1. The series connection has high power factor to the power grid. The intermediate frequency power supply is a voltage type series inverter power supply. The rectification has been working at zero degree. The rectification is not adjusted, and only the inverter is adjusted. Therefore, the power factor is high, greater than 0.95, and there is no higher harmonic. In all smelting plants, substantial benefits are provided to users in energy saving, operation and production.

2. Series connection can save power consumption. Because the series resonant circuit is designed with small reactive current, the power consumption is greatly reduced. 0.5T 300kW medium frequency furnace iron 1450 kwh power consumption 680 kwh, chemical steel 1600 kwh power consumption 720 kwh. The parallel thyristor 0.5T medium frequency furnace needs 500kW transformer to drive, while the series inverter 0.5T medium frequency furnace needs only 300kW transformer to work normally, and the power consumption is very small. With the increase of the furnace, the power consumption is reduced to 520 kwh / T, and the long-term calculation saves more than 100000 yuan per year.

3. The series connection keeps constant power output during the smelting process. Compared with the parallel inverter medium frequency power supply, the power regulation mode is different. The parallel medium frequency power supply adjusts the DC voltage, while the series inverter is not affected by the amount of furnace charge, and maintains constant power throughout the smelting process. Especially when smelting stainless steel, copper, industrial silicon, aluminum and other non-magnetic materials, it shows its advantages. Fast melting speed, less burning loss of furnace charge elements, better energy-saving effect and effective reduction of casting cost.

4. The power transformer has a small capacity. Taking the half ton furnace as an example, the half ton series medium frequency furnace only needs 300kW, and the low-voltage measurement voltage of the transformer is 380V. Thus, for general casting enterprises, only one transformer of less than 315KVA can be used, and power consumption such as lighting, traveling crane and water pump can share one transformer. In some areas, the power supply departments only require that the transformer is more than 315KW to pay 28 yuan per kwh per month, thus saving more than 100000 yuan per year.