Development Of Building DC Power Supply Device And Application Research Of Multi-energy Dispatching Strategy

In recent years,the energy crisis and the demand for energy conservation and emission reduction have led to the increasing use of renewable energy in buildings,which has led to the transformation of building energy forms.On the one hand,photovoltaic and other renewable energy sources increase a large amount of DC power supply in the building;on the other hand,frequency conversion equipment and electric vehicles in the building bring a large amount of DC load to the user side.AC power supply goes through a complex "direct-ac-direct" conversion between renewable energy and load,resulting in low efficiency.DC power supply of buildings can realize the direct utilization of photovoltaic and other renewable energy direct current.Compared with ac power supply,it can reduce the voltage transformation link,improve the system efficiency,and improve the power quality,which has become one of the research hotspots in the fields of renewable energy and green building.At present,the research on DC power supply for buildings in China is still in the theoretical and experimental stage,and there is a lack of mature standards and solutions in the aspects of DC power supply key DC/DC converter and DC power supply system management and control.This paper takes DC power supply for buildings as the research content,and the main work is as follows:First,this paper introduces the advantage of DC power supply system and research status at home and abroad,gives the architecture typical topology,the DC power supply system mainly including photovoltaic cells,the energy storage unit,parallel converter,dc load,protection devices,such as DC bus set two 48 V and 380 V voltage grade,and analyzes the system control mode and working mode.Secondly,study the system in typical converter topology and control strategy of energy storage unit of the bidirectional DC/DC converter chooses two phase staggered parallel Buck/Boost topology,a staggered parallel bi-directional DC/DC converter is proposed switch control method,first set up two phase staggered parallel bi-directional DC/DC switching dynamic model,selecting system of energy storage function as a common Lyapunov function,establish a system of optimal switching rate,analyzed the system stability of equilibria in the switch,in the Matlab simulation prove the validity of the proposed control strategy.The grid-connected bidirectional AC/DC converter adopts T-type tri-level topology,proposes adirect current predictive control method,directly models the large signal of the system,selects the switch state which makes the current pulsation minimum to operate on the switch tube,calculates the duty cycle of the switch signal,and verifies the effectiveness of the control strategy in Matlab simulation.Then,the bidirectional DC/DC converter is designed with hardware and software.The core board is controlled by DSP chip and CPLD chip.The switch tube uses SiC power MOSFET.The converter software design,including DSP program design and CPLD program design,the establishment of a 5kW bidirectional DC/DC converter prototype,the establishment of hardware experimental platform,converter performance and switching control strategy for experimental verification.Finally,the multi-energy scheduling strategy of DC power supply in buildings is analyzed,and the system is divided into two control structures: the bottom equipment layer and the upper management layer.The bottom equipment layer is mainly the real-time control of each converter to maintain the constant DC bus voltage.The upper management realized the optimal economic operation of the system by using scheduling algorithm,proposed the multi-energy scheduling model based on time-of-use electricity price,solved the model by using particle swarm optimization algorithm,and obtained the optimal scheduling scheme of the system.