Abstract : This paper introduces the development history and current status of inverter technology in China, and looks forward to its future development. Keywords : Inverter, Development, China In recent years, AC inverter technology has made rapid progress in China. Inverter speed control boasts superior performance in terms of speed range, speed accuracy, dynamic response, low-speed torque, communication function, intelligent control, power factor, energy saving, work efficiency, and ease of use, which are unmatched by other AC speed control methods. With its advantages of small size, light weight, strong versatility, wide application range, complete protection functions, high reliability, and simple operation, it is widely welcomed by industries such as steel, metallurgy, mining, petrochemical, pharmaceutical, food, textile, printing and dyeing, machinery, power, building materials, and papermaking. The economic and social benefits of using inverters are very significant. I. Overview of the Development of Inverter Technology in China : With the continuous development of production technology, the weaknesses of DC drives have gradually become apparent. The presence of a commutator increases the maintenance workload of DC motors, limiting their single-unit capacity, maximum speed, and operating environment. People turned to asynchronous motors, which are simpler in structure, more reliable in operation, easier to maintain, and cheaper. However, the speed control performance of asynchronous motors is insufficient to meet production requirements. Therefore, starting in the 1930s, research into AC speed control technology was undertaken, but progress was slow. For a considerable period, DC speed control dominated the electrical drive field with its superior performance. Since the 1960s, and especially since the 1970s, the rapid development of power electronics, control technology, and microelectronics has made AC speed control performance comparable to DC speed control. Currently, AC speed control is gradually replacing DC speed control. Over the past decade, my country's frequency converter industry has grown rapidly from nothing. Statistics show that there are currently more than 70 frequency converter manufacturers of varying sizes nationwide, with annual sales of around 700 million yuan. This only accounts for a small portion of the national frequency converter market; 80%-90% of the domestic market is occupied by various foreign frequency converters. Looking back at the development history of frequency converters in my country, the expectation of the Chinese people is to develop marketable products that suit my country's national conditions and gradually expand market share. my country is a developing country, and its research and development capabilities for many products lag behind those of developed countries. With reform and opening up and rapid economic development, a huge market has formed, open to both domestic and foreign companies, with many advanced products imported from developed countries. In the late 1980s, Dalian Electric Machinery Plant imported a frequency converter production line from Toshiba of Japan. The frequency converter model was 130G, using high-power transistors (GTRs) as power devices, an MCS-51 chip as the CPU, SPWM modulation, and a V/F=C control strategy. This may have been the earliest large-scale assembly of relatively advanced foreign frequency converters in my country. Although this type of frequency converter was not the best at the time, it was much more advanced than those using thyristors as power devices. In industrial applications, it was difficult to start under heavy loads, and the GTR power devices frequently failed, resulting in poor low-speed torque and reliability. Meanwhile, the Fuji inverters sold in my country were the G5/P5, and the Sanken inverters were the SVF, comparable to the 130G inverter in performance and reliability. In the early 1990s, Taiwan's Puchuan entered the mainland market, bringing the Pi89 inverter, a copy of the Japanese Kasuga KV-8. Its power supply wasn't a switching power supply; it used high-power transistors (GTR), an 8085 CPU, SPWM modulation, and a V/F=C control strategy. Puchuan's marketing strategy in mainland China differed from other manufacturers; it adopted the form of joint ventures. Within a short period, across the vast country, from south to north and east to west, it established joint ventures such as Qingpu, Hanpu, Xipu, Shangpu, Nanpu, Fangpu, Puda, and Putian. Its R&D center was located in Shenzhen, and later a joint venture factory was built in Dalian. This was the largest and most comprehensive inverter marketing network in China at the time. The chassis, main control board, and drive board for the inverters assembled by each joint venture were all manufactured in Taiwan and then shipped in. Thanks to the effective integration of domestic resources, sales performance was excellent in those years, and the Pi89 frequency converter became a major product in the domestic frequency converter market at the time. However, due to issues with product performance and quality, and the subsequent entry of frequency converters with better performance and quality into my country, the Pi89 frequency converter market quickly shrank and was eventually eliminated. At the same time, Taiwan's Yanggang Company entered the mainland market, forming a joint venture with Guizhou Radio Equipment Factory to create Donggang Company. Their products were similar to the Pi89 frequency converters, but their performance and quality were unsatisfactory, and they too quickly disappeared from the market. my country's electrical drive industry was established in 1954. At that time, the first batch of students specializing in this field graduated from various colleges and universities. Simultaneously, the Ministry of Machinery Industry established my country's first complete set of electrical drive equipment, which was the predecessor of the later Tianjin Electrical Drive Design Institute. Due to well-known reasons, in the late 1980s and early 1990s, very few technicians had any experience with frequency converters or were familiar with frequency conversion technology. In the joint venture of Puchuan, many technicians were seeing frequency converters for the first time. They learned frequency conversion technology during the assembly process and gradually mastered the development and application techniques, laying a foundation for similar work in the future. In 1993, Puchuan collaborated with the Department of Electrical Engineering at Tsinghua University to develop a voltage space vector control frequency converter. Several Tsinghua University graduate students were working on the development in Shenzhen. Their product is the PI97 and its improved versions, which are still sold today. Later, Anbangxin's frequency converters clearly show traces of the PI97. For a period, Puchuan and Lijia Taiwan formed a joint venture. The Lijia 4001 frequency converter was a copy of the Mingdian 86S, and the Lijia 5001 frequency converter imitated the Sanken MF. The Lijia 4001 frequency converter also used V/F, SPWM, GTR, and a 16-bit microcontroller CPU. Its power supply was already a switching power supply, and its overall performance was better than the PI89 and 130G, but still not ideal. More than 10 years have passed since Puchuan entered the mainland market. During this time, many frequency converter manufacturers have come and gone, totaling nearly 100. In recent years, the frequency converter market has undergone significant changes; many entered and exited quickly, leaving only about 70 remaining. In addition, there are many wholly-owned subsidiaries and joint ventures of foreign and Taiwanese manufacturers in China, such as ABB Beijing, SIEMENS Tianjin, Fuji, Taian, and Delta, all of which have wholly-owned or joint venture subsidiaries in China. During the assembly of frequency converters, our technical personnel have the opportunity to learn about advanced frequency converter technologies and management methods, and these personnel have become an important force in the domestic frequency converter technology field. Market competition has led to the rise of several large domestic companies, such as Huawei and Senlan. As the largest frequency converter manufacturer in China, Senlan started by making V/f control frequency converters, gradually improving and perfecting its frequency converter technology. Through years of technical practice, accumulation, and absorption of advanced foreign technologies, it has been able to develop vector control frequency converters with advanced rotor flux orientation and self-correcting algorithms for flux observation, achieving complete decoupling of magnetic field and torque, achieving 200% rated torque at 1Hz, and even 100% torque at zero frequency. Examples include the SB80 series frequency converters. Therefore, although there is still a gap between domestic and foreign frequency converter technology, it has narrowed. II. The Current Status and Development Prospects of Domestic Variable Frequency Technology There are already many variable frequency drive (VFD) manufacturers in China, but most of their products are V/f control and voltage space vector control VFDs. These are generally fine for loads with low speed control accuracy and dynamic performance requirements. This is the most common type of load in industrial applications, where reliability is paramount. The main reason for the low market share of domestically produced VFDs is their relatively poor product quality. V/f control and voltage space vector control VFDs are technically much simpler than vector control VFDs. However, because most domestic manufacturers operate on a workshop-style production model with limited testing methods, the consistency and stability of quality are difficult to guarantee. Even among V/f control VFDs, foreign products are of higher quality than domestic ones, likely due to differences in manufacturing processes. The biggest gap lies in the semiconductor power device manufacturing industry. A few years ago, some domestic manufacturers produced substandard GTRs (Glass Transistors), which were not used in VFD assembly. These manufacturers quickly disappeared, and the semiconductor power device manufacturing industry remains largely undeveloped. Furthermore, the domestic VFD manufacturing industry changes rapidly; new companies, often spun off from other companies, emerge frequently. This is both a good and a bad thing. The downside is that it has somewhat hampered the development of frequency converter technology. Another aspect of frequency converter technology is its application. For many years, the State Economic and Trade Commission, together with relevant national departments, has been committed to the development and promotion of frequency converter technology, providing key support in technology development and transformation. It organized evaluation and recommendation work for variable frequency speed control technology and made its promotion and application a key investment direction for energy-saving technological transformation projects for fans and pumps. At the same time, it encouraged units to adopt the "same loan, same repayment" approach, focusing on development, demonstration projects, and widespread application. The state established a fan and pump energy-saving center to provide information consulting and training. From 1995 to 1997, my country invested 350 million yuan in the transformation of variable frequency speed control technology for fans and pumps, with a total transformation capacity of 1 million KW, saving 700 million kWh of electricity annually, with an average investment payback period of about 2 years. According to relevant data, my country has achieved considerable success in the application of variable frequency speed control technology, with annual sales reaching several billion yuan, indicating that the application of frequency converters in my country is very widespread. From simple manual control to multi-machine control based on RS-485 networks, and complex control systems formed by networking with computers and PLCs, frequency converters (VDCs) are crucial in large-scale integrated automation systems, advanced control and optimization technologies, and large-scale specialized systems such as continuous casting and rolling production lines, high-speed paper production lines, cable and fiber optic production lines, chemical fiber production lines, and building material production lines. Their role is electrical drive control, requiring high levels of complexity, precision, and dynamic response, and they have completely replaced DC speed control technology. In recent years, VDCs have developed advanced control functions such as winding, lifting, and master-slave control, making system configuration more convenient and easier, and elevating VDC application technology to a new level. With the development of VDC technology and intensifying market competition, to seize market opportunities, it is essential to prioritize R&D, providing strong financial and human resources support to develop products with distinct intellectual property rights. Soon, Chinese-made VDCs will be on par with foreign products in terms of efficiency and quality, making the localization of VDC production inevitable.