A new fast digital P-I-D control LLC resonant converter

This paper proposes a new fast response frequency digital control with multi-sampling point for LLC resonant dc-dc converter. In the power supply system, the digitally controlled LLC resonant converter will be widely used, because it is a high power efficiency characteristic. However it is necessary to improve the digital control method because the delay time based on calculation occurs. In the conventional method, the sampling rate is single and the calculation process of P-D and I controls are series. On the other hand, in the proposed method, the sampling rate is multiple and the calculation process of P-D and I controls are parallel. Since the calculation process is divided into P-D and I controls, they are calculated at different sampling rates and the fast P-D calculation result is obtained. Therefore, good transient responses are obtained as the real time P-D control is useful for a transient response.