The Energy Matching Model describes the elements of the energy chain of a PV powered product. The purpose of this model is to optimize the matching between these elements. The main elements of the Energy Matching Model, depicted in figure 2, are: a) user context defined incident light, b) PV power converter, c) electrical energy storage media, d) energy use in the functional product application and e) user context defined power/energy use pattern of the product.

Through so called matching interfaces (MI 1-3) the elements in the energy chain interface with each other. In addition to these interfaces, the overall energy balance also has to be analysed. The feedback-loop through the overall application matching interface (OMI) is closed by two overall energy balance tracks.

To evaluate, quantify and predict to what extent the matching between the elements is actually achieved the Figure of Matching algorithm is developed. This is a combination of the stimulus — response concept and the correlation concept. The Figure of Matching algorithm is illustrated in figure 3.

According to Kan [2] the Energy Matching Model and the Figure of Matching have to be used as essential tools in each design phase to create successful PV powered products.