Pulse delay control strategy for improved power control and efficiency in multiple resonant load systems

Nowadays, induction heating cookers are becoming more popular due to their high performance and efficiency. Among the different alternatives available, the total-active-surface concept is leading the technology development. This technology is based on a set of inductors placed in a matrix-like distribution. The main benefit of this technology is the possibility of using as many pots are needed, with any shape, and in any position in the whole appliance surface. In order to obtain an efficient and high-power-density implementation new multiple-output power converters are required. The aim of this paper is to propose a new control strategy for the series resonant multi-inverter topology in order to obtain accurate power control in each inductor while keeping a high efficiency. To achieve this aim, the Pulse Delay Control is proposed. The main analytical and simulation results are presented, and the proposal is validated through a multi-load prototype.