Beijing Variable Frequency Power Supply Factory Quotation, Beijing Variable Frequency Power Supply Factory Phone, Beijing Variable Frequency Power Supply Factory Wholesale. Variable Frequency Power Supply is a common term in China, but more accurately, it should be called AC Power Frequency Converter, abbreviated as AFC. The entire history of variable frequency power supply development is largely in line with the advancement of electronic devices. Before and after the 1980s, electronic variable frequency power supplies were mainly based on Japanese small instrument power supplies, which were mostly made using crystal amplification. These entered mainland China through Taiwan in the 1980s. The characteristics of the power supplies during this period were: low power, good precision, and low efficiency. In the 1980s, China embarked on the path of reform and opening up, and during this phase, China's import and export equipment gradually increased, especially for electrical appliances such as microwave ovens and air conditioners. As a result, there was a high demand for high-power variable frequency power supplies for testing. Due to the inability of existing products to meet the demand for this market application, power supply manufacturers sought new technologies to expand the power of the power supplies. Based on the technical conditions and electronic devices of the time, there were two main developments: one was to maintain the crystal amplification method and use multiple machines in parallel to expand capacity; the other was to use power crystal modules. The multi-stage crystal amplification method required solving the circulating current issue and was inefficient, consuming too much during industrial production. The power crystal module variable frequency method had a slow response, limited power, low working voltage, and voltage withstand of about 600V. The output used PAM filtering (a combination of a single sine wave with low-frequency filtering), resulting in significant distortion of the output waveform. These two methods still did not meet the increasing demand for power, so when high-power loads required variable frequency testing, the method of motor-driven generator (M+G) was often used to meet the need.