High-performance Single-phase AC Electronic Load Design based on Active PFC and SPWM Control Strategy

Aiming at the problems of low simulation accuracy, slow dynamic response speed and poor grid-connected current quality in the current single-phase AC electronic load, this design deeply studies the efficient main power topology and load simulation strategy with fast dynamic response and low steady-state error. Based on the STM32F103C8T6 single-chip microcomputer platform, the system adopts the active power factor correction (APFC) dual-loop control strategy and unipolar modulation method to significantly improve the response speed of the system and reduce the steady-state error. In order to achieve adjustable power factor (PFC), this design adopts AC-DC-AC conversion topology. Among them, the front-end circuit is responsible for simulating the load characteristics, and a one-cycle control technology is used to ensure high-precision load simulation; the energy feedback unit of the latter stage uses the hysteresis current control technology, which effectively reduces the harmonic components in the input current, thereby improving the power factor. Through simulation analysis and actual circuit test verification, this design scheme shows significant improvement in simulation accuracy and dynamic response compared with traditional methods. Specifically, the 60 W single-phase AC electronic load constructed according to the above scheme can be flexibly adjusted in the power factor range of 0.70 to 0.94 under the condition that the input voltage U1 is 30 V and the current I1 is 2A, and the efficient feedback of electric energy to the power grid is realized. This design not only improves the overall performance of the single-phase AC electronic load, but also provides a feasible technical path for the effective utilization of energy, which has a good engineering application prospect.