XINLI BOILER

Treatment method of overvoltage of biomass boiler frequency converter

13 Dec, 2021

　　(1) For the breaking overvoltage of the phase-shifting transformer of the frequency converter, a resistance-capacitance absorption network and a zinc oxide arrester are used to form an overvoltage absorption circuit, which has achieved better results.

　　(2) For the overvoltage generated by the transformer with load closing, you can choose a switch with good periodic performance (the switch will have a different period after long-term operation); use a good resistance-capacitance absorption circuit or active suppressor technical solution; use static electricity Transformers with shielding measures can also effectively suppress the closing overvoltage. However, the difficulty of making the electrostatic shielding layer for high-power transformers will be quite large.

　　(3) For the overvoltage generated by the commutation of the rectifier element, the points to note are: the reverse withstand voltage value of the rectifier element must be sufficient, and the absorption loop and the freewheeling loop must be properly measured. Otherwise, the rectifier device may be broken down by overvoltage. (4) Since the overvoltage of the inverter is basically generated when the transformer is opened and closed, it is necessary to start with the transformer to find ways to suppress the overvoltage of the inverter. You can use:

　　①Increase the magnetizing inductance and capacitance to ground of the transformer, and increasing the magnetizing inductance will reduce the no-load current, which will all cause an increase in the cost of the transformer.

　　②Increase the capacitance of the transformer to ground: It is easy to analyze in principle, but in fact, due to the structure and material limitations of the transformer itself, it is impossible to make a transformer with any insulation method or high insulation level, so it is necessary to increase it significantly The ground capacitance C of the transformer is also quite difficult.