A Simple Average Current Sampling Method for Three-Phase Interleaved Three-Level DC-DC Converter

A novel average current sampling method (ACSM) for three-phase interleaved three-level DC-DC converter (TPTLC) is proposed in this paper. The proposed method effectively reduces the cost of current sensors by utilizing two dc-side current sensors to represent the average currents of six inductors. ACSM reduces the sampling frequency and the calculation burden on the Digital Signal Processor (DSP) by sampling at the lowest point of the triangular wave based on carrier modulation. Furthermore, ACSM mitigates sampling errors in steady-state operation. However, it is important to note that in non-ideal cases, the presence of ripple modulation waves can introduce sampling errors in ACSM. The main objective of this paper is to provide a detailed illustration of the ACSM method. To evaluate its performance, simulation models incorporating ACSM and voltage-current dual-loop control are developed. These models are used to qualitatively analyze the dynamic behaviors and compare them with traditional sampling techniques. The results obtained from the simulations confirm the effectiveness of the proposed ACSM, and indicate that any resulting errors have minimal impact on the output parameters. The proposed carrier-based sampling method demonstrates promising performance, offering a new degree of freedom for PWM converters.