Induction heating is widely used in industry and even consumer appliances as a contact-free heating technique with many distinct advantages. Although we have looked only at induction heating for industrial applications, some of its attributes make it attractive in the kitchen as well. Of course, the kitchen-cooking scenario is not as constrained or well-defined as […]
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Basics of induction heating, Part 3: Implementation
Induction heating is widely used in industry and even consumer appliances as a contact-free heating technique with many distinct advantages. The induction coil and workpiece are at the system’s core, but there’s much more to an induction-heating arrangement (Figure 1). In addition, there’s a power supply and resonant-tank circuit as a power amplifier which creates […]
Basics of induction heating, Part 2: Principles
Induction heating is widely used in industry and even consumer appliances as a contact-free heating technique with many distinct advantages. The understanding of induction heating begins with basic electromagnetic principles and that very ancient electrical component still in very wide use: the transformer. However, an induction-heating transformer does not resemble a standard AC-line power transformer, […]
Basics of induction heating, Part 1: Introduction
Induction heating is widely used in industry and even consumer appliances as a contact-free heating technique with many distinct advantages. A very common design challenge for many engineers is to manage and dissipate excess heat produced within or impinging on a system so the temperature of that system or some of its components does not […]
Unipolar vs. Bipolar drive for stepper motors, Part 3: drive ICs
Stepper motors can be configured for unipolar or bipolar drive; each approach has different performance attributes and tradeoffs. Despite their usefulness and suitability of stepper motors for precision positioning, especially in back-and-forth motion applications, one of the factors which delayed their widespread adoption was the challenge of providing the needed driver management. However, the introduction […]
Unipolar vs. Bipolar drive for stepper motors, Part 2: Tradeoffs
Stepper motors can be configured for unipolar or bipolar drive; each approach has different performance attributes and tradeoffs. The previous part of this article presented the basics of different coil windings and connections for unipolar and bipolar stepper-motor configurations. As in most engineering situations, the next questions are: what is the impact of these differences? […]
Unipolar vs. Bipolar drive for stepper motors, Part 1: principles
Stepper motors can be configured for unipolar or bipolar drive; each approach has different performance attributes and tradeoffs. Stepper motors are widely used, and, as with so many basic components, they are simple in some ways but also have multiple configurations and operating subtleties. For steppers (the “motor” part of the two-word term is often […]
Voltage rail splitters and virtual grounds for batteries and PFCs
Rail splitters are usually associated with battery-powered devices, but that’s not always the case. There are several definitions of a “rail splitter,” sometimes referred to as a “virtual ground” or “pseudo ground.” The most common meaning is creating a new “0V” reference point, usually the mid-point Vin/2 of a single supply voltage such as a […]
Power supply regulations, requirements, and standards
Regulatory standards cover safety and electromagnetic compatibility (EMC) and efficiency. Safety and EMC standards are relatively straightforward, and their numbers are limited. Efficiency is a different matter: Society’s drive to reduce greenhouse gas emissions results in increasingly sophisticated energy efficiency standards for all types of power converters. It started with relatively simple ENERGY STAR standards […]
Power supply control techniques
Power supply control has evolved from primitive ferroresonant regulation and linear power supplies to simple hysteretic control, analog voltage-mode control, analog current-mode control, and now various approaches to digital control. Compared with switched-mode power supplies, the output of ferroresonant designs is not as precisely regulated, while linear regulation can produce very tightly regulated and very […]