The development of variable frequency drive (VFD) technology stemmed from the widespread need for stepless speed control of AC motors. Traditional DC speed control technology was limited in its application due to its large size and high failure rate.
After the 1960s, power electronic devices widely adopted thyristors and their upgraded versions. However, their speed control performance was far from sufficient. In 1968, high-tech companies represented by Danfoss began mass-producing frequency converters, ushering in a new era of industrialization for frequency converters.
From the 1970s onwards, breakthroughs were made in the research of pulse width modulation variable voltage variable frequency (PWM-VVVF) speed control. After the 1980s, the improvement of microprocessor technology made it easier to implement various optimization algorithms.
In the mid-to-late 1980s, VVVF frequency converter technology in developed countries such as the US, Japan, Germany, and the UK became practical, and products entered the market and gained widespread application. The earliest frequency converters were likely developed by the Japanese based on British patents. However, the US and Germany, leveraging their advantages in electronic component manufacturing and electronic technology, quickly seized the high-end market.
Compared to the development of frequency converters abroad, my country's application of frequency converters started relatively late, only gaining widespread adoption in the late 1990s. The development of domestic frequency converter technology can be summarized as follows: the overall technology of frequency converters is relatively backward, and there is a significant gap compared to the advanced achievements in frequency control research abroad; there is a technological gap in the core components used in frequency converters. Currently, almost no domestic manufacturers can produce the key power devices needed for frequency converter production, resulting in our core technology being dependent on foreign countries and requiring imports; major products are concentrated in low-voltage products and the mid-to-low-end market. Due to low product reliability and manufacturing quality, domestic frequency converter products currently mainly target low-voltage and general-performance markets, while the high-performance, high-power market is mainly occupied by large foreign companies.
After entering the 21st century, domestic frequency converters gradually rose to prominence and have gradually seized the high-end market. Shanghai and Shenzhen have become the forefront of domestic frequency converter development.