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Switches
Published in Kevin Robinson, Practical Audio Electronics, 2020
Extending the scope of the topic beyond simple mechanical switches, four more involved approaches to switching electrical signals may be considered: electrically actuated mechanical switches (relays), mechanically actuated electronic switches (touch switches), switching transducers (sensor switches), and purely electronic switches. These four categories are examined briefly in the sections which follow.
Recent Trends in Transformer Technology
Published in S.V. Kulkarni, S.A. Khaparde, Transformer Engineering, 2017
With the rapid development in power electronics devices and topologies, the costs of the above schemes are expected to reduce in near future. Ensuring reliability of electronic switches is a concern. Topologies have also been suggested in the literature for distribution transformers [17].
Recent advances in printable carbon nanotube transistors for large-area active matrices
Published in Journal of Information Display, 2021
Kevin Schnittker, Muhammadeziz Tursunniyaz, Joseph B. Andrews
Active matrices allow for large-area distributed control using the minimum number of addressable connections. They are now ubiquitous in our everyday lives, enabling technologies such as displays and touch-screen sensors. In short, active matrices allow for each node to be addressed via an electronic switch. This ensures that individual nodes do not electrically affect surrounding nodes. If a system has m × n nodes, each node can be individually addressed using only m + n electrical connections [1]. A passive matrix offers the same advantage in terms of connectivity, but each node is electrically coupled with the nodes on a shared row, therefore bearing significant interdependencies and cross-talk that are deleterious [2]. A brief schematic diagram of a common active-matrix circuit with a two-transistor, one-capacitor (2T1C) architecture is shown in Figure 1A.
Asymmetric diode-clamped multi-level inverter based renewable power generation system
Published in International Journal of Electronics, 2021
Jinn-Chang Wu, Hurng-Liahng Jou, Syue-Yu Liou
Common MLI architectures include cascade H-bridge type (CHT) (Malarvizhi & Gnanambal, 2015; Nezhad et al., 2019; Wanjekeche, 2018), flying capacitor type (FCT) (Caris et al., 2017; Lei et al., 2017; Thielemans et al., 2012), and diode-clamped type (DCT) (Cui & Ge, 2018; Lee et al., 2018; Schaefer et al., 2017; Susheela et al., 2018; Zhou et al., 2017). In general, the voltage change in each switching operation for the power electronic switch is symmetric. Hence, more power semiconductor components are needed for the MLI with more voltage levels. However, asymmetric DC bus voltages can be provided to the H-bridge power converters to obtain asymmetric switching voltage in the CHT-MLI to increase the voltage levels without the penalty of increasing the amount of power semiconductor components (Nezhad et al., 2019). Nevertheless, the asymmetric switching is less used in the FCT-MLI and DCT-MLI.
Impact of symmetrical short-circuit fault on doubly-fed induction generator controller
Published in International Journal of Electronics, 2020
Muhammad Shahzad Nazir, Wang Qi
The primary protection device of DFIG converter is crowbar protection (Harandi et al., 2019). The crowbar resistance connects the active crowbar control device and prevents from restoring the DFIG control. The dc chopper brake resistor is connected in parallel with the dc-link capacitor to control overcharge under low grid voltage. This method can effectively suppress the over-voltage of IGBTs and disperse energy but has no effect on the rotor current value. It is installed in PMSGs as a dc-link capacitor protector in dc converter topology (Morais et al., 2019; Tawfiq et al., 2019). The similar technique of series dynamic brake resistance has been used in the stator-side of the generator (Phan & Trinh, 2019). Dynamic resistors in series can be installed in series with the rotor to limit the over-current of the rotor. In the controller, the power electronic switch is on in normal operation, and the resistance is off in fault state. In rotor windings, this resistance is connected in series (Lopez et al., 2015).