Design Of Malignant Load Control System Based On SoC

Safe power management has become an issue of increasing concern.In densely populated areas such as college apartments,because contemporary college students lack a basic understanding of the safety of electricity,they are often acts of using high-powered,pulling wires and stealing electricity,which brings great security risks to campus life.At present,the malignant load recognition system on the market has problems such as high price and inaccurate recognition.Therefore,how to design an intelligent,real-time,effective and stable malignant load identification system is a hot topic of current research.Commonly used malignant load identification algorithms such as power limitation method,have been unable to adapt to the increasingly rich campus life.The high power threshold setting does not prevent the high-power malignant load,and the low threshold setting affects campus life.Therefore,this paper studies a variety of load characteristics and analyzes the existing problems of the malignant load identification algorithm,and gives a new algorithm.The algorithm combines with the hardware system for analysis and demonstration.The paper mainly includes the following points:(1)Aim at the high-power malignant load,this paper gives a load identification algorithm based on area.By collecting 128 points of current data,cycle is 0.02 s,it is judged whether there is waveform jump in the current data point.When there is no obvious jump in the current data,it indicates that the circuit does not contain the nonlinear load,while the system into the phase algorithm.The system curves the voltage and current waveforms by the least squares method to obtain the respective phases.According to the characteristic of resistive load has no phase influence on the current waveform,the system judges whether the current voltage phase difference is zero.When the phase difference is zero,the system uses the difference equation to calculate power.If the power set by system is exceeded,the power grid is powered off by the relay.If the current data is detected have a significant jump,it indicates that the circuit contains a nonlinear load.The composition calculates the power of the linear load and the nonlinear load through the area method.When the linear load power exceeds the set power,the system controls the relay to power off.The advantage of this method is that the operation of the system is reduced.But this method has certain drawbacks that the power threshold is set for the system,and the low power malignant load such as the electric blanket cannot be effectively recognized.(2)For the low-power malignant load,the window-based fast Fourier malignant load identification algorithm is given,which has a faster calculation rate than the traditional Fourier algorithm.At the same time,the window function is introduced to reduce the spectrum leakage and improve the sampling precision.The fundamental odd harmonic components of the current waveform are analyzed by the algorithm.The characteristic matrix is to store the relevant data of the commonly used.The historical matrix is used tocollect and judge the circuit data in real time.When the same data in the characteristic matrix appears,the system controls relay to power off.The method is complementary to the algorithm based on area and phase,and can effectively judge the malignant load.(3)In order to verify the above theoretical algorithm,this paper builds a hardware system for actual verification.This system is mainly composed of SoC chip RN8302 combined with Cortex-M3 as the core of STM32F105.This paper elaborates the overall design idea of the system,and gives the key circuit diagram design of voltage and current sampling,RN8302 minimum system,external communication,leakage detection and backup battery charging.The paper focuses on the design process of the malicious load software.In order to verify the effectiveness of the algorithm,this paper combines the hardware system to analyze the experimental data,verify the feasibility and effectiveness of the method.The algorithm can solve the problem of safe electricity use in the current densely populated areas.It can provide a design reference for the electricity safety management of college apartments.