| 摘要 |
<p>The total harmonic distortion (THD) of the output voltage and output current of an inverter is maintained within required ranges simultaneously. The inverter output voltage, the current from/to the grid and the grid voltage are measured and a control signal is generated to be converted into pulse-width-modulation signals to drive the inverter switches. The controller consists of a current outer loop and a voltage inner loop. Both the inner-loop and outer-loop controllers have an internal model having high gains at the fundamental and all harmonic frequencies of interest. The difference of the current reference and the current from/to the grid is fed into the outer-loop current controller and the output of the first internal model is fed into a transfer function block, of which the output is added onto the grid voltage to generate the voltage reference for the inner-loop controller. The difference of the voltage reference and the inverter output voltage is then fed into the internal model of the inner-loop voltage controller, of which the output is fed into another transfer function block to generate the control signal for the inverter, which is then converted into pulse-width-modulated signals to drive the inverter switches.</p> |
