https://us02web.zoom.us/j/83155749569?pwd=bjZmVVNoUk5YYnBKd0gxR2QxZkcvUT09
The passcode is: 510054
Speaker: Jun Lin
Ph.d. student under the supervision of Prof. George Weiss
Wednesday, December 23rd, 2020, at 15:00
Plug-and-play control of Virtual Infinite Capacitor
Abstract:
We discuss the design and implementation of the virtual infinite capacitor (VIC), which is a nonlinear active capacitor realized using a bidirectional converter. It can replace large and unreliable electrolytic capacitors, and it is intended for DC systems where random fluctuations of the DC bus voltage may occur, i.e., no a-priori knowledge of the ripple frequencies is required (except a reasonable range). To make the VIC easy to use, like a conventional passive capacitor, several plug-and-play or decentralized control algorithms have been proposed, where the circuit has only two terminals and the DC voltage does not have to be known in advance.
We focus here on the so-called "direct" and "indirect" approaches. In the direct control approach, the DC bus voltage is the control target, and the VIC is considered as a “source”. The PnP VIC automatically adjusts the reference of the terminal voltage of the VIC until the equilibrium voltage of the DC bus is reached. It needs a mechanism, termed “charge balance control” to compensate the losses within the bidirectional converter. Whereas for the indirect approach, the VIC is considered as a “load”. The buffering capacitor charge is directly regulated, resulting in much better dynamics under sudden load variations. This choice of control leads to a much simpler control structure, as the charge balance control loop is not needed.
Towards the end of the presentation, we will talk about the virtual oscillator based decentralized control. Several VICs on a DC microgrid can share the total energy ripples in proportion to their storage capacities. A frequency adaptive control law is proposed such that each VIC can deal with ripples at an unknown frequency.
השתתפות בסמינר תיתן קרדיט שמיעה = עפ"י רישום שם מלא + מספר ת.ז. בצ'אט
