A Novel Induction Heating System Using Multilevel Neutral Point Clamped Inverter

摘要

Contribution to Knowledge:The main knowledge contribution of the dissertation can be summarized as follows:1-A new design of induction heating power supply configuration with two categories of LLC topologies:A Novel induction heating power supply topology using multilevel neutral point clamped inverter (MNPCI) is investigated and verified. The proposed converter topology decreases the switching losses by decreasing the DC link voltage to half its DC rail voltage value with the aid of operation under soft switching mode condition. Depending on the modified LLC optimum design being introduced, it shares the advantage features of both voltage fed and current fed inverters with the capability to absorb the undesired parasitic components in the design. The new design involves adding new circuit parameter that helps in controlling the power transfer from the MNPCI to the resonant load tank. All the analytical analysis made and the corresponding experimental work verifies the prototype configuration.This contribution was presented by the author and published in: {B.M. Flayyih; M.Z. Ahmed; M. Ambroze, ''A Novel Hybrid Voltage-Current Fed Induction Heating Power Supply System Using Multilevel Neutral Point Clamped Inverter '', Energycon 2014 IEEE International Energy Conference, Dubrovnik-Croatia. From 13th - 16th May 2014}.2-An optimum power control of induction heating system by reducing harmonic distortion content:The development of IH system has become a pressing need to improve the power transfer from power supply to the IH load of the application required, and due to variable characteristic of IH load workpiece during the heating cycle, it is necessary to develop an IH system that operates using resonant inverters with switching frequency that changes according to changing load conditions during the IH application process, in order to keep tuning with natural resonant frequency of the system and keep working under optimal operational point.A novel super frequency induction heating power supply using MNPCI with optimum control algorithm is introduced. The control strategy is to keep phase shift angle between voltage and current approximately zero at all load conditions to ensure maximum power transfer whatever the load parameters changes, that is necessary to reduce the switching losses and increase the efficiency. The load topology being used consists of variable LLC resonant tank with values chosen carefully to coincide with the design.Afterword, an Optimum Harmonic Control of a proposed induction heating power supply with MNPCI is also introduced in this research. The proposed system achieves the soft switching mode for both current and voltage with low harmonic distortion and the capability to maximize the heating power by controlling the harmonics. The modulation strategy depends on changing the ON switching time of the prototype to an optimized value that achieves natural switching with lowest possible harmonic distortion and thus, gaining highest heating power efficiency.This contribution was also presented by the author and published in {B.M. Flayyih; M.Z. Ahmed; S. MacVeigh, ''A Comprehensive Power Analysis of Induction Heating Power Supply System Using Multilevel Neutral Point Clamped Inverter With Optimum Control Algorithm '', 2015 IEEE 11th International Conference on Power Electronics and Drive Systems (PEDS), From 9th - 12th June 2015, Sydney, Australia}.This contribution is also presented by the author in: {B.M. Flayyih; M.Z. Ahmed; M. Ambroze, ''An Optimum Harmonic Control of Induction Heating Power Supply System Using Multilevel Neutral Point Clamped Inverter'', The IEEE Transportation Electrification Conference and Expo Asia-Pacific (ITEC2016), Busan, Korea on 1st - 4th June, 2016}.