Abstract : This paper mainly discusses the classification, characteristics, and typical circuit diagrams of current-source and voltage-source frequency converters, the implementation methods of modern medium-voltage frequency converter technology, the hazards and control methods of frequency converter harmonics, and proposes some relevant technical requirements to be considered when selecting medium-voltage frequency converters. Keywords : Frequency converter, current source, voltage source, three-level harmonics, power factor. With the rapid development of AC speed control technology, low-voltage AC frequency converters have been widely used as speed control devices. Medium-voltage frequency converters have also begun to be widely used after several years of development. This paper aims to explore how to better solve some common problems in the use of medium-voltage frequency converters, such as motor temperature rise, noise, and even frequency converter failures. 1. Implementation Methods of Frequency Conversion Technology Frequency conversion methods are divided into AC-AC and AC-DC-AC methods. Because AC-AC frequency converters have insurmountable disadvantages such as low power factor, many high-order harmonics, low output frequency, narrow range of variation, and a large number of components, most commonly used frequency converters adopt the AC-DC-AC conversion method. An AC-DC-AC inverter consists of three parts: a rectifier, an intermediate DC link, and an inverter. Based on the intermediate DC link, inverters are divided into two main categories : current-source inverters and voltage-source inverters. 1.1 Current-Source Inverter A typical main circuit structure is shown in Figure 1. [b][align=center]For more details, please click: Analysis of Medium and High Power Inverter Technology Applications[/align][/b]