Power supply circuit model and sliding mode control of supercritical unit boiler system commissioning

Abstract

AbstractIn the process of power control and commissioning of supercritical unit boiler system, there are some problems such as large steady‐state error and slow response speed. In order to optimize the control performance of supercritical unit boiler system, the power supply loop model and sliding mode control method of supercritical unit boiler system debugging power supply are proposed. Firstly, the power supply circuit model is established according to the data of voltage doubling rectifier circuit, inverter circuit, high frequency transformer and LC resonant circuit. Secondly, the capacitance voltage value and the inductance current value are calculated in the power supply circuit model. Finally, based on the numerical results, a terminal sliding mode controller and a linear sliding mode controller are established to complete the double closed‐loop terminal sliding mode control and realize the power control of the debugging power supply. The experimental results show that when the input voltage is 50 V and the current is 14 V, the input voltage and current waveforms remain stable. When the input voltage is between 40 and 50 V, the change of switching frequency is small, only increasing from 22 to 26 kHz. The steady state of the power supply is high, and when the input voltage increases, the DC offset is 21.2. The convergence time in the calculation process is less than 200 ms. The instantaneous change of inductance is 0.7 A. The steady‐state error is less than 0.005 V. The output voltage distortion rate is less than 4%. It is proved that this method has strong control performance in the supercritical unit boiler system.