Low-frequency harmonic current suppression for a dc pulsed power supply based on improved ADRC
Abstract: The instantaneous output power of a dc pulsed power supply (DPPS) pulsates, resulting in the generation of low-frequency harmonic current (LFHC) in a front-end dc-dc converter. To suppress the LFHC and improve the dynamic performance of the front-end dc-dc converter, an improved active disturbance rejection control (ADRC) is proposed, taking into account the closed-loop output impedance. A moving average filter (MAF) and a phase-leading network (PN) are embedded in the forward path of the ADRC. The low gain characteristics of the MAF at the pulse repetition frequency (fpr) and its integer multiples are utilized to effectively suppress the propagation of the LFHC. The addition of a PN allows the voltage-loop cutoff frequency to exceed fpr, thereby significantly improving the load transient response of the system. Furthermore, a closed-loop parameter design method based on frequency response analysis is introduced. Finally, an 800W (average)/2kW (peak) DPPS was fabricated and tested, and the experimental results verified the effectiveness of the proposed control strategy.
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