Huang Yonghong

Effective voltage flicker detection approach based on a new modified S-transform algorithm

Higher standards have been placed on the flexibility and accuracy of characteristic detection methods of voltage flicker characteristics due to sporadic flicker disturbances. S-transform as a tool of signal analysis has been limited in practical application because of the fixed shape of its Gaussian window function. Some existing modified S-transform algorithms have demonstrated increased adaptability and flexibility by an additional parameter in Gaussian window function. However, the additional parameter is selected by empirical data in some modification, which have exposed errors brought by human factors. In this paper, a new improvement is achieved by introducing the measurement criteria of time-frequency concentration which can be used to optimize the additional parameter of Gaussian window function. The core of this scheme is to obtain an optimal parameter through maximizing the value of measurement criteria of time-frequency concentration. The algorithm is tested on a set of synthetic signals and a voltage flicker disturbance signal. The results show it can demonstrate much more detection accuracy and the ability to resist the cross term interferences than other modification.

Design of indoor swimming pool water temperature control system based on fuzzy controller and Smith predictor

All modern indoor swimming pools have a large volume, the water temperature control system is the serious delay and serious inertia nonlinear system. The traditional PLC control system based on PID controller can not meet the control requirements. This paper presents an integrated control system composed of a fuzzy automatic optimization algorithm and the Smith predictor compensator to adjust the temperature of pool water. Experiments and applications show that the proposed control scheme to solve the serious delay and serious inertia system can achieve good control effect.

Interactive detection method applied in DVR

To satisfy the real-time and accuracy requirements of voltage sag detection, an interactive Dynamic Voltage Restorer (DVR) combined generalized S-transform and RMS is proposed. Generalized S-transform is improved by time-frequency aggregation performance criteria, to obtain high time-frequency resolution, realizing the detection and localization of mutation signal. The generalized inverse S-transform is performed on the processed mode to get the effect of de-noising and filtering. Based on the effective value detection method, the value of voltage sag is calculated, and the interactive voltage sag detection is realized by isolating the switch. This method can improve the detection accuracy and response speed of DVR, and have good signal de-noising ability. Finally, the feasibility and timeliness are verified by simulation and experiment.

Soft-sensor modeling of foot-and-mouth disease vaccine suspension culture based on relevance vector machine

The suspension culture of animal cells in vitro involves complex biochemical reaction and metabolism of a large number of cells. The on-line detection of some biological parameters (such as glucose concentration, lactic acid concentration and cell density and so on) is very important and difficult to achieve. The off-line analysis also will lead to the delay of the system regulation and control. In order to estimate the key parameters of suspension culture of foot-and-mouth disease (FMD) vaccine by a more precise method, a soft-sensor method based on relevance vector machine (RVM) is adopted in this paper. Firstly, the auxiliary variables of the model are determined by using the uniform incidence degree algorithm, and the dominant variables are determined by characteristics of the FMD vaccine during the preparation process, then the soft-sensor model is established by using the RVM algorithm. Compared with SVM, the simulation results show that the RVM algorithm can solve the problem of real-time detection of biological parameters in the animal cell culture effectively. It can also reduce the complexity of the model and has a certain practical value.

Study on the experiment of ultracapacitor in HES for HEV

Due to the short cycle life and small power density of battery in energy storage system for Hybrid electric vehicles (HEV), introduce the ultracapacitor as a solution, and design a hybrid energy storage system (HES) which combines the battery and ultracapacitor, so the HES made the best of characteristics of high energy density of battery and high power density of ultracapacitor. Firstly, study on discharging experiment of battery and ultracapacitor. Secondly, use the battery and HES as the power source respectively to carry out the experiment. Finally, compare and summary the results. The results show that ultracapacitor can absorb the peak power of load so as to protect the battery.

Research on the ultracapacitor/battery hybrid system

The ultracapacitor/battery hybrid system makes the best of the characteristics of high energy density of battery and long cycle life of ultracapacitor. The mathematical model of ultracapacitor/battery hybrid system was set up, and the characters of it such as peak power enhancement were studied and the correlative factors were analyzed in this paper. Ultracapacitor and battery are connected in parallel by a bi-directional buck-boost converter. Model the ultracapacitor/battery hybrid system under MATLAB 7 and use a double loop PWM to control. The result shows that battery and ultracapacitor could work in optimizing discharge condition when the load power is pulsating. The bi-directional buck-boost converter has better performance and practicability.