromagnetic disturbance signal is recorded, and the characteristics of amplitude and time-frequency of the recorded signal are analyzed. Thirdly, the characteristics of the logged signal are compared to the IEC61000-4 standard. Finally, this paper puts forward some suggestions about improving the Electromagnetic Compatibility performance of merging unit.
An FPGA-Based Modified Adaptive PID Controller for DC/DC Buck Converters
Ling Lv,Changyuan Chang,Zhiqi Zhou,Yubo Yuan 전력전자학회 2015 JOURNAL OF POWER ELECTRONICS Vol.15 No.2
On the basis of the conventional PID control algorithm, a modified adaptive PID (MA-PID) control algorithm is presented to improve the steady-state and dynamic performance of closed-loop systems. The proposed method has a straightforward structure without excessively increasing the complexity and cost. It can adaptively adjust the values of the control parameters (Kp, Ki and Kd) by following a new control law. Simulation results show that the line transient response of the MA-PID is better than that of the adaptive digital PID because the differential coefficient Kd is introduced to changes. In addition, experimental results based on a FPGA indicate that the MA-PID control algorithm reduces the recovery time by 62.5% in response to a 1V line transient, 50% in response to a 500mA load transient, and 23.6% in response to a steady-state deviation, when compared with the conventional PID control algorithm.
An FPGA-Based Modified Adaptive PID Controller for DC/DC Buck Converters
Lv, Ling,Chang, Changyuan,Zhou, Zhiqi,Yuan, Yubo The Korean Institute of Power Electronics 2015 JOURNAL OF POWER ELECTRONICS Vol.15 No.2
On the basis of the conventional PID control algorithm, a modified adaptive PID (MA-PID) control algorithm is presented to improve the steady-state and dynamic performance of closed-loop systems. The proposed method has a straightforward structure without excessively increasing the complexity and cost. It can adaptively adjust the values of the control parameters ($K_p$, $K_i$ and $K_d$) by following a new control law. Simulation results show that the line transient response of the MA-PID is better than that of the adaptive digital PID because the differential coefficient $K_d$ is introduced to changes. In addition, experimental results based on a FPGA indicate that the MA-PID control algorithm reduces the recovery time by 62.5% in response to a 1V line transient, 50% in response to a 500mA load transient, and 23.6% in response to a steady-state deviation, when compared with the conventional PID control algorithm.