The Parallel Control Of Single-stage Four-quadrant High Frequency Link Inverter

The requirement of high quality and reliability power supply is increasing. Paralleloperation of multi-inverters can achieve huge capability and redundancy power supply. Itwas considered to be one of the significant developmental directions of current invertertechnology. Digital control is the trend of future development.This thesis mainly research on the parallel control of single-stage four-quadrant highfrequency link inverters. the digital control is achieved through DSP TMS320LF2407A.There are only a few data wires but no analogue wires. Current-sharing scheme presentedin this paper achieves better circulating-current and realizes current sharing.Firstly, The control scheme of single-phase high-frequency-link inverter is analyzed.At the base of analyzing and referring the parallel methods at present, A control schemewhich is dual loop with feed forward control is used. The high-frequency-link invertermathematical model has been established.Secondary, The model of parallel multi-inverters system is analyzed. Thecharacteristic of circulating current and power is derived. The inverter output voltageamplitude and phase is correlative with both output active power and reactive power isevolved. Current-sharing is achieved by adjusting the voltage references. A novel methodof regulating DC circulating current is presented.Through the theoretical analysis, A novel parallel current-sharing scheme is presentedwhich is competitive in synchronization and CAN-Bus is adopted to achievecurrent-sharing. The algorithm presented is simple but has better performance. Thesimulation results approve the scheme.Finally, A 1 kW system prototypes is designed and analyzed. The control circuits andprogram is designed. Two inverters parallel experiment is carried out mainly. The schemeis verified by the experimental results.