Application of variable-load control in cylinder pressure control of free-piston engine generator

In order to control the cylinder pressure of free-piston engine generator, a variable-load control method is proposed. The control of the total impedance of the system circuit is achieved by the construction of a variable equivalent load, so that the loop current is changed, and then the electromagnetic resistance acting on the mover changes. In order to make the electromagnetic force change in accordance with the expected law, a closed-loop control strategy is designed. Simulation results show that, using this control strategy, the proposed variable-load control method can stabilize the piston motion, thus achieving a stable cylinder pressure.