Abstract: For the deficiencies of high cost and poor controllability in elevator brake power supplies controlled by analog chips, a brake power supply system based on a digital controller was designed. Using an STC32G microcontroller as the controller, the AC voltage was converted into DC voltage through a rectification and filtering circuit, and then using a Buck converter for voltage reduction to power the brake coil. The STC32G built-in 12 bit high-precision analog-to-digital converter (ADC) module was used for sampling voltage and current, and for real-time voltage feedback adjustment.Based on sliding mode control theory, the approaching law function was improved, and a new type of non singular terminal sliding mode controller was designed to further improve the dynamic response and anti-interference performance of the brake power supply.Finally, a simulation model based on Matlab/Simulink and an STC32G experimental platform were built to verify the effectiveness of the designed power supply.The results show that compared to the PI controller, the new non-singular terminal sliding mode controller improves the voltage recovery time by more than 62.5% and 66.7% under the conditions of reference voltage change and load mutation, respectively. The designed brake power supply system exhibits good dynamic and steady-state performance, as well as strong anti-interference capability.