Voltage detection circuit for fuel cell diagnosis

A voltage detection circuit for fuel cell diagnosis is connected with the output end of a diagnosed fuel cell and comprises a high-voltage side filtering processing circuit and a low-voltage side filtering processing circuit. The high-voltage side filtering processing circuit and the low-voltage side filtering processing circuit are connected through a differential isolation operational amplifier circuit, the input end of the high-voltage side filtering processing circuit is connected with a high-voltage sampling node of the fuel cell, and the low-voltage side filtering processing circuit is connected with a controller impedance calculation unit. Under the condition that interference noise in a high-voltage circuit of the system is larger than that of useful alternating current signals, high-quality useful alternating current voltage signals are collected and processed through measures of signal filtering, frequency screening and the like, and then impedance calculation is conducted on the DSP control unit, s