【作者】 王鹏宇；

【导师】 王明彦；

【作者基本信息】 哈尔滨工业大学 ， 电气工程， 2007， 硕士

【摘要】 由于大功率场合的变频调速方案可以收到显著的节能效果,因此,大功率交流电机变频调速技术的研究已经发展成各国节能事业的主导方向之一。随着变频技术的快速发展,逆变技术、PWM调制技术等相关领域都有了长足的发展,但作为变频器输入级的高功率整流器等技术却相对发展较慢。目前,多数变频器厂商的产品中采用不控整流二重化技术,其特点是结构简单,成本低,且相对于普通的不控整流结构,其交流侧电流谐波有了明显的改善。但其缺点仍十分明显,如交流侧THD仍较高,功率因数较低等,这将直接导致电力系统中谐波与无功的增加。围绕抑制谐波电流、提高整流器的功率因数等方向,本文提出了一种新型的复合型高功率因数整流器,并从拓扑结构、控制系统等几个方面展开深入研究。这种新型的复合型整流器拓扑结构,和传统的多重化整流器等相比,THD达到了电力系统小于5%的要求,功率因数在0.95以上,且当其作为三电平逆变器的输入级时,能够在整流侧实现NPC(中点钳位)控制功能,对改善三电平变频器的性能起着重要的作用。为了实现对拓扑结构实用性的验证,本文首先对复合型整流器主电路进行了研究,提出了基于瞬时无功功率理论的谐波检测控制策略以及滞环电流PWM调制方法。中点电位平衡问题是影响三电平变频器性能的一个重要问题,为了实现变频器输出性能的最优,本文实现了在整流侧进行NPC(中点钳位)控制的方法。这种方法和传统的在逆变侧进行中点电位平衡控制的方法相比,减轻了逆变侧的控制负担,减小了变频器输出电压、电流谐波,提高了三电平变频器的输出性能。最后,制作了一台以TMS320F2812为控制核心的复合型整流器低压小功率模拟实验样机,进行了实验研究工作。仿真和实验结果表明本文提出的新型复合型整流器拓扑结构及其控制策略能够实现中高压下的高功率因数和低输入电流谐波的电能变换。更多还原

【Abstract】 In virtue of the advantage of high-power variable frequency technology which can realize a significant power-saving effect, its research has developed into one of the national leading direction of power saving. With the rapid development of variable frequency technology, the inverter technology, PWM technology, and other relevant areas also have a considerable development. But rectifier technology which serves as the input unit of the high-power converters has developed slowly. Currently, the majority products of converter manufacturers use uncontrolled 12-pulse rectifier, of which the character is simple and low cost. Compared to the regular uncontrolled rectifier, its line-side current harmonics has been noticeably reduced. Its shortcomings, however, are still evident. For example, the value of THD remains high and power factor is low, both of which can lead directly to the high harmonics of power system and increasing reactive power. In order to inhibit harmonic current and improve the power factor, this paper proposes a novel type of hybrid high power factor rectifier, and researches its topology and control strategy.Compared to the traditional topology of multi-pulse rectifier, this novel hybrid rectifier realizes a lower THD, which is less than 5% required by the power system, and its power factor is above 0.95. Moreover, when used as an input unit of three-level converter, it can achieve the NPC (neutral-point clamp) control, which is important to improve the performance of three-level converter. To prove the practicability of the topology, the paper first analyzes the main circuit of the rectifier, and then presents a harmonic detection method based on the instantaneous reactive power theory and PWM hysteresis current control strategy.Neutral-point potential balancing, which influences the performance of three-level converter, is also important. In order to achieve the optimal output voltage of converter, this paper presents a control strategy for the NPC on rectifier side. Compared to the traditional ones, this method alleviates the burden of control on inverter side, reduces the output voltage and current harmonics of converter and improves the performance of three-level converter. Finally, a low voltage and low power hybrid rectifier, which is based on the control chip TMS320F2812, is designed and applied. Simulation and experiment results show that the proposed novel hybrid rectifier topology and control strategy can achieve power transformation of the high power factor and low input harmonic current under high voltage.更多还原