高精度宽频带逆变器直流漂移的多重采样频率控制方法研究

针对某大功率高精度宽频带逆变器交流输出对直流漂移电压的特殊要求 ,采用了对输出交流电流进行双向分离、分别采样、对比调偏的控制方案。逆变器输出随机运行在 3～50 0 0Hz的宽频带范围内 ,当采样频率与输出频率同步或者采样频率为输出频率的整数倍时可能带来严重的检测误差 ;采样频率与输出频率接近时产生的低频拍频会使调偏控制同频振荡。文中提出了一种使用互质的多个采样频率同时采样的方法 ,较好地解决了这一问题。并给出了仿真和实验结果。

A Novel Multiple Sample Frequencies Control Scheme for Compensating the Output DC Drift of A Wide-band High-precision Inverter

Aiming at the special requirement for compensating the output DC drift of a wide band and high precision power inverter, a novel control scheme is introduced. Firstly two direction signals of the output AC current are separated, secondly sample the two direction DC signal respectively, and then compare them each other and adjust a control offset finally. The inverter output frequency ranges randomly between 3 to 5000Hz, if the sample frequency and the detected signal frequency are synchronized or the later is a multiple of the former a serious sample error will be produced, and a very low beat frequency by the adjacent two frequencies will cause an compensating oscillation in the same beat frequency. In this paper several relatively prime sample frequencies are simultaneously used to sample two direction signal respectively, and the problems are solved better. Finally simulation and experiment results are given.