China International Youth Conference on Electrical Engineering (CIYCEE 2024)

In order to mitigate grid-side current harmonics, a DC bus voltage feedback based virtual damping method for motor control in electrolytic capacitorless systems is proposed in this paper. Firstly, according to transfer function analysis, the virtual damping method with different configurations is thoroughly investigated, revealing the distortions in bus voltage and  motor phase currents that are triggered by LC resonance between line inductance and DC bus film capacitor. To solve this issue, a novel DC bus voltage feedback control loop is designed. In this way, a damping current is generated, and the corresponding damping voltage is injected into the driver through the principle of minimum perturbation, where the equivalent damping can be achieved. By using the proposed method, the DC bus current sensor is not needed, and the DC bus voltage distortion can be significantly reduced. Simulations are carried out to verify the effectiveness of the  proposed method.

Virtual damping,resonance,voltage feedback,electrolytic capacitorless drive,current feedback