单周控制三相PFC中积分日间常数的影响

单周控制作为一种新型的控制方式被广泛应用于各种三相功率因数校正(PFC)电路的控制中。由于单周控制单元中的积分器需采用模拟电路实现,模拟电路积分时间常数易受电路参数的变化而变化。该文对单周控制三相六开关全桥PFC的三个积分器实现方案和单个积分器实现方案中时间常数的变化进行了分析,分析结果表明:积分时间常数变化时,三个积分器实现方案会在相电流中引入直流分量,并引起电流畸变;而在单个积分器实现方案中,可以自动抑制直流分量的产生。同时分析了积分时间常数与系统稳定性和电压应力之间的关系,提出了确定积分时间常数的原则。实验结果证明了理论分析的正确性。

The Effect of Integration Time Constant of One Cycle Controlled Three-Phase Power Factor Correction

One cycle control is broadly applied in so many three-phase power factor correction circuits as a new control method.But one cycle controller is usually realized by analog circuit and the parameter is easy to vary with the environment,so the integration time constant will vary at the same time.The effect of integration time constant variation to system performance is analysed in this paper about one cycle controlled three-phase six-switch PFC circuit.The result indicates that when the control equation is realized by three integrators,the variation will introduce dc component in the input phase current and the current waveform will be distorted,meanwhile,in single integration realization method,the dc component can be cancelled automatically and the waveform will not be effected.At the same time,how to determine the integration time constant is discussed from the viewpoint of system stability and switching voltage stress.All the findings are supported by the experimental results.