Abstract

Control systems for ac electric drive frequency converters are based on pulse width modulation (PWM) algorithms. Their use leads to problems: significant output voltage and current distortion, the appearance of shaft torque pulsation and its rotation frequency, and, as a result, an increase in vibrations and noise of the drive motor. Semiconductor PMW converters are also characterized by underutilized voltage. The solution to these problems is possible through applying space vector modulation (SVM) algorithms, however the voltage efficiency remains at the PWM level. To solve these problems, it is reasonable to use modified SVM algorithms that will provide semiconductor converter operation in the overmodulation mode. This article considers the development of overmodulation algorithms, the application of which will solve these problems. The following developed algorithms for the overmodulation of spatial vector control systems are presented: an alternating active overmodulation algorithm, adaptive overmodulation algorithm, and synchronous overmodulation algorithm. Their mathematical formulation is given. It is shown that overmodulation algorithms provide an increased voltage utilization factor of the autonomous inverter. When using the developed overmodulation algorithms, the output current of the autonomous inverter has a quasi-sinusoidal shape. The minimum autonomous inverter output current distortion coefficient is provided when using the synchronous overmodulation algorithm at a level of no more than 10%. The switching frequency of the autonomous inverter becomes lower, which leads to reduced switching losses. It is shown that the use of overmodulation algorithms is feasible and provides higher values of such indicators of electric energy conversion efficiency as: output current and voltage distortion coefficients, voltage utilization factor of the autonomous inverter, amplitude of the fundamental harmonic at the same value of the space vector modulation period and switching frequency.

中文翻译：

---

在空间矢量控制下提高自主逆变器的利用率

摘要

交流电驱动变频器的控制系统基于脉宽调制（PWM）算法。它们的使用会导致问题：输出电压和电流畸变严重，轴转矩脉动及其旋转频率的出现，结果导致驱动电动机的振动和噪声增加。半导体PMW转换器的特征还在于未充分利用电压。通过应用空间矢量调制（SVM）算法可以解决这些问题，但是电压效率仍保持在PWM级别。为了解决这些问题，合理的做法是使用改进的SVM算法，该算法将以过调制模式提供半导体转换器的工作。本文考虑了过调制算法的发展，其应用将解决这些问题。提出了以下针对空间矢量控制系统过调制的已开发算法：交替主动过调制算法，自适应过调制算法和同步过调制算法。给出了它们的数学公式。结果表明，过调制算法提高了自主逆变器的电压利用率。当使用开发的过调制算法时，自主逆变器的输出电流具有准正弦形状。使用同步过调制算法时，以不超过10％的水平提供最小的自主逆变器输出电流失真系数。自主逆变器的开关频率变得更低，从而降低了开关损耗。