Research On Distributed Control Parallel Critical Technology To Voltage-Type Inverters

With the progressing of technology in all areas of national economy and the extensive applications of information system in weaponry equipment, more and more requirements were putted forward to power supply, mainly including reliability, capacity, flexibility, and the voltage waveform quality etc. These requirements relate with the parallel technology of inverters directly or indirectly.This paper focused on the investigation of distributed controlled sine-wave inverters based on the new controller and the related parallel technology. the waveform control of inverter was realized directly; at the same time, because the lower output impedance of the inverters, the more loop current between inverters in parallel operation, so, the methods of increasing loop impedance were given. The main research content of the paper was composed of five part.The paper derived relations between input and output of SPWM sine-wave inverters controlled object by the cycle average method of power electronic switching Signals, established the inverters controlled object model that not depend on the load, and provided foundation for the parameter design of inverters control loop. Considering the design needs of the alternating-current controller to instantaneous voltage feedback sine-wave inverters, the A.C. control system transient analysis and steady-state analysis were researched, the relationship between the transient process of control system and system parameters were pointed out which would theoretically supported the controller design of the sine-wave instantaneous feedback inverters. It also pointed out the deficiencies when the P or PI controller were used in inverters control loop controllers which were widely used in the instantaneous feedback sine-wave inverter at present, and putted forward the basic requirements to controller for reducing or eliminating the tracking error of the instantaneous feedback inverters.By the output model of inverters, the paper respectively analyzed the impact and damage that the magnitude difference and phase difference between modules done to the inverter parallel, it also derived the relationship between the inverter current sharing error and loop current value when N inverter modules are parallel, and educed the conclusion that they are equal, which provided theoretical basis for inhibition of loop current when the inverter modules were parallel.Researched the issues when the new controller-repetitive controller applied in instantaneous feedback sine-wave inverters feedback control,and toward the stability analysis difficult for that repetitive control system contain delay time unit e-Ts, it offered a new simple method to get system stability conclusions by chart changed. Because the difficulty of repetitive controller realization with the analogy method, so digital control methods on DSP were widespread used at present, but its applied areas were limited. This paper presented a method to realize analogy repetitive controller with high-precision analog delay circuit,and used to the instantaneous feedback control of sine-wave inverters, transient and steady-state analysis were carried on, and ideal effects were achieved by simulation and experiment.The paper researched the problems of another new A.C controller——the proportional and resonant controller's application in sine-wave CVCF inverters, provided design method of the proportional and resonant controller which was based on Root-Locus method in detail. Carried on the transient and steady-state analysis of system, and tracking capability of the output sine-wave voltage to the input reference sine signal analyzed. The paper also pointed out the superiority of this kind of control fashion in sine waveform phase tracking. But the capacity of this type of inverters to suppress harmonic is limited, this paper given a reducing harmonic method that increased a harmonic feedback inner loop. The high gain second order HPF filter was designed and used to filter fundamental frequency composition of output voltage, third and over third harmonic were amplified, and used to derive feedback harmonic signals, and the stability design of harmonic feedback loop was gone on. Simulation and experimental study carried on and better control effects achieved. It also pointed out that the inverter designed has many characteristics like the output voltage waveform of high quality, high output voltage stability, the small output impedance, sine-wave phase that has strong track capacity and so on, it's a kind of inverters that has fine performance.To the proportional and resonant control sine-wave instantaneous feedback inverters, the paper researched distributed control parallel technology of inverters, and considering this kind of inverters have a low output impedance which is do harm to the parallel operation of inverters, it offered a method of improving loop impedance; it also carries on the parallel inverter system stability analysis which comes to a relevant conclusion. It taken two inverter modules in parallel as a example, carried on the simulation and the experimental study separately, and obtained the ideal control effect.Based on the detailed study of the new controller's applications in sine-wave instantaneous feedback inverters and the distributed control parallel technology of inverters, the paper obtained one high performance parallel method of inverters, which can widely apply to the parallel of inverters.