Passivity-Based Design of Resonant Current Controllers Without Involving Partial Derivative

In terms of digital control delay, dissipation of the current controller is necessary to enhance the interactive stability between grid-following converters and the grid. The key principle is to make the real part of the converter output admittance non-negative below Nyquist frequency. Besides the fundamental current control, a phase-lead compensation should be introduced for the dissipative design of harmonic resonant controllers. However, derivation of the compensation angle requires calculating the partial derivative of real part of converter output admittance, which is nontrivial, especially in the presence of grid voltage feedforward. This letter provides a simple calculation method for the compensation angle to achieve dissipativity, and its effectiveness is verified through experiments.