Comprehensive Power Control Performance Investigations of Resonant Inverter for Induction Metal Surface Hardening

Abstract

Many types of steel are treated with heat to increase toughness and resistance to wear. Induction heating seems to be appropriate and provides several advantages in comparison with conventional techniques. In this paper, control techniques for full bridge resonant inverter aimed to induction heating are evaluated comprehensively, through simulation and experiment, and compared to each other in terms of heating rate, efficiency and input power factor, using one metal sample hardened to 1mm in depth up to 600°C, with a 400 W power supply. These techniques are implemented digitally in way to allow a high resolution power control. The simulation results obtained are satisfactory, and agree with those of the experiments. Furthermore, the study shows the control strategy based on frequency may not be sufficient, but should be associated with other control techniques in order to address appropriately the hardening process, bearing in mind processing time, efficiency and input power factor. The strategy with the input DC voltage and the pulse density modulation (PDM) controls appear to suit the surface metal treating for large temperature variation, and enable the heating process to perform well when compared to the other techniques based on phaseshift and PWM duty cycle control.

A comprehensive overview of power converter topologies for induction heating applications

“…The choice for selection of frequency and power rating for induction heating applications is shown in Figure 41. 3,16,21,22,71,79,105 The selection of semiconductor switches for various power levels is shown in Figure 42. 6 It helps the design engineers to select the switching frequency for various IH applications and also in choosing the semiconductor switches based on the power levels.…”

“…Among the tested one, PDM‐based control technique possesses better power regulation and wide range of soft switching. Comprehensive power‐control performance for induction metal‐surface hardening application is proposed in Ref 79. Authors have used a variable dc link voltage, PWM, variable frequency, PS and PDM controls to vary the output power.…”

“…It summarizes on the whole converter topologies, which are being used for various IH applications. The choice for selection of frequency and power rating for induction heating applications is shown in Figure 41 3,16,21,22,71,79,105 . The selection of semiconductor switches for various power levels is shown in Figure 42 6 .…”

Investigations into series resonant inverter power control parameters for an effective metal induction surface hardening

“…8. A matching transformer was used to allow a higher current density while ensuring isolation from this power supply [19]. By doing so, the hardening process can be achieved appropriately according to the industrial standards, while keeping an inverter system with a lower rating component and, therefore, at a low cost.…”

Implementation of Boost PFC in the Induction Heating System for EMI–RFI Suppression

“…This effect results in the flow of alternating current in a fine layer in the direction of work piece. Thus heating effect is highly enhanced due to the current induced in the work piece [28][29][30][31]. In Section 1.1 proposed IH model has been analyzed with the incorporation of Boost PFC.…”