Vector Control of Pump Unit Electric Drive with Medium Voltage Induction Motor

摘要

When operating powerful pump units with medium voltage induction motors, the possible mechanical shocks during start-up and load ripple must be taken into account. Any abrupt change in torque on the motor side, or on the load side, leads to mechanical loads and fatigue in the shafts. Sudden changes in torque can lead to hydraulic shocks in the piping system. This is one of the factors, together with the thermal overload, preferably of soft-start methods, by using a soft-start or a frequency converter. The latter provides an additional advantage - it can cover changes in load resistances during operation and also allows you to quickly go through any resonant frequencies at start-up and avoid operation at these frequencies. The need for speed control is obvious when the technological process itself requires it. In circulating centrifugal pump units in systems with low static head, the reduction of the speed, respectively the flow, leads to a reduction of the energy consumption. The greater the static head in the system, the smaller the savings, but still there. Therefore, when the technological process allows to reduce the productivity by frequency control, a large energy savings can be implemented. Additional savings are achieved by increasing the life of the equipment. Paper deals with energy savings by vector control of a medium voltage induction motor driving a centrifugal pump unit.