A photovoltaic-thermoelectric hybrid system consisting of photovoltaic (PV) modules and multi-couple thermoelectric elements is investigated by using a thermodynamic method. General formulas of the efficiency and power output of the hybrid system are derived. Optimum performance characteristics are revealed. The effects of structural parameters of the thermoelectric generator (TEG) and the operating conditions of PV modules on the performance of the hybrid system are analyzed. Optimal problems related to the load matching in the design of practical hybrid power generation systems are discussed. The results obtained here may offer some theoretical bases for the optimal design of real photovol talc-thermoelectric hybrid power generation systems. (C) 2015 Elsevier Ltd. All rights reserved.