Ac speed regulation system is widel

Ac speed regulation system is widely used in industrial production, but it is easy to be affected by power grid voltage disturbance, such as voltage drop, voltage surge, voltage instantaneous interruption, etc. Voltage sags account for the vast majority of all voltage failures. The fault will last from 0.5 to 30 cycles until it is disconnected by a fuse or short circuit breaker. Grid voltage drop will interrupt the normal operation of frequency conversion speed regulation system, leading to the termination of some important loads and production process, which has a great impact on industrial applications.There are two possibilities for utilizing slip power: consumption or feedback to the grid. Therefore, modern asynchronous motor speed regulation system can be divided into three types according to different methods of dealing with sliding power: sliding power consumption type speed regulation system, sliding power feedback type speed regulation system and sliding power non-variable type speed regulation system.(1) slip power consumable speed regulation systemSlip power consumable speed regulation system is a speed regulation system which converts all slip power into heat energy for consumption. This speed control system is the least efficient. It reduces the speed, but at the cost of increasing the power consumption of slippage. Generally used for simple structure, low requirements of small capacity occasions.(2) slip power feedback type speed regulation systemIn the slip power feedback speed regulation system, only a small part of the slip power is consumed, and most of the slip power is fed back to the grid through the converter. The power of the feedback grid is inversely proportional to the speed.(3) variable slip power speed regulation systemNo matter the speed is high or low, even if the consumption of rotor copper loss is inevitable, the consumption of sliding power is basically the same, so the efficiency of this system is very high. At present, in the ac speed regulation system, this kind of system is most widely used.