The Research Of Control Technology For Wireless Parallel Inverters

Comparing with single inverter, parallel operation of multi-inverters can achieve huge capability and redundancy power supply. It also improves the power supply agility and stability, therefore it was considered to be one of the significant developmental directions of current inverter technology. From the view of theory and practice, there are some problems to be solved on inverter parallel operation, thus this paper takes inverter parallel operation control technology as the research content.According to the inverter parallel operation with wire or not, classified control mode and compared their advantages and disadvantages respectively, and then it gained the conclusion that parallel operation technology of inverter with wireless takes the advantages of resisting disturbance, enlarging capability, maintaining expediently and operating reliably. Confirmed parallel operation technology of inverter with wireless to be the research emphases.Inverter module characteristic affects parallel operation system crucially, accordingly the paper introduced the design of double loop control SPWM converter with voltage outer loop and current inner loop which based on the practical system requirements. Inverter mathematical model has been established, designed the filter inductance, capacitance and various controller parameters. Constructed the emulational model of double loop control SPWM converter, emulational result shows that the designed inverter satisfied the system demands.Through theoretical analysis of multi-inverters parallel operation model, the paper evolved that the inverter output voltage amplitude and phase is correlative with both output active power and reactive power. Explained the method of using indirect way to control output voltage amplitude and phase in order to achieve power share. In addition, analyzed the reason what induces circulating current which influences parallel operation system, found that difference between any parallel operation inverter output voltage amplitude and phase results in reactive power circulating current and active power circulating current. Paper made certain to adopt measure active and reactive component of output power in order to modify output voltage amplitude and phase, then achieved eliminating circulating current and realizing current share.After analyzing the parallel operation technology of inverter with wireless theoretically, we got the basic algorithm of droop control. Based on this strategy, the paper presented inverter output active power and reactive power adjust output voltage amplitude and phase together, ameliorated the basic algorithm. More over, differential items of active power and reactive power were added to the algorithm to improve the dynamic performance, and then we got the improved parallel control algorithm which based on new droop characteristic. Parallel operation model of inverter with wireless which adopting new algorithm has been founded, educed the significant parameters which determine power sharing performance. Emulational research showed that the improved system obtained preferable stability and dynamic response, the power sharing performance and circulating current restraining performance satisfied parallel operation requirements > system design is reasonable.