A Simple Current Sensorless Scheme for MPPT Implementation in Low Power Thermoelectric Generators

To extract the maximum power from Thermoelectric Generator (TEG) under dynamically varying conditions, Maximum Power Point Tracking (MPPT) technique is used. Most of the existing MPPT techniques require direct measurement of current for MPPT implementation. However, the use of current sensors for low-power TEG applications increases the overall systems cost and size. This paper presents a new current sensorless scheme for MPPT operation implemented in DCDC Buck converter. The current estimation method is derived based on the input - output voltage relationship of the converter while operating under Discontinues Conduction Mode (DCM). The proposed MPPT technique is simple and cost effective for low power TEG. The efficacy of the proposed method is tested for a 17.6W TEG model using simulation and hardware experimentation using Perturb and Observe (P&O) algorithm. Also, the proposed methodology is compared with a current sensor (LEM LA-55P) based MPP tracking system which yielded satisfactory results.