Synchronous voltage zero-cross detection device of polycrystalline silicon reduction furnace power supply

The invention relates to a synchronous voltage zero-cross detection device of a polycrystalline silicon reduction furnace power supply and polycrystalline silicon reduction furnace control equipment, and the synchronous voltage zero-cross detection device comprises a phase-delay-free differential circuit and a zero-cross detection circuit, and a synchronous voltage generation element of the polycrystalline silicon reduction furnace power supply is connected with the phase-delay-free differential circuit. And the phase-delay-free differential circuit is connected with the zero-cross detection circuit. The phase-delay-free differential circuit obtains the synchronous voltage generated by the synchronous voltage generation element, the synchronous voltage is preprocessed and then transmitted to the zero-cross detection circuit, the zero-cross detection circuit is used for outputting a voltage signal according to the preprocessed synchronous voltage, and the voltage signal is used for representing the zero point