CONTROLLER AND CONTROL METHOD FOR ALTERNATING CURRENT CONTACTOR

A controller for an alternating current contactor. The controller comprises: a filtering and rectification circuit (101, 102), which filters and rectifies external alternating current; an electromagnet component (103), which is driven by an output of the filtering and rectification circuit and performs actions of attraction, holding or releasing; a power transistor circuit (104), which is connected to the electromagnet component; and a microcontroller (112), which controls on or off of the power transistor circuit to control the electromagnet component so as to perform the actions of attraction, holding or releasing. The controller further comprises: a voltage control loop, which provides a voltage feedback signal to the microcontroller and the microcontroller generates a control signal according to the voltage feedback signal, wherein the control signal is a PWM control signal having different duty cycles during the attraction and holding of the electromagnet component so that the current does not exceed a predetermined current threshold during the attraction and holding of the electromagnet component; and a current control loop, which provides a current feedback signal to the microcontroller and the microcontroller turns off the power transistor circuit upon detecting an overcurrent exceeding the current threshold.