基于离散变频的异步电动机软启动器设计

The Design of Asynchronous Motor Soft Starter Based on Discrete Variable Frequency

关键词:  异步电机  软启动器  离散变频  电流检测

Key Words:asynchronous motor  soft starter  discrete variable frequency  current-sensing

摘要:针对异步电机起动转矩小、起动电流大、且无法起动重载等问题,设计了一种基于离散变频控制方法的软启动器。首先设计了基于三相反并联晶闸管主电路和高性能DSP28335主控制器的软启动器硬件,利用高速A/D实现电流有效值计算。然后分析基于离散变频的软起动控制策略,提出7-4-3分频之后转工频调压的软起动方法并完成离散变频软件设计。最后通过Matlab仿真和在某造纸厂的制浆车间试验表明，离散变频软起动方法在相同负载率下可以有效降低起动电流,从而验证离散变频的有效性。

Abstract:Aiming at the problems of asynchronous motor such as small starting torque, large starting current and can not starting heavy-load, a soft starter based on discrete variable frequency control method was designed. Firstly, the hardware of soft starter based on three-phase anti parallel thyristor main circuit and high performance DSP28335 was designed, the calculating the effective value of current using high speed A/D was realized. Then, the soft start control strategy based on discrete variable frequency was analyzed, the soft starting method of 7-4-3 frequency division to power frequency voltage regulation was presented and the discrete frequency software design was completed. Finally, the Matlab simulation and experimental results showed that the discrete variable frequency soft start method could effectively reduce the starting current at the same load rate, the efficiency of discrete frequency conversion was verified．