Development of a current source resonant inverter for high current MHz induction heating

Abstract

High frequency industrial induction heating processes typically employ resonant inverters to reach high efficiency at high power levels. Advancements in wide band gap (WBG) device technology has made it feasible to push the possible frequency of these processes into the MHz regime using solid state technology. Several topologies can be applied, each with advantages and drawbacks. This paper presents a current source resonant inverter (CSRI) employing a custom designed power module utilizing 1700V SiC MOSFETs for MHz operation of a high‐Q resonant tank for induction heating, which presents new challenges in the inverter module design. An integrated gate driver structure is demonstrated driving four MOSFETs in parallel in MHz operation. Theoretical analysis predicts substantial parasitic influence on inverter operation, and thus an inverter is constructed to provide experimental verification of MHz operation, while the challenges associated with high frequency CSRI operation are discussed. In the experimental inverter setup, the fabricated power module achieves >90% efficiency for a calculated reactive power of 170 kVA and 2.3 kW output power during unloaded operation, validating the inverter design for extension to higher power loaded operation.

Demonstration of a Class E push-pull resonant inverter for MHz induction heating

“…For low impedance induction heating loads as well as high frequency operation, the Class E push-pull topology investigated here is attractive for several reasons. These include constant current drawn from the DC source, and the use of a parallel resonant tank which allows for current gain as well as inherent work coil short circuit capability [9], [12], [13]. In addition, the switch gates are driven with reference to the same potential and, as shown in red and green in Fig.…”

“…This can be drastically improved by replacing the tubes with solid state devices, in particular by taking advantage of wide band gap (WBG) technology [4], [5]. In a variety of applications, DC-AC inverters (or equivalently, switched-mode amplifiers) operating with high efficiency at MHz frequencies and several kW have been demonstrated [6]- [9]. These advancements hold promise for further utilization of WBG devices for RF inverters in heating applications by pushing towards higher operating frequency, power delivery, and efficiency of the inverters.…”

Single-Stage LLC Resonant Converter for Induction Heating System with Improved Power Quality

“…A wide variety of inverter topologies have been developed for the same purpose. Voltage and current resonant inverters are among the most commonly used types [9,10]. Out of these, the voltage-fed resonant inverter is widely used because it has numerous control possibilities [11,12].…”

Modeling and Operation of Series-Parallel Resonant Load in Industrial RF Dielectric Heating Application

“…However, a research gap exists on a comprehensive study of industrial RF heating plant load network such that the semiconductor based RF generator can be integrated as turn-key solution. There has been publications on industrial RF induction heating utilizing semiconductor technology [22], [23]. But a generalized discussion on load design does not exist.…”