可切换智能负载的T型三电平电力弹簧负载电压谐波含量和超调量研究

Study on Harmonic Content and Overshoot of Load Voltage of T-type Three-Level Electric Spring with Switchable Smart Loads

首次把单相T型三电平逆变器应用在可切换智能负载的电力弹簧中,降低了负载电压的谐波含量,建立了可切换智能负载的T型三电平电力弹簧的数学模型。并推导了传统载波调制对可切换智能负载的T型三电平电力弹簧直流侧中点电位的影响,引入了中点电位控制方案,结合积分分离控制思想得到了可切换智能负载的T型三电平电力弹簧的控制策略。该控制策略能有效降低负载电压在网侧电压波动时的超调量。最后,通过Matlab/Simulink仿真验证,在稳关键和非关键负载电压时,改进后的谐波含量降低了3.47%和1.65%,超调量降低了0.34%和0.1%。

The single-phase T-type three-level inverter is firstly applied to the electric spring with switchable smart load,which reduces the harmonic content of the load voltage and a mathematical model of the T-type three-level electric spring with switchable smart load is established.And,the influence of the traditional carrier modulation on the mid-point potential of the T-type three-level electric spring with switchable smart load on the DC side is derived,and the control scheme of the mid-point potential is introduced,which combines with the integral separation control idea to obtain the control strategy of the T-type three-level electric spring with switchable smart load.The control strategy can effectively reduce the overshoot of the load voltage during the fluctuation of the grid voltage.Finally,it is verified by Matlab/Simulink simulation that the improved harmonic content is reduced by 3.47%and 1.65%,and the overshoot is reduced by 0.34%and 0.1%when stabilizing the critical and non-critical load voltages.