Key Issues and Improvement of High Power AC Current Source

Aiming at the characteristics of high power capacity and small waveform distortion in AC resistance testing of large cross-section conductor, an AC current supply based on PA52 power amplifier is proposed. According to the working principle of the improved Howland current pump and bridge circuit driving technology, the main circuit of power supply is designed, which is composed of voltage control current source and coupling transformer. The protection and compensation circuits are designed according to the characteristics of inductive load. The output capacity of AC current source is improved by means of parallel power amplifier and coupling transformer, and the coupling transformer is designed. Combined with the theoretical analysis and performance measurement, the feasibility of key technologies such as noise gain compensation, power amplifier parallel current expansion and coupling transformer rising current are verified.