Research on the application of selective harmonic elimination pulse width modulation technology in fire emergency power supply

Fire Emergency Power Supply (FEPS) can replace the mains power supply to supply power to the load and maintain the normal operation of firefighting equipment in the event of a fire and the mains power supply stops. At present, the main inverter control method used in FEPS on the market is sinusoidal pulse width modulation (SPWM) control, which is relatively mature. However, in order to improve the output voltage quality, the carrier frequency is often set relatively high when using SPWM control method, which leads to high switching losses in FEPS. This article uses Selective Harmonic Eliminated Pulse Width Modulation (SHEPWM) instead of SPWM to control FEPS. Based on Fourier analysis, a unipolar 1/2 cycle SHEPWM FEPS inverter model is established, and a unipolar 1/2 cycle SHEPWM FEPS control system is designed to control the phase, amplitude, and model freedom of the inverter output voltage. A comprehensive simulation model of SHEPWM FEPS was built in MATLAB SIMULINK. By changing the DC power supply and load, the simulation results were analyzed to verify the feasibility of applying SHEPWM technology in FEPS.