A 25 kW, 25 kHz Induction Heating Power Supply for MOVPE System Using L-LC Resonant Inverter

Abstract

A topology named L-LC resonant inverter (RI) for induction heating (IH) applications takes most of the merits of the conventional series and parallel resonant schemes, while eliminating their limitations. In this paper, fundamental frequency AC analysis of L-LC RI is revisited, and a new operating point is suggested featuring enhanced current gain and near in-phase operation as compared to the conventional operating point. An approximate analysis of the circuit with square-wave voltage source is also described highlighting the effect of auxiliary inductor on the source current waveform. The analysis also leads to an optimum choice of the auxiliary inductance. The requirements of the metal organic vapour phase epitaxy (MOVPE) system in which a graphite susceptor is required to be heated to 1200 ∘ C demanding a 25 kW, 25 kHz IH power supply, the configuration of developed IH system, and experimental results are presented.

Design, Analysis and Experimental Verification of the Self-Resonant Inverter for Induction Heating Crucible Melting Furnace Based on IGBTs Connected in Parallel

“…As a conclusion from the presented literature review: the self-resonant converters for induction heating [21][22][23][24] are an applicable technology giving reliable and budget-friendly solutions; induction heating inverters, with an installed power higher than 10-15 kW for industrial and laboratory research purposes [29][30][31], can be constructed by IGBT transistors connected in parallel, but the literature presenting such applications specifically for self-resonated inverters is insufficient; although the paralleling of transistors is an object of significant research [40][41][42][43][44], the application of this topology in the self-resonance architectures requires additional investigation. In general, from the literature, it is clear that the topology of self-resonant inverters for induction crucible melting furnaces has the potential to reach higher powers with paralleled transistors.…”

“…A converter structure with proven application in induction heating, giving high power density and the ability to operate with soft-switching, is the full-bridge circuit with a parallel or series resonant tank, based on different modulation techniques, such as Phase-Shift Modulation (PSM), Pulse-Frequency Modulation (PFM), Pulse-Density Modulation (PDM) and Asymmetrical Duty-Cycle (ADC) [25][26][27][28][29][30][31]. These types of modulation offer flexible control over the wide range of output powers [25].…”

“…In the same class, transformer-based converters are the LLC resonant inverters. A powerful inverter of this type, rated at 25 kW with a fixed frequency of 25 kHz, is presented in [30]. Transformer-less topologies based on a full-bridge can be realised as matrix converters, whose topology requires bi-directional switches [31].…”