An experimental study of the control characteristics of a 1 kW class free‐piston stirling converter (FPSC) with alternating current (AC) bus controls is conducted. A performance test rig is constructed using a commercial beta‐type FPSC, and an AC bus controller that includes a tuning capacitor, a set of load resistors, and an AC power supply is developed. Experiment parameters include the tuning capacitance and load resistance for the AC bus circuit and the control voltage and control frequency for AC bus control under various head temperatures of the test FPSC. In addition, preliminary experiments under load resistance control scheme were conducted to identify the natural operational characteristics of the test FPSC without an external active control scheme and to determine the proper ranges of the experiment parameters for AC bus control. The experimental results are presented in terms of the output power, the power factor, and the thermal‐to‐electric efficiency of the FPSC with respect to the load resistance and the AC bus control parameters. In particular, the effect of the control frequency with respect to the FPSC operating frequency, as well as the influence of the alternator inductance on the control characteristics of FPSC are discussed in detail. Finally, it is anticipated that this research will yield a better physical understanding of comprehensive AC bus parameters related to the performance of FPSCs, will provide a simple and accurate control method for laboratory experiments on FPSCs, and will provide fundamental data for those who design advanced virtual tuning capacitor controllers.

Stirling engines are the engines that convert heat energy into mechanical work. This study models a 50 W linear generator designed for integration with a Stirling engine. To develop a model, the base design of the already developed 1 kW model was used, and its size was proportionally reduced to match the stroke of the Stirling engine. By reducing the length of the 1 kW model to a length scale factor (LSF) of 0.5, the stroke level of the engine was determined. However, the radius of the LSF 0.5 linear generator model was adjusted to match the engine. After finalizing the 50 W linear generator dimensions, the model was simulated using MAXWELL v14. software to compute output power and other electrical parameters. This study also analyzed the losses of the 50 W linear generator and its phasor diagram. Later, the output values generated using MAXWELL software were compared with the results obtained using SAGE v11. software for verification. The outcome of this study was a model that achieved an output power of 50 W with an efficiency of 90% and a generator size of 96 mm. Because of its versatility, low weight, and high efficiency, it can be used in a wide range of applications. Due to its small size, it can be utilized for empowering humanoid robots, radioisotope power, space exploration, etc.