Switched-power-junction

In order to account for the abstraction of ideal, no power consuming switching in a bond graph with invariant causalities that holds for all system modes, Umarikar extended 0- and 1-junctions by allowing for more than one bond to impose an effort on a 0-junction and more than one bond imposing a flow on a 1-junction with the constraint that only one of the causality imposing bonds is active at a time instant [12, 13], These extensions are called switched power junctions and are not to be confused with controlled junctions to be referred to subsequently. Figure 2.2 illustrates the idea. 

As early as 1974, Thoma introduced the concept of time dependent junctions [24] in order to switch off and on connections between power ports. Mosterman picked up this idea and introduced controlled Junctions [21], In contrast to switched power junctions, a local control algorithm associated with a controlled junction switches off all adjacent bonds of a controlled junction when a switching device considered as an ideal switch turns off and re-activates all bonds when the switch is closed. That is, an ideal switch in ON-mode is represented by a standard 0- or 1-junction. In OFF-mode the junction is replaced by a source of value zero as shown in Fig. 2.10. 

Umarikar, A. C., Umanand, L. (2005). Modelling of switched systems in bond graphs using the concept of switched power junctions. Journal of the Franklin Institute, 342, 131-147. 

Junco et al. use this power inverter as an example for the application of their implementation of the non-standard switched power junctions (SPJs) (Chap. 2) in the modelling language of the 20sim modelling and simulation software [28]. In [29], and [30, Chap. 8], they model the transistor-diode pair in each half-bridge by means of a SPJ and address the dynamic behaviour of the healthy system. 

A number of research works on Z-source inverters has been reported in the literature (see, for instance, [42-44]). A bond graph model of a mono-phase Z-source inverter with a series RL load has been presented in [45]. The approach uses switched power junctions (SPJs) [20] and residual sinks [46]. 

Appendix Bond Graph Modeling and Simulation of a Power Electronic Inverter Using Switched Power Junctions... 

Accordingly, equations can be formulated for a switched power 1-junction. 

Josephson junctions may be arranged in a variety of ways for other purposes. Perhaps, the best-known application is to computers combinations of Josephson junctions can be designed to act as a very fast switch with low power dissipation or as a memory element. The theoretical switching time is about lOpsec and the power dissipation about InW, giving a product of switching time per power consumption several orders of magnitude better than that of transistors. 

Power supply capabilities for thermoelectric coolers range from the simple open-loop direct current supply with a switch to sophisticated feedback systems with close temperature regulation and fast response. The only limitation on the supply is that ripple be maintained at a point lower than 10 to 15%. Open-loop systems will generally contain a transformer, rectifiers, choke, and chassis with heat sink for the rectifiers. In feedback systems, a thermistor is used to sense temperature at the cold junction. This signal is compared with the desired temperature setting to obtain an error signal. 

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