Diaphragm pump or diaphragm compressor, control method and controller

The invention relates to a diaphragm pump or a diaphragm compressor, a control method and a controller. The diaphragm pump or the diaphragm compressor comprises a working chamber, a power chamber, a diaphragm piece arranged between the working chamber and the power chamber in a sealed mode, and a motor providing driving force for the diaphragm piece. The driving device comprises a flywheel which is arranged on a driving path from a motor to a diaphragm sheet so as to acquire driving force from the motor and provide the driving force to the diaphragm sheet; the power fluid storage cavity communicates with the power chamber and is used for receiving the power fluid discharged from the power chamber and providing the power fluid for the power chamber; and the valve is arranged on a communication path of the power fluid storage cavity and the power chamber and is used for connecting and disconnecting the communication path of the power fluid storage cavity and the power chamber. According to the diaphragm pump or