Patent ID: 11971457
Assignee: TONGJI UNIVERSITY
Field: Electrical machinery, apparatus, energy (Electrical engineering)
Classification: CPC G  H | IPC G  H

Claim 0:
1. A method for measuring AC impedance of a battery in a composite power supply power system, wherein an impedance of a fuel cell and an impedance of a lithium battery are respectively measured based on an AC impedance measurement device, comprising the steps of:
S1: determining an amplitude of an AC disturbance signal, a control system controlling a DC/DC voltage converter to work to generate the AC disturbance signal, an output signal of the fuel cell changing, and an output signal of the lithium battery changing accordingly, each of said output signals including a current signal and a voltage signal;
S2: real-time acquiring the current signal and the voltage signal of the fuel cell, real-time acquiring the current signal and the voltage signal of the lithium battery, and respectively calculating a real-time output power of the fuel cell and a real-time output power of the lithium battery;
S3: calculating a real-time demand power Ploaddemand of a load according to the real-time output power of the fuel cell and the real-time output power of the lithium battery, and calculating a real-time change rate of the real-time demand power Ploaddemand, and if the real-time change rate of the real-time demand power Ploaddemand is less than a preset stability threshold, executing step S4, otherwise, calculating the impedance of the fuel cell, and waiting for a preset time length T1 before executing step S5;
S4: calculating the impedance of the fuel cell and the impedance of the lithium battery respectively, waiting for a preset time length T2 and then executing step S5; and
S5: the control system obtaining an impedance measurement control signal, and if the control signal is an end signal, ending the impedance measurement, otherwise, executing step S1.