Research On Flexible Load Power Response Control Method Based On Back-to-back Converter

Renewable energy power generation is developing rapidly because of the increasing environmental pollution and energy shortage.DG is the main form of renewable energy power generation.The output power of DG is affected by the intermittent effect of renewable energy,and the volatility is strong and difficult to predict.Therefore,the integration of large-scale distributed power sources into the power grid has brought huge challenges to the balance of power supply and demand.Flexible load has the potential to participate in active distribution network dispatch,and can be used as a regulating resource to participate in real-time power balance control of the grid.It is effective to use the virtual energy storage characteristics of flexible loads to improve the shortcomings of demand-side load response control,such as inflexible control and uncontrollable reactive power,because flexible loads have great application potential in responding to higher-level power demands.However,the specific control method has not been studied in depth.In order to solve the above problems and tap the potential of flexible load power control to participate in grid power balance control,a flexible load power response control model based on back-to-back converters is established in this thesis,and its collaborative control method is proposed.The main contents of this thesis are as follows.1.The reactive power response control method of flexible load is studied.The basic principle of the back-to-back converter is analyzed,the flexible load control structure based on the back-to-back converter is established,and the flexible load reactive power control model based on the back-to-back converter and its control loop are designed.The reactive power response control method of flexible load is proposed.A simulation experiment is used to verify the effectiveness of the control method.2.The virtual energy storage control method based on flexible load is studied.The virtual energy storage characteristics of the flexible load are analyzed,and the virtual energy storage power control model based on the flexible load is established.Combined with flexible load reactive power response control,a comprehensive control method of virtual energy storage power based on flexible load is proposed.A simulation experiment is used to verify the effectiveness of the control method.3.The power response coordinated control strategy of multiple flexible loads is studied.The basic principles of multi-agent technology are analyzed,the concept of hierarchical collaborative control of multiple flexible loads is expounded,and the power response collaborative control architecture of multiple flexible loads is designed.The hierarchical control module in cooperative control is studied,including the control strategies of the steady-state control layer and the dynamic control layer.The multi-flexible load power response hierarchical cooperative control method is proposed.A simulation experiment is used to verify the effectiveness of the collaborative control strategy.