基于状态观测器的逆变器数字双环控制技术研究

该文首先比较了逆变器模型与直流电机模型的相似性，提出逆变器的控制可以借鉴直流电机的双闭环控制方法。然后针对输出电压的交叉反馈作用，采用了控制对象的解耦，消除了输出电压对内环的影响，简化了问题。数字控制具有很多优点，但是它引入的采样延时和计算延时对系统的性能影响很大。为了提高控制的实时性和鲁棒性，建立了基于改进z变换的状态观测器和扰动观测器，合理设计其极点，可以得到无差拍观测器，并在此基础上实现内环电容电流的无差拍控制。考虑内环的快速性，外环可以采用简单的比例调节器，从而整个数字双环控制系统的设计非常简单。最后，实验证明这种方法可以保证良好静态和动态性能，在非线性负载下，也能得到良好的输出电压波形。

STUDY ON DIGITAL DUAL-LOOP CONTROL FOR INVERTERS BASED ON STATE-OBSERVER

This paper compared the model of inverter and DC motor at first and proposed that the dual-loop control for DC motor can be used to that of inverter. Then decouple of the control object was adopted to eliminate the influence on the inner loop induced by output voltage and simplified the model. Digital control has many advantages, but sampling-delay and calculation-delay influence system characteristics. In order to improve system real-time and robustness, state-observer and disturbance-observer were established based on modified z transformation. Deadbeat observer can be achieved by reaso-nable design of the poles and capacitor current deadbeat control can be also achieved. Proportional controller can be adopted concerning the fast response of inner loop. Thus the design of whole system is very simple. At last, experimental result proved that it can promise nice static and dynamic characteris-tics, and nice output voltage waveform can be also achieved under nonlinear load.