Abstract
In applications of pulse-width modulation (PWM) rectifiers, the high quality of the DC power is required. The fluctuation of grid voltage and the switching of equipment connected to the DC supply are likely to cause a sudden change in the DC-link voltage, resulting in equipment instability or even damage. Considering the bandwidth of the closed-loop current dynamic, this paper presents a novel DC-link voltage control strategy of PWM rectifiers based on the reduced-order linear extended state observer (RLESO). Using a first-order RLESO to observe and even compensate the model variations caused by grid voltage and DC-link voltage fluctuations or load transients, the proposed method can effectively improve the dynamic performance against grid and load disturbances, as well as for sudden changes in DC-link reference voltage. Combined with frequency domain analysis, this paper theoretically analyzes the sensitivity, stability, and tracking performance of the proposed method, providing a basis for the selection of controller parameters. And finally, simulation and experimental results are presented to demonstrate its validity and the superiority over the traditional PI control strategy.
Highlights
Three-phase voltage-source pulse-width modulation (PWM) rectifiers have such advantages as sinusoidal grid current, adjustable DC-link voltage, operation at unit power factor and bidirectional energy flow [1]–[4], which is of great research significance and application value
Considering the bandwidth of the closed-loop current dynamic, this paper presents a novel DC-link voltage control strategy of PWM rectifiers based on the reduced-order linear extended state observer (RLESO)
Using a first-order RLESO to observe and even compensate the model variations caused by grid voltage and DC-link voltage fluctuations or load disturbance, the proposed method can effectively improve the dynamic performance against grid and load disturbances, as well as for sudden changes in DC-link reference voltage
Summary
Three-phase voltage-source PWM rectifiers have such advantages as sinusoidal grid current, adjustable DC-link voltage, operation at unit power factor and bidirectional energy flow [1]–[4], which is of great research significance and application value. Z. Pan et al.: DC-Link Voltage Disturbance Rejection Strategy of PWM Rectifiers Based on RLESO introduced a full discrete sliding mode controller and a load current estimator with the low-pass filter, but more tuning parameters are required. The authors in [15] proposed a nonlinear active disturbance rejection control method, which has good effects in resisting grid voltage disturbance and load disturbance without current sensors, but the nonlinear controller is difficult to be analyzed or designed in frequency domain. If the influence of current loop is considered, a higher-order observer is necessary In this paper, another mechanism model is constructed to analyze the causes of DC-link voltage fluctuations. Considering the bandwidth of the closed-loop current dynamic, this paper presents a novel DC-link voltage control strategy of PWM rectifiers based on the reduced-order linear extended state observer (RLESO).
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