为了降低开关损耗,中高功率逆变器运行的开关频率都比较低,通常只有几千 Hz 有时甚至只有几百 Hz,载波调制或是常规的 SVPWM 在降低开关频率之后会产生严重的电流畸变,需要使用特殊的开关策略控制逆变器.目前,适用于中高功率逆变器的控制策略主要有最优脉宽调制以及预测控制两大类.最优脉宽调制策略基于调制的思想,是一类较为成熟的逆变器低开关频率控制策略,应用广泛,但其计算量大、动态特性差的问题逐渐被学者们发现.预测控制虽然早在1983年就被提出,但由于当时控制器的硬件限制,一直没有引起重视,直至近年来才受到国内外学者的关注,并掀起了研究热潮.该文对最优脉宽调制以及预测控制进行了回顾,剖析了它们的设计思想,总结了近几年的研究成果,分析了各类方法的特点和局限,对待研究的问题进行了阐述,对未来的研究方向进行了展望.
In order to reduce switching losses, medium and high power motor drive systems operate at very low switching frequencies, which are usually several kilohertz or even several hundred hertz. Carrier modulation or ordinary SVPWM strategy will generate serious current distortion, owing to such low switching frequencies. Hence, special switching strategies are applied. Optimal pulse modulation and predictive control are commonly used for such special applications. Optimal pulse modulation is based on the idea of modulation. Although it is a mature and widely used method, its limitation,such as huge computation and low dynamic characteristics, has already been discovered by scholars. An alternative method is predictive control, which was proposed in 1983. However, due to the restriction of hardware, it took over 20 years to draw the attention of scholars. In recently, intensive research on predictive control started. In this paper, optimal pulse modulation and predictive control are reviewed and the design principles of two methods are analyzed. Research results of recent years are summarized while the benefits and defects of these methods are surveyed. Finally the problems worth for further investigations are prospected.