Multi-inverter Parallel Control Technology

Based on the existing problems of system dynamic response and nonlinear load regulating in the paralleled inverters system, a new method of instantaneous current-sharing controller design is proposed in this paper. Moreover, its principle, control strategy and system design of this new control system are explored in detail. The main contributions of the paper are summarized as follows:1. The parallel operation of inverters depends on the performance of single inverter, so single inverter is designed at first in the chapter 2. Math model of inverter is constructed and the parameters of filter and controller are designed .The rationality of parameters are proved by simulation results.2. The paralleled inverters system is modeling at first, and the influence of filter on the parallel operation for inverters is analyzed qualitatively, and the working modes of paralleled inverters which will caused circumfluence are argued also.3. Based on the generation principle and control circuit of SPWM, the strategy of synchronization control is put forward and the controller of frequency and phase adjustment is introduced. A kind of voltage signal compensation is researched in order to resolve the cumulative effect.4. On the basis of analyzing and comparing four kinds of parallel operation schemes for inverters, a new control strategy of paralleled inverters is proposed and a current-sharing controller based on H∞ robust control is designed. As such, robust control theories of mixed sensitivity are utilized and rational weighting functions and appropriate Riccati arithmetic are investigated. The corresponding simulation results prove the effectiveness of this current-sharing controller. From the simulation results, we can also draw a conclusion that the parallel control scheme has fast dynamic response and equal current sharing for both linear and nonlinear loads5. System design of paralleled inv(?)rters system with instantaneous average current-sharing scheme is presented as a whole. Several main aspects such as the system structure, signal generating circuit of reference synchronization and the distributed control circuit of current-sharing etc. are investigated. Simulation results demonstrate that fast dynamic response, tight output regulation and equal current distribution can be achieved in the proposed paralleled inverters system.