A New Single-Phase Direct Frequency Controller Having Reduced Switching Count without Zero-Crossing Detector for Induction Heating System

Abstract

Induction heating (IH) is an environmentally friendly solution for heating and melting processes. The required high-frequency magnetic field is accomplished through frequency controllers. Direct frequency controllers (DFC) are preferred to dual converters as they have low conversion losses, compact size, and simple circuit arrangement due to low component count. Numerous frequency controllers with complex switching algorithms are employed in the induction heating process. They have a complicated circuit arrangement, and complex control as their switching sequences have to synchronize with source voltage that requires the zero-crossing detection of the input voltage. They also have a shoot-through problem and poor power quality. Therefore, this research proposes a novel frequency controller with a low count of six controlled switching devices without a zero-crossing detector (ZCD) having a simple control arrangement. The required switching signals are simply generated by using any pulse-width-modulated (PWM) generator. The performance of the proposed topology is verified through simulation results obtained using the MATLAB/Simulink environment and experimental setup.

A Simple Two-Stage AC-AC Circuit Topology Employed as High-Frequency Controller for Domestic Induction Heating System

“…The number of switching transistors employed in the suggested circuit is four, so only four gate driving circuits and four dc supplied are required. The switching transistors and diodes employed in [17] and [18] are eight and six, respectively. Therefore, there is a need for eight and six gate driving and dc supply circuits, respectively.…”

“…The cost against reducing the switching transistors in [19] is paid with an additional bulky low-frequency center tap transformer. The current and voltage rating of all operating diodes and transistors in the proposed circuit and converter in [17][18][19] equals load rms voltage and load rms current. The power losses caused by the solid-state devices are switching, conduction, and leakage losses.…”

“…The conduction of two transistors and two diodes in the proposed topology and converters in [17][18][19] helps realize the operation in any operating mode. Therefore, the total conduction losses of two transistors and two diodes in one PWM switching transition are realized as:…”

“…This overall impact increases the circuit size, cost, and complication. The reduction of two controlled switches (IGBTs or MOSFETs) and two diodes is ensured in [18] to simplify the circuit in terms of size and cost. Its realization only requires six diodes and six MOSFETs, as shown in Figure 2.…”

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“…Poor quality of power supply may result into increased power losses, production loss, and power outages and causes undesirable behavior of equipment and may cause damage to the equipment connected to the LV side of the transformer. It economically affects the customers by damaging their appliances connected to the power source [18][19][20][21][22][23][24][25][26].…”