| In recent years,with the large-scale access of new energy in the grid,it has been difficult to meet the demand of grid security and stability by the regulation of the power side alone.The development and utilization of demand-side load resources that can participate in frequency-based demand response can help the power grid achieve safe and stable power supply,and also help the power system complete the transformation from "source follows load" to "source-load interaction".The factory inverter motor is easy to control intelligently,can be adjusted quickly,and has a large regulation potential.In-depth research on the control scheme and response potential of frequency-based demand response of factory inverter motor is of great significance for the stable operation of power system.The main work and results of this thesis are as follows:Based on the working principles of constant voltage frequency ratio frequency regulation and vector control frequency regulation of inverter motor,we study the regulation characteristics of factory inverter motor,build the corresponding motor model on MATLAB/Simulink simulation platform,compare and analyze the changes of motor speed and mechanical torque under the same variable speed signal,the simulation results show that the inverter motor under vector control can achieve fast and stable regulation of speed in a shorter time.According to the constructed vector control model,the variation law of the active power of the inverter motor with speed change under different load torques is studied,and the regulation potential of the factory inverter motor as a fast regulation resource involved in frequency-based demand response is analyzed.Based on the working principle of power system frequency regulation and frequency-based demand response,a control scheme for single inverter motor participation in frequency-based demand response and an inverter motor aggregation control scheme are proposed.For the frequency control module in the scheme,based on the shortcomings of the conventional control method based on active frequency sag characteristics,a frequency-based demand response control method based on model predictive control is proposed,which enables the factory inverter motor to adjust its own load power more quickly in response to the system frequency change according to the system frequency deviation and rate of change of frequency while meeting the factory production constraints,thus reducing the system frequency deviation.The frequency response model is built in the single machine test system and IEEE 3 machine 9 node system for simulation and verification,and the advantages of the method over the traditional control method in terms of control accuracy and response speed are compared and analyzed,and the results show that the control method can effectively reduce the system frequency response deviation.A quantitative analysis method of potential based on load forecasting is proposed to accurately evaluate and analyze the magnitude of response potential that can be involved in frequency-based demand response using factory inverter dust collector fans as an example.The method purposefully studies the operating characteristics of factory inverter dust collector fans and derives its theoretical adjustable frequency interval by combining factory safety production constraints and energy saving requirements.Further,an ensemble empirical modal decomposition-convolutional neural network-long and short-term memory neural network load prediction model based on feature filtering is designed to achieve accurate prediction of motor load data,and the predicted data is used to analyze and calculate the theoretical demand response potential.The proposed load prediction model is compared with the commonly used load prediction models to verify its prediction accuracy,and the response potential of factory inverter dust collector fans is quantitatively evaluated based on the predicted load data combined with adjustable frequency intervals. |
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