Today, many electrical systems are demanding higher operating voltages and temperatures, along with higher capacitance values – particularly in the fast-growing area of power electronics for electric vehicles (EVs). Therefore, electrical design engineers are looking to use multilayer ceramic capacitors (MLCCs) in these applications due to their inherent low inductance and wide operating temperature range.
Impedance, measured in ohms, extends the concept of “opposition” to alternating current (AC) applications. It accounts for resistance, the opposition of current flow, and reactance, the measure of opposing alternating current – an effect of inductance and/or capacitance. In direct current (DC) applications, we talk in terms of resistance, not reactance. Chances are: This isn’t new information. But there’s a reason we wanted to cover this topic – impedance values play an important role in capacitor selection.
Space missions present a unique set of environmental challenges that demand high reliability down to the smallest electronic components. Mission failures could cost human lives. From in-flight systems to power supplies, every single system contributes to the success of a space project, so they must maintain high quality and safety standards for long durations.
In power electronics, rectification is the conversion of alternating current (AC) to direct current (DC). After the AC signal enters a rectifier circuit consisting of power diodes, the resulting raw rectified waveform yields a series of half sine waves with significant ripple. In order to minimize the pulsating DC voltage, a smoothing capacitor is placed in parallel with the load across the rectifier output. As the rectifier voltage rises, the capacitor charges and stores energy like a reservoir. Then when the rectifier voltage falls, the capacitor discharges, greatly reducing the ripple voltage.
As more consumers consider trading in their combustion vehicles for electric vehicles (EVs), EV manufacturers are trying to rapidly innovate on internal and external charging technologies to ease consumer fears relating to range anxiety and charging times. Therefore, EV manufacturers are focused on developing technologies that will increase the efficiency of both on-board and external power conversion and management devices.
To help customers with filter selection, we generally provide a lot of information on what our filters can do. But in this new Filter Basics Series, we are taking a step back to cover some background information on how filters do what they do. Regardless of the technology behind the filter, there are several key concepts that all filters share that we will dive into throughout this series. By providing this detailed fundamental filter information, we hope to help you simplify your future filtering decisions.
To kick-off this series, our first post breaks down the basic properties impacting capacitor and inductor performance including resistance, capacitance, inductance, and impedance.
Capacitors are essential passive components for designing any electrical circuit. But there are so many options to choose from with a wide range of specifications that it can be overwhelming to determine what capacitor may be the best fit for your application. One early decision that circuit designers must make is to determine if a single-layer capacitor (SLC) or multi-layer ceramic capacitor (MLCC) is the right fit for their application needs.
When an electrical device fails, oftentimes, the root cause can be traced to a field failure of a capacitor. While it is rare for the failure to be caused by a capacitor defect that was introduced during manufacturing, it can happen. This is especially true when multi-layer ceramic capacitors (MLCCs) are used versus other more simplistic capacitor types such as single-layer capacitors (SLCs) since the manufacturing process involves stacking many layers of dielectric and electrodes on top one another.
In recent years, multilayer ceramic capacitors (MLCCs) have emerged as an excellent capacitor option for the high-power electrical systems needed in electric vehicle (EVs) due to their small physical size, low inductance, and ability to operate at higher temperatures. However, EV engineers are facing two big challenges with using MLCCs including DC bias that can cause capacitance loses of 80 to 90 percent of their quoted value and self-heating issues from AC ripple that can lead to inefficiencies in circuits as well as increased cooling demands.
Many power electronics today are being designed for use in high-temperature, high-voltage environments, such as inside electric vehicles (EVs). However, size, weight, and power (SWaP) are also key factors driving electronic product development. These conflicting design criteria are an issue for many electrical engineers because space is not available to simply add a cooling system, as this will add weight and increase the product’s overall footprint. Therefore, many of these electronic components are susceptible to “running hot” at the high temperatures and high voltages used in these tiny spaces.