Induction Heating System Topology Review

Focus:

This 28-page application note explains the principles of operation for induction heating (IH) systems, with extensive discussion on the power converters used in these systems. Faraday’s and Ampere’s laws and skin effect are used to explain principles of induction. Discussion of power converter requirements starts with an explanation of how resonant conversion enables lower switching losses than hard-switching, and the benefits of zero-voltage switching (ZVS) over zero-current switching (ZCS). The article proceeds to describe operation of an IH rice cooker with attention to its power converter requirements, particularly the control circuitry. Advantages and disadvantages of two resonant converter topologies--the half-bridge series and the quasi-resonant--are discussed. Operation of an IH power system based on a half-bridge series resonant converter is explained at length followed by a similar discussion for a system based on a quasi-resonant converter. With the rice cooker power system discussion as background, the operation of a power system for an IH cooker (a.k.a stove or range) is explained and an application circuit for an IH cooker power system based on a quasi-resonant converter is presented and its operation is explained. Article concludes with a list of references on power system design for induction heating.

What you’ll learn:

• How to understand the principles of operation for induction heating applications and their power systems
• How to understand the operation of the half-bridge series and quasi-resonant converters in induction heating cookers (stoves) and rice cookers
• How to determine values of resonant inductance and capacitance in induction heating applications

Notes:

Fairchild Semiconductor Application Note AN9012, Rev D, published July 2000.

View the Source

Author & Publication:

no author specified, Discrete Application Power Device Division, Fairchild Semiconductor, Vendor website, Jul 01 2000

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