电压补偿在变频调速系统中的应用研究

针对异步电动机在恒压频比控制策略下低频启动时重载启动转矩不足的问题,提出在交交变频调速系统中采用电压补偿措施来提高电动机的带载能力;介绍了电压补偿原理及补偿值计算公式,通过仿真实验对无电压补偿和有电压补偿时的频谱、转速、转矩及电动机具有不同负载时的电压补偿效果进行了对比。仿真结果表明,电压补偿在变频调速系统中具有良好的补偿效果:①在有电压补偿的情况下,定子输出电压谐波含量较大,波形对称性较好,电动机带负载能力较强。②电动机负载越大,其稳态运行时的转速越小,而启动转矩大小不变,转速的降落基本保持恒定。

Research on application of voltage compensation in frequency-conversion speed-regulation system

For problem that asynchronous motor has inadequate starting torque with heavy load during low-frequency starting under control strategy of constant proportion of voltage to frequency,the paper proposed to use voltage compensation measure to improve carrying capacity of motor in cycloconverter-fed frequency-conversion speed-regulation system.It introduced voltage compensation principle and calculation of compensation values,and compared spectrum,speed and torque with and without voltage compensation,and different voltage compensation effects of the motor with different loads.The simulation results show that the voltage compensation has good compensation effect in the frequency-conversion speed-regulation system: ① The stator output voltage has high harmonic content,the waveform has good symmetry,and motor has strong load capacity under voltage compensation.② The greater the motor load is,the slower its rotational speed becomes,but the starting torque remains unchanged,and the speed decline maintains substantially constant.