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The exchanging recurrence is an imperative control parameter of PWM rectifier to diminish exchanging misfortunes and EMI clamor. This paper proposed a variable exchanging recurrence PWM (VSFPWM) methodology for DC-connect voltage swell control in two-level rectifier. DC-connect voltage swell is controlled by the DC-interface current straightforwardly, and can be anticipated synchronously with PWM signals. An ongoing forecast model of DC-interface voltage swell is determined for a typical voltage arranged control (VOC) PWM rectifier. At that point, VSFPWM control is presented, which changes the changing recurrence cycle to cycle with a confinement of DC-connect voltage swell pinnacle esteem. Moreover, the dynamic conduct is additionally seen when the proposed VSFPWM control plot is received. Detail recreation and test correlations are done among VSFPWM and typical consistent exchanging recurrence PWM (CSFPWM), which exhibit the benefits of the proposed technique.
Fig.1 Control structure of AFE rectifier
EXPECTED SIMULATION RESULTS
Fig.2 Comparison between the prediction and the simulation results of the
DC-link voltage ripple in one line-cycle
Fig.3 DC-link voltage ripple comparison
Fig.4 Switching frequency comparison
Fig.5 AC-side current
Fig.6 Spectrum comparison (a) AC-side (2) DC-link
Fig.7 Step response (a) Step response of DC-link voltage (f) The change of
switching frequency with VSFPWM
The commitment of this paper is build up the VSFPWM procedure for DC-connect voltage swell control. Unique in relation to the past work on the AC-side current swell or torque swell, the DC-interface voltage swell is almost not influenced by the PWM current swell of AC-side. In a rectifier framework, the DC-connect voltage swell is dictated by the PWM technique and load current, and the pinnacle estimation of it is essential for DC-interface capacitor structure or choice. The proposed VSFPWM completely uses the opportunity of exchanging recurrence, which is regularly ignored in the PWM module. In any case, the proposed VSFPWM is unique in relation to the irregular PWM , which changes the exchanging recurrence dependent on the insights and no expectation show is utilized. It ought to be noticed that the proposed system can be connected to an alternate power factor than the unitary one and not can be connected direct to the rectifier with nonpartisan wire (four wire). Barely any ends can be determined as pursues:
(1) DC-interface voltage swell expectation model can be worked in the time sensitive area. With the three-stage obligation cycles, AC-side current and load current estimated by the present sensors, the DC-interface voltage swell pinnacle can be anticipated for refreshing the exchanging recurrence in next cycle. The forecast strategy additionally applies to other PWM strategies, and furthermore be utilized for structure and investigation of DC capacitors and DC battery dependability.
(2) In an entire line period, the exchanging recurrence of VSFPWM consistently changes beneath the planned steady exchanging recurrence, keeping the DC-interface voltage swell constantly under the prerequisite. Utilizing the proposed VSFPWM methodology, the exchanging misfortunes decline fundamentally, and EMI commotion decreases particularly.
(3) The dynamic property of VSFPWM is right off the bat explored in an ordinary shut circle control framework. Actually, VSFPWM still has a decent unique reaction, without about debilitating the following execution appeared normal CSFPWM. The open-circle Bode plot shows the VSFPWM strategies simply decline a tad of transfer speed of both voltage control circle and the current in CSFPWM as a result of the decrease of normal exchanging recurrence.