逆变器系统中准PCI控制器及其物理模型分析

Analysis of Quasi-Proportional Complex Integral Controller and Its Physical Model in Inverter System

逆变器系统中理想比例复数积分(PCI)控制器在谐振频率处增益为无穷大,且在其他频率处没有增益,由此可以消除稳态误差,但是无限大的增益将会引起稳定性问题。提出一种基于αβ静止坐标系可消除交流稳态误差的准PCI(QPCI)控制器,此控制器可利用αβ静止坐标轴之间的耦合产生相互谐振实现对正弦信号的跟踪,同时在谐振频率处引入通频带宽ωc,既消除稳态误差又保证系统稳定性。此外还从物理模型重构的角度揭示准PCI控制器运行原理,以及参数对其性能的影响。通过对LCL型三相并网逆变器进行仿真和实验,对比PCI和准PCI的性能,验证了准PCI的正确性和优越性。

The ideal proportional complex integral （PCI） controller can generate an infinite gain at the resonant frequency but no gains at other frequencies, which can eliminate the steady-state error completely. However, the infinite amplitude may cause stability problems. In this paper, a quasi-proportional complex integral （QPCI） controller is presented for eliminating the steady-state error in the stationary frame. The QPCI controller uses the cross-axis to produce resonance with each other, which achieves the tracking of sine signals. Meanwhile, introducing the frequency bandwidth ωc can both eliminate the steady state error and ensure the system stability. In order to deeply understand the principle operation of the controller and the impacts of parameters, this paper structures a physical circuit model. The theoretical analysis, simulations and experiments are carried out to compare the performance of the PCI, quasi PCI and the traditional quasi PR with three-phase grid connected inverter.