Study of Reduction Method of Harmonic Currents in Power Systems Generated by Switching Regulators

对于小容量的整流电路，如消费类电子产品和家用电器，一般采用电容输入型整流电路。众所周知，电力系统谐波的产生已成为一个社会问题。对于这种电源，各种带有电容输入整流器的开关稳压器已经变得更加常见，通常用于电视机。因此，随着这些设备的应用范围的扩大，在电力系统中产生了各种各样的谐波。谐波问题将在未来变得更加严重。这种设备将更多地用于类似的工业应用。在这种情况下，已经研究和报道了各种改进的电路来降低谐波。然而，它们的目的是使输入电流波形为正弦，从而增加了成本。电容输入式整流电路所产生的谐波，除三次和五次谐波外，不随电力系统中设备数量的增加而成比例增加，并保持恒定的某一值。考虑到电力系统中变压器所消除的三次谐波以及对输入电流进行正弦波化的成本较高，我们不必坚持使输入电流为正弦波。从这个角度出发，我们研究了一种降低正激变换器整流电路谐波的方法，正激变换器多用于各种开关稳压器。所提出的开关稳压器既能降低自身谐波，又能消除电力系统中其他整流电路产生的谐波。作者在各种期刊上报道了各种消除谐波的技术来降低电力系统中的谐波。

For rectifier circuits with small capacity such as those for consumer electronics and appliances, capacitor input type rectifier circuits are generally used. It is well known that the generation of the harmonics in the power system becomes a social problem. For such power supply, various switching regulators with capacitor input rectifiers have become more common, typically for the television set. Consequently, as the application of those equipment is expanded, various harmonics are much generated in the power system. The harmonics problem will become more serious in the future. Such equipment will be more used similarly in industrial applications.Under such circumstances, various improved circuits to reduce harmonics have been studied and reported. However, their purposes are intended to make the input current waveform sinusoidal, thereby increasing the cost. The harmonics generated by the capacitor input type rectifier circuit, except the third and fifth harmonics, do not increase in proportion to the number of the equipment in the power system, and are kept constant a certain value. Considering that the third harmonics eliminated by the transformer of the power system and the cost is high for sinusoidalizing the input current, we need not persist on making the input current sinusoida 1wave.From such point of view, we have studied a method to reduce the harmonics for the rectifier circuit of the forward converter, which is more used in a variety switching regulators. The proposed switching regulators do not only reduce their own harmonics but also eliminate other harmonics in the power system which are generated by other rectifier circuits. The authors have reported various harmonic eliminating techniques to reduce the harmonics in the power system in various periodicals.