Medium voltage frequency converter generally refers to the voltage of 660V~690V, 1140V frequency converter. At present, the medium voltage inverter is used in submersible electric pumps, water injection pumps, main shaft fans in coal mines, belt machines, coal diggers (explosion-proof) and other fields.High voltage inverter generally refers to the voltage greater than 1140V inverter. At present, pump loads are widely used in metallurgy, chemical industry, electric power, municipal water supply and mining industries. With the development of the market economy and the improvement of the degree of intelligence, the use of high voltage inverter to speed control the pump load is not only good for improving the process and improving product quality, but also the requirements of energy saving and equipment economic operation, which is an inevitable trend of sustainable development. There are many advantages to speed control of pump loads.