The structure of the LLCL filter The LLCL filter is a higher order filter. Its principle is to replace the capacitor C1 in the LCL filter with an LC resonant branch to achieve a better switching frequency harmonic filtering effect and reduce the volume. The inverter structure that adopts LLCL filter is shown as in Figure 1. […]
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A calculation method of ripple current was given in the design of a single inductance filter in the previous article, and another method of calculation of ripple current will be introduced here. Also considering that the prototype adopts the unipolar SPWM strategy, the expression of the bridge arm output voltage Uinv is Among them, M is […]
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The structure of the LCL filter The filtering capability of a single inductor is limited and the volume and loss are relatively large. However, the LCL type filter has the advantages of small size and low loss, and is widely used in grid-connected inverters. The grid-connected inverter structure using LCL filter is shown in Figure […]
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Overview of the network filter The PWM modulation of the grid inverter leads to a large number of switching frequency and its multiplier harmonic voltages in the output voltage of the bridge arm, and finally leads to corresponding harmonic currents in the grid current. However, in order to make the grid-connected inverter friendly to the […]
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