PDM-MPPT based solar powered induction heating system

Abstract

In the study, the maximum power obtained from the photovoltaic (PV) panels with the proposed 32 model pulse density modulation (PDM) controlled serial resonant inverter has transferred to the work-piece (copper and 304 stainless steel) and therefore induction heating has performed. The designed PV powered induction heating system has achieved maximum power point tracking (MPPT) at resonance frequency and under varying solar irradiation conditions. PV simulator is used as a power source for induction heating. Thus, it is provided to monitor the controlled output power. Phase-locked loop (PLL) applications are widely used in induction heating applications to achieve zero voltage switching (ZVS) and zero current switching (ZCS). In many PLL applications, the frequency tracking is too slow and unreliable. Therefore, a sliding mode controller is developed to provide robust and fast PLL. Furthermore, pulse density modulation (PDM) control strategy is developed to work at the resonance frequency for all power levels. The PDM power control is a good solution for the design of high-frequency inverters because of the great reduction of switching losses and electromagnetic noise. In the experimental system, resonance frequency in the system is determined as 37.5 kHz for stainless steel and 39.5 kHz for copper. Perturb-observe (P&O) algorithm is used to track the maximum power in PV panels. Thus, over 99% tracking efficiency has been achieved by the proposed PDM-MPPT algorithm. ATMEL328P-AU microcontroller has used to control the SMC-PLL algorithm and PDM-MPPT algorithm in the system.