Fuzzy logic based voltage control scheme for improvement in dynamic response of the class D inverter based high frequency induction heating system

Abstract

Abstract:In high frequency induction heating systems, the effective load parameters change during the different operating conditions. It is necessary to maintain constant input voltage to the induction heating load to improve the quality of the heating. The resonant based high frequency converter is generally used for these applications for the reduction of switching losses. The resonant condition is also affected during the variation in load parameters. The controller should provide a good voltage regulation with less response time and less overshoot during the loading conditions. In this paper, a load adaptive fuzzy logic control scheme is proposed to perform the voltage control of the high frequency inverter under variable load conditions. A frequency tracking control system is also employed for the inverter system using the phase lock loop. The phase lock loop ensures the resonant frequency operation of the inverter during the change in load parameters. The state space model of the system is discussed to study the inverter during different operating conditions. The fuzzy logic controller based closed loop control scheme is developed using the MATLAB simulation tool. The responses of the conventional and fuzzy logic controllers are studied for load voltage regulation and the effectiveness of the control schemes is verified. The dynamic behavior of the system is studied under no load and loaded conditions with the two controllers. The fuzzy based closed loop control scheme improves the dynamic response of the system compared to the conventional controller. The response of the induction heating system is validated with a hardware prototype. The results are presented in order to confirm the proposed control strategy.

Induction Heating in Domestic Cooking and Industrial Melting Applications: A Systematic Review on Modelling, Converter Topologies and Control Schemes

“…The small-signal model of the half-bridge series resonant inverter is developed in this section. The equivalent circuit of SRI-fed IH load shown in Figure 4 could be modelled using the following state equations [44]: By applying KVL to the circuit shown in Figure 4, the following expressions were obtained:…”

“…The general block diagram of a two-stage power conversion scheme is shown in Figure 5. The various inverter topologies used for IH applications are a single-switch (SS) resonant inverter [40,[45][46][47], a half-bridge (HB) inverter [5,20,43,[48][49][50][51][52] and a full-bridge (FB) resonant inverter [44,[53][54][55][56]. SS resonant inverters are used in the medical field where the power requirement is less than 2 kW.…”

“…For varying loads, the power semiconductor switches enter into the hard switching mode, which increases the switching stresses. To overcome this problem, two loop controls were developed with a phase-locked loop (PLL) and PI controller [41,44,79,80]. A PLL, first loop control, is used to track the resonant frequency to maintain soft switching in the inverter, and the outer loop controls the output power.…”

“…This combination of modulation results in better efficiency, lower input power usage and high efficiency compared to other techniques. To validate it, the most commonly used FB inverter [44] topology-fed IH system is developed. Switching pulses, output voltage, and current is recorded using the RIGOL oscilloscope.…”

An observer based temperature estimation in cooking heterogeneous mixtures: a Turkish coffee machine application

“…The development of automated home appliences for cooking the heterogeneous food mixtures have been arisen for few decades led by the technological improvements. Resistive and induction heaters are widely used in such cooking machines, however induction heaters are preferred mostly due to their advantages such as fast and controllable heating, efficiency, cleaning and safety [1][2][3]. The measurement systems utilizing various type of sensors play a crucial role in such appliances as well for carrying out an accurate control of the process and an efficient operation.…”