The objective of this paper is to develop a SPICE- compatible equivalent circuit of a thermoelectric module. A methodology is developed for extracting the parameters of the proposed model from manufacturers' data of thermoelectric coolers (TECs) and thermoelectric generators (TEGs). The model could be helpful in analyzing the drive requirements of TECs and loading effects of TEGs. The present model is compatible with PSPICE or other electric circuit simulators. An important feature of the model is its ability to generate small-signal transfer functions that can be used to design feedback networks for temperature control applications

The objective of this work was to develop a PSPICE-compatible equivalent circuit of a thermoelectric cooler (TEC). Equivalent circuits are convenient tools for power electronics engineers since they help in presenting a problem in electronic circuit terms and can assist in the design of power stages and the control circuitry and algorithms. A methodology is developed for extracting the parameters of the proposed model from manufacturers' data of TECs. The present model is compatible with PSPICE or other electronic circuit simulators. An important feature of the model is its ability to generate small-signal transfer functions that can be used to design feedback networks for temperature-control applications. Several examples of successful utilization of the model are presented. Data of many different manufacturers were examined and the model parameters were extracted. In all cases, the model was found to reproduce accurately the performance of commercial TECs. The accuracy of the model was also verified by experiments.

The problem of maximum power point tracking of high output dc voltage converters that apply piezoelectric transformers (PT) and voltage doublers was studied theoretically and experimentally. It was shown that the operating frequency of the PT, at which maximum power is reached, is a function of the load. Hence, under load variations, and to overcome parameter instability, there is a need for some frequency tracking mechanism that will help to lock the operating frequency to the optimum one. The proposed method to achieve frequency tracking is based on a phase locked loop (PLL). The PLL inputs are the phase of the input voltage driving the PT and the phase of the current flowing through one of the voltage doubler diodes. Theoretical analysis, verified by experiments, shows that when the phase shift of the diode current relative the phase of the input voltage is zero, the voltage gain of the system is at its maximum. By applying this approach, the system's operation can be made independent of input voltage, load variations, temperature (within a permitted range), and the spread and nonlinearity of the PT parameters, as well as their drift with time.

In this paper, the applicability of the well-known single-diode equivalent circuit to modeling amorphous silicon photovoltaic modules is questioned. It is shown that, unlike in mono- and polycrystalline modules, all of the equivalent circuit parameters are irradiation dependent. This dependence may be derived from either manufacturer-provided or measured I-V curves for different irradiation levels. In order to extract the equivalent circuit parameters, the suggested approach combines numerical solution of two transcendental and two regular algebraic equation systems with single-parameter fitting procedure. Two additional parameters are introduced to describe temperature dependence of photocurrent and diode reverse saturation current. As result, a set of seven parameters is obtained, comprehensively describing the panel performance for arbitrary ambient conditions. It is shown that characteristic curves obtained using the proposed approach match well the manufacturer-provided data for various values of temperature and irradiation.