Linear Stabilization of a DC Bus Supplying a Constant Power Load: A General Design Approach

Abstract

In this paper, an oscillation compensation technique is proposed to improve the stability margin of an electrical system constituted by a dc power supply, an LC filter, and a constant power load. This is realized here by an actuator (inverter-permanentmagnet synchronous motor). To design the compensator, input impedance of the constant power load and output impedance of the filter are required and derived in this paper. To develop the load input impedance expression, small signal approximation is employed and all dynamics are taken into account except by the inverter ones only, which can often be neglected in practical applications. Then, the control structure of the whole system is slightly modified to implement the oscillation compensation block that increases the stability margin, and thus, permits to reduce the dc-link capacitance value. In this paper, the proposed method is applied to an actuator designed for aerospace applications. The influence of the actuator control parameters and the input filter parameters on the stability of the dc-link voltage is discussed. Simulations and experimentations confirm the validity of the proposed approach.

Dynamic Assessment of Source–Load Interactions in Marine MVDC Distribution

“…Two-port MVDC distribution system. The system is partitioned at the arrow in accordance with stability definition and the conditions for measuring impedance/admittance [16], [35]. …”

“…These stability-related problems and their possible solutions can also be found in [16]- [24]. DC-side modeling of power electronic systems as impedance is reported in [16]- [18] for dc applications. These works show that the small-signal analysis is a suitable method to linearize the power electronic systems.…”

“…Another major challenge is the stability of the MVDC distribution system that arises due to the presence of the high-power motor drives and their constant power load (CPL) behavior [15]. These stability-related problems and their possible solutions can also be found in [16]- [24]. DC-side modeling of power electronic systems as impedance is reported in [16]- [18] for dc applications.…”

“…These works show that the small-signal analysis is a suitable method to linearize the power electronic systems. Furthermore, the impedance stability criteria can be applied to assess the relative stability by means of Nyquist or Bode diagrams [16]- [18]. This is further extended to multiterminal dc systems in [19].…”

Bifurcation Analysis of a DC–DC Bidirectional Power Converter Operating with Constant Power Loads

“…In this way, assuming the above hypothesis, the dynamic behaviors of these two sources are not taken into account in this work. Furthermore, a DC architecture is based on multistage power converters where point-of-load (POL) converters can be seen by the feeder converter as CPLs, namely P L [Emadi et al, 2006;Liutanakul et al, 2010;Kwasinski et al, 2011]. Fig.…”