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Countering Threats from Transients in Magnetics

In the realm of electrical engineering, transients in magnetic components pose significant challenges that can lead to system failures. Understanding and mitigating these threats is crucial for ensuring the reliability and longevity of electrical systems. This article delves into the origins of elec...

Understanding Electrical Transients in Magnetics

Electrical transients are sudden, short-duration spikes in voltage or current. They can arise from various sources such as lightning strikes, switching operations, or inherent instabilities within the system. These transients can cause severe stress on magnetic components, leading to potential malfunctions or catastrophic failures.

 

Causes of Electrical Transients

Electrical transients can originate from external factors like environmental conditions or input/output operations. Internally, they can be caused by the natural response of the system's reactive components: resistors, inductors, and capacitors. These components, governed by the laws of physics, react to changes in state variables, resulting in oscillations, amplification, or decay of signals.

 

Effects on Magnetic Components

Magnetic components, such as transformers and inductors, are particularly susceptible to transients. For instance, transformers can exhibit parasitic components that affect their response to sudden voltage or current changes. These parasitic elements can cause amplification, oscillation, or even breakdown under transient conditions.

 

Mitigating Transient Threats

Effective mitigation of transient threats involves understanding the behavior of magnetic components under dynamic conditions and implementing design strategies to counteract these effects.

 

Component Functions and Response

  1. Resistors: Dissipate energy to manage power levels.
  2. Inductors: Generate opposing voltages to slow current changes.
  3. Capacitors: Absorb or release charge to stabilize voltage changes.

The induced voltage and current in inductors and capacitors are inversely proportional to the circuit's time constant. A smaller time constant means faster energy transfer, which can lead to higher transient voltages or currents.

 

Transformer Design Considerations

Transformers must be designed to handle dynamic impedance transformations and provide necessary isolation. Realistic transformer models must account for parasitic components, which can significantly influence their behavior during transients. High voltage transformers, for instance, are prone to series resonance due to leakage inductance and self-capacitance, leading to oscillations and potential saturation.

 

Practical Mitigation Techniques

  1. High Bandwidth Instruments: Use to detect latent transient amplification and persistent ringing during normal operations.
  2. Worst Case Analysis: Evaluate bias currents and flux density for worst-case scenarios, including maximum voltage and temperature conditions.
  3. Current Transformer Verification: Ensure that protection circuits can detect transient overcurrents despite reduced output due to saturation.
  4. Residual Magnetization Control: Verify that residual magnetization does not impair operation, ensuring sufficient headroom for magnetization.
  5. Design of Experiments (DOEs), Risk Reduction Tests (RRTs), and Accelerated Stress Tests (ASTs): Implement these throughout the design stages to mitigate risks effectively.
  6. Protective Components: Use components like MOVs (Metal Oxide Varistors) to safeguard circuits from lightning-induced transients.

 

Countering threats from transients in magnetics requires a thorough understanding of the underlying causes and the implementation of robust design strategies. By employing high bandwidth detection instruments, performing worst-case analyses, and integrating protective measures, engineers can significantly reduce the risk of transient-induced failures in magnetic components. Adopting a proactive approach to design and testing ensures the resilience and reliability of electrical systems in the face of transient threats.

Published on 22 May 2020 by Victor W. Quinn / Stéphane PERES

New entity, Exxelia Magnetics

This is an internal merger of two innovative, professional and complementary companies both designer and manufacturer of high-end would magnetic components, which have a history of successfully working together for a year. Exxelia Magnetics will have greater scale, breadth and capabilities to compete more effectively in the global marketplace. Exxelia Microspire Microspire was founded in 1978 and became part of Exxelia Group in 2008. Exxelia Microspire has been designing, developing and manufacturing wound components for over 35 years: transformers and inductors, electro-magnets, rotors and stators. Exxelia Microspire has several manufacturing sites, notably newly located low production cost facilities offering competitive solutions. Exxelia Microspire’s know-how includes standard winding technologies: linear (in RM, ETD, EP, EFD, ER, EQ and other formats) and toroid. For harsh environment applications with shock, vibration, and high temperature issues, Microspire offers innovative specific technologies including SESI, TT and CCM. Exxelia Microspire’s qualified technologies, clearly defined design rules and industrial organization provide the platform on which it is able to offer its customers optimal solutions. Exxelia N'Ergy Exxelia N’Ergy (ex N’Ergy) was acquired in 2015 by Exxelia Group.  Exxelia N’Ergy designs and manufactures passive specific electromagnetic components in small and medium range: Transformers, Chokes, Sensors (tachometer, gyros, …), Electromagnets.

Exxelia onboard Solar Orbiter

Solar Orbiter, a European Space Agency mission, was launched on an Atlas V rocket 411 (AV-087) from Space Launch Complex 41 at Cape Canaveral Air Force Station at 11:03 p.m. EST on Sunday, Feb. 9 2020. The satellite reached its first working orbit around the Sun, called “halo orbit” and is ready to begin its first scientific observation campaign. The campaign will last six months, during which time the 55 payloads will be turned on one by one and tested before being used to perform scientific observations. Solar Orbiter is a highly complex scientific laboratory. Deploying such a mission is a one-of-a-kind achievement! The mission will take years and is one of the most highly anticipated scientific experiments of our time. And you know what they say: your best work comes when you're up against the toughest challenges. Unfortunately, these challenges aren't only in labs, but also in space. To study the Sun and its activity like never before, scientists are sending a probe into orbit around it. Solar Orbiter will be facing temperatures of up to 500°C, which is usually not survivable for complex equipment. But do you know what's even more challenging than getting data from a 500°C hot solar environment? Getting that data with expensive equipment that doesn't work, because you don't have enough reliable components at your disposal! That's why we, at Exxelia, were so happy when we heard that thousands of our capacitors and magnetics were chosen by the European Space Agency to achieve this mission; we're talking about components that will keep working in those kinds of harsh environments! They will help scientists better understand energy flow and particle acceleration within our own solar system and beyond. Shockingly, the Sun is mostly a mystery. We have some understanding of its composition, but it's unclear how the phenomena we see happen. Solar Orbiter is going to help us get a better idea of what makes the Sun tick by taking some of the most detailed images and observations of our star ever taken. Among the instruments on Solar Orbiter are: a Wide-Angle Imager and a Coronal Imager. Each will provide high-resolution images—an order of magnitude higher than those captured by NASA's Solar Dynamics Observatory—and spectacular views of the Sun's polar regions. The Wide-Angle Imager will capture images in five wavelengths, while the Coronal Imager will use seven wavelengths to observe phenomena that affect the upper layers of the solar atmosphere, such as magnetic fields and plasma flows. Our capacitors and magnetics are critical for stabilizing and powering these instruments on their mission to explore our home star! They need to be able to perform in a very hostile environment with temperatures ranging from -150°C (-238°F) to 500°C (932°F). Temperatures will reach their highest during the closest flybys of the Sun—which will take place as close as 15 million kilometers (about 93 million miles) from its surface. Our space capacitors and magnetics are capable of withstanding such high temperatures. They'll even keep functioning in cryogenic conditions, as low as -150°C (-238°F). These components are also very durable, which makes them perfectly suited for this mission.     Choosing the right capacitors for such a mission was not easy. The requirements and technical constraints were very strict. We had also to support and select the materials that could handle the launch vibrations and the shock of the rocket launching phase, we also had to achieve a very long life and high reliability in order to succeed in the mission. This project proves that our EXXELIA components are incredibly reliable and have nothing to envy to other electronic components on the market. Several other tests have been conducted by ESA in this project such as solar radiation, thermal shock... Exxelia ESA QLP Products Onboard Solar Orbiter : 14,400 CNC chips ceramic capacitors 14,400 CEC chips ceramic capacitors 520 of our CNC stacks ceramic capacitors 470 SESI QPL Inductors 380 MSCI RF Inductors  287 ESA qualified CTC21/E Tantalum Capacitors 50 ESA Film Capacitors PM94

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