The intelligent control design and realization of an AC contactor with wide-range input voltage

The intelligent control design and realization proposal of an AC contactor with wide-range input voltage are introduced in this paper, the hardware and software design are emphasized especially. By using power electronic device MOSFET to control and adjust the voltage on the contactor's coil self-adaptively in PWM(Pulse Width Modulation) mode, this kind of contactor can work reliably and stably with a wide range AC or DC input voltage (AC24∼380V or DC24∼220V). So the contactor can be used in all the voltage class and solve the problem that the contactor could not work when the voltage of power system exceeds the certain value. The hardware design of this new type of contactor is based on microcontroller PIC16F873 and the following modules are included: voltage measuring circuit of power supply and coil, PWM control circuit, zero current measure of main circuit, keyboard, LCD display, RS232/RS485 communication interface etc. Therefore the contactor also has the function of energy saving, silent operation, less arc or no arc break, setting, display, communication, remote operation and so on. The test results at the end of this paper show that the design of this contactor is accurate and effective. Accordingly, the performance and characteristic of the contactor would be enhanced considerably and the types of product would be reduced greatly as well. Meanwhile, it is easy to foresee that this kind of new AC contactor would have a large market and broad application prospect.