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Magnetic Ceramics
Published in Lionel M. Levinson, Electronic Ceramics, 2020
Although the naturally occurring ferrite, magnetite, has been known for a very long time, the first practical use of a synthetic ferrite was not until the twentieth century. The discovery of modern ferrites is attributed to Kato and Takei (1), who examined some cobalt ferrites in the early 1930s. Shortly after that, Snoek (1936) and his coworkers (2) at the Philips Research Laboratories in the Netherlands developed the first soft ferrites for commercial applications. Néel (3) published the first explanatory theories on the origin of magnetism in ferrites. Further investigation on the technology of ferrites was made by Guillaud (4) and his coworkers. After World War II, there was rapid development of many types of ferrites, including those for high-frequency uses, for microwave applications, and as permanent magnets. With the availability of purified raw materials and highly developed ferrite technology of powder making and sintering, magnetic properties have improved significantly so that they compete strongly with metallic magnetic materials. The present heightened interest in ferrites is brought about by the recent growth in the use of high-frequency power supplies, primarily for computers and other digital devices. This type of power supply uses transistor switching and is therefore called a switched mode power supply.
Integrated Switched-Mode Power Converters
Published in Ali Emadi, Alireza Khaligh, Zhong Nie, Young Joo Lee, and Digital Control, 2017
Ali Emadi, Alireza Khaligh, Zhong Nie, Young Joo Lee
An SMPS offers three main advantages over a conventional linear power supply: high efficiency and less heat generation, tighter regulation, and small size and weight. Conventional linear power suppliers are inefficient because they regulate by dumping the excess power into heat. Conventional linear power supplies are typically 40%–50% efficient, while switches have efficiencies from 60%–90%. Another key benefit of SMPSs is their ability to closely regulate the output voltage. Switched-mode supplies regulate continuously and follow load changes almost immediately. In addition, switchers have the unique ability to maintain the correct output under low input conditions. In fact, switchers can actually produce an output voltage that is higher than the DC voltage applied to the input. A final advantage of switchers is their relatively small size and weight. Because switches operate at high frequencies, the parts are smaller than those needed for a conventional 60 Hz power supply of small power rating. The transformers, capacitors, and coils are also physically smaller and lighter [1]-[5].
Applications II – power supplies
Published in D.A. Bradley, Power Electronics, 2017
If a comparison is made between a conventional, linear power supply and an SMPS of the same rating, the SMPS will be of smaller size, lighter weight and higher efficiency. It will also be less sensitive to variations in the input voltage level. On the debit side, an SMPS will tend to have a larger output ripple, a reduced dynamic response and a worse regulation. An SMPS may also be a source of both electromagnetic and radio frequency (RF) interference which may appear in the supply, as radiated noise or in the output.
Euler–Lagrange passivity-based controller for the three-level Ćuk PFC converter for electric vehicle battery charging application
Published in International Journal of Control, 2023
Kumari Shipra, Rakesh Maurya, S. N. Sharma
There is a growing demand for electric vehicles (EVs) compared to internal combustion engine-based (Williamson, 2013) automobiles due to various advantages, such as low maintenance, low transportation cost, high efficiency, low fuel consumption and reduction in CO2 emission (Larminie & Lowry, 2012). So, the efficient onboard EV battery chargers are getting more attention from researchers, academicians and practice engineers. Conventionally, the switched mode power supply (SMPS) has been widely used to provide regulated power supply for various electronic equipment such as personal computers, television sets, communication systems, data centres and battery chargers. In much equipment, high-power factor and low total harmonic distortion (THD) are the necessary parts for power supply to meet IEC 61000-3-2 Class C standard (I. F II, 1993). The improved power qualities in terms of supply current THD and input power factor are the primary requirements for the efficient EVs battery charger. To meet the needs related to power quality, several converter topologies, such as boost, Ćuk, and fly-back converter, are reported (Erickson & Maksimovic, 2007; Jha & Singh, 2016). Due to significant losses in the diode bridges, the low efficiency of the conventional power factor correction (PFC) is noticed. To improve the efficiency, a bridgeless Ćuk PFC converter is proposed in Fardoun et al. (2012). The concept of PFC using the Ćuk converter has many advantages such as low conduction losses and large voltage conversion ratio. In addition to the above, nowadays, a three-level (TL) converter topology has been proposed to reduce the filter size and the switching voltage stress (Choi & Lee, 2016; Ruan et al., 2008).
Analysis of the high-gain BOCUK DC-DC converter-based PFC using an LQR controller for SMPS applications
Published in Automatika, 2023
L. Annie Isabella, M.G. Umamaheswari, G. Marimuthu
SMPS uses a switching regulator to control and stabilize the load voltage by switching the load current on and off. It has a higher power conversion efficiency and low overall power loss and hence it is a reliable power source. Smaller size, less weight, high efficiency, higher performance and flexibility are the advantages of SMPS [1–3]. High-gain DC–DC converters are a type of switching power converter that provides high-voltage gain, low switching stress, low ripple and low cost when used as SMPS. Many researchers have constructed SMPS with a two-stage conversion method [3–5] for Power Factor Correction (PFC) and load voltage control utilizing an assembly of two DC–DC converters coupled in series. Two-stage conversion is replaced here by single-stage conversion technique involving dual-loop control. The inner loop shapes the line current, and the outer loop offers load voltage regulation. Single-stage conversion technique [6–12] with dual-loop control reduces the number of components and sensors used. Discontinuous Conduction Mode (DCM)-based converters [13] are not found to be attractive since the discontinuous input inductor current distorts source current, reduces efficiency and increases losses. Isolated (Flyback, push-pull, forward, etc.) and non-isolated (buck, boost, Cuk, etc.) converters are used for power conversion in SMPS applications. A transformer makes isolated converters [13–15] undesirable as the transformer core gets saturated. Due to the lack of a transformer, non-isolated converter topologies are typically preferred over isolated converter topologies and it has the following advantages such as low cost, small size, minimal weight, reduced losses and high efficiency. PFC converters play a vital role in reducing the high harmonic current levels and poor power factors in SMPS applications. PFC converters permit effective line current shaping and regulated load voltage. Protection of the utility from peak currents and emulation of the converter circuit as a resistor are desirable for implementing DC–DC converters in several applications. The Boost, Cuk and SEPIC converters prove more effective among DC–DC converters in PFC due to an input side inductance which is in series with the bridge rectifier. Boost converters [16] are often used for PFC, but they have significant drawbacks, including limited voltage gain, high-voltage stress over the semiconductor switch and high reverse recovery current across the diode, all of which reduce the converter’s efficiency. The DC–DC Cuk converter [17,18] can provide the load voltage with polarity inversion. This converter also offers good isolation, variation in voltage magnitude, current limit, higher steady-state performance and protection towards the short circuit. High current stresses on the switch and diode are major drawbacks of the DC–DC Cuk converter.