数字双闭环瞬时值控制逆变器外特性研究

数字双闭环控制通过电流环的无差拍控制实现对负载扰动的抑制,从而提高系统的动态响应速度,但由于没有实现电压的无差拍控制,稳态精度不够理想。本文在介绍电容电流瞬时值反馈控制逆变器数字双闭环控制模型的基础上,建立了系统的闭环传递函数,并从理论上分析了影响数字双环控制逆变器外特性的因素。滤波电感参数的实际偏差和直流电压的波动对逆变器的外特性有较大影响。通过适当的参数设计和在控制器中引入直流电压的解耦控制可以解决在实际参数与控制器参数不一致时输出电压精度不高的问题。仿真和试验结果证明了理论分析的正确性,尤其是加入直流电压解耦控制明显提高了逆变器的输出稳态精度。

External Characteristics of Digital Control Inverter with Instantaneous Dual-Loop Feedback

To restrain the disturbance of the load and achieve fast dynamic response, the current deadbeat control is introduced in digital dual-loop control.But the output voltage is not under the deadbeat control and the output precision is not good.By introducing a digital dual-loop control model of inverter feedback with the capacitor current,the system transfer function is figured out and its external characteristic is analyzed.The conclusion show that it is affected by the inductor error between the control parameter and the actual value and fluctuation of the input DC voltage.To improve the external characteristic,suitable parameter selection is proposed to reduce the influence of inductor value error and DC decoupling method is adopted to release from the influence of the swing of DC link.Simulation and experimental results prove that the static performance of the inverter is enhanced.Especially the introducing DC decouple control improves the precision of the output voltage in evidence.