A vacuum thermionic-thermophotovoltaic hybrid generator is proposed

and a theoretical model of the vacuum thermionic-thermophotovoltaic hybrid generator is established based on the energy balance equation.General expressions are obtained for the output power and conversion efficiency

and the optimization parameters are determined. The effects of heat source temperature and electrode work function on the output voltage

power and efficiency of the hybrid generator are studied. The results show that

the maximum conversion efficiency of the hybrid generator reaches 24.3%

which increases by 6.9 percentage points compared with the solo vacuum thermionic converter

and the optimal output power is 3.5 times that of the latter. The hybrid generator achieves a stable output even at different parameters when it is coupled with a thermophotovoltaic module. It is an effective way to improve the performance further by increasing the heat source temperature or reducing the anode work function. It is expected to provide a useful guide for developing thermionic hybrid power generation technology combined with solar or nuclear energy in the future.